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  |  - Bold-face text is marked =text=.                               |
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  |    respectively.                                                  |
  |  - sqrt(x) represents the square root of x.                       |
  |  - [oe] and [OE] represent the oe-ligatures.                      |
  |  - Greek letters are written between square brackets, as in [tau] |
  |    or [theta].                                                    |
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  |    rather than to the original Table of Contents.                 |
  |  - The table on operating costs of trains gives 'Other expenses   |
  |    per square mile.' This has been changed to 'Per mile' the same |
  |    as the other expenses.                                         |
  |  - The table on dimensions of farm and road locomotives gives the |
  |    diameter of the boiler shell as 30 feet, which seems unlikely. |
  |  - Feet are sometimes used as unit of area, both knots and knots  |
  |    per hour as unit of speed.                                     |
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  |    and hyphenation have not been corrected. Exceptions:           |
  |      'Desagulier' to 'Desaguliers'                                |
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  |      'Desagulier' to 'Desaguliers'                                |
  |      'éléver' to 'élever'.                                        |
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                 THE INTERNATIONAL SCIENTIFIC SERIES.

                            VOLUME XXIV.




                                 THE
                   INTERNATIONAL SCIENTIFIC SERIES.

   EACH BOOK COMPLETE IN ONE VOLUME, 12MO, AND BOUND IN CLOTH.


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          New York: D. APPLETON & CO., 1, 3, & 5 Bond Street.




         [Illustration: THE GRECIAN IDEA OF THE STEAM-ENGINE.]




                  THE INTERNATIONAL SCIENTIFIC SERIES.

                              A HISTORY
                               OF THE
                     GROWTH OF THE STEAM-ENGINE.

                                  BY

                  ROBERT H. THURSTON, A. M., C. E.,

    PROFESSOR OF ENGINEERING STEVENS INSTITUTE OF TECHNOLOGY, PAST
  PRESIDENT AMERICAN SOCIETY MECHANICAL ENGINEERS, MEMBER OF SOCIETY
      OF CIVIL ENGINEERS, SOCIÉTÉ DES INGÉNIEURS CIVILS, VEREIN
        DEUTSCHE INGENIEURE, OESTERREICHISCHER INGENIEUR- UND
          ARCHITEKTEN-VEREIN; ASSOCIATE BRITISH INSTITUTION
                  OF NAVAL ARCHITECTS, ETC., ETC.

                     _SECOND REVISED EDITION._

                             NEW YORK:
                     D. APPLETON AND COMPANY,
                     1, 3, AND 5 BOND STREET.
                              1886.




                      COPYRIGHT, 1878, 1884,
                      BY ROBERT H. THURSTON.




PREFACE.


This little work embodies the more generally interesting portions of
lectures first written for delivery at the STEVENS INSTITUTE OF
TECHNOLOGY, in the winter of 1871-'72, to a mixed audience, composed,
however, principally of engineers by profession, and of mechanics; it
comprises, also, some material prepared for other occasions.

These lectures have been rewritten and considerably extended, and have
been given a form which is more appropriate to this method of
presentation of the subject. The account of the gradual development of
the philosophy of the steam-engine has been extended and considerably
changed, both in arrangement and in method. That part in which the
direction of improvement during the past history of the steam-engine,
the course which it is to-day taking, and the direction and limitation
of that improvement in the future, are traced, has been somewhat
modified to accord with the character of the revised work.

The author has consulted a large number of authors in the course of
his work, and is very greatly indebted to several earlier writers. Of
these, Stuart[1] is entitled to particular mention. His "History" is
the earliest deserving the name; and his "Anecdotes" are of
exceedingly great interest and of equally great historical value. The
artistic and curious little sketches at the end of each chapter are
from John Stuart, as are, usually, the drawings of the older forms of
engines.

  [1] "History of the Steam-Engine," London, 1824. "Anecdotes of the
  Steam-Engine," London, 1829.

Greenwood's excellent translation of Hero, as edited by Bennett
Woodcroft (London, 1851), can be consulted by those who are curious to
learn more of that interesting old Greek treatise.

Some valuable matter is from Farey,[2] who gives the most extended
account extant of Newcomen's and Watt's engines. The reader who
desires to know more of the life of Worcester, and more of the details
of his work, will find in the very complete biography of Dircks[3] all
that he can wish to learn of that great but unfortunate inventor.
Smiles's admirably written biography of Watt[4] gives an equally
interesting and complete account of the great mechanic and of his
partners; and Muirhead[5] furnishes us with a still more detailed
account of his inventions.

  [2] "Treatise on the Steam-Engine," London, 1827.

  [3] "Life, Times, and Scientific Labors of the Second Marquis of
  Worcester," London, 1865.

  [4] "Lives of Boulton and Watt," London, 1865.

  [5] "Life of James Watt," D. Appleton & Co., New York, 1859.
  "Mechanical Inventions of James Watt," London, 1854.

For an account of the life and work of John Elder, the great pioneer
in the introduction of the now standard double-cylinder, or
"compound," engine, the student can consult a little biographical
sketch by Prof. Rankine, published soon after the death of Elder.

The only published sketch of the history of the science of
thermo-dynamics, which plays so large a part of the philosophy of the
steam-engine, is that of Prof. Tait--a most valuable monograph.

The section of this work which treats of the causes and the extent of
losses of heat in the steam-engine, and of the methods available, or
possibly available, to reduce the amount of this now immense waste of
heat, is, in some respects, quite new, and is equally novel in the
method of its presentation. The portraits with which the book is well
furnished are believed to be authentic, and, it is hoped, will lend
interest, if not adding to the real value of the work.

Among other works which have been of great assistance to the author,
and will be found, perhaps, equally valuable to some of the readers of
this little treatise, are several to which reference has not been made
in the text. Among them the following are deserving of special
mention: Zeuner's "Wärmetheorie," the treatises of Stewart and of
Maxwell, and McCulloch's "Mechanical Theory of Heat," a short but
thoroughly logical and exact mathematical treatise; Cotterill's
"Steam-Engine considered as a Heat-Engine," a more extended work on
the same subject, which will be found an excellent companion to, and
commentary upon, Rankine's "Steam-Engine and Prime Movers," which is
the standard treatise on the theory of the steam-engine. The works of
Bourne, of Holley, of Clarke, and of Forney, are standards on the
practical every-day matters of steam-engine construction and
management.

The author is almost daily in receipt of inquiries which indicate that
the above remarks will be of service to very many young engineers, as
well as to many to whom the steam-engine is of interest from a more
purely scientific point of view.




                           CONTENTS.


                          CHAPTER I.

             THE STEAM-ENGINE AS A SIMPLE MACHINE.
                                                                  PAGE
  SECTION I.--THE PERIOD OF SPECULATION--FROM HERO TO WORCESTER,
  B. C. 200 TO A. D. 1650                                            1

  Introduction--the Importance of the Steam-Engine, 1; Hero and
  his Treatise on Pneumatics, 4; Hero's Engines, B. C. 200, 8;
  William of Malmesbury on Steam, A. D. 1150, 10; Hieronymus
  Cardan on Steam and the Vacuum, 10; Malthesius on the Power of
  Steam, A. D. 1571, 10; Jacob Besson on the Generation of Steam,
  A. D. 1578, 11; Ramelli's Work on Machines, A. D. 1588, 11;
  Leonardo da Vinci on the Steam-Gun, 12; Blasco de Garay's
  Steamer, A. D. 1543, 12; Battista della Porta's Steam-Engine,
  A. D. 1601, 13; Florence Rivault on the Force of Steam, A. D.
  1608, 15; Solomon de Caus's Apparatus, A. D. 1615, 16; Giovanni
  Branca's Steam-Engine, A. D. 1629, 16; David Ramseye's
  Inventions, A. D. 1630, 17; Bishop John Wilkins's Schemes, A.
  D. 1648, 18; Kircher's Apparatus, 19.

  SECTION II.--THE PERIOD OF APPLICATION--WORCESTER, PAPIN, AND
  SAVERY                                                            19

  Edward Somerset, Marquis of Worcester, A. D. 1663, 19;
  Worcester's Steam Pumping-Engines, 21; Jean Hautefeuille's
  Alcohol and Gunpowder Engines, A. D. 1678, 24; Huyghens's
  Gunpowder-Engine, A. D. 1680, 25; Invention in Great Britain,
  26; Sir Samuel Morland, A. D. 1683, 27; Thomas Savery and his
  Engine, A. D. 1698, 31; Desaguliers's Savery Engines, A. D.
  1718, 41; Denys Papin and his Work, A. D. 1675, 45; Papin's
  Engines, A. D. 1685-1695, 50; Papin's Steam-Boilers, 51.


                             CHAPTER II.

            THE STEAM-ENGINE AS A TRAIN OF MECHANISM.

  THE MODERN TYPE AS DEVELOPED BY NEWCOMEN, BEIGHTON, AND SMEATON   55

  Defects of the Savery Engine, 55; Thomas Newcomen, A. D. 1705,
  57; the Newcomen Steam Pumping-Engine, 59; Advantages of
  Newcomen's Engine, 60; Potter's and Beighton's Improvements, A.
  D. 1713-'18, 61; Smeaton's Newcomen Engines, A. D. 1775, 64;
  Operation of the Newcomen Engine, 65; Power and Economy of the
  Engine, 69; Introduction of the Newcomen Engine, 70.


                            CHAPTER III.

  THE DEVELOPMENT OF THE MODERN STEAM-ENGINE. JAMES WATT AND HIS
                           CONTEMPORARIES.

  SECTION I.--JAMES WATT AND HIS INVENTIONS                         79

  James Watt, his Birth and Parentage, 79; his Standing in
  School, 81; he learns his Trade in London, 81; Return to
  Scotland and Settlement in Glasgow, 82; the Newcomen Engine
  Model, 83; Discovery of Latent Heat, 84; Sources of Loss in the
  Newcomen Engine, 85; Facts experimentally determined by Watt,
  86; Invention of the Separate Condenser, 87; the Steam-Jacket
  and other Improvements, 90; Connection with Dr. Roebuck, 91;
  Watt meets Boulton, 93; Matthew Boulton, 93; Boulton's
  Establishment at Soho, 95; the Partnership of Boulton and Watt,
  97; the Kinneil Engine, 97; Watt's Patent of 1769, 98; Work of
  Boulton and Watt, 101; the Rotative Engine, 103; the Patent of
  1781, 104; the Expansion of Steam--its Economy, 105; the
  Double-Acting Engine, 110; the "Compound" Engine, 110; the
  Steam-Hammer, 111; Parallel Motions, the Counter, 112; the
  Throttle-Valve and Governor, 114; Steam, Vacuum, and Water
  Gauges, 116; Boulton & Watt's Mill-Engine, 118; the Albion Mill
  and its Engine, 119; the Steam-Engine Indicator, 123; Watt in
  Social Life, 125; Discovery of the Composition of Water, 126;
  Death of James Watt, 128; Memorials and Souvenirs, 128.

  SECTION II.--THE CONTEMPORARIES OF JAMES WATT                    132

  William Murdoch and his Work, 132; Invention of Gas-Lighting,
  134; Jonathan Hornblower and the Compound Engine, 135; Causes
  of the Failure of Hornblower, 137; William Bull and Richard
  Trevithick, 138; Edward Cartwright and his Engine, 140.


                           CHAPTER IV.

                     THE MODERN STEAM-ENGINE.

  THE SECOND PERIOD OF APPLICATION--1800-1850--STEAM-LOCOMOTION
  ON RAILROADS                                                     144

  Introduction, 144; the Non-Condensing Engine and the
  Locomotive, 147; Newton's Locomotive, 1680, 149; Nathan Read's
  Steam-Carriage, 150; Cugnot's Steam-Carriage, 1769, 151; the
  Model Steam-Carriage of Watt and Murdoch, 1784, 153; Oliver
  Evans and his Plans, 1786, 153; Evans's Oruktor Amphibolis,
  1804, 157; Richard Trevithick's Steam-Carriage, 1802, 159;
  Steam-Carriages of Griffiths and others, 160; Steam-Carriages
  of Goldsworthy Gurney, 1827, 161; Steam-Carriages of Walter
  Hancock, 1831, 165; Reports to the House of Commons, 1831, 170;
  the Introduction of the Railroad, 172; Richard Trevithick's
  Locomotives, 1804, 174; John Stevens and the Railroad, 1812,
  178; William Hedley's Locomotives, 1812, 181; George
  Stephenson, 183; Stephenson's Killingworth Engine, 1813, 186;
  Stephenson's Second Locomotive, 1815, 187; Stephenson's
  Safety-Lamp, 1815, 187; Robert Stephenson & Co., 1824, 190; the
  Stockton & Darlington Engine, 1825, 191; the Liverpool &
  Manchester Railroad, 1826, 193; Trial of Competing Engines at
  Rainhill, 1829, 195; the Rocket and the Novelty, 198;
  Atmospheric Railways, 201; Character of George Stephenson,
  204; the Locomotive of 1833, 204; Introduction of Railroads in
  Europe, 206; Introduction of Railroads in the United States,
  207; John Stevens's Experimental Railroad, 1825, 207; Horatio
  Allen and the "Stourbridge Lion," 1829, 208; Peter Cooper's
  Engine, 1829, 209; E. L. Miller and the S. C. Railroad, 1830,
  210; the "American" Type of Engine of John B. Jervis, 1832,
  212; Robert L. Stevens and the T-rail, 1830, 214; Matthias W.
  Baldwin and his Engine, 1831, 215; Robert Stephenson on the
  Growth of the Locomotive, 220.


                           CHAPTER V.

                    THE MODERN STEAM-ENGINE.

  THE SECOND PERIOD OF APPLICATION--1800-1850 (CONTINUED)--THE
  STEAM-ENGINE APPLIED TO SHIP-PROPULSION                          221

  Introduction, 221; Ancient Prophecies, 223; the Earliest
  Paddle-Wheel, 223; Blasco de Garay's Steam-Vessel, 1543, 224;
  Experiments of Dionysius Papin, 1707, 214; Jonathan Hulls's
  Steamer, 1736, 225; Bernouilli and Gauthier, 228; William
  Henry, 1782, 230; the Comte d'Auxiron, 1772, 232; the Marquis
  de Jouffroy, 1776, 233; James Rumsey, 1774, 234; John Fitch,
  1785, 285; Fitch's Experiments on the Delaware, 1787, 237;
  Fitch's Experiments at New York, 1796, 240; the Prophecy of
  John Fitch, 241; Patrick Miller, 1786-'87, 241; Samuel Morey,
  1793, 243; Nathan Read, 1788, 244; Dundas and Symmington, 1801,
  246; Henry Bell and the Comet, 1811, 248; Nicholas Roosevelt,
  1798, 250; Robert Fulton, 1802, 251; Fulton's Torpedo-Vessels,
  1801, 252; Fulton's First Steamboat, 1803, 253; the Clermont,
  1807, 257; Voyage of the Clermont to Albany, 259; Fulton's
  Later Steamboats, 260; Fulton's War-Steamer Fulton the First,
  1815, 261; Oliver Evans, 1804, 263; John Stevens's
  Screw-Steamer, 1804, 264; Stevens's Steam-Boilers, 1804, 264;
  Stevens's Iron-Clad, 1812, 268; Robert L. Stevens's
  Improvements, 270; the "Stevens Cut-off," 1841, 276; the
  Stevens Iron-Clad, 1837, 277; Robert L. Thurston and John
  Babcock, 1821, 280; James P. Allaire and the Messrs. Copeland,
  281; Erastus W. Smith's Compound Engine, 283; Steam-Navigation
  on Western Rivers, 1811, 283; Ocean Steam-Navigation, 1808,
  285; the Savannah, 1819, 286; the Sirius and the Great Western,
  1838, 289; the Cunard Line, 1840, 290; the Collins Line, 1851,
  291; the Side-Lever Engine, 292; Introduction of
  Screw-Steamers, 293; John Ericsson's Screw-Vessels, 1836, 294;
  Francis Pettit Smith, 1837, 296; the Princeton, 1841, 297;
  Advantages of the Screw, 299; the Screw on the Ocean, 300;
  Obstacles to Improvement, 301; Changes in Engine-Construction,
  302; Conclusion, 303.


                           CHAPTER VI.

                    THE STEAM-ENGINE OF TO-DAY.

  THE PERIOD OF REFINEMENT--1850 TO DATE                           303

  Condition of the Steam-Engine at this Time, 303; the Later
  Development of the Engine, 304; Stationary Steam-Engines, 307;
  the Steam-Engine for Small Powers, 307; the Horizontal Engine
  with Meyer Valve-Gear, 311; the Allen Engine, 314; its
  Performance, 316; the Detachable Valve-Gear, 316; the Sickels
  Cut-off, 317; Expansion adjusted by the Governor, 318; the
  Corliss Engine, 319; the Greene Engine, 321; Perkins's
  Experiments, 323; Dr. Alban's Work, 325; the Perkins Compound
  Engine, 327; the Modern Pumping-Engine, 328; the Cornish
  Engine, 328; the Steam-Pump, 331; the Worthington
  Pumping-Engine, 333; the Compound Beam and Crank Engine, 335;
  the Leavitt Pumping-Engine, 336; the Stationary Steam-Boiler,
  338; "Sectional" Steam-Boilers, 343; "Performance" of Boilers,
  344.

  SECTION II.--PORTABLE AND LOCOMOTIVE ENGINES.                    347

  The Semi-Portable Engine, 348; Performance of Portable Engines,
  350; their Efficiency, 352; the Hoadley Engine, 354; the Mills
  Farm and Road Engine, 356; Fisher's Steam-Carriage, 356;
  Performance of Road-Engines, 357; Trial of Road-Locomotives by
  the Author, 358; Conclusions, 358; the Steam Fire-Engine, 360;
  the Rotary Steam-Engine and Pump, 365; the Modern Locomotive,
  368; Dimensions and Performance, 373; Compound Engines for
  Locomotives, 376; Extent of Modern Railroads, 378;

  SECTION III.--MARINE ENGINES.                                    379

  The Modern Marine Engine, 379; the American Beam Engine, 379;
  the Oscillating Engine and Feathering Wheel, 381; the two
  "Rhode Islands," 382; River-Boat Engines on the Mississippi,
  384; Steam Launches and Yachts, 386; Marine Screw-Engines, 389;
  the Marine Compound Engine, 390; its Introduction by John Elder
  and others, 393; Comparison with the Single-Cylinder Engine,
  395; its Advantages, 396; the Surface Condenser, 397; Weight of
  Machinery, 398; Marine Engine Performance, 398; Relative
  Economy of Simple and Compound Engines, 399; the
  Screw-Propeller, 399; Chain-Propulsion, or Wire-Rope Towage,
  402; Marine Steam-Boilers, 403; the Modern Steamship, 405;
  Examples of Merchant Steamers, 406; Naval
  Steamers--Classification, 409; Examples of Iron-Clad Steamers,
  412; Power of the Marine Engine, 415; Conclusion, 417.


                          CHAPTER VII.

              THE PHILOSOPHY OF THE STEAM-ENGINE.

  THE HISTORY OF ITS GROWTH; ENERGETICS AND THERMO-DYNAMICS        419

  General Outline, 419; Origin of its Power, 419; Scientific
  Principles involved in its Operation, 420; the Beginnings of
  Modern Science, 421; the Alexandrian Museum, 422; the
  Aristotelian Philosophy, 424; the Middle Ages, 426; Galileo's
  Work, 428; Da Vinci and Stevinus, 429; Kepler, Hooke, and
  Huyghens, 429; Newton and the New Mechanical Philosophy, 430;
  the Inception of the Science of Energetics, 483; the
  Persistence of Energy, 433; Rumford's Experiments, 434;
  Fourier, Carnot, Seguin, 437; Mayer and the Mechanical
  Equivalent of Heat, 438; Joule's Determination of its Value,
  438; Prof. Rankine's Investigations, 442; Clausius-Thompson's
  Principles, 444; Experimental Work of Boyle, Black, and Watt,
  446; Robison's, Dalton's, Ure's, and Biot's Study of Pressures
  and Temperatures of Steam, 447; Arago's and Dulong's
  Researches, 447; Franklin Institute Investigation, 447;
  Cagniard de la Tour--Faraday, 447; Dr. Andrews and the Critical
  Point, 448; Donny's and Dufour's Researches, 448; Regnault's
  Determination of Temperatures and Pressures of Steam, 449;
  Hirn's Experiments, 450; Résumé of the Philosophy of the
  Steam-Engine, 451; Energy--Definitions and Principles, 451; its
  Measure, 452; the Laws of Energetics, 453; Thermo-dynamics,
  453; its Beginnings, 454; its Laws, 454; Rankine's General
  Equation, 455; Rankine's Treatise on the Theory of
  Heat-Engines, 456; Merits of the Great Philosopher, 456.


                         CHAPTER VIII.

              THE PHILOSOPHY OF THE STEAM-ENGINE.

  ITS APPLICATION; ITS TEACHINGS RESPECTING THE CONSTRUCTION OF
  THE ENGINE AND ITS IMPROVEMENT                                   457

  Origin of all Energy, 457; the Progress of Energy through
  Boiler and Engine, 458; Conditions of Heat-Development in the
  Boiler, 458; the Steam in the Engine, 458; the Expansion of
  Steam, 459; Conditions of Heat-Utilization, 460; Loss of Power
  in the Engine, 462; Conditions affecting the Design of the
  Steam-Engine, 466; the Problem stated, 466; Economy as affected
  by Pressure and Temperature, 467; Changes which have already
  occurred, 468; Direction of Changes now in Progress, 470;
  Summary of Facts, 471; Characteristics of a Good Steam-Engine,
  473; Principles of Steam-Boiler Construction, 476.




                      LIST OF ILLUSTRATIONS.


  FRONTISPIECE: The Grecian Idea of the Steam-Engine.

  FIG.                                                            PAGE
    1. Opening Temple-Doors by Steam, B. C. 200                      6
    2. Steam Fountain, B. C. 200                                     7
    3. Hero's Engine, B. C. 200                                      8
    4. Porta's Apparatus, A. D. 1601                                14
    5. De Caus's Apparatus, A. D. 1605                              15
    6. Branca's Steam-Engine, A. D. 1629                            17
    7. Worcester's Steam-Fountain, A. D. 1650                       21
    8. Worcester's Engine, A. D. 1665                               22
    9. Wall of Raglan Castle                                        22
   10. Huyghens's Engine, 1680                                      26
   11. Savery's Model, 1698                                         34
   12. Savery's Engine, 1698                                        35
   13. Savery's Engine, A. D. 1702                                  37
   14. Papin's Two-Way Cock                                         42
   15. Engine Built by Desaguliers in 1718                          43
   16. Papin's Digester, 1680                                       48
   17. Papin's Engine                                               50
   18. Papin's Engine and Water-Wheel, A. D. 1707                   53
   19. Newcomen's Engine, A. D. 1705                                59
   20. Beighton's Valve-Gear, A. D. 1718                            63
   21. Smeaton's Newcomen Engine                                    65
   22. Boiler of Newcomen Engine, 1763                              67
   23. Smeaton's Portable-Engine Boiler, 1765                       73
   24. The Newcomen Model                                           84
   25. Watt's Experiment                                            89
   26. Watt's Engine, 1774                                          98
   27. Watt's Engine, 1781                                         104
   28. Expansion of Steam                                          108
   29. The Governor                                                115
   30. Mercury Steam-Gauge and Glass Water-Gauge                   117
   31. Boulton & Watt's Double-Acting Engine, 1784                 119
   32. Valve-Gear of the Albion Mills Engine                       121
   33. Watt's Half-Trunk Engine, 1784                              122
   34. The Watt Hammer, 1784                                       123
   35. James Watt's Workshop                                       129
   36. Murdoch's Oscillating Engine, 1785                          134
   37. Hornblower's Compound Engine, 1781                          136
   38. Bull's Pumping-Engine, 1798                                 139
   39. Cartwright's Engine, 1798                                   141
   40. The First Railroad-Car, 1825                                144
   41. Leupold's Engine, 1720                                      148
   42. Newton's Steam-Carriage, 1680                               149
   43. Read's Steam-Carriage, 1790                                 150
   44. Cugnot's Steam-Carriage, 1770                               151
   45. Murdoch's Model, 1784                                       153
   46. Evans's Non-Condensing Engine, 1800                         156
   47. Evans's "Oruktor Amphibolis," 1804                          157
   48. Gurney's Steam-Carriage                                     163
   49. Hancock's "Autopsy", 1833                                   168
   50. Trevithick's Locomotive, 1804                               175
   51. Stephenson's Locomotive of 1815. Section                    187
   52. Stephenson's No. 1 Engine, 1825                             191
   53. Opening of the Stockton and Darlington Railroad, 1815       192
   54. The "Novelty," 1829                                         197
   55. The "Rocket," 1829                                          198
   56. The Atmospheric Railroad                                    202
   57. Stephenson's Locomotive, 1833                               203
   58. The Stephenson Valve-Gear, 1833                             206
   59. The "Atlantic," 1832                                        210
   60. The "Best Friend," 1830                                     211
   61. The "West Point," 1831                                      212
   62. The "South Carolina," 1831                                  213
   63. The "Stevens" Rail and Enlarged Section                     215
   64. "Old Ironsides," 1832                                       216
   65. The "E. L. Miller," 1834                                    217
   66. Hulls's Steamboat, 1736                                     226
   67. Fitch's Model, 1785                                         236
   68. Fitch & Voight's Boiler, 1787                               238
   69. Fitch's First Boat, 1787                                    238
   70. John Fitch, 1788                                            239
   71. John Fitch, 1796                                            240
   72. Miller, Taylor & Symmington, 1788                           242
   73. Read's Boiler in Section, 1788                              245
   74. Read's Multi-Tubular Boiler, 1788                           245
   75. The "Charlotte Dundas," 1801                                247
   76. The "Comet," 1812                                           248
   77. Fulton's Experiments                                        253
   78. Fulton's Table of Resistances                               254
   79. Barlow's Water-Tube Boiler, 1793                            256
   80. The "Clermont," 1807                                        258
   81. Engine of the "Clermont," 1808                              258
   82. Launch of the "Fulton the First," 1804                      262
   83. Section of Steam-Boiler, 1804                               264
   84. Engine, Boiler, and Screw-Propellers used by Stevens, 1804  265
   85. Stevens's Screw Steamer, 1804                               265
   86. John Stevens's Twin-Screw Steamer, 1805                     269
   87. The Feathering Paddle-Wheel                                 272
   88. The "North America" and "Albany," 1827-'30                  274
   89. Stevens's Return Tubular Boiler, 1832                       275
   90. Stevens's Valve-Motion                                      276
   91. The "Atlantic," 1851                                        290
   92. The Side-Lever Engine, 1849                                 291
   93. Vertical Stationary Steam-Engine                            308
   94. Vertical Stationary Steam-Engine. Section                   309
   95. Horizontal Stationary Steam-Engine                          312
   96. Horizontal Stationary Steam-Engine                          313
   97. Corliss Engine                                              319
   98. Corliss Engine Valve-Motion                                 320
   99. Greene Engine                                               321
  100. Thurston's Greene-Engine Valve-Gear                         322
  101. Cornish Pumping-Engine, 1880                                329
  102. Steam-Pump                                                  331
  103. The Worthington Pumping-Engine, 1876. Section               333
  104. The Worthington Pumping-Engine                              334
  105. Double-Cylinder Pumping-Engine, 1878                        335
  106. The Lawrence Water-Works Engine                             336
  107. The Leavitt Pumping-Engine                                  337
  108. Babcock & Wilcox's Vertical Boiler                          341
  109. Stationary "Locomotive" Boiler                              342
  110. Galloway Tube                                               343
  111. Harrison's Sectional Boiler                                 345
  112. Babcock and Wilcox's Sectional Boiler                       346
  113. Root Sectional Boiler                                       347
  114. Semi-Portable Engine, 1878                                  348
  115. Semi-Portable Engine, 1878                                  349
  116. The Portable Steam-Engine, 1878                             354
  117. The Thrashers' Road-Engine, 1878                            355
  118. Fisher's Steam-Carriage                                     356
  119. Road and Farm Locomotive                                    357
  120. The Latta Steam Fire-Engine                                 361
  121. The Amoskeag Engine. Section                                363
  122. The Silsby Rotary Steam Fire-Engine                         364
  123. Rotary Steam-Engine                                         365
  124. Rotary Pump                                                 366
  125. Tank Engine, New York Elevated Railroad                     369
  126. Forney's Tank-Locomotive                                    370
  127. British Express Engine                                      371
  128. The Baldwin Locomotive. Section                             372
  129. The American Type of Express Engine, 1878                   374
  130. Beam Engine                                                 380
  131. Oscillating Steam-Engine and Feathering Paddle-Wheel        381
  132. The Two "Rhode Islands," 1836-1876                          383
  133. A Mississippi Steamboat                                     384
  134. Steam-Launch, New York Steam-Power Company                  386
  135. Launch-Engine                                               387
  136. Horizontal, Direct-acting Naval Screw Engine                389
  137. Compound Marine Engine. Side Elevation                      390
  138. Compound Marine Engine. Front Elevation and Section         391
  139. Screw-Propeller                                             400
  140. Tug-Boat Screw                                              401
  141. Hirsch Screw                                                401
  142. Marine Fire-Tubular Boiler. Section                         403
  143. Marine High-Pressure Boiler. Section                        404
  144. The Modern Steamship                                        407
  145. Modern Iron-Clads                                           410
  146. The "Great Eastern"                                         415
  147. The "Great Eastern" at Sea                                  416




                         PORTRAITS.


  NO.                                                             PAGE
   1. Edward Somerset, the Second Marquis of Worcester              20
   2. Thomas Savery                                                 31
   3. Denys Papin                                                   46
   4. James Watt                                                    80
   5. Matthew Boulton                                               94
   6. Oliver Evans                                                 154
   7. Richard Trevithick                                           174
   8. Colonel John Stevens                                         178
   9. George Stephenson                                            183
  10. Robert Fulton                                                251
  11. Robert L. Stevens                                            270
  12. John Elder                                                   393
  13. Benjamin Thompson, Count Rumford                             434
  14. James Prescott Joule                                         439
  15. Prof. W. J. M. Rankine                                       443




  ["A Machine, receiving at distant times and from many hands new
  combinations and improvements, and becoming at last of signal
  benefit to mankind, may be compared to a rivulet swelled in its
  course by tributary streams, until it rolls along a majestic river,
  enriching, in its progress, provinces and kingdoms.

  "In retracing the current, too, from where it mingles with the
  ocean, the pretensions of even ample subsidiary streams are merged
  in our admiration of the master-flood, glorying, as it were, in its
  expansion. But as we continue to ascend, those waters which, nearer
  the sea, would have been disregarded as unimportant, begin to rival
  in magnitude and share our attention with the parent stream; until,
  at length, on our approaching the fountains of the river, it appears
  trickling from the rock, or oozing from among the flowers of the
  valley.

  "So, also, in developing the rise of a machine, a coarse instrument
  or a toy may be recognized as the germ of that production of
  mechanical genius, whose power and usefulness have stimulated our
  curiosity to mark its changes and to trace its origin. The same
  feelings of reverential gratitude which attached holiness to the
  spot whence mighty rivers sprang, also clothed with divinity, and
  raised altars in honor of, inventors of the saw, the plough, the
  potter's wheel, and the loom."--STUART.]




THE GROWTH OF THE STEAM-ENGINE.




CHAPTER I.

_THE STEAM-ENGINE AS A SIMPLE MACHINE._


SECTION I.--THE PERIOD OF SPECULATION--FROM HERO TO WORCESTER, B. C.
200 TO A. D. 1650.

One of the greatest of modern philosophers--the founder of that system
of scientific philosophy which traces the processes of evolution in
every department, whether physical or intellectual--has devoted a
chapter of his "First Principles" of the new system to the
consideration of the multiplication of the effects of the various
forces, social and other, which are continually modifying this
wonderful and mysterious universe of which we form a part. Herbert
Spencer, himself an engineer, there traces the wide-spreading,
never-ceasing influences of new inventions, of the introduction of new
forms of mechanism, and of the growth of industrial organization, with
a clearness and a conciseness which are so eminently characteristic of
his style. His illustration of this idea by reference to the manifold
effects of the introduction of steam-power and its latest embodiment,
the locomotive-engine, is one of the strongest passages in his work.
The power of the steam-engine, and its inconceivable importance as an
agent of civilization, has always been a favorite theme with
philosophers and historians as well as poets. As Religion has always
been, and still is, the great _moral_ agent in civilizing the world,
and as Science is the great _intellectual_ promoter of civilization,
so the Steam-Engine is, in modern times, the most important _physical_
agent in that great work.

It would be superfluous to attempt to enumerate the benefits which it
has conferred upon the human race, for such an enumeration would
include an addition to every comfort and the creation of almost every
luxury that we now enjoy. The wonderful progress of the present
century is, in a very great degree, due to the invention and
improvement of the steam-engine, and to the ingenious application of
its power to kinds of work that formerly taxed the physical energies
of the human race. We cannot examine the methods and processes of any
branch of industry without discovering, somewhere, the assistance and
support of this wonderful machine. Relieving mankind from manual toil,
it has left to the intellect the privilege of directing the power,
formerly absorbed in physical labor, into other and more profitable
channels. The intelligence which has thus conquered the powers of
Nature, now finds itself free to do head-work; the force formerly
utilized in the carrying of water and the hewing of wood, is now
expended in the God-like work of THOUGHT. What, then, can be more
interesting than to trace the history of the growth of this wonderful
machine?--the greatest among the many great creations of one of God's
most beneficent gifts to man--the power of invention.

While following the records and traditions which relate to the
steam-engine, I propose to call attention to the fact that its history
illustrates the very important truth: _Great inventions are never, and
great discoveries are seldom, the work of any one mind_. Every great
invention is really either an aggregation of minor inventions, or the
final step of a progression. It is not a creation, but _a growth_--as
truly so as is that of the trees in the forest. Hence, the same
invention is frequently brought out in several countries, and by
several individuals, simultaneously. Frequently an important invention
is made before the world is ready to receive it, and the unhappy
inventor is taught, by his failure, that it is as unfortunate to be in
advance of his age as to be behind it. Inventions only become
successful when they are not only needed, but when mankind is so far
advanced in intelligence as to appreciate and to express the necessity
for them, and to at once make use of them.

More than half a century ago, an able New England writer, in a
communication to an English engineering periodical, described the new
machinery which was built at Newport, R. I., by John Babcock and
Robert L. Thurston, for one of the first steamboats that ever ran
between that city and New York. He prefaced his description with a
frequently-quoted remark to the effect that, as Minerva sprang, mature
in mind, in full stature of body, and completely armed, from the head
of Jupiter, so the steam-engine came forth, perfect at its birth, from
the brain of James Watt. But we shall see, as we examine the records
of its history, that, although James Watt was _an_ inventor, and
probably the greatest of the inventors of the steam-engine, he was
still but one of the many men who have aided in perfecting it, and who
have now made us so familiar with it, and its tremendous power and its
facile adaptations, that we have almost ceased to admire it, or to
wonder at the workings of the still more admirable intelligence that
has so far perfected it.

Twenty-one centuries ago, the political power of Greece was broken,
although Grecian civilization had risen to its zenith. Rome, ruder
than her polished neighbor, was growing continually stronger, and was
rapidly gaining territory by absorbing weaker states. Egypt, older in
civilization than either Greece or Rome, fell but two centuries later
before the assault of the younger states, and became a Roman province.
Her principal city was at this time Alexandria, founded by the great
soldier whose name it bears, when in the full tide of his prosperity.
It had now become a great and prosperous city, the centre of the
commerce of the world, the home of students and of learned men, and
its population was the wealthiest and most civilized of the then known
world.

It is among the relics of that ancient Egyptian civilization that we
find the first records in the early history of the steam-engine. In
Alexandria, the home of Euclid, the great geometrician, and possibly
contemporary with that talented engineer and mathematician,
Archimedes, a learned writer, called Hero, produced a manuscript which
he entitled "Spiritalia seu Pneumatica."

It is quite uncertain whether Hero was the inventor of any number of
the contrivances described in his work. It is most probable that the
apparatus described are principally devices which had either been long
known, or which were invented by Ctesibius, an inventor who was famous
for the number and ingenuity of the hydraulic and pneumatic machines
that he devised. Hero states, in his Introduction, his intention to
describe existing machines and earlier inventions, and to add his own.
Nothing in the text, however, indicates to whom the several machines
are to be ascribed.[6]

  [6] The British Museum contains four manuscript copies of Hero's
  "Pneumatics," which were written in the fifteenth and sixteenth
  centuries. These manuscripts have been examined with great care, and
  a translation from them prepared by Prof. J. G. Greenwood, and
  published at the desire of Mr. Bennett Woodcroft, the author of a
  valuable little treatise on "Steam Navigation." This is, so far as
  the author is aware, the only existing English translation of any
  portion of Hero's works.

The first part of Hero's work is devoted to applications of the
syphon. The 11th proposition is the first application of heat to
produce motion of fluids.

An altar and its pedestal are hollow and air-tight. A liquid is poured
into the pedestal, and a pipe inserted, of which the lower end passes
beneath the surface of the liquid, and the upper extremity leads
through a figure standing at the altar, and terminates in a vessel
inverted above this altar. When a fire is made on the altar, the heat
produced expands the confined air, and the liquid is driven up the
tube, issuing from the vessel in the hand of the figure standing by
the altar, which thus seems to be offering a libation. This toy
embodies the essential principle of all modern heat-engines--the
change of energy from the form known as heat-energy into mechanical
energy, or work. It is not at all improbable that this prototype of
the modern wonder-working machine may have been known centuries before
the time of Hero.

Many forms of hydraulic apparatus, including the hand fire-engine,
which is familiar to us, and is still used in many of our smaller
cities, are described, the greater number of which are probably
attributable to Ctesibius. They demand no description here.

A hot-air engine, however, which is the subject of his 37th
proposition, is of real interest.

Hero sketches and describes a method of opening temple-doors by the
action of fire on an altar, which is an ingenious device, and contains
all the elements of the machine of the Marquis of Worcester, which is
generally considered the first real steam-engine, with the single and
vital defect that the expanding fluid is air instead of steam. The
sketch, from Greenwood's translation, exhibits the device very
plainly. Beneath the temple-doors, in the space _A B C D_, is placed a
spherical vessel, _H_, containing water. A pipe, _F G_, connects the
upper part of this sphere with the hollow and air-tight shell of the
altar above, _D E_. Another pipe, _K L M_, leads from the bottom of
the vessel, _H_, over, in syphon-shape, to the bottom of a suspended
bucket, _N X_. The suspending cord is carried over a pulley and led
around two vertical barrels, _O P_, turning on pivots at their feet,
and carrying the doors above. Ropes led over a pulley, _R_, sustain a
counterbalance, _W_.

[Illustration: FIG. 1.--Opening Temple-Doors by Steam, B. C. 200.]

On building a fire on the altar, the heated air within expands, passes
through the pipe, _F G_, and drives the water contained in the vessel,
_H_, through the syphon, _K L M_, into the bucket, _N X_. The weight
of the bucket, which then descends, turns the barrels, _O P_, raises
the counterbalance, and opens the doors of the temple. On
extinguishing the fire, the air is condensed, the water returns
through the syphon from the bucket to the sphere, the counterbalance
falls, and the doors are closed.

Another contrivance is next described, in which the bucket is replaced
by an air-tight bag, which, expanding as the heated air enters it,
contracts vertically and actuates the mechanism, which in other
respects is similar to that just described.

In these devices the spherical vessel is a perfect anticipation of
the vessels used many centuries later by several so-called inventors
of the steam-engine.

Proposition 45 describes the familiar experiment of a ball supported
aloft by a jet of fluid. In this example steam is generated in a close
cauldron, and issues from a pipe inserted in the top, the ball dancing
on the issuing jet.

No. 47 is a device subsequently reproduced--perhaps reinvented by the
second Marquis of Worcester.

[Illustration: FIG. 2.--Steam Fountain, B. C. 200.]

A strong, close vessel, _A B C D_, forms a pedestal, on which are
mounted a spherical vessel, _E F_, and a basin. A pipe, _H K_, is led
from the bottom of the larger vessel into the upper part of the
sphere, and another pipe from the lower part of the latter, in the
form of a syphon, over to the basin, _M_. A drain-pipe, _N O_, leads
from the basin to the reservoir, _A D_. The whole contrivance is
called "A fountain which is made to flow by the action of the sun's
rays."

It is operated thus: The vessel, _E F_, being filled nearly to the top
with water, or other liquid, and exposed to the action of the sun's
rays, the air above the water expands, and drives the liquid over,
through the syphon, _G_, into the basin, _M_, and it will fall into
the pedestal, _A B C D_.

Hero goes on to state that, on the removal of the sun's rays, the air
in the sphere will contract, and that the water will be returned to
the sphere from the pedestal. This can, evidently, only occur when the
pipe _G_ is closed previous to the commencement of this cooling. No
such cock is mentioned, and it is not unlikely that the device only
existed on paper.

Several steam-boilers are described, usually simple pipes or
cylindrical vessels, and the steam generated in them by the heat of
the fire on the altar forms a steam-blast. This blast is either
directed into the fire, or it "makes a blackbird sing," blows a horn
for a triton, or does other equally useless work. In one device, No.
70, the steam issues from a reaction-wheel revolving in the horizontal
plane, and causes dancing images to circle about the altar. A more
mechanical and more generally-known form of this device is that which
is frequently described as the "First Steam Engine." The sketch from
Stuart is similar in general form, but more elaborate in detail, than
that copied by Greenwood, which is here also reproduced, as
representing more accurately the simple form which the mechanism of
the "Æolipile," or Ball of Æolus, assumed in those early times.

[Illustration: FIG. 3.--Hero's Engine, B. C. 200.]

The cauldron, _A B_, contains water, and is covered by the steam-tight
cover, _C D_. A globe is supported above the cauldron by a pair of
tubes, terminating, the one, _C M_, in a pivot, _L_, and the other,
_E F_, opening directly into the sphere at _G_. Short, bent pipes, _H_
and _K_, issue from points diametrically opposite each other, and are
open at their extremities.

A fire being made beneath the cauldron, steam is formed and finds exit
through the pipe, _E F G_, into the globe, and thence rushes out of
the pipes, _H K_, turning the globe on its axis, _G L_, by the
unbalanced pressure thus produced.

The more elaborate sketch which forms the frontispiece represents a
machine of similar character. Its design and ornamentation illustrate
well the characteristics of ancient art, and the Greek idea of the
steam-engine.

This "Æolipile" consisted of a globe, _X_, suspended between
trunnions, _O S_, through one of which steam enters from the boiler,
_P_, below. The hollow, bent arms, _W_ and _Z_, cause the vapor to
issue in such directions that the reaction produces a rotary movement
of the globe, just as the rotation of reaction water-wheels is
produced by the outflowing water.

It is quite uncertain whether this machine was ever more than a toy,
although it has been supposed by some authorities that it was actually
used by the Greek priests for the purpose of producing motion of
apparatus in their temples.

It seems sufficiently remarkable that, while the power of steam had
been, during all the many centuries that man has existed upon the
globe, so universally displayed in so many of the phenomena of natural
change, that mankind lived almost up to the Christian era without
making it useful in giving motion even to a toy; but it excites still
greater surprise that, from the time of Hero, we meet with no good
evidence of its application to practical purposes for many hundreds of
years.

Here and there in the pages of history, and in special treatises, we
find a hint that the knowledge of the force of steam was not lost; but
it is not at all to the credit of biographers and of historians, that
they have devoted so little time to the task of seeking and recording
information relating to the progress of this and other important
inventions and improvements in the mechanic arts.

Malmesbury states[7] that, in the year A. D. 1125, there existed at
Rheims, in the church of that town, a clock designed or constructed by
Gerbert, a professor in the schools there, and an organ blown by air
escaping from a vessel in which it was compressed "by heated water."

  [7] Stuart's "Anecdotes."

Hieronymus Cardan, a wonderful mathematical genius, a most eccentric
philosopher, and a distinguished physician, about the middle of the
sixteenth century called attention, in his writings, to the power of
steam, and to the facility with which a vacuum can be obtained by its
condensation. This Cardan was the author of "Cardan's Formula," or
rule for the solution of cubic equations, and was the inventor of the
"smoke-jack." He has been called a "philosopher, juggler, and madman."
He was certainly a learned mathematician, a skillful physician, and a
good mechanic.

Many traces are found, in the history of the sixteenth century, of the
existence of some knowledge of the properties of steam, and some
anticipation of the advantages to follow its application. Matthesius,
A. D. 1571, in one of his sermons describes a contrivance which may be
termed a steam-engine, and enlarges on the "tremendous results which
may follow the volcanic action of a small quantity of confined
vapor;"[8] and another writer applied the steam æolipile of Hero to
turn the spit, and thus rivaled and excelled Cardan, who was
introducing his "smoke-jack."

  [8] "Berg-Postilla, oder Sarepta von Bergwerk und Metallen."
  Nuremberg, 1571.

As Stuart says, the inventor enumerated its excellent qualities with
great minuteness. He claimed that it would "eat nothing, and giving,
withal, an assurance to those partaking of the feast, whose
suspicious natures nurse queasy appetites, that the haunch has not
been pawed by the turnspit in the absence of the housewife's eye, for
the pleasure of licking his unclean fingers."[9]

  [9] "History of the Steam-Engine," 1825.

Jacob Besson, a Professor of Mathematics and Natural Philosophy at
Orleans, and who was in his time distinguished as a mechanician, and
for his ingenuity in contriving illustrative models for use in his
lecture-room, left evidence, which Beroaldus collected and published
in 1578,[10] that he had found the spirit of his time sufficiently
enlightened to encourage him to pay great attention to applied
mechanics and to mechanism. There was at this time a marked awakening
of the more intelligent men of the age to the value of practical
mechanics. A scientific tract, published at Orleans in 1569, and
probably written by Besson, describes very intelligently the
generation of steam by the communication of heat to water, and its
peculiar properties.

  [10] "Theatrum Instrumentorum et Machinarum, Jacobi Bessoni, cum
  Franc Beroaldus, figuarum declaratione demonstrativa." Lugduni,
  1578.

The French were now becoming more interested in mechanics and the
allied sciences, and philosophers and literati, of native birth and
imported by the court from other countries, were learning more of the
nature and importance of such studies as have a bearing upon the work
of the engineer and of the mechanic.

Agostino Ramelli, an Italian of good family, a student and an artist
when at leisure, a soldier and an engineer in busier times, was born
and educated at Rome, but subsequently was induced to make his home in
Paris. He published a book in 1588,[11] in which he described many
machines, adapted to various purposes, with a skill that was only
equaled by the accuracy and general excellence of his delineations.
This work was produced while its author was residing at the French
capital, supported by a pension which had been awarded him by Henry
III. as a reward for long and faithful services.

  [11] "Le diverse et artificiose machine del Capitano Agostino
  Ramelli, del Ponte della Prefia." Paris, 1588.

The books of Besson and of Ramelli are the first treatises of
importance on general machinery, and were, for many years, at once the
sources from which later writers drew the principal portion of their
information in relation to machinery, and wholesome stimulants to the
study of mechanism. These works contain descriptions of many machines
subsequently reinvented and claimed as new by other mechanics.

Leonardo da Vinci, well known as a mathematician, engineer, poet, and
painter, of the sixteenth century, describes, it is said, a steam-gun,
which he calls the "Architonnerre," and ascribes to Archimedes. It was
a machine composed of copper, and seems to have had considerable
power. It threw a ball weighing a talent. The steam was generated by
permitting water in a closed vessel to fall on surfaces heated by a
charcoal fire, and by its sudden expansion to eject the ball.

In the year 1825, the superintendent of the royal Spanish archives at
Simancas furnished an account which, it was said, had been there
discovered of an attempt, made in 1543 by Blasco de Garay, a Spanish
navy-officer under Charles V., to move a ship by paddle-wheels,
driven, as was inferred from the account, by a steam-engine.

It is impossible to say to how much credit the story is entitled, but,
if true, it was the first attempt, so far as is now known, to make
steam useful in developing power for practical purposes. Nothing is
known of the form of the engine employed, it only having been stated
that a "vessel of boiling water" formed a part of the apparatus.

The account is, however, in other respects so circumstantial, that it
has been credited by many; but it is regarded as apocryphal by the
majority of writers upon the subject. It was published in 1826 by M.
de Navarrete, in Zach's "Astronomical Correspondence," in the form of
a letter from Thomas Gonzales, Director of the Royal Archives at
Simancas, Spain.

In 1601, Giovanni Battista della Porta, in a work called "Spiritali,"
described an apparatus by which the pressure of steam might be made to
raise a column of water. It included the application of the
condensation of steam to the production of a vacuum into which the
water would flow.

Porta is described as a mathematician, chemist, and physicist, a
gentleman of fortune, and an enthusiastic student of science. His home
in Naples was a rendezvous for students, artists, and men of science
distinguished in every branch. He invented the magic lantern and the
camera obscura, and described it in his commentary on the
"Pneumatica." In his work,[12] he described this machine for raising
water, as shown in Fig. 4, which differs from one shown by Hero in the
use of steam pressure, instead of the pressure of heated air, for
expelling the liquid.

  [12] "Pneumaticorum libri tres," etc., 4to. Naples, 1601. "I Tre
  Libri de' Spiritali." Napoli, 1606.

The retort, or boiler, is fitted to a tank from which the bent pipe
leads into the external air. A fire being kindled under the retort,
the steam generated rises to the upper part of the tank, and its
pressure on the surface of the water drives it out through the pipe,
and it is then led to any desired height. This was called by Porta an
improved "Hero's Fountain," and was named his "Steam Fountain." He
described with perfect accuracy the action of condensation in
producing a vacuum, and sketched an apparatus in which the vacuum thus
secured was filled by water forced in by the pressure of the external
atmosphere. His contrivances were not apparently ever applied to any
practically useful purpose. We have not yet passed out of the age of
speculation, and are just approaching the period of application. Porta
is, nevertheless, entitled to credit as having proposed an essential
change in this succession, which begins with Hero, and which did not
end with Watt.

[Illustration: FIG. 4.--Porta's Apparatus, A. D. 1601.]

The use of steam in Hero's fountain was as necessary a step as,
although less striking than, any of the subsequent modifications of
the machine. In Porta's contrivance, too, we should note particularly
the separation of the boiler from the "forcing vessel"--a plan often
claimed as original with later inventors, and as constituting a fair
ground for special distinction.

The rude engraving (Fig. 4) above is copied from the book of Porta,
and shows plainly the boiler mounted above a furnace, from the door of
which the flame is seen issuing, and above is the tank containing
water. The opening in the top is closed by the plug, as shown, and the
steam issuing from the boiler into the tank near the top, the water
is driven out through the pipe at the left, leading up from the bottom
of the tank.

[Illustration: FIG. 5.--De Caus's Apparatus, A. D. 1605.]

Florence Rivault, a Gentleman of the Bedchamber to Henry IV., and a
teacher of Louis XIII., is stated by M. Arago, the French philosopher,
to have discovered, as early as 1605, that water confined in a
bomb-shell and there heated would explode the shell, however thick its
walls might be made. The fact was published in Rivault's treatise on
artillery in 1608. He says: "The water is converted into air, and its
vaporization is followed by violent explosion."

In 1615, Salomon de Caus, who had been an engineer and architect under
Louis XIII. of France, and later in the employ of the English Prince
of Wales, published a work at Frankfort, entitled "Les Raisons des
Forces Mouvantes, avec diverses machines tant utile que plaisante," in
which he illustrated his proposition, "Water will, by the aid of fire,
mount higher than its source," by describing a machine designed to
raise water by the expanding power of steam.

In the sketch here given (Fig. 5), and which is copied from the
original in "Les Raisons des Forces Mouvantes," etc., _A_ is the
copper ball containing water; _B_, the cock at the extremity of the
pipe, taking water from the bottom, _C_, of the vessel; _D_, the cock
through which the vessel is filled. The sketch was probably made by De
Caus's own hand.

The machine of De Caus, like that of Porta, thus consisted of a metal
vessel partly filled with water, and in which a pipe was fitted,
leading nearly to the bottom, and open at the top. Fire being applied,
the steam formed by its elastic force drove the water out through the
vertical pipe, raising it to a height limited only by either the
desire of the builder or the strength of the vessel.

In 1629, Giovanni Branca, of the Italian town of Loretto, described,
in a work[13] published at Rome, a number of ingenious mechanical
contrivances, among which was a steam-engine (Fig. 6), in which the
steam, issuing from a boiler, impinged upon the vanes of a horizontal
wheel. This it was proposed to apply to many useful purposes.

  [13] "Le Machine deverse del Signior Giovanni Branca, cittadino
  Romano, Ingegniero, Architetto della Sta. Casa di Loretto." Roma,
  MDCXXIX.

At this time experiments were in progress in England which soon
resulted in the useful application of steam-power to raising water.

[Illustration: FIG. 6.--Branca's Steam-Engine, A. D. 1629.]

A patent, dated January 21, 1630, was granted to David Ramseye[14] by
Charles I., which covered a number of distinct inventions. These were:
"1. To multiply and make saltpeter in any open field, in fower acres
of ground, sufficient to serve all our dominions. 2. To raise water
from low pitts by fire. 3. To make any sort of mills to goe on
standing waters by continual motion, without help of wind, water, or
horse. 4. To make all sortes of tapistrie without any weaving-loom, or
waie ever yet in use in this kingdome. 5. To make boats, shippes, and
barges to goe against strong wind and tide. 6. To make the earth more
fertile than usual. 7. To raise water from low places and mynes, and
coal pitts, by a new waie never yet in use. 8. To make hard iron soft,
and likewise copper to be tuffe and soft, which is not in use in this
kingdome. 9. To make yellow waxe white verie speedilie."

  [14] Rymer's "F[oe]dera," Sanderson. Ewbank's "Hydraulics," p. 419.

This seems to have been the first authentic reference to the use of
steam in the arts which has been found in English literature. The
patentee held his grant fourteen years, on condition of paying an
annual fee of £3 6_s._ 8_d._ to the Crown.

The second claim is distinct as an application of steam, the language
being that which was then, and for a century and a half subsequently,
always employed in speaking of its use. The steam-engine, in all its
forms, was at that time known as the "fire-engine." It would seem not
at all improbable that the third, fifth, and seventh claims are also
applications of steam-power.

Thomas Grant, in 1632, and Edward Ford, in 1640, also patented
schemes, which have not been described in detail, for moving ships
against wind and tide by some new and great force.

Dr. John Wilkins, Bishop of Chester, an eccentric but learned and
acute scholar, described, in 1648, Cardan's smoke-jack, the earlier
æolipiles, and the power of the confined steam, and suggested, in a
humorous discourse, what he thought to be perfectly feasible--the
construction of a flying-machine. He says: "Might not a 'high
pressure' be applied with advantage to move wings as large as those of
the 'ruck's' or the 'chariot'? The engineer might probably find a
corner that would do for a coal-station near some of the 'castles'"
(castles in the air). The reverend wit proposed the application of the
smoke-jack to the chiming of bells, the reeling of yarn, and to
rocking the cradle.

Bishop Wilkins writes, in 1648 ("Mathematical Magic"), of æolipiles as
familiar and useful pieces of apparatus, and describes them as
consisting "of some such material as may endure the fire, having a
small hole at which they are filled with water, and out of which (when
the vessels are heated) the air doth issue forth with a strong and
lasting violence." "They are," the bishop adds, "frequently used for
the exciting and contracting of heat in the melting of glasses or
metals. They may also be contrived to be serviceable for sundry other
pleasant uses, as for the moving of sails in a chimney-corner, the
motion of which sails may be applied to the turning of a spit, or the
like."

Kircher gives an engraving ("Mundus Subterraneus") showing the
last-named application of the æolipile; and Erckern ("Aula
Subterranea," 1672) gives a picture illustrating their application to
the production of a blast in smelting ores. They seem to have been
frequently used, and in all parts of Europe, during the seventeenth
century, for blowing fires in houses, as well as in the practical work
of the various trades, and for improving the draft of chimneys. The
latter application is revived very frequently by the modern inventor.


SECTION II.--THE PERIOD OF APPLICATION--WORCESTER, PAPIN, AND SAVERY.

We next meet with the first instance in which the expansive force of
steam is supposed to have actually been applied to do important and
useful work.

In 1663, Edward Somerset, second Marquis of Worcester, published a
curious collection of descriptions of his inventions, couched in
obscure and singular language, and called "A Century of the Names and
Scantlings of Inventions by me already Practised."

One of these inventions is an apparatus for raising water by steam.
The description was not accompanied by a drawing, but the sketch here
given (Fig. 7) is thought probably to resemble one of his earlier
contrivances very closely.

Steam is generated in the boiler _a_, and thence is led into the
vessel _e_, already nearly filled with water, and fitted up like the
apparatus of De Caus. It drives the water in a jet out through the
pipe _f_. The vessel _e_ is then shut off from the boiler _a_, is
again filled through the pipe _h_, and the operation is repeated.
Stuart thinks it possible that the marquis may have even made an
engine with a piston, and sketches it.[15] The instruments of Porta
and of De Caus were "steam fountains," and were probably applied, if
used at all, merely to ornamental purposes. That of the Marquis of
Worcester was actually used for the purpose of elevating water for
practical purposes at Vauxhall, near London.

  [15] "Anecdotes of the Steam-Engine," vol. i., p. 61.

[Illustration: Edward Somerset, the Second Marquis of Worcester.]

How early this invention was introduced at Raglan Castle by Worcester
is not known, but it was probably not much later than 1628. In 1647
Dircks shows the marquis probably to have been engaged in getting out
parts of the later engine which was erected at Vauxhall, obtaining
his materials from William Lambert, a brass-founder. His patent was
issued in June, 1663.

[Illustration: FIG. 7.--Worcester's Steam Fountain, A. D. 1650.]

We nowhere find an illustrated description of the machine, or such an
account as would enable a mechanic to reproduce it in all its details.
Fortunately, the cells and grooves (Fig. 9) remaining in the wall of
the citadel of Raglan Castle indicate the general dimensions and
arrangement of the engine; and Dircks, the biographer of the inventor,
has suggested the form of apparatus shown in the sketch (Fig. 8) as
most perfectly in accord with the evidence there found, and with the
written specifications.

The two vessels, _A A´_, are connected by a steam-pipe, _B B´_, with
the boiler, _C_, behind them. _D_ is the furnace. A vertical
water-pipe, _E_, is connected with the cold-water vessels, _A A´_, by
the pipes, _F F´_, reaching nearly to the bottom. Water is supplied by
the pipes, _G G´_, with valves, _a a´_, dipping into the well or
ditch, _H_. Steam from the boiler being admitted to each vessel, _A_
and _A´_, alternately, and there condensing, the vacuum formed permits
the pressure of the atmosphere to force the water from the well
through the pipes, _G_ and _G´_. While one is filling, the steam is
forcing the charge of water from the other up the discharge-pipe, _E_.
As soon as each is emptied, the steam is shut off from it and turned
into the other, and the condensation of the steam remaining in the
vessel permits it to fill again. As will be seen presently, this is
substantially, and almost precisely, the form of engine of which the
invention is usually attributed to Savery, a later inventor.

[Illustration: FIG. 8.--Worcester's Engine, A. D. 1665.]

[Illustration: FIG. 9.--Wall of Raglan Castle.]

Worcester never succeeded in forming the great company which he hoped
would introduce his invention on a scale commensurate with its
importance, and his fate was that of nearly all inventors. He died
poor and unsuccessful.

His widow, who lived until 1681, seemed to have become as confident as
was Worcester himself that the invention had value, and, long after
his death, was still endeavoring to secure its introduction, but with
equal non-success. The steam-engine had taken a form which made it
inconceivably valuable to the world, at a time when no more efficient
means of raising water was available at the most valuable mines than
horse-power; but the people, greatly as it was needed, were not yet
sufficiently intelligent to avail themselves of the great boon, the
acceptance of which was urged upon them with all the persistence and
earnestness which characterizes every true inventor.

Worcester is described by his biographer as having been a learned,
thoughtful, studious, and good man--a Romanist without prejudice or
bigotry, a loyal subject, free from partisan intolerance; as a public
man, upright, honorable, and humane; as a scholar, learned without
being pedantic; as a mechanic, patient, skillful, persevering, and of
wonderful ingenuity, and of clear, almost intuitive, apprehension.

Yet, with all these natural advantages, reinforced as they were by
immense wealth and influence in his earlier life, and by hardly
lessened social and political influence when a large fortune had been
spent in experiment, and after misfortune had subdued his spirits and
left him without money or a home, the inventor failed to secure the
introduction of a device which was needed more than any other.
Worcester had attained practical success; but the period of
speculation was but just closing, and that of the application of steam
had not quite yet arrived.

The second Marquis of Worcester stands on the record as the first
steam-engine builder, and his death marks the termination of the first
of those periods into which we have divided the history of the growth
of the steam-engine.

The "water-commanding engine," as its inventor called it, was the
first instance in the history of the steam-engine in which the
inventor is known to have "reduced his invention to practice."

It is evident, however, that the invention of the separate boiler,
important as it was, had been anticipated by Porta, and does not
entitle the marquis to the honor, claimed for him by many English
authorities, of being _the_ inventor of the steam-engine. Somerset was
simply _one_ of those whose works collectively made the steam-engine.

After the time of Worcester, we enter upon a stage of history which
may properly be termed a period of application; and from this time
forward steam continued to play a more and more important part in
social economy, and its influence on the welfare of mankind augmented
with a rapidly-increasing growth.

The knowledge then existing of the immense expansive force of steam,
and the belief that it was destined to submit to the control of man
and to lend its immense power in every department of industry, were
evidently not confined to any one nation. From Italy to Northern
Germany, and from France to Great Britain, the distances, measured in
time, were vastly greater then than now, when this wonderful genius
has helped us to reduce weeks to hours; but there existed,
notwithstanding, a very perfect system of communication, and the
learning of every centre was promptly radiated to every other. It thus
happened that, at this time, the speculative study of the steam-engine
was confined to no part of Europe; inventors and experimenters were
busy everywhere developing this promising scheme.

Jean Hautefeuille, the son of a French _boulanger_, born at Orleans,
adopted by the Duchess of Bouillon at the suggestion of De Sourdis,
profiting by the great opportunities offered him, entered the Church,
and became one of the most learned men and greatest mechanicians of
his time. He studied the many schemes then brought forward by
inventors with the greatest interest, and was himself prolific of new
ideas.

In 1678, he proposed the use of alcohol in an engine, "in such a
manner that the liquid should evaporate and be condensed, _tour à
tour_, without being wasted"[16]--the first recorded plan, probably,
for surface-condensation and complete retention of the working-fluid.
He proposed a gunpowder-engine, of which[17] he described three
varieties.

  [16] Stuart's "Anecdotes."

  [17] "Pendule Perpetuelle, avec la manière d'élever d'eau par le
  moyen de la poudre à canon," Paris, 1678.

In one of these engines he displaced the atmosphere by the gases
produced by the explosion, and the vacuum thus obtained was utilized
in raising water by the pressure of the air. In the second machine,
the pressure of the gases evolved by the combustion of the powder
acted directly upon the water, forcing it upward; and in the third
design, the pressure of the vapor drove a piston, and this engine was
described as fitted to supply power for many purposes. There is no
evidence that he constructed these machines, however, and they are
here referred to simply as indicating that all the elements of the
machine were becoming well known, and that an ingenious mechanic,
combining known devices, could at this time have produced the
steam-engine. Its early appearance should evidently have been
anticipated.

Hautefeuille, if we may judge from evidence at hand, was the first to
propose the use of a piston in a heat-engine, and his gunpowder-engine
seems to have been the first machine which would be called a
heat-engine by the modern mechanic. The earlier "machines" or
"engines," including that of Hero and those of the Marquis of
Worcester, would rather be denominated "apparatus," as that term is
used by the physicist or the chemist, than a machine or an engine, as
the terms are used by the engineer.

Huyghens, in 1680, in a memoir presented to the Academy of Sciences,
speaks of the expansive force of gunpowder as capable of utilization
as a convenient and portable mechanical power, and indicates that he
had designed a machine in which it could be applied.

This machine of Huyghens is of great interest, not simply because it
was the first gas-engine and the prototype of the very successful
modern explosive gas-engine of Otto and Langen, but principally as
having been the first engine which consisted of a cylinder and piston.
The sketch shows its form. It consisted of a cylinder, _A_, a piston,
_B_, two relief-pipes, _C C_, fitted with check-valves and a system of
pulleys, _F_, by which the weight is raised. The explosion of the
powder at _H_ expels the air from the cylinder. When the products of
combustion have cooled, the pressure of the atmosphere is no longer
counterbalanced by that of air beneath, and the piston is forced down,
raising the weight. The plan was never put in practice, although the
invention was capable of being made a working and possibly useful
machine.

[Illustration: FIG. 10.--Huyghens's Engine, 1680.]

At about this period the English attained some superiority over their
neighbors on the Continent in the practical application of science and
the development of the useful arts, and it has never since been lost.
A sudden and great development of applied science and of the useful
arts took place during the reign of Charles II., which is probably
largely attributable to the interest taken by that monarch in many
branches of construction and of science. He is said to have been very
fond of mathematics, mechanics, chemistry, and natural history, and to
have had a laboratory erected, and to have employed learned men to
carry on experiments and lines of research for his satisfaction. He
was especially fond of the study and investigation of the arts and
sciences most closely related to naval architecture and navigation,
and devoted much attention to the determination of the best forms of
vessels, and to the discovery of the best kinds of ship-timber. His
brother, the Duke of York, was equally fond of this study, and was his
companion in some of his work.

Great as is the influence of the monarch, to-day, in forming the
tastes and habits and in determining the direction of the studies and
labors of the people, his influence was vastly more potent in those
earlier days; and it may well be believed that the rapid strides taken
by Great Britain from that time were, in great degree, a consequence
of the well-known habits of Charles II., and that the nation, which
had an exceptional natural aptitude for mechanical pursuits, should
have been prompted by the example of its king to enter upon such a
course as resulted in the early attainment of an advanced position in
all branches of applied science.

The appointment, under Sir Robert Moray, the superintendent of the
laboratory of the king, of Master Mechanic, was conferred upon Sir
Samuel Morland, a nobleman who, in his practical knowledge of
mechanics and in his ingenuity and fruitfulness of invention, was
apparently almost equal to Worcester. He was the son of a Berkshire
clergyman, was educated at Cambridge, where he studied mathematics
with great interest, and entered public life soon after. He served the
Parliament under Cromwell, and afterward went to Geneva. He was of a
decidedly literary turn of mind, and wrote a history of the Piedmont
churches, which gave him great repute with the Protestant party. He
was induced subsequently, on the accession of Charles II., to take
service under that monarch, whose gratitude he had earned by revealing
a plot for his assassination.

He received his appointment and a baronetcy in 1660, and immediately
commenced making experiments, partly at his own expense and partly at
the cost of the royal exchequer, which were usually not at all
remunerative. He built hand fire-engines of various kinds, taking
patents on them, which brought him as small profits as did his work
for the king, and invented the speaking-trumpet, calculating machines,
and a capstan. His house at Vauxhall was full of curious devices, the
products of his own ingenuity.

He devoted much attention to apparatus for raising water. His devices
seem to have usually been modifications of the now familiar
force-pump. They attracted much attention, and exhibitions were made
of them before the king and queen and the court. He was sent to France
on business relating to water-works erected for King Charles, and
while in Paris he constructed pumps and pumping apparatus for the
satisfaction of Louis XIV. In his book,[18] published in Paris in
1683, and presented to the king, and an earlier manuscript,[19] still
preserved in the British Museum, Morland shows a perfect familiarity
with the power of steam. He says, in the latter: "Water being
evaporated by fire, the vapors require a greater space (about two
thousand times) than that occupied by the water; and, rather than
submit to imprisonment, it will burst a piece of ordnance. But, being
controlled according to the laws of statics, and, by science, reduced
to the measure of weight and balance, it bears its burden peaceably
(like good horses), and thus may be of great use to mankind,
especially for the raising of water, according to the following table,
which indicates the number of pounds which may be raised six inches,
1,800 times an hour, by cylinders half-filled with water, and of the
several diameters and depths of said cylinders."

  [18] "Elevation des Eaux par toute sorte de Machines réduite à la
  Mesure au Poids et à la Balance, présentée a Sa Majesté Très
  Chrétienne, par le Chevalier Morland, Gentilhomme Ordinaire de la
  Chambre Privée et Maistre de Mechaniques du Roy de la Grande
  Bretagne, 1683."

  [19] "Les Principes de la Nouvelle Force de Feu, inventée par le
  Chevalier Morland, l'an 1682, et présentée a Sa Majesté Très
  Chrétienne, 1683."

He then gives the following table, a comparison of which with modern
tables proves Morland to have acquired a very considerable and
tolerably accurate knowledge of the volume and pressure of saturated
steam:

  -------------------------+------------------------
         CYLINDERS.        |    POUNDS.
  -----------+-------------+----------------------
    Diameter |    Depth    |    Weight
    in Feet. |   in Feet.  | to be Raised.
  -----------+-------------+----------------------
       1     |      2      |        15
       2     |      4      |       120
       3     |      6      |       405
       4     |      8      |       960
       5     |     10      |     1,876
       6     |     10      |     3,240
  -----------+-------------+----------------------
   Number of cylinders having a diameter of 6 feet
            and a depth of 12 feet.
             |             |
       1     |     12      |     3,240
       2     |     12      |     6,480
       3     |     12      |     9,720
       4     |     12      |    12,960
       5     |     12      |    16,200
       6     |     12      |    19,440
       7     |     12      |    22,680
       8     |     12      |    25,920
       9     |     12      |    29,190
      10     |     12      |    32,400
      20     |     12      |    64,800
      30     |     12      |    97,200
      40     |     12      |   129,600
      50     |     12      |   162,000
      60     |     12      |   194,400
      70     |     12      |   226,800
      80     |     12      |   259,200
      90     |     12      |   291,600
  -----------+-------------+----------------------

The rate of enlargement of volume in the conversion of water into
steam, as given in Morland's book, appears remarkably accurate when
compared with statements made by other early experimenters.
Desaguliers gave the ratio of volumes at 14,000, and this was accepted
as correct for many years, and until Watt's experiments, which were
quoted by Dr. Robison as giving the ratio at between 1,800 and 1,900.
Morland also states the "duty" of his engines in the same manner in
which it is stated by engineers to-day.

Morland must undoubtedly have been acquainted with the work of his
distinguished contemporary, Lord Worcester, and his apparatus seems
most likely to have been a modification--perhaps improvement--of
Worcester's engine. His house was at Vauxhall, and the establishment
set up for the king was in the neighborhood. It may be that Morland is
to be credited with greater success in the introduction of his
predecessor's apparatus than the inventor himself.

Dr. Hutton considered this book to have been the earliest account of
the steam-engine, and accepts the date--1682--as that of the
invention, and adds, that "the project seems to have remained obscure
in both countries till 1699, when Savery, who probably knew more of
Morland's invention than he owned, obtained a patent," etc. We have,
however, scarcely more complete or accurate knowledge of the extent of
Morland's work, and of its real value, than of that of Worcester.
Morland died in 1696, at Hammersmith, not far from London, and his
body lies in Fulham church.

From this time forward the minds of many mechanicians were earnestly
at work on this problem--the raising of water by aid of steam.
Hitherto, although many ingenious toys, embodying the principles of
the steam-engine separately, and sometimes to a certain extent
collectively, had been proposed, and even occasionally constructed,
the world was only just ready to profit by the labors of inventors in
this direction.

But, at the end of the seventeenth century, English miners were
beginning to find the greatest difficulty in clearing their shafts of
the vast quantities of water which they were meeting at the
considerable depths to which they had penetrated, and it had become a
matter of vital importance to them to find a more powerful aid in that
work than was then available. They were, therefore, by their
necessities stimulated to watch for, and to be prepared promptly to
take advantage of, such an invention when it should be offered them.

The experiments of Papin, and the practical application of known
principles by Savery, placed the needed apparatus in their hands.

[Illustration: Thomas Savery.]

THOMAS SAVERY was a member of a well-known family of Devonshire,
England, and was born at Shilston, about 1650. He was well educated,
and became a military engineer. He exhibited great fondness for
mechanics, and for mathematics and natural philosophy, and gave much
time to experimenting, to the contriving of various kinds of
apparatus, and to invention. He constructed a clock, which still
remains in the family, and is considered an ingenious piece of
mechanism, and is said to be of excellent workmanship.

He invented and patented an arrangement of paddle-wheels, driven by a
capstan[20] for propelling vessels in calm weather, and spent some
time endeavoring to secure its adoption by the British Admiralty and
the Navy Board, but met with no success. The principal objector was
the Surveyor of the Navy, who dismissed Savery, with a remark which
illustrates a spirit which, although not yet extinct, is less
frequently met with in the public service now than then: "What have
interloping people, that have no concern with us, to do to pretend to
contrive or invent things for us?"[21] Savery then fitted his
apparatus into a small vessel, and exhibited its operation on the
Thames. The invention was never introduced into the navy, however.

  [20] Harris, "Lexicon Technicum," London, 1710.

  [21] "Navigation Improved; or, The Art of Rowing Ships of all rates
  in Calms, with a more Easy, Swift, and Steady Motion, than Oars
  can," etc., etc. By Thomas Savery, Gent. London, 1698.

It was after this time that Savery became the inventor of a
steam-engine. It is not known whether he was familiar with the work of
Worcester, and of earlier inventors. Desaguliers[22] states that he
had read the book of Worcester, and that he subsequently endeavored to
destroy all evidence of the anticipation of his own invention by the
marquis by buying up all copies of the century that he could find, and
burning them. The story is scarcely credible. A comparison of the
drawings given of the two engines exhibits, nevertheless, a striking
resemblance; and, assuming that of the marquis's engine to be correct,
Savery is to be given credit for the finally successful introduction
of the "semi-omnipotent" "water-commanding" engine of Worcester.

  [22] "Experimental Philosophy," vol. ii., p. 465.

The most important advance in actual construction, therefore, was made
by Thomas Savery. The constant and embarrassing expense, and the
engineering difficulties presented by the necessity of keeping the
British mines, and particularly the deep pits of Cornwall, free from
water, and the failure of every attempt previously made to provide
effective and economical pumping-machinery, were noted by Savery, who,
July 25, 1698, patented the design of the first engine which was ever
actually employed in this work. A working-model was submitted to the
Royal Society of London in 1699, and successful experiments were made
with it. Savery spent a considerable time in planning his engine and
in perfecting it, and states that he expended large sums of money upon
it.

Having finally succeeded in satisfying himself with its operation, he
exhibited a model "Fire-Engine," as it was called in those days,
before King William III. and his court, at Hampton Court, in 1698, and
obtained his patent without delay. The title of the patent reads: "A
grant to Thomas Savery, Gentl., of the sole exercise of a new
invention by him invented, for raising of water, and occasioning
motion to all sorts of mill-works, by the impellant force of fire,
which will be of great use for draining mines, serving towns with
water, and for the working of all sorts of mills, when they have not
the benefit of water nor constant winds; to hold for 14 years; with
usual clauses."

Savery now went about the work of introducing his invention in a way
which is in marked contrast with that usually adopted by the inventors
of that time. He commenced a systematic and successful system of
advertisement, and lost no opportunity of making his plans not merely
known, but well understood, even in matters of detail. The Royal
Society was then fully organized, and at one of its meetings he
obtained permission to appear with his model "fire-engine" and to
explain its operation; and, as the minutes read, "Mr. Savery
entertained the Society with showing his engine to raise water by the
force of fire. He was thanked for showing the experiment, which
succeeded, according to expectation, and was approved of." He
presented to the Society a drawing and specifications of his machine,
and "The Transactions"[23] contain a copperplate engraving and the
description of his model. It consisted of a furnace, _A_, heating a
boiler, _B_, which was connected by pipes, _C C_, with two copper
receivers, _D D_. There were led from the bottom of these receivers
branch pipes, _F F_, which turned upward, and were united to form a
rising main, or "forcing-pipe," _G_. From the top of each receiver was
led a pipe, which was turned downward, and these pipes united to form
a suction-pipe, which was led down to the bottom of the well or
reservoir from which the water was to be drawn. The maximum lift
allowable was stated at 24 feet.

  [23] "Philosophical Transactions, No. 252." Weld's "Royal Society,"
  vol. i., p. 357. Lowthorp's "Abridgment," vol. i.

[Illustration: FIG. 11.--Savery's Model, 1698.]

The engine was worked as follows: Steam is raised in the boiler, _B_,
and a cock, _C_, being opened, a receiver, _D_, is filled with steam.
Closing the cock, _C_, the steam condensing in the receiver, a vacuum
is created, and the pressure of the atmosphere forces the water up,
through the supply-pipe, from the well into the receiver. Opening the
cock, _C_, again, the check-valve in the suction-pipe at _E_ closes,
the steam drives the water out through the forcing-pipe, _G_, the
clack-valve, _E_, on that pipe opening before it, and the liquid is
expelled from the top of the pipe. The valve, _C_, is again closed;
the steam again condenses, and the engine is worked as before. While
one of the two receivers is discharging, the other is filling, as in
the machine of the Marquis of Worcester, and thus the steam is drawn
from the boiler with tolerable regularity, and the expulsion of water
takes place with similar uniformity, the two systems of receivers and
pipes being worked alternately by the single boiler.

In another and still simpler little machine,[24] which he erected at
Kensington (Fig. 12), the same general plan was adopted, combining a
suction-pipe, _A_, 16 feet long and 3 inches in diameter; a single
receiver, _B_, capable of containing 13 gallons; a boiler, _C_, of
about 40 gallons capacity; a forcing-pipe, _D_, 42 feet high, with the
connecting pipe and cocks, _E F G_; and the method of operation was as
already described, except that _surface-condensation_ was employed,
the cock, _F_, being arranged to shower water from the rising main
over the receiver, as shown. Of the first engine Switzer says: "I have
heard him say myself, that the very first time he played, it was in a
potter's house at Lambeth, where, though it was a small engine, yet it
(the water) forced its way through the roof, and struck off the tiles
in a manner that surprised all the spectators."

  [24] Bradley, "New Improvements of Planting and Gardening." Switzer,
  "Hydrostatics," 1729.

[Illustration: FIG. 12.--Savery's Engine, 1698.]

The Kensington engine cost £50, and raised 3,000 gallons per hour,
filling the receiver four times a minute, and required a bushel of
coal per day. Switzer remarks: "It must be noted that this engine is
but a small one in comparison with many others that are made for
coal-works; but this is sufficient for any reasonable family, and
other uses required of it in watering all middling gardens." He
cautions the operator: "When you have raised water enough, and you
design to leave off working the engine, take away all the fire from
under the boiler, and open the cock (connected to the funnel) to let
out the steam, which would otherwise, were it to remain confined,
perhaps burst the engine."

With the intention of making his invention more generally known, and
hoping to introduce it as a pumping-engine in the mining districts of
Cornwall, Savery wrote a prospectus for general circulation, which
contains the earliest account of the later and more effective form of
engine. He entitled his pamphlet "The Miner's Friend; or, A
Description of an Engine to raise Water by Fire described, and the
Manner of fixing it in Mines, with an Account of the several Uses it
is applicable to, and an Answer to the Objections against it." It was
printed in London in 1702, for S. Crouch, and was distributed among
the proprietors and managers of mines, who were then finding the flow
of water at depths so great as, in some cases, to bar further
progress. In many cases, the cost of drainage left no satisfactory
margin of profit. In one mine, 500 horses were employed raising water,
by the then usual method of using horse-gins and buckets.

The approval of the King and of the Royal Society, and the countenance
of the mine-adventurers of England, were acknowledged by the author,
who addressed his pamphlet to them.

The engraving of the engine was reproduced, with the description, in
Harris's "Lexicon Technicum," 1704; in Switzer's "Hydrostatics," 1729;
and in Desaguliers's "Experimental Philosophy," 1744.

The sketch which here follows is a neater engraving of the same
machine. Savery's engine is shown in Fig. 13, as described by Savery
himself, in 1702, in "The Miner's Friend."

_L_ is the boiler in which steam is raised, and through the pipes _O
O_ it is alternately let into the vessels _P P_.

[Illustration: FIG. 13.--Savery's Engine, A. D. 1702.]

Suppose it to pass into the left-hand vessel first. The valve _M_
being closed, and _R_ being opened, the water contained in _P_ is
driven out and up the pipe _S_ to the desired height, where it is
discharged.

The valve _R_ is then closed, and the valve in the pipe _O_; the valve
_M_ is next opened, and condensing water is turned upon the exterior
of _P_ by the cock _Y_, leading water from the cistern _X_. As the
steam contained in _P_ is condensed, forming a vacuum there, a fresh
charge of water is driven by atmospheric pressure up the pipe _T_.

Meantime, steam from the boiler has been let into the right-hand
vessel _P_, the cock _W_ having been first closed, and _R_ opened.

The charge of water is driven out through the lower pipe and the cock
_R_, and up the pipe _S_ as before, while the other vessel is
refilling preparatory to acting in its turn.

The two vessels are thus alternately charged and discharged, as long
as is necessary.

Savery's method of supplying his boiler with water was at once simple
and ingenious.

The small boiler, _D_, is filled with water from any convenient
source, as from the stand-pipe, _S_. A fire is then built under it,
and, when the pressure of steam in _D_ becomes greater than in the
main boiler, _L_, a communication is opened between their lower ends,
and the water passes, under pressure, from the smaller to the larger
boiler, which is thus "fed" without interrupting the work. _G_ and _N_
are _gauge-cocks_, by which the height of water in the boilers is
determined; they were first adopted by Savery.

Here we find, therefore, the first really practicable and commercially
valuable steam-engine. Thomas Savery is entitled to the credit of
having been the first to introduce a machine in which the power of
heat, acting through the medium of steam, was rendered generally
useful.

It will be noticed that Savery, like the Marquis of Worcester, used a
boiler separate from the water-reservoir.

He added to the "water-commanding engine" of the marquis the system of
_surface-condensation_, by which he was enabled to charge his vessels
when it became necessary to refill them; and added, also, the
secondary boiler, which enabled him to supply the working-boiler with
water without interrupting its work.

The machine was thus made capable of working uninterruptedly for a
period of time only limited by its own decay.

Savery never fitted his boilers with safety-valves, although it was
done earlier by Papin; and in deep mines he was compelled to make use
of higher pressures than his rudely-constructed boilers could safely
bear.

Savery's engine was used at a number of mines, and also for supplying
water to towns; some large estates, country houses, and other private
establishments, employed them for the same purpose. They did not,
however, come into general use among the mines, because, according to
Desaguliers, they were apprehensive of danger from the explosion of
the boilers or receivers. As Desaguliers wrote subsequently: "Savery
made a great many experiments to bring this machine to perfection, and
did erect several which raised water very well for gentlemen's seats,
but could not succeed for mines, or supplying towns, where the water
was to be raised very high and in great quantities; for then the steam
required being boiled up to such a strength as to be ready to tear all
the vessels to pieces." "I have known Captain Savery, at York's
buildings, to make steam eight or ten times stronger than common air;
and then its heat was so great that it would melt common soft solder,
and its strength so great as to blow open several joints of the
machine; so that he was forced to be at the pains and charge to have
all his joints soldered with spelter or hard solder."

Although there were other difficulties in the application of the
Savery engine to many kinds of work, this was the most serious one,
and explosions did occur with fatal results. The writer just quoted
relates, in his "Experimental Philosophy," that a man who was ignorant
of the nature of the engine undertook to work a machine which
Desaguliers had provided with a safety-valve to avoid this very
danger, "and, having hung the weight at the further end of the
steelyard, in order to collect more steam in order to make his work
the quicker, he hung also a very heavy plumber's iron upon the end of
the steelyard; the consequence proved fatal; for, after some time, the
steam, not being able, with the safety-cock, to raise up the steelyard
loaded with all this unusual weight, burst the boiler with a great
explosion, and killed the poor man." This is probably the earliest
record of a steam-boiler explosion.

Savery proposed to use his engine for driving mills; but there is no
evidence that he actually made such an application of the machine,
although it was afterward so applied by others. The engine was not
well adapted to the drainage of surface-land, as the elevation of
large quantities of water through small heights required great
capacity of receivers, or compelled the use of several engines for
each case. The filling of the receivers, in such cases, also compelled
the heating of large areas of cold and wet metallic surfaces by the
steam at each operation, and thus made the work comparatively wasteful
of fuel. Where used in mines, they were necessarily placed within 30
feet or less of the lowest level, and were therefore exposed to danger
of submergence whenever, by any accident, the water should rise above
that level. In many cases this would result in the loss of the engine,
and the mine would remain "drowned," unless another engine should be
procured to pump it out. Where the mine was deep, the water was forced
by the pressure of steam from the level of the engine-station to the
top of the lift. This compelled the use of pressures of several
atmospheres in many cases; and a pressure of three atmospheres, or
about 45 pounds per square inch, was considered, in those days, as
about the maximum pressure allowable. This difficulty was met by
setting a separate engine at every 60 or 80 feet, and pumping the
water from one to the other. If any one engine in the set became
disabled, the pumping was interrupted until that one machine could be
repaired. The size of Savery's largest boilers was not great, their
maximum diameter not exceeding two and a half feet. This made it
necessary to provide several of his engines, usually, for a single
mine, and at each level. The first cost and the expense of repairs
were exceedingly serious items. The expense and danger, either real or
apparent, were thus sufficient to deter many from their use, and the
old method of raising water by horse-power was adhered to.

The consumption of fuel with these engines was very great. The steam
was not generated economically, as the boilers used were of such
simple forms as only could then be produced, and presented too little
heating surface to secure a very complete transfer of heat from the
gases of combustion to the water within the boiler. This waste in the
generation of steam in these uneconomical boilers was followed by
still more serious waste in its application, without expansion, to the
expulsion of water from a metallic receiver, the cold and wet sides of
which absorbed heat with the greatest avidity. The great mass of the
liquid was not, however, heated by the steam, and was expelled at the
temperature at which it was raised from below.

Savery quaintly relates the action of his machine in "The Miner's
Friend," and so exactly, that a better description could scarcely be
asked: "The steam acts upon the surface of the water in the receiver,
which surface only being heated by the steam, it does not condense,
but the steam gravitates or presses with an elastic quality like air,
and still increasing its elasticity or spring, until it counterpoises,
or rather exceeds, the weight of the column of water in the
force-pipe, which then it will necessarily drive up that pipe; the
steam then takes some time to recover its power, but it will at last
discharge the water out at the top of the pipe. You may see on the
outside of the receiver how the water goes out, as well as if it were
transparent; for, so far as the steam is contained within the vessel,
it is dry without, and so hot as scarcely to endure the least touch of
the hand; but so far as the water is inside the vessel, it will be
cold and wet on the outside, where any water has fallen on it; which
cold and moisture vanish as fast as the steam takes the place of the
water in its descent."

After Savery's death, in 1716, several of these engines were erected
in which some improvements were introduced. Dr. Desaguliers, in 1718,
built a Savery engine, in which he avoided some defects which he, with
Dr. Gravesande, had noted two years earlier. They had then proposed
to adopt the arrangement of a single receiver which had been used by
Savery himself, as already described, finding, by experiment on a
model which they had made for the purpose, that one could be
discharged three times, while the same boiler would empty two
receivers but once each. In their arrangement, the steam was shut back
in the boiler while the receiver was filling with water, and a high
pressure thus accumulated, instead of being turned into the second
receiver, and the pressure thus kept comparatively low.

[Illustration: FIG. 14.--Papin's Two-Way Cock.]

In the engine built in 1718, Desaguliers used a spherical boiler,
which he provided with the lever safety-valve already applied by
Papin, and adopted a comparatively small receiver--one-fifth the
capacity of the boiler--of slender cylindrical form, and attached a
pipe leading the water for condensation into the vessel, and effected
its distribution by means of the "rose," or a "sprinkling-plate," such
as is still frequently used in modern engines having jet-condensers.
This substitution of jet for surface-condensation was of very great
advantage, securing great promptness in the formation of a vacuum and
a rapid filling of the receiver. A "two-way cock" admitted steam to
the receiver, or, being turned the other way, admitted the cold
condensing water. The dispersion of the water in minute streams or
drops was a very important detail, not only as securing great
rapidity of condensation, but enabling the designer to employ a
comparatively small receiver or condenser.

The engine is shown in Fig. 15, which is copied from the "Experimental
Philosophy" of Desaguliers.

[Illustration: FIG. 15.--Engine built by Desaguliers in 1718.]

The receiver, _A_, is connected to the boiler, _B_, by a steam-pipe,
_C_, terminating at the two-way cock, _D_; the "forcing-pipe," _E_,
has at its foot a check-valve, _F_, and the valve _G_ is a similar
check at the head of the suction-pipe. _H_ is a strainer, to prevent
the ingress of chips or other bodies carried to the pipe by the
current; the cap above the valves is secured by a bridle, or stirrup,
and screw, _I_, and may be readily removed to clear the valves or to
renew them; _K_ is the handle of the two-way cock; _M_ is the
injection-cock, and is kept open during the working of the engine; _L_
is the chimney-flue; _N_ and _O_ are gauge-cocks fitted to pipes
leading to the proper depths within the boiler, the water-line being
somewhere between the levels of their lower ends; _P_ is a lever
safety-valve, as first used on the "Digester" of Papin; _R_ is the
reservoir into which the water is pumped; _T_ is the flue, leading
spirally about the boiler from the furnace, _V_, to the chimney; _Y_
is a cock fitted in a pipe through which the rising-main may be filled
from the reservoir, should injection-water be needed when that pipe is
empty.

Seven of these engines were built, the first of which was made for the
Czar of Russia. Its boiler had a capacity of "five or six hogsheads,"
and the receiver, "holding one hogshead," was filled and emptied four
times a minute. The water was raised "by suction" 29 feet, and forced
by steam pressure 11 feet higher.

Another engine built at about this time, to raise water 29 feet "by
suction," and to force it 24 feet higher, made 6 "strokes" per minute,
and, when forcing water but 6 or 8 feet, made 8 or 9 strokes per
minute. Twenty-five years later a workman overloaded the safety-valve
of this engine, by placing the weight at the end and then adding "a
very heavy plumber's iron." The boiler exploded, killing the
attendant.

Desaguliers says that one of these engines, capable of raising ten
tons an hour 38 feet, in 1728 or 1729, cost £80, exclusive of the
piping.

Blakely, in 1766, patented an improved Savery engine, in which he
endeavored to avoid the serious loss due to condensation of the steam
by direct contact with the water, by interposing a cushion of oil,
which floated upon the water and prevented the contact of the steam
with the surface of the water beneath it. He also used air for the
same purpose, sometimes in double receivers, one supported on the
other. These plans did not, however, prove satisfactory.

Rigley, of Manchester, England, soon after erected Savery engines, and
applied them to the driving of mills, by pumping water into
reservoirs, from whence it returned to the wells or ponds from which
it had been raised, turning water-wheels as it descended.

Such an arrangement was in operation many years at the works of a Mr.
Kiers, St. Pancras, London. It is described in detail, and
illustrated, in Nicholson's "Philosophical Journal," vol. i., p. 419.
It had a "wagon-boiler" 7 feet long, 5 wide, and 5 deep; the wheel was
18 feet in diameter, and drove the lathes and other machinery of the
works. In this engine Blakely's plan of injecting air was adopted. The
injection-valve was a clack, which closed automatically when the
vacuum was formed.

The engine consumed 6 or 7 bushels of good coals, and made 10 strokes
per minute, raising 70 cubic feet of water 14 feet, and developing
nearly 3 horse-power.

Many years after Savery's death, in 1774, Smeaton made the first
duty-trials of engines of this kind. He found that an engine having a
cylindrical receiver 16 inches in diameter and 22 feet high,
discharging the water raised 14 feet above the surface of the water in
the well, making 12 strokes, and raising 100 cubic feet per minute,
developed 2-2/3 horse-power, and consumed 3 hundredweight of coals in
four hours. Its duty was, therefore, 5,250,000 pounds raised one foot
per bushel of 84 pounds of coals, or 62,500 "foot-pounds" of work per
pound of fuel. An engine of slightly greater size gave a duty about 5
per cent. greater.

When Louis XIV. revoked the edict of Nantes, by which Henry IV. had
guaranteed protection to the Protestants of France, the terrible
persecutions at once commenced drove from the kingdom some of its
greatest men. Among these was Denys Papin.

It was at about this time that the influence of the atmospheric
pressure on the boiling-point began to be observed, Dr. Hooke having
found that the boiling-point was a fixed temperature under the
ordinary pressure of the atmosphere, and the increase in temperature
and pressure of steam when confined having been shown by Papin with
his "Digester."

Denys Papin was of a family which had attached itself to the
Protestant Church; but he was given his education in the school of the
Jesuits at Blois, and there acquired his knowledge of mathematics. His
medical education was given him at Paris, although he probably
received his degree at Orleans. He settled in Paris in 1672, with the
intention of practising his profession, and devoted all his spare
time, apparently, to the study of physics.

[Illustration: Denys Papin.]

Meantime, that distinguished philosopher, Huyghens, the inventor of
the clock and of the gunpowder-engine, had been induced by the
linen-draper's apprentice, Colbert, now the most trusted adviser of
the king, to take up his residence in Paris, and had been made one of
the earliest members of the Academy of Science, which was founded at
about that time. Papin became an assistant to Huyghens, and aided him
in his experiments in mechanics, having been introduced by Madame
Colbert, who was also a native of Blois. Here he devised several
modifications of the instruments of Guericke, and printed a
description of them.[25] This little book was presented to the
Academy, and very favorably noticed. Papin now became well known among
contemporary men of science at Paris, and was well received
everywhere. Soon after, in the year 1675, as stated by the _Journal
des Savants_, he left Paris and took up his residence in England,
where he very soon made the acquaintance of Robert Boyle, the founder,
and of the members of the Royal Society. Boyle speaks of Papin as
having gone to England in the hope of finding a place in which he
could satisfactorily pursue his favorite studies.

  [25] "Nouvelles Expériences du Vuide, avec la description des
  Machines qui servent à le faire." Paris, 1674.

Boyle himself had already been long engaged in the study of
pneumatics, and had been especially interested in the investigations
which had been original with Guericke. He admitted young Papin into
his laboratory, and the two philosophers worked together at these
attractive problems. It was while working with Boyle that Papin
invented the double air-pump and the air-gun.

Papin and his work had now become so well known, and he had attained
so high a position in science, that he was nominated for membership in
the Royal Academy, and was elected December 16, 1680. He at once took
his place among the most talented and distinguished of the great men
of his time.

He probably invented his "Digester" while in England, and it was first
described in a brochure written in English, under the title, "The New
Digester." It was subsequently published in Paris.[26] This was a
vessel, _B_ (Fig. 16), capable of being tightly closed by a screw,
_D_, and a lid, _C_, in which food could be cooked in water raised by
a furnace, _A_, to the temperature due to any desired safe pressure of
steam. The pressure was determined and limited by a weight, _W_, on
the safety-valve lever, _G_. It is probable that this essential
attachment to the steam-boiler had previously been used for other
purposes; but Papin is given the credit of having first made use of it
to control the pressure of steam.

  [26] "La manière d'amollir les os et de faire cuire toutes sortes de
  viandes," etc.

[Illustration: FIG. 16.--Papin's Digester, 1680.]

From England, Papin went to Italy, where he accepted membership and
held official position in the Italian Academy of Science. Papin
remained in Venice two years, and then returned to England. Here, in
1687, he announced one of his inventions, which is just becoming of
great value in the arts. He proposed to transmit power from one point
to another, over long distances, by the now well-known "pneumatic"
method. At the point where power was available, he exhausted a
chamber by means of an air-pump, and, leading a pipe to the distant
point at which it was to be utilized, there withdrew the air from
behind a piston, and the pressure of the air upon the latter caused it
to recede into the cylinder, in which it was fitted, raising a weight,
of which the magnitude was proportionate to the size of the piston and
the degree of exhaustion. Papin was not satisfactorily successful in
his experiments; but he had created the germ of the modern system of
pneumatic transmission of power. His disappointment at the result of
his efforts to utilize the system was very great, and he became
despondent, and anxious to change his location again.

In 1687 he was offered the chair of Mathematics at Marburg by Charles,
the Landgrave of Upper Hesse, and, accepting the appointment, went to
Germany. He remained in Germany many years, and continued his
researches with renewed activity and interest. His papers were
published in the "Acta Eruditorum" at Leipsic, and in the
"Philosophical Transactions" at London. It was while at Marburg that
his papers descriptive of his method of pneumatic transmission of
power were printed.[27]

  [27] "Recueil des diverses Pieces touchant quelques Nouvelles
  Machines et autres Sujets Philosophiques," M. D. Papin. Cassel,
  1695.

In the "Acta Eruditorum" of 1688 he exhibited a practicable plan, in
which he exhausted the air from a set of engines or pumps by means of
pumps situated at a long distance from the point of application of the
power, and at the place where the prime mover--which was in this case
a water-wheel--was erected.

After his arrival at the University of Marburg, Papin exhibited
to his colleagues in the faculty a modification of Huyghens's
gunpowder-engine, in which he had endeavored to obtain a more perfect
vacuum than had Huyghens in the first of these machines. Disappointed
in this, he finally adopted the expedient of employing steam to
displace the air, and to produce, by its condensation, the perfect
vacuum which he sought; and he thus produced _the first steam-engine
with a piston_, and the first piston steam-engine, in which
condensation was produced to secure a vacuum. It was described in the
"Acta" of Leipsic,[28] in June, 1690, under the title, "Nova Methodus
ad vires motrices validissimas leri pretio comparandeo" ("A New Method
of securing cheaply Motive Power of considerable Magnitude"). He
describes first the gunpowder-engine, and continues by stating that,
"until now, all experiments have been unsuccessful; and after the
combustion of the exploded powder, there always remains in the
cylinder about one-fifth its volume of air." He says that he has
endeavored to arrive by another route at the same end; and "as, by a
natural property of water, a small quantity of this liquid, vaporized
by the action of heat, acquires an elasticity like that of the air,
and returns to the liquid state again on cooling, without retaining
the least trace of its elastic force," he thought that it would be
easy to construct machines in which, "by means of a moderate heat, and
without much expense," a more perfect vacuum could be produced than
could be secured by the use of gunpowder.

  [28] "Acta Eruditorum," Leipsic, 1690.

[Illustration: FIG. 17.--Papin's Engine.]

The first machine of Papin (Fig. 17) was very similar to the
gunpowder-engine already described as the invention of Huyghens. In
place of gunpowder, a small quantity of water is placed at the bottom
of the cylinder, _A_; a fire is built beneath it, "the bottom being
made of very thin metal," and the steam formed soon raises the piston,
_B_, to the top, where a latch, _E_, engaging a notch in the
piston-rod, _H_, holds it up until it is desired that it shall drop.
The fire being removed, the steam condenses, and a vacuum is formed
below the piston, and the latch, _E_, being disengaged, the piston is
driven down by the superincumbent atmosphere and raises the weight
which has been, meantime, attached to a rope, _L_, passing from the
piston-rod over pulleys, _T T_. The machine had a cylinder two and a
half inches in diameter, and raised 60 pounds once a minute; and Papin
calculated that a machine of a little more than two feet diameter of
cylinder and of four feet stroke would raise 8,000 pounds four feet
per minute--i. e., that it would yield about one horse-power.

The inventor claimed that this new machine would be found useful in
relieving mines from water, in throwing bombs, in ship-propulsion,
attaching revolving paddles--i. e., paddle-wheels--to the sides of the
vessel, which wheels were to be driven by several of his engines, in
order to secure continuous motion, the piston-rods being fitted with
racks which were to engage ratchet-wheels on the paddle-shafts.

"The principal difficulty," he says, answering anticipated objections,
"is that of making these large cylinders."

In a reprint describing his invention, in 1695, Papin gives a
description of a "newly-invented furnace," a kind of fire-box
steam-boiler, in which the fire, completely surrounded by water, makes
steam so rapidly that his engine could be driven at the rate of four
strokes per minute by the steam supplied by it.

Papin also proposed the use of a peculiar form of furnace with this
engine, which, embodying as it does some suggestions that very
probably have since been attributed to later inventors, deserves
special notice. In this furnace, Papin proposed to burn his fuel on a
grate within a furnace arranged with a _down-draught_, the air
entering above the grate, passing _down_ through the fire, and from
the ash-pit through a side flue to the chimney. In starting the fire,
the coal was laid on the grate, covered with wood, and the latter was
ignited, the flame, passing downward through the coal, igniting that
in turn, and, as claimed by Papin, the combustion was complete, and
the formation of smoke was entirely prevented. He states, in "Acta
Eruditorum," that the heat was intense, the saving of fuel very great,
and that the only difficulty was to find a refractory material which
would withstand the high temperature attained.

This is the first fire-box and flue boiler of which we have record.
The experiment is supposed to have led Papin to suggest the use of a
hot-blast, as practised by Neilson more than a century later, for
reducing metals from their ores.

Papin made another boiler having a flue winding through the
water-space, and presenting a heating surface of nearly 80 square
feet. The flue had a length of 24 feet, and was about 10 inches
square. It is not stated what were the maximum pressures carried on
these boilers; but it is known that Papin had used very high pressures
in his digesters--probably between 1,200 and 1,500 pounds per square
inch.

In the year 1705, Leibnitz, then visiting England, had seen a Savery
engine, and, on his return, described it to Papin, sending him a
sketch of the machine. Papin read the letter and exhibited the sketch
to the Landgrave of Hesse, and Charles at once urged him to endeavor
to perfect his own machine, and to continue the researches which he
had been intermittently pursuing since the earlier machine had been
exhibited in public.

In a small pamphlet printed at Cassel in 1707,[29] Papin describes a
new form of engine, in which he discards the original plan of a
modified Huyghens engine, with tight-fitting piston and cylinder,
raising its load by indirect action, and makes a modified Savery
engine, which he calls the "Elector's Engine," in honor of his patron.
This is the engine shown in the engraving, and as proposed to be used
by him in turning a water-wheel.

  [29] "Nouvelle manière d'élever l'Eau par la Force du Feu, mis en
  Lumière," par D. Papin. Cassel, 1707.

The sketch is that given by the inventor in his memoir. It consists
(Fig. 18) of a steam-boiler, _a_, from which steam is led through the
cock, _c_, to the working cylinder, _n n_. The water beneath the
floating-piston, _h_, which latter serves simply as a cushion to
protect the steam from sudden condensation or contact with the water,
is forced into the vessel _r r_, which is a large air-chamber, and
which serves to render the outflow of water comparatively uniform, and
the discharge occurs by means of the pipe _q_, from which the water
rises to the desired height. A fresh supply of water is introduced
through the funnel _k_, after condensation of the steam in _n n_, and
the operation of expulsion is repeated.

[Illustration: FIG. 18.--Papin's Engine and Water-Wheel, A. D. 1707.]

This machine is evidently a retrogression, and Papin, after having
earned the honor of having invented the first steam-engine of the
typical form which has since become so universally applied, forfeited
that credit by his evident ignorance of its superiority over existing
devices, and by attempting unsuccessfully to perfect the inferior
device of another inventor.

Subsequently, Papin made an attempt to apply the steam-engine to the
propulsion of vessels, the account of which will be given in the
chapter on Steam-Navigation.

Again disappointed, Papin once more visited England, to renew his
acquaintance with the _savans_ of the Royal Society; but Boyle had
died during the period which Papin had spent in Germany, and the
unhappy and disheartened inventor and philosopher died in 1810,
without having seen any one of his many devices and ingenious
inventions a practical success.

[Illustration]




CHAPTER II.

_THE STEAM-ENGINE AS A TRAIN OF MECHANISM._

  "The introduction of new Inventions seemeth to be the very chief of
  all human Actions. The Benefits of new Inventions may extend to all
  Mankind universally; but the Good of political Achievements can
  respect but some particular Cantons of Men; these latter do not
  endure above a few Ages, the former forever. Inventions make all Men
  happy, without either Injury or Damage to any one single Person.
  Furthermore, new Inventions are, as it were, new Erections and
  Imitations of God's own Works."--BACON.


THE MODERN TYPE, AS DEVELOPED BY NEWCOMEN, BEIGHTON, AND SMEATON.

At the beginning of the eighteenth century every element of the modern
type of steam-engine had been separately invented and practically
applied. The character of atmospheric pressure, and of the pressure of
gases, had become understood. The nature of a vacuum was known, and
the method of obtaining it by the displacement of the air by steam,
and by the condensation of the vapor, was understood. The importance
of utilizing the power of steam, and the application of condensation
in the removal of atmospheric pressure, was not only recognized, but
had been actually and successfully attempted by Morland, Papin, and
Savery.

Mechanicians had succeeded in making steam-boilers capable of
sustaining any desired or any useful pressure, and Papin had shown how
to make them comparatively safe by the attachment of the
safety-valve. They had made steam-cylinders fitted with pistons, and
had used such a combination in the development of power.

It now only remained for the engineer to combine known forms of
mechanism in a practical machine which should be capable of
economically and conveniently utilizing the power of steam through the
application of now well-understood principles, and by the intelligent
combination of physical phenomena already familiar to scientific
investigators.

Every essential fact and every vital principle had been learned, and
every one of the needed mechanical combinations had been successfully
effected. It was only requisite that an inventor should appear,
capable of perceiving that these known facts and combinations of
mechanism, properly illustrated in a working machine, would present to
the world its greatest physical blessing.

The defects of the simple engines constructed up to this time have
been noted as each has been described. None of them could be depended
upon for safe, economical, and continuous work. Savery's was the most
successful of all. But the engine of Savery, even with the
improvements of Desaguliers, was unsafe where most needed, because of
the high pressures necessarily carried in its boilers when pumping
from considerable depths; it was uneconomical, in consequence of the
great loss of heat in its forcing-cylinders when the hot steam was
surrounded at its entrance by colder bodies; it was slow in operation,
of great first cost, and expensive in first cost and in repairs, as
well as in its operation. It could not be relied upon to do its work
uninterruptedly, and was thus in many respects a very unsatisfactory
machine.

The man who finally effected a combination of the elements of the
modern steam-engine, and produced a machine which is unmistakably a
true engine--i. e., a train of mechanism consisting of several
elementary pieces combined in a train capable of transmitting a force
applied at one end and of communicating it to the resistance to be
overcome at the other end--was THOMAS NEWCOMEN, an "iron-monger" and
blacksmith of Dartmouth, England. The engine invented by him, and
known as the "Atmospheric Steam-Engine," is the first of an entirely
new type.

The old type of engine--the steam-engine as a simple machine--had been
given as great a degree of perfection, by the successive improvements
of Worcester, Savery, and Desaguliers, as it was probably capable of
attaining by any modification of its details. The next step was
necessarily a complete change of type; and to effect such a change, it
was only necessary to combine devices already known and successfully
tried.

But little is known of the personal history of Newcomen. His position
in life was humble, and the inventor was not then looked upon as an
individual of even possible importance in the community. He was
considered as one of an eccentric class of schemers, and of an order
which, concerning itself with mechanical matters, held the lowest
position in the class.

It is supposed that Savery's engine was perfectly well known to
Newcomen, and that the latter may have visited Savery at his home in
Modbury, which was but fifteen miles from the residence of Newcomen.
It is thought, by some biographers of these inventors, that Newcomen
was employed by Savery in making the more intricate forgings of his
engine. Harris, in his "Lexicon Technicum," states that drawings of
the engine of Savery came into the hands of Newcomen, who made a model
of the machine, set it up in his garden, and then attempted its
improvement; but Switzer says that Newcomen "was as early in his
invention as Mr. Savery was in his."

Newcomen was assisted in his experiments by John Calley, who, with
him, took out the patent. It has been stated that a visit to Cornwall,
where they witnessed the working of a Savery engine, first turned
their attention to the subject; but a friend of Savery has stated
that Newcomen was as early with his general plans as Savery.

After some discussion with Calley, Newcomen entered into
correspondence with Dr. Hooke, proposing a steam-engine to consist of
a _steam-cylinder containing a piston similar to that of Papin's, and
to drive a separate pump_, similar to those generally in use where
water was raised by horse or wind power. Dr. Hooke advised and argued
strongly against their plan, but, fortunately, the obstinate belief of
the unlearned mechanics was not overpowered by the disquisitions of
their distinguished correspondent, and Newcomen and Calley attempted
an engine on their peculiar plan. This succeeded so well as to induce
them to continue their labors, and, in 1705, to patent,[30] in
combination with Savery--who held the exclusive right to practise
surface-condensation, and who induced them to allow him an interest
with them--an engine combining a steam-cylinder and piston,
surface-condensation, a separate boiler, and separate pumps.

  [30] It has been denied that a patent was issued, but there is no
  doubt that Savery claimed and received an interest in the new
  engine.

In the atmospheric-engine, as first designed, the slow process of
condensation by the application of the condensing water to the
exterior of the cylinder, to produce the vacuum, caused the strokes of
the engine to take place at very long intervals. An improvement was,
however, soon effected, which immensely increased the rapidity of
condensation. A jet of water was thrown directly _into_ the cylinder,
thus effecting for the Newcomen engine just what Desaguliers had done
for the Savery engine previously. As thus improved, the Newcomen
engine is shown in Fig. 19.

Here _b_ is the boiler. Steam passes from it through the cock, _d_,
and up into the cylinder, _a_, equilibrating the pressure of the
atmosphere, and allowing the heavy pump-rod, _k_, to fall, and, by
the greater weight acting through the beam, _i i_, to raise the
piston, _s_, to the position shown. The rod _m_ carries a
counterbalance, if needed. The cock _d_ being shut, _f_ is then
opened, and a jet of water from the reservoir, _g_, enters the
cylinder, producing a vacuum by the condensation of the steam. The
pressure of the air above the piston now forces it down, again raising
the pump-rods, and thus the engine works on indefinitely.

[Illustration: FIG. 19.--Newcomen's Engine, A. D. 1705.]

The pipe _h_ is used for the purpose of keeping the upper side of the
piston covered with water, to prevent air-leaks--a device of Newcomen.
Two gauge-cocks, _c c_, and a safety-valve, _N_, are represented in
the figure, but it will be noticed that the latter is quite different
from the now usual form. Here, the pressure used was hardly greater
than that of the atmosphere, and the weight of the valve itself was
ordinarily sufficient to keep it down. The condensing water, together
with the water of condensation, flows off through the open pipe _p_.
Newcomen's first engine made 6 or 8 strokes a minute; the later and
improved engines made 10 or 12.

The steam-engine has now assumed a form that somewhat resembles the
modern machine.

The Newcomen engine is seen at a glance to have been a combination of
earlier ideas. It was the engine of Huyghens, with its cylinder and
piston as improved by Papin, by the substitution of steam for the
gases generated by the explosion of gunpowder; still further improved
by Newcomen and Calley by the addition of the method of condensation
used in the Savery engine. It was further modified, with the object of
applying it directly to the working of the pumps of the mines by the
introduction of the overhead beam, from which the piston was suspended
at one end and the pump-rod at the other.

The advantages secured by this combination of inventions were many and
manifest. The piston not only gave economy by interposing itself
between the impelling and the resisting fluid, but, by affording
opportunity to make the area of piston as large as desired, it enabled
Newcomen to use any convenient pressure and any desired proportions
for any proposed lift. The removal of the water to be lifted from the
steam-engine proper and handling it with pumps, was an evident cause
of very great economy of steam.

The disposal of the water to be raised in this way also permitted the
operations of condensation of steam, and the renewal of pressure on
the piston, to be made to succeed each other with rapidity, and
enabled the inventor to choose, unhampered, the device for securing
promptly the action of condensation.

Desaguliers, in his account of the introduction of the engine of
Newcomen, says that, with his coadjutor Calley, he "made several
experiments in private about the year 1710, and in the latter end of
the year 1711 made proposals to drain the water of a colliery at
Griff, in Warwickshire, where the proprietors employed 500 horses, at
an expense of £900 a year; but, their invention not meeting with the
reception they expected, in March following, through the acquaintance
of Mr. Potter, of Bromsgrove, in Worcestershire, they bargained to
draw water for Mr. Back, of Wolverhampton, where, after a great many
laborious attempts, they did make the engine work; but, not being
either philosophers to understand the reason, or mathematicians enough
to calculate the powers and proportions of the parts, they very
luckily, by accident, found what they sought for.

"They were at a loss about the pumps, but, being so near Birmingham,
and having the assistance of so many admirable and ingenious workmen,
they came, about 1712, to the method of making the pump-valves,
clacks, and buckets, whereas they had but an imperfect notion of them
before. One thing is very remarkable: as they were at first working,
they were surprised to see the engine go several strokes, and very
quick together, when, after a search, they found a hole in the piston,
which let the cold water in to condense the steam in the inside of the
cylinder, whereas, before, they had always done it on the outside.
They used before to work with a buoy to the cylinder, inclosed in a
pipe, which buoy rose when the steam was strong and opened the
injection, and made a stroke; thereby they were only capable of giving
6, 8, or 10 strokes in a minute, till a boy, named Humphrey Potter, in
1713, who attended the engine, added (what he called a _scoggan_) a
catch, that the beam always opened, and then it would go 15 or 16
strokes a minute. But, this being perplexed with catches and strings,
Mr. Henry Beighton, in an engine he had built at Newcastle-upon-Tyne
in 1718, took them all away but the beam itself, and supplied them in
a much better manner."

In illustration of the application of the Newcomen engine to the
drainage of mines, Farey describes a small machine, of which the pump
is 8 inches in diameter, and the lift 162 feet. The column of water
to be raised weighed 3,535 pounds. The steam-piston was made 2
feet in diameter, giving an area of 452 square inches. The net
working-pressure was assumed at 10-3/4 pounds per square inch; the
temperature of the water of condensation and of uncondensed vapor
after the entrance of the injection-water being usually about 150°
Fahr. This gave an excess of pressure on the steam-side of 1,324
pounds, the total pressure on the piston being 4,859 pounds. One-half
of this excess is counterweighted by the pump-rods, and by weight on
that end of the beam; and the weight, 662 pounds, acting on each side
alternately as a surplus, produced the requisite rapidity of movement
of the machine. This engine was said to make 15 strokes per minute,
giving a speed of piston of 75 feet per minute, and the power exerted
usefully was equivalent to 265,125 pounds raised one foot high per
minute. As the horse-power is equivalent to 33,000 "foot-pounds" per
minute, the engine was of 265125/33000 = 8.034--almost exactly 8
horse-power.

It is instructive to contrast this estimate with that made for a
Savery engine doing the same work. The latter would have raised the
water about 26 feet in its "suction-pipe," and would then have forced
it, by the direct pressure of steam, the remaining distance of 136
feet; and the steam-pressure required would have been nearly 60 pounds
per square inch. With this high temperature and pressure, the waste of
steam by condensation in the forcing-vessels would have been so great
that it would have compelled the adoption of two engines of
considerable size, each lifting the water one-half the height, and
using steam of about 25 pounds pressure. Potter's rude valve-gear was
soon improved by Henry Beighton, in an engine which that talented
engineer erected at Newcastle-upon-Tyne in 1718, and in which he
substituted substantial materials for the cords, as in Fig. 20.

In this sketch, _r_ is a plug-tree, plug-rod, or plug-frame, as it is
variously called, suspended from the great beam, with which it rises
and falls, bringing the pins _p_ and _k_, at the proper moment, in
contact with the handles _k k_ and _n n_ of the valves, moving them in
the proper direction and to the proper extent. A lever safety-valve is
here used, at the suggestion, it is said, of Desaguliers. The piston
was packed with leather or with rope, and lubricated with tallow.

[Illustration: FIG. 20.--Beighton's Valve-Gear, A. D. 1718.]

After the death of Beighton, the atmospheric engine of Newcomen
retained its then standard form for many years, and came into
extensive use in all the mining districts, particularly in Cornwall,
and was also applied occasionally to the drainage of wet lands, to the
supply of water to towns, and it was even proposed by Hulls to be used
for ship-propulsion.

The proportions of the engines had been determined in a hap-hazard
way, and they were in many cases very unsafe. John Smeaton, the most
distinguished engineer of his time, finally, in 1769, experimentally
determined proper proportions, and built several of these engines of
very considerable size. He built his engines with steam-cylinders of
greater length of stroke than had been customary, and gave them such
dimensions as, by giving a greater excess of pressure on the
steam-side, enabled him to obtain a greatly-increased speed of piston.
The first of his new style of engine was erected at Long Benton, near
Newcastle-upon-Tyne, in 1774.

Fig. 21[31] illustrates its principal characteristic features. The
boiler is not shown.

  [31] A fac-simile of a sketch in Galloway's "On the Steam-Engine,"
  etc.

The steam is led to the engine through the pipe, _C_, and is regulated
by turning the cock in the receiver, _D_, which connects with the
steam-cylinder by the pipe, _E_, which latter pipe rises a little way
above the bottom of the cylinder, _F_, in order that it may not drain
off the injection-water into the steam-pipe and receiver.

The steam-cylinder, about ten feet in length, is fitted with a
carefully-made piston, _G_, having a flanch rising four or five inches
and extending completely around its circumference, and nearly in
contact with the interior surface of the cylinder. Between this flanch
and the cylinder is driven a "packing" of oakum, which is held in
place by weights; this prevents the leakage of air, water, or steam,
past the piston, as it rises and falls in the cylinder at each stroke
of the engine. The chain and piston-rod connect the piston to the
beam, _I I_. The arch-heads at each end of the beam keep the chains of
the piston-rod and the pump-rods perpendicular and in line.

[Illustration: FIG. 21.--Smeaton's Newcomen Engine.]

A "jack-head" pump, _N_, is driven by a small beam deriving its motion
from the plug-rod at _g_, raises the water required for condensing
the steam, and keeps the cistern, _O_, supplied. This "jack-head
cistern" is sufficiently elevated to give the water entering the
cylinder the velocity requisite to secure prompt condensation. A
waste-pipe carries away any surplus water. The injection-water is led
from the cistern by the pipe, _P P_, which is two or three inches in
diameter, and the flow of water is regulated by the injection-cock,
_r_. The cap at the end, _d_, is pierced with several holes, and the
stream thus divided rises in jets when admitted, and, striking the
lower side of the piston, the spray thus produced very rapidly
condenses the steam, and produces a vacuum beneath the piston. The
valve, _e_, on the upper end of the injection-pipe, is a check-valve,
to prevent leakage into the engine when the latter is not in
operation. The little pipe, _f_, supplies water to the upper side of
the piston, and, keeping it flooded, prevents the entrance of air when
the packing is not perfectly tight.

The "working-plug," or plug-rod, _Q_, is a piece of timber slit
vertically, and carrying pins which engage the handles of the valves,
opening and closing them at the proper times. The steam-cock, or
regulator, has a handle, _h_, by which it is moved. The iron rod, _i
i_, or spanner, gives motion to the handle, _h_.

The vibrating lever, _k l_, called the _Y_, or the "tumbling-bob,"
moves on the pins, _m n_, and is worked by the levers, _o p_, which in
turn are moved by the plug-tree. When _o_ is depressed, the loaded
end, _k_, is given the position seen in the sketch, and the leg _l_ of
the _Y_ strikes the spanner, _i i_, and, opening the steam-valve, the
piston at once rises as steam enters the cylinder, until another pin
on the plug-rod raises the piece, _P_, and closes the regulator again.
The lever, _q r_, connects with the injection-cock, and is moved,
when, as the piston rises, the end, _q_, is struck by a pin on the
plug-rod, and the cock is opened and a vacuum produced. The cock is
closed on the descent of the plug-tree with the piston. An
eduction-pipe, _R_, fitted with a clock, conveys away the water in the
cylinder at the end of each down-stroke; the water thus removed is
collected in the hot-well, _S_, and is used as feed-water for the
boiler, to which it is conveyed by the pipe _T_. At each down-stroke,
while the water passes out through _R_, the air which may have
collected in the cylinder is driven out through the "snifting-valve,"
_s_. The steam-cylinder is supported on strong beams, _t t_; it has
around its upper edge a guard, _v_, of lead, which prevents the
overflow of the water on the top of the piston. The excess of this
water flows away to the hot-well through the pipe _W_.

Catch-pins, _x_, are provided, to prevent the beam descending too far
should the engine make too long a stroke; two wooden springs, _y y_,
receive the blow. The great beam is carried on sectors, _z z_, to
diminish losses by friction.

The boilers of Newcomen's earlier engines were made of copper where in
contact with the products of combustion, and their upper parts were of
lead. Subsequently, sheet-iron was substituted. The steam-space in the
boiler was made of 8 or 10 times the capacity of the cylinder of the
engine. Even in Smeaton's time, a chimney-damper was not used, and the
supply of steam was consequently very variable. In the earlier
engines, the cylinder was placed on the boiler; afterward, they were
placed separately, and supported on a foundation of masonry. The
injection or "jack-head" cistern was placed from 12 to 30 feet above
the engine, the velocity due the greater altitude being found to give
the most perfect distribution of the water and the promptest
condensation.

[Illustration: FIG. 22.--Boiler of Newcomen's Engine, 1768.]

Smeaton covered the lower side of his steam-pistons with wooden plank
about 2-1/4 inches thick, in order that it should absorb and waste
less heat than when the iron was directly exposed to the steam. Mr.
Beighton was the first to use the water of condensation for feeding
the boiler, taking it directly from the eduction-pipe, or the
"hot-well." Where only a sufficient amount of pure water could be
obtained for feeding the boiler, and the injection-water was "hard,"
Mr. Smeaton applied a heater, immersed in the hot-well, through which
the feed passed, absorbing heat from the water of condensation _en
route_ to the boiler. Farey first proposed the use of the
"coil-heater"--a pipe, or "worm," which, forming a part of the
feed-pipe, was set in the hot-well.

As early as 1743, the metal used for the cylinders was cast-iron. The
earlier engines had been fitted with brass cylinders. Desaguliers
recommended the iron cylinders, as being smoother, thinner, and as
having less capacity for heat than those of brass.

In a very few years after the invention of Newcomen's engine it had
been introduced into nearly all large mines in Great Britain; and many
new mines, which could not have been worked at all previously, were
opened, when it was found that the new machine could be relied upon to
raise the large quantities of water to be handled. The first engine in
Scotland was erected in 1720 at Elphinstone, in Stirlingshire. One was
put up in Hungary in 1723.

The first mine-engine, erected in 1712 at Griff, was 22 inches in
diameter, and the second and third engines were of similar size. That
erected at Ansthorpe was 23 inches in diameter of cylinder, and it was
a long time before much larger engines were constructed. Smeaton and
others finally made them as large as 6 feet in diameter.

In calculating the lifting-power of his engines, Newcomen's method was
"to square the diameter of the cylinder in inches, and, cutting off
the last figure, he called it 'long hundredweights;' then writing a
cipher on the right hand, he called the number on that side 'odd
pounds;' this he reckoned tolerably exact at a mean, or rather when
the barometer was above 30 inches, and the air heavy." In allowing for
frictional and other losses, he deducted from one-fourth to one-third.
Desaguliers found the rule quite exact. The usual mean pressure
resisting the motion of the piston averaged, in the best engines,
about 8 pounds per square inch of its area. The speed of the piston
was from 150 to 175 feet per minute. The temperature of the hot-well
was from 145° to 175° Fahr.

Smeaton made a number of test-trials of Newcomen engines to determine
their "duty"--i. e., to ascertain the expenditure of fuel required to
raise a definite quantity of water to a stated height. He found an
engine 10 inches in diameter of cylinder, and of 3 feet stroke, could
do work equal to raising 2,919,017 pounds of water one foot high, with
a bushel of coals weighing 84 pounds.

One of Smeaton's larger engines, erected at Long Benton, was 52 inches
in diameter of cylinder and of 7 feet stroke of piston, and made 12
strokes per minute. Its load was equal to 7-1/2 pounds per square inch
of piston-area, and its effective capacity about 40 horse-power. Its
duty was 9-1/2 millions of pounds raised one foot high per bushel of
coals. Its boiler evaporated 7.88 pounds of water per pound of fuel
consumed. It had 35 square feet of grate-surface and 142 square feet
of heating-surface beneath the boilers, and 317 square feet in the
flues--a total of 459 square feet. The moving parts of this engine
weighed 8-1/2 tons.

Smeaton erected one of these engines at the Chasewater mine, in
Cornwall, in 1775, which was of very considerable size. It was 6 feet
in diameter of steam-cylinder, and had a maximum stroke of piston of
9-1/2 feet. It usually worked 9 feet. The pumps were in three lifts of
about 100 feet each, and were 16-3/4 inches in diameter. Nine strokes
were made per minute. This engine replaced two others, of 64 and of 62
inches diameter of cylinder respectively, and both of 6 feet stroke.
One engine at the lower lift supplied the second, which was set above
it. The lower one had pumps 18-1/2 inches in diameter, and raised the
water 144 feet; the upper engine raised the water 156 feet, by pumps
17-1/2 inches in diameter. The later engine replacing them exerted
76-1/2 horse-power. There were three boilers, each 15 feet in
diameter, and having each 23 square feet of grate-surface. The chimney
was 22 feet high. The great beam, or "lever," of this engine was built
up of 20 beams of fir in two sets, placed side by side, and ten deep,
strongly bolted together. It was over 6 feet deep at the middle and 5
feet at the ends, and was 2 feet thick. The "main centres," or
journals, on which it vibrated were 8-1/2 inches in diameter and 8-1/2
inches long. The cylinder weighed 6-1/2 tons, and was paid for at the
rate of 28 shillings per hundredweight.

By the end of the eighteenth century, therefore, the engine of
Newcomen, perfected by the ingenuity of Potter and of Beighton, and by
the systematic study and experimental research of Smeaton, had become
a well-established form of steam-engine, and its application to
raising water had become general. The coal-mines of Coventry and of
Newcastle had adopted this method of drainage; and the tin and the
copper mines of Cornwall had been deepened, using, for drainage,
engines of the largest size.

Some engines had been set up in and about London, the scene of
Worcester's struggles and disappointments, where they were used to
supply water to large houses. Others were in use in other large cities
of England, where water-works had been erected.

Some engines had also been erected to drive mills indirectly by
raising water to turn water-wheels. This is said by Farey to have been
first practised in 1752, at a mill near Bristol, and became common
during the next quarter of a century. Many engines had been built in
England and sent across the channel, to be applied to the drainage of
mines on the Continent. Belidor[32] stated that the manufacture of
these "fire-engines" was exclusively confined to England; and this
remained true many years after his time. When used for the drainage of
mines, the engine usually worked the ordinary lift or bucket pump;
when employed for water-supply to cities, the force or plunger pump
was often employed, the engine being placed below the level of the
reservoir. Dr. Rees states that this engine was in common use among
the collieries of England as early as 1725.

  [32] "Architecture Hydraulique," 1734.

The Edmonstone colliery was licensed, in 1725, to erect an engine, not
to exceed 28 inches diameter of cylinder and 9 feet stroke of piston,
paying a royalty of £80 per annum for eight years. This engine was
built in Scotland, by workmen sent from England, and cost about
£1,200. Its "great cost" is attributed to an extensive use of brass.
The workmen were paid their expenses and 15_s._ per week as wages. The
builders were John and Abraham Potter, of Durham. An engine built in
1775, having a steam-cylinder 48 inches in diameter and of 7 feet
stroke, cost about £2,000.

Smeaton found 57 engines at work near Newcastle in 1767, ranging in
size from 28 to 75 inches in diameter of cylinder, and of,
collectively, about 1,200 horse-power. Fifteen of these engines gave
an average of 98 square inches of piston to the horse-power, and the
average duty was 5,590,000 pounds raised 1 foot high by 1 bushel (84
pounds) of coal. The highest duty noted was 7.44 millions; the lowest
was 3.22 millions. The most efficient engine had a steam-cylinder 42
inches in diameter; the load was equivalent to 9-1/4 pounds per square
inch of piston-area, and the horse-power developed was calculated to
be 16.7.

Price, writing in 1778, says, in the Appendix to his "Mineralogia
Cornubiensis:" "Mr. Newcomen's invention of the fire-engine enabled us
to sink our mines to twice the depth we could formerly do by any other
machinery. Since this invention was completed, most other attempts at
its improvement have been very unsuccessful; but the vast consumption
of fuel in these engines is an immense drawback on the profit of our
mines, for every fire-engine of magnitude consumes £3,000 worth of
coals per annum. This heavy tax amounts almost to a prohibition."

Smeaton was given the description, in 1773, of a _stone_ boiler, which
was used with one of these engines at a copper mine at Camborne, in
Cornwall. It contained three copper flues 22 inches in diameter. The
gases were passed through these flues successively, finally passing
off to the chimney. This boiler was cemented with hydraulic mortar. It
was 20 feet long, 9 feet wide, and 8-1/2 feet deep. It was heated by
the waste heat from the roasting-furnaces. This was one of the
earliest flue-boilers ever made.

In 1780, Smeaton had a list of 18 large engines working in Cornwall.
The larger number of them were built by Jonathan Hornblower and John
Nancarron. At this time, the largest and best-known pumping-engine for
water-works was at York Buildings, in Villiers Street, Strand, London.
It had been in operation since 1752, and was erected beside one of
Savery's engines, built in 1710. It had a steam-cylinder 45 inches in
diameter, and a stroke of piston of 8 feet, making 7-1/2 strokes per
minute, and developing 35-1/2 horse-power. Its boiler was dome-shaped,
of copper, and contained a large central fire-box and a spiral flue
leading outward to the chimney. Another somewhat larger machine was
built and placed beside this engine, some time previous to 1775. Its
cylinder was 49 inches in diameter, and its stroke 9 feet. It raised
water 102 feet. This engine was altered and improved by Smeaton in
1777, and continued in use until 1813.

Smeaton, as early as 1765, designed a _portable_ engine,[33] in which
he supported the machinery on a wooden frame mounted on short legs and
strongly put together, so that the whole machine could be transported
and set at work wherever convenient.

  [33] Smeaton's "Reports," vol. i., p. 223.

[Illustration: FIG. 23.--Smeaton's Portable-Engine Boiler, 1765.]

In place of the beam, a large pulley was used, over which a chain was
carried, connecting the piston with the pump-rod, and the motion was
similar to that given by the discarded beam. The wheel was supported
on A-frames, resembling somewhat the "gallows-frames" still used with
the beam-engines of American river-boats. The sills carrying the two
A's supported the cylinder. The injection-cistern was supported above
the great pulley-wheel. The valve-gearing and the injection-pump were
worked by a smaller wheel, mounted on the same axis with the larger
one. The boiler was placed apart from the engine, with which it was
connected by a steam-pipe, in which was placed the "regulator," or
throttle-valve. The boiler (Fig. 23) "was shaped like a large
tea-kettle," and contained a fire-box, _B_, or internal furnace, of
which the sides were made of cast-iron. The fire-door, _C_, was placed
on one side and opposite the flue, _D_, through which the products of
combustion were led to the chimney, _E_; a short, large pipe, _F_,
leading downward from the furnace to the outside of the boiler, was
the ash-pit. The shell of the boiler, _A_, was made of iron plate
one-quarter of an inch thick. The steam-cylinder of the engine was 18
inches in diameter, the stroke of piston 6 feet, the great wheel 6-1/2
feet in diameter, and the A-frames 9 feet high. The boiler was made 6
feet, the furnace 34 inches, and the grate 18 inches in diameter. The
piston was intended to make 10 strokes per minute, and the engine to
develop 4-1/8 horse-power.

In 1773, Smeaton prepared plans for a pumping-engine to be set up at
Cronstadt, the port of St. Petersburg, to empty the great dry dock
constructed by Peter the Great and Catherine, his successor. This
great dock was begun in 1719. It was large enough to dock ten of the
ships of that time, and had previously been imperfectly drained by two
great windmills 100 feet high. So imperfectly did they do their work,
that a _year_ was required to empty the dock, and it could therefore
only be used once in each summer. The engine was built at the Carron
Iron Works, in England. It had a cylinder 66 inches in diameter, and a
stroke of piston of 8-1/2 feet. The lift varied from 33 feet when the
dock was full to 53 feet when it was cleared of water. The load on the
engine averaged about 8-1/3 pounds per square inch of piston-area.
There were three boilers, each 10 feet in diameter, and 16 feet 4
inches high to the apex of its hemispherical dome. They contained
internal fire-boxes with grates of 20 feet area, and were surrounded
by flues helically traversing the masonry setting. The engine was
started in 1777, and worked very successfully.

The lowlands of Holland were, before the time of Smeaton, drained by
means of windmills. The uncertainty and inefficiency of this method
precluded its application to anything like the extent to which
steam-power has since been utilized. In 1440, there were 150 inland
lakes, or "_meers_," in that country, of which nearly 100, having an
extent of over 200,000 acres, have since been drained. The "Haarlemmer
Meer" alone covers nearly 50,000 acres, and forms the basin of a
drainage-area of between 200,000 and 300,000 acres, receiving a
rainfall of 54,000,000 tons, which must be raised 16 feet in
discharging it. The beds of these lakes are from 10 to 20 feet lower
than the water-level in the adjacent canals. In 1840, 12,000 windmills
were still employed in this work. In the following year, William II.,
at the suggestion of a commission, decreed that only steam-engines
should be employed to do this immense work. Up to this time the
average consumption of fuel for the pumping-engines in use is said to
have been 20 pounds per hour per horse-power.

The first engine used was erected in 1777 and 1778, on the Newcomen
plan, to assist the 34 windmills employed to drain a lake near
Rotterdam. This lake covered 7,000 acres, and its bed was 12 feet
below the surface of the river Meuse, which passes it, and empties
into the sea in the immediate neighborhood. The iron parts of the
engine were built in England, and the machine was put together in
Holland. The steam-cylinder was 52 inches in diameter, and the stroke
of piston 9 feet. The boiler was 18 feet in diameter, and contained a
double flue. The main beam was 27 feet long. The pumps were 6 in
number, 3 cylindrical and 3 having a square cross-section; 3 were of 6
feet and 3 of 2-1/2 feet stroke. Two pumps only were worked at
high-tide, and the others were added one at a time, as the tide fell,
until, at low-tide, all 6 were at work.

The size of this engine, and the magnitude of its work, seem
insignificant when compared with the machinery installed 60 years
later to drain the Haarlemmer Meer, and with the work done by the
last. These engines are 12 feet in diameter of cylinder and 10 feet
stroke of piston, and work--they are 3 in number--the one 11 pumps of
63 inches diameter and 10 feet stroke, the others 8 pumps of 73 inches
diameter and of the same length of stroke. The modern engines do a
"duty" of 75,000,000 to 87,000,000 with 94 pounds of coal, consuming
2-1/4 pounds of coal per hour and per horse-power.

The first steam-engine applied to working the blowing-machinery of a
blast-furnace was erected at the Carron Iron-Works, in Scotland, near
Falkirk, in 1765, and proved very unsatisfactory. Smeaton
subsequently, in 1769 or 1770, introduced better machinery into these
works and improved the old engine, and this use of the steam-engine
soon became usual. This engine did its work indirectly, furnishing
water, by pumping, to drive the water-wheels which worked the
blowing-cylinders. Its steam-cylinder was 6 feet in diameter, and the
pump-cylinder 52 inches. The stroke was 9 feet.

A direct-acting engine, used as a blowing-engine, was not constructed
until about 1784, at which time a single-acting blowing-cylinder, or
air-pump, was placed at the "out-board" end of the beam, where the
pump-rod had been attached. The piston of the air-cylinder was loaded
with the weights needed to force it down, expelling the air, and the
engine did its work in raising the loaded piston, the air-cylinder
filling as the piston rose. A large "accumulator" was used to equalize
the pressure of the expelled air. This consisted of another
air-cylinder, having a loaded piston which was left free to rise and
fall. At each expulsion of air by the blowing-engine this cylinder was
filled, the loaded piston rising to the top. While the piston of the
former was returning, and the air-cylinder was taking in its charge of
air, the accumulator would gradually discharge the stored air, the
piston slowly falling under its load. This piston was called the
"floating piston," or "fly-piston," and its action was, in effect,
precisely that of the upper portion of the common blacksmith's
bellows.

Dr. Robison, the author of "Mechanical Philosophy," one of the very
few works even now existing deserving such a title, describes one of
these engines[34] as working in Scotland in 1790. It had a
steam-cylinder 40 or 44 inches in diameter, a blowing-cylinder 60
inches in diameter, and the stroke of piston was 6 feet. The
air-pressure was 2.77 pounds per square inch as a maximum in the
blowing-cylinder; and the floating piston in the regulating-cylinder
was loaded with 2.63 pounds per square inch. Making 15 or 18 strokes
per minute, this engine delivered about 1,600 cubic feet of air, or
120-1/2 pounds in weight, per minute, and developed 20 horse-power.

  [34] "Encyclopædia Britannica," 1st edition.

At about the same date a change was made in the blowing-cylinder. The
air entered at the bottom, as before, but was forced out at the top,
the piston being fitted with valves, as in the common lifting-pump,
and the engine thus being arranged to do the work of expulsion during
the down-stroke of the steam-piston.

Four years later, the regulating-cylinder, or accumulator, was given
up, and the now familiar "water-regulator" was substituted for it.
This consists of a tank, usually of sheet-iron, set open-end downward
in a large vessel containing water. The lower edge of the inner tank
is supported on piers a few inches above the bottom of the large one.
The pipe carrying air from the blowing-engine passes above this
water-regulator, and a branch-pipe is led down into the inner tank. As
the air-pressure varies, the level of the water within the inverted
tank changes, rising as pressure falls at the slowing of the motion of
the piston, and falling as the pressure rises again while the piston
is moving with an accelerated velocity. The regulator, thus receiving
surplus air to be delivered when needed, greatly assists in regulating
the pressure. The larger the regulator, the more perfectly uniform the
pressure. The water-level outside the inner tank is usually five or
six feet higher than within it. This apparatus was found much more
satisfactory than the previously-used regulator, and, with its
introduction, the establishment of the steam-engine as a
blowing-engine for iron-works and at blast-furnaces may be considered
as having been fully established.

Thus, by the end of the third quarter of the eighteenth century, the
steam-engine had become generally introduced, and had been applied to
nearly all of the purposes for which a single-acting engine could be
used. The path which had been opened by Worcester had been fairly laid
out by Savery and his contemporaries, and the builders of the Newcomen
engine, with such improvements as they had been able to effect, had
followed it as far as they were able. The real and practical
introduction of the steam-engine is as fairly attributable to Smeaton
as to any one of the inventors whose names are more generally known in
connection with it. As a mechanic, he was unrivaled; as an engineer,
he was head and shoulders above any constructor of his time engaged in
general practice. There were very few important public works built in
Great Britain at that time in relation to which he was not consulted;
and he was often visited by foreign engineers, who desired his advice
with regard to works in progress on the Continent.

[Illustration]




CHAPTER III.

_THE DEVELOPMENT OF THE MODERN STEAM-ENGINE. JAMES WATT AND HIS
CONTEMPORARIES._

  The world is now entering upon the Mechanical Epoch. There is
  nothing in the future more sure than the great triumphs which that
  epoch is to achieve. It has already advanced to some glorious
  conquests. What miracles of invention now crowd upon us! Look
  abroad, and contemplate the infinite achievements of the
  steam-power.

  And yet we have only begun--we are but on the threshold of this
  epoch.... What is it but the setting of the great distinctive seal
  upon the nineteenth century?--an advertisement of the fact that
  society has risen to occupy a higher platform than ever before?--a
  proclamation from the high places, announcing honor, honor immortal,
  to the workmen who fill this world with beauty, comfort, and
  power--honor to be forever embalmed in history, to be perpetuated in
  monuments, to be written in the hearts of this and succeeding
  generations!--KENNEDY.


SECTION I.--JAMES WATT AND HIS INVENTIONS.

The success of the Newcomen engine naturally attracted the attention
of mechanics, and of scientific men as well, to the possibility of
making other applications of steam-power.

The best men of the time gave much attention to the subject, but,
until James Watt began the work that has made him famous, nothing more
was done than to improve the proportions and slightly alter the
details of the Newcomen and Calley engine, even by such skillful
engineers as Brindley and Smeaton. Of the personal history of the
earlier inventors and improvers of the steam-engine, very little is
ascertained; but that of Watt has become well known.

[Illustration: James Watt.]

JAMES WATT was of an humble lineage, and was born at Greenock, then a
little Scotch fishing village, but now a considerable and a busy town,
which annually launches upon the waters of the Clyde a fleet of
steamships whose engines are probably, in the aggregate, far more
powerful than were all the engines in the world at the date of Watt's
birth, January 19, 1736. His grandfather, Thomas Watt, of
Crawfordsdyke, near Greenock, was a well-known mathematician about the
year 1700, and was for many years a schoolmaster at that place. His
father was a prominent citizen of Greenock, and was at various times
chief magistrate and treasurer of the town. James Watt was a bright
boy, but exceedingly delicate in health, and quite unable to attend
school regularly, or to apply himself closely to either study or play.
His early education was given by his parents, who were respectable and
intelligent people, and the tools borrowed from his father's
carpenter-bench served at once to amuse him and to give him a
dexterity and familiarity with their use that must undoubtedly have
been of inestimable value to him in after-life.

M. Arago, the eminent French philosopher, who wrote one of the
earliest and most interesting biographies of Watt, relates anecdotes
of him which, if correct, illustrate well his thoughtfulness and his
intelligence, as well as the mechanical bent of the boy's mind. He is
said, at the age of six years, to have occupied himself during leisure
hours with the solution of geometrical problems; and Arago discovers,
in a story in which he is described as experimenting with the
tea-kettle,[35] his earliest investigations of the nature and
properties of steam.

  [35] The same story is told of Savery and of Worcester.

When finally sent to the village school, his ill health prevented his
making rapid progress; and it was only when thirteen or fourteen years
of age that he began to show that he was capable of taking the lead in
his class, and to exhibit his ability in the study, particularly, of
mathematics. His spare time was principally spent in sketching with
his pencil, in carving, and in working at the bench, both in wood and
metal. He made many ingenious pieces of mechanism, and some beautiful
models. His favorite work seemed to be the repairing of nautical
instruments. Among other pieces of apparatus made by the boy was a
very fine barrel-organ. In boyhood, as in after-life, he was a
diligent reader, and seemed to find something to interest him in every
book that came into his hands.

At the age of eighteen, Watt was sent to Glasgow, there to
reside with his mother's relatives, and to learn the trade of a
mathematical-instrument maker. The mechanic with whom he was placed
was soon found too indolent, or was otherwise incapable of giving
much aid in the project, and Dr. Dick, of the University of Glasgow,
with whom Watt became acquainted, advised him to go to London.
Accordingly, he set out in June, 1755, for the metropolis, where, on
his arrival, he arranged with Mr. John Morgan, in Cornhill, to work a
year at his chosen business, receiving as compensation 20 guineas. At
the end of the year he was compelled, by serious ill-health, to return
home.

Having become restored to health, he went again to Glasgow in 1756,
with the intention of pursuing his calling there. But, not being the
son of a burgess, and not having served his apprenticeship in the
town, he was forbidden by the guilds, or trades-unions, to open a shop
in Glasgow. Dr. Dick came to his aid, and employed him to repair some
apparatus which had been bequeathed to the college. He was finally
allowed the use of three rooms in the University building, its
authorities not being under the municipal rule. He remained here until
1760, when, the trades no longer objecting, he took a shop in the
city; and in 1761 moved again, into a shop on the north side of the
Trongate, where he earned a scanty living without molestation, and
still kept up his connection with the college. He did some work as a
civil engineer in the neighborhood of Glasgow, but soon gave up all
other employment, and devoted himself entirely to mechanics.

He spent much of his leisure time--of which he had, at first, more
than was desirable--in making philosophical experiments and in the
manufacture of musical instruments, in making himself familiar with
the sciences, and in devising improvements in the construction of
organs. In order to pursue his researches more satisfactorily, he
studied German and Italian, and read Smith's "Harmonics," that he
might become familiar with the principles of construction of musical
instruments. His reading was still very desultory; but the
introduction of the Newcomen engine in the neighborhood of Glasgow,
and the presence of a model in the college collections, which was
placed in his hands, in 1763, for repair, led him to study the history
of the steam-engine, and to conduct for himself an experimental
research into the properties of steam, with a set of improvised
apparatus.

Dr. Robison, then a student of the University, who found Watt's shop a
pleasant place in which to spend his leisure, and whose tastes
affiliated so strongly with those of Watt that they became friends
immediately upon making acquaintance, called the attention of the
instrument-maker to the steam-engine as early as 1759, and suggested
that it might be applied to the propulsion of carriages. Watt was at
once interested, and went to work on a little model, having tin
steam-cylinders and pistons connected to the driving-wheels by an
intermediate system of gearing. The scheme was afterwards given up,
and was not revived by Watt for a quarter of a century.

Watt studied chemistry, and was assisted by the advice and instruction
of Dr. Black, who was then making the researches which resulted in the
discovery of "latent heat." His proposal to repair the model Newcomen
engine in the college collections led to his study of Desaguliers's
treatise, and of the works of Switzer and others. He thus learned what
had been done by Savery and by Newcomen, and by those who had improved
the engine of the latter.

In his own experiments he used, at first, apothecaries' phials and
hollow canes for steam reservoirs and pipes, and later a Papin's
digester and a common syringe. The latter combination made a
non-condensing engine, in which he used steam at a pressure of 15
pounds per square inch. The valve was worked by hand, and Watt saw
that an automatic valve-gear only was needed to make a working
machine. This experiment, however, led to no practical result. He
finally took hold of the Newcomen model, which had been obtained from
London, where it had been sent for repairs, and, putting it in good
working order, commenced experiments with that.

The Newcomen model, as it happened, had a boiler which, although made
to a scale from engines in actual use, was quite incapable of
furnishing steam enough to work the engine. It was about nine inches
in diameter; the steam-cylinder was two inches in diameter, and of six
inches stroke of piston, arranged as in Fig. 24, which is a picture of
the model as it now appears. It is retained among the most
carefully-preserved treasures of the University of Glasgow.

[Illustration: FIG. 24.--The Newcomen Model.]

Watt made a new boiler for the experimental investigation on which he
was about to enter, and arranged it in such a manner that he could
measure the quantity of water evaporated and of steam used at every
stroke of the engine.

He soon discovered that it required but a very small quantity of steam
to heat a very large quantity of water, and immediately attempted to
determine with precision the relative weights of steam and water in
the steam-cylinder when condensation took place at the down-stroke of
the engine, and thus independently proved the existence of that
"latent heat," the discovery of which constitutes, also, one of the
greatest of Dr. Black's claims to distinction. Watt at once went to
Dr. Black and related the remarkable fact which he had thus detected,
and was, in turn, taught by Black the character of the phenomenon as
it had been explained to his classes by the latter some little time
previously. Watt found that, at the boiling-point, his steam,
condensing, was capable of heating six times its weight of water such
as was used for producing condensation.

Perceiving that steam, weight for weight even, was a vastly greater
absorbent and reservoir of heat than water, Watt saw plainly the
importance of taking greater care to economize it than had previously
been customary. He first attempted to economize in the boiler, and
made boilers with wooden "shells," in order to prevent losses by
conduction and radiation, and used a larger number of flues to secure
more complete absorption of the heat from the furnace-gases. He also
covered his steam-pipes with non-conducting materials, and took every
precaution that his ingenuity could devise to secure complete
utilization of the heat of combustion. He soon found, however, that he
was not working at the most important point, and that the great source
of loss was to be found in defects which he noted in the action of the
steam in the cylinder. He soon concluded that the sources of loss of
heat in the Newcomen engine--which would be greatly exaggerated in a
small model--were:

First, the dissipation of heat by the cylinder itself, which was of
brass, and was both a good conductor and a good radiator.

Secondly, the loss of heat consequent upon the necessity of cooling
down the cylinder at every stroke, in producing the vacuum.

Thirdly, the loss of power due to the pressure of vapor beneath the
piston, which was a consequence of the imperfect method of
condensation.

He first made a cylinder of non-conducting material--wood soaked in
oil and then baked--and obtained a decided advantage in economy of
steam. He then conducted a series of very accurate experiments upon
the temperature and pressure of steam at such points on the scale as
he could readily reach, and, constructing a curve with his results,
the abscesses representing temperatures and the pressures being
represented by the ordinates, he ran the curve backward until he had
obtained closely-approximate measures of temperatures less than 212°,
and pressures less than atmospheric. He thus found that, with the
amount of injection-water used in the Newcomen engine, bringing the
temperature of the interior, as he found, down to from 140° to 175°
Fahr., a very considerable back-pressure would be met with.

Continuing his examination still further, he measured the amount of
steam used at each stroke, and, comparing it with the quantity that
would just fill the cylinder, he found that at least _three-fourths
was wasted_. The quantity of cold water necessary to produce the
condensation of a given weight of steam was next determined; and he
found that one pound of steam contained enough heat to raise about six
pounds of cold water, as used for condensation, from the temperature
of 52° to the boiling-point; and, going still further, he found that
he was compelled to use, at each stroke of the Newcomen engine, _four
times as much injection-water as should suffice to condense a cylinder
full of steam_. This confirmed his previous conclusion that
three-fourths of the heat supplied to the engine was wasted.

Watt had now, therefore, determined by his own researches, as he
himself enumerates them,[36] the following facts:

  [36] Robison's "Mechanical Philosophy," edited by Brewster.

"1. The capacities for heat of iron, copper, and of some sorts of
wood, as compared with water.

"2. The bulk of steam compared with that of water.

"3. The quantity of water evaporated in a certain boiler by a pound of
coal.

"4. The elasticities of steam at various temperatures greater than
that of boiling water, and an approximation to the law which it
follows at other temperatures.

"5. How much water in the form of steam was required every stroke by a
small Newcomen engine, with a wooden cylinder 6 inches in diameter and
12 inches stroke.

"6. The quantity of cold water required in every stroke to condense
the steam in that cylinder, so as to give it a working-power of about
7 pounds on the square inch."

After these well-devised and truly scientific investigations, Watt was
enabled to enter upon his work of improving the steam-engine with an
intelligent understanding of its existing defects, and with a
knowledge of their cause. Watt soon saw that, in order to reduce the
losses in the working of the steam in the steam-cylinder, it would be
necessary to find some means, as he said, to keep the cylinder "always
as hot as the steam that entered it," notwithstanding the great
fluctuations of temperature and pressure of the steam during the up
and the down strokes. He has told us how, finally, the happy thought
occurred to him which relieved him of all difficulty, and led to the
series of modifications which at last gave to the world the modern
type of steam-engine.

He says:[37] "I had gone to take a walk on a fine Sabbath afternoon. I
had entered the Green by the gate at the foot of Charlotte street, and
had passed the old washing-house. I was thinking upon the engine at
the time, and had gone as far as the herd's house, when the idea came
into my mind that, as steam was an elastic body, it would rush into a
vacuum, and, if a communication were made between the cylinder and an
exhausted vessel, it would rush into it, and might be there condensed
without cooling the cylinder. I then saw that I must get rid of the
condensed steam and injection-water if I used a jet, as in Newcomen's
engine. Two ways of doing this occurred to me: First, the water might
be run off by a descending pipe, if an offlet could be got at the
depth of 35 or 36 feet, and any air might be extracted by a small
pump. The second was, to make the pump large enough to extract both
water and air." "I had not walked farther than the Golf-house, when
the whole thing was arranged in my mind."

  [37] "Reminiscences of James Watt," Robert Hart; "Transactions of
  the Glasgow Archæological Society," 1859.

Referring to this invention, Watt said to Prof. Jardine:[38] "When
analyzed, the invention would not appear so great as it seemed to be.
In the state in which I found the steam-engine, it was no great effort
of mind to observe that the quantity of fuel necessary to make it work
would forever prevent its extensive utility. The next step in my
progress was equally easy--to inquire what was the cause of the great
consumption of fuel. This, too, was readily suggested, viz., the waste
of fuel which was necessary to bring the whole cylinder, piston, and
adjacent parts from the coldness of water to the heat of steam, no
fewer than from 15 to 20 times in a minute." It was by pursuing this
train of thought that he was led to devise the separate condenser.

  [38] "Lives of Boulton and Watt," Smiles.

On Monday morning Watt proceeded to make an experimental test of his
new invention, using for his steam-cylinder and piston a large brass
surgeon's-syringe, 1-3/4-inch diameter and 10 inches long. At each end
was a pipe leading steam from the boiler, and fitted with a cock to
act as a steam-valve. A pipe led also from the top of the cylinder to
the condenser, the syringe being inverted and the piston-rod hanging
downward for convenience. The condenser was made of two pipes of thin
tin plate, 10 or 12 inches long, and about one-sixth of an inch in
diameter, standing vertically, and having a connection at the top
with a horizontal pipe of larger size, and fitted with a
"snifting-valve." Another vertical pipe, about an inch in diameter,
was connected to the condenser, and was fitted with a piston, with a
view to using it as an "air-pump." The whole was set in a cistern of
cold water. The piston-rod of the little steam-cylinder was drilled
from end to end to permit the water to be removed from the cylinder.
This little model (Fig. 25) worked very satisfactorily, and the
perfection of the vacuum was such that the machine lifted a weight of
18 pounds hung upon the piston-rod, as in the sketch. A larger model
was immediately afterward constructed, and the result of its test
confirmed fully the anticipations which had been awakened by the first
experiment.

[Illustration: FIG. 25.--Watt's Experiment.]

Having taken this first step and made such a radical improvement, the
success of this invention was no sooner determined than others
followed in rapid succession, as consequences of the exigencies
arising from the first change in the old Newcomen engine. But in the
working out of the forms and proportions of the details of the new
engine, even Watt's powerful mind, stored as it was with
happily-combined scientific and practical information, was occupied
for years. In attaching the separate condenser, he first attempted
surface-condensation; but this not succeeding well, he substituted the
jet. Some provision became at once necessary for preventing the
filling of the condenser with water.

Watt at first intended adopting the expedient which had worked
satisfactorily with the less effective condensation of Newcomen's
engine--i. e., leading a pipe from the condenser to a depth greater
than the height of a column of water which could be counterbalanced by
the pressure of the atmosphere; but he subsequently employed the
air-pump, which relieves the condenser not only of the water, but of
the air which also usually collects in considerable volume in the
condenser, and vitiates the vacuum. He next substituted oil and tallow
for water in the lubrication of the piston and keeping it steam-tight,
in order to avoid the cooling of the cylinder incident to the use of
the latter. Another cause of refrigeration of the cylinder, and
consequent waste of power in its operation, was seen to be the
entrance of the atmosphere, which followed the piston down the
cylinder at each stroke, cooling its interior by its contact. This the
inventor concluded to prevent by covering the top of the cylinder,
allowing the piston-rod to play through a "stuffing-box"--which device
had long been known to mechanics.

He accordingly not only covered the top, but surrounded the whole
cylinder with an external casing, or "steam-jacket," and allowed the
steam from the boiler to pass around the steam-cylinder and to press
upon the upper surface of the piston, where its pressure was variable
at pleasure, and therefore more manageable than that of the
atmosphere. It also, besides keeping the cylinder hot, could do
comparatively little harm should it leak by the piston, as it could be
condensed, and thus readily disposed of.

When he had concluded to build the larger experimental engine, Watt
determined to give his whole time and attention to the work, and hired
a room in an old deserted pottery near the Broomielaw. Here he worked
with a mechanic--John Gardiner, whom he had taken into his
employ--uninterruptedly for many weeks. Meantime, through his friend
Dr. Black, probably, he had made the acquaintance of Dr. Roebuck, a
wealthy physician, who had, with other Scotch capitalists, just
founded the celebrated Carron Iron-Works, and had opened a
correspondence with him, in which he kept that gentleman informed of
the progress of his work on the new engine.

This engine had a steam-cylinder, Watt tells us, of "five or six"
inches diameter, and of two feet stroke. It was of copper,
smooth-hammered, but not bored out, and "not very true." This was
encased in another cylinder of wood. In August, 1765, he tried the
small engine, and wrote Dr. Roebuck that he had had "good success,"
although the machine was very imperfect. "On turning the
exhausting-cock, the piston, when not loaded, ascended as quick as the
blow of a hammer, and as quick when loaded with 18 pounds (being 7
pounds on the inch) as it would have done if it had had an injection
as usual." He then tells his correspondent that he was about to make
the larger model. In October, 1765, he finished the latter. The
engine, when ready for trial, was still very imperfect. It
nevertheless did good work for so rude a machine.

Watt was now reduced to poverty, and, after borrowing considerable
sums from friends, he was finally compelled to give up his scheme for
the time, and to seek employment in order to provide for his family.
During an interval of about two years he supported himself by
surveying, and by the work of exploring coal-fields in the
neighborhood of Glasgow for the magistrates of the city. He did not,
however, entirely give up his invention.

In 1767, Dr. Roebuck assumed Watt's liabilities to the amount of
£1,000, and agreed to provide capital for the prosecution of his
experiments and to introduce his invention; and, on the other hand,
Watt agreed to surrender to Dr. Roebuck two-thirds of the patent.
Another engine was next built, having a steam-cylinder seven or eight
inches in diameter, which was finished in 1768. This worked
sufficiently well to induce the partners to ask for a patent, and the
specifications and drawings were completed and presented in 1769.

Watt also built and set up several Newcomen engines, partly, perhaps,
to make himself thus thoroughly familiar with the practical details of
engine-building. Meantime, also, he prepared the plans for, and
finally had built, a moderately large engine of his own new type. Its
steam-cylinder was 18 inches in diameter, and the stroke of piston was
5 feet. This engine was built at Kinneil, and was finished in
September, 1769. It was not all satisfactory in either its
construction or its operation. The condenser was a surface-condenser
composed of pipes somewhat like that used in his first little model,
and did not prove to be satisfactorily tight. The steam-piston leaked
seriously, and repeated trials only served to make more evident its
imperfections. He was assisted in this time of need by both Dr. Black
and Dr. Roebuck; but he felt strongly the risks which he ran of
involving his friends in serious losses, and became very despondent.
Writing to Dr. Black, he says: "Of all things in life, there is
nothing more foolish than inventing;" and probably the majority of
inventors have been led to the same opinion by their own experiences.

"Misfortunes never come singly;" and Watt was borne down by the
greatest of all misfortunes--the loss of a faithful and affectionate
wife--while still unable to see a successful issue of his schemes.
Only less disheartening than this was the loss of fortune of his
steadfast friend, Dr. Roebuck, and the consequent loss of his aid. It
was at about this time, in the year 1769, that negotiations were
commenced which resulted in the transfer of the capitalized interest
in Watt's engine to the wealthy manufacturer whose name, coupled with
that of Watt, afterward became known throughout the civilized world,
as the steam-engine in its new form was pushed into use by his energy
and business tact.

Watt met Mr. Boulton, who next became his partner, in 1768, on his
journey to London to procure his patent, and the latter had then
examined Watt's designs, and, at once perceiving their value, proposed
to purchase an interest. Watt was then unable to reply definitely to
Boulton's proposition, pending his business arrangements with Dr.
Roebuck; but, with Roebuck's consent, afterwards proposed that Boulton
should take a one-third interest with himself and partner, paying
Roebuck therefor one-half of all expenses previously incurred, and
whatever he should choose to add to compensate "for the risk he had
run." Subsequently, Dr. Roebuck proposed to transfer to Boulton and to
Dr. Small, who was desirous of taking interest with Boulton, one-half
of his proprietorship in Watt's inventions, on receiving "a sum not
less than one thousand pounds," which should, after the experiments on
the engine were completed, be deemed "just and reasonable." Twelve
months were allowed for the adjustment of the account. This proposal
was accepted in November, 1769.

[Illustration: Matthew Boulton.]

MATTHEW BOULTON, who now became a partner with James Watt, was the son
of a Birmingham silver stamper and piecer, and succeeded to his
father's business, building up a great establishment, which, as well
as its proprietor, was well known in Watt's time. Watt, writing to Dr.
Roebuck before the final arrangement had been made, urged him to close
with Boulton for "the following considerations:

"1st. From Mr. Boulton's own character as an ingenious, honest, and
rich man. 2dly. From the difficulty and expense there would be of
procuring accurate and honest workmen and providing them with proper
utensils, and getting a proper overseer or overseers. If, to avoid
this inconvenience, you were to contract for the work to be done by a
master-workman, you must give up a great share of the profit. 3dly.
The success of the engine is far from being verified. If Mr. Boulton
takes his chance of success from the account I shall write Dr. Small,
and pays you any adequate share of the money laid out, it lessens your
risk, and in a greater proportion than I think it will lessen your
profits. 4thly. The assistance of Mr. Boulton's and Dr. Small's
ingenuity (if the latter engage in it) in improving and perfecting the
machine may be very considerable, and may enable us to get the better
of the difficulties that might otherwise damn it. Lastly, consider my
uncertain health, my irresolute and inactive disposition, my inability
to bargain and struggle for my own with mankind: all which disqualify
me for any great undertaking. On our side, consider the first outlay
and interest, the patent, the present engine, about £200 (though there
would not be much loss in making it into a common engine), two years
of my time, and the expense of models."

Watt's estimate of the value of Boulton's ingenuity and talent was
well-founded. Boulton had shown himself a good scholar, and had
acquired considerable knowledge of the languages and of the sciences,
particularly of mathematics, after leaving the school from which he
graduated into the shop when still a boy. In the shop he soon
introduced a number of valuable improvements, and he was always on the
lookout for improvements made by others, with a view to their
introduction in his business. He was a man of the modern style, and
never permitted competitors to excel him in any respect, without the
strongest efforts to retain his leading position. He always aimed to
earn a reputation for good work, as well as to make money. His
father's workshop was at Birmingham; but Boulton, after a time, found
that his rapidly-increasing business would compel him to find room for
the erection of a more extensive establishment, and he secured land at
Soho, two miles distant from Birmingham, and there erected his new
manufactory, about 1762.

The business was, at first, the manufacture of ornamental metal-ware,
such as metal buttons, buckles, watch-chains, and light filigree and
inlaid work. The manufacture of gold and silver plated-ware was soon
added, and this branch of business gradually developed into a very
extensive manufacture of works of art. Boulton copied fine work
wherever he could find it, and often borrowed vases, statuettes, and
bronzes of all kinds from the nobility of England, and even from the
queen, from which to make copies. The manufacture of inexpensive
clocks, such as are now well known throughout the world as an article
of American trade, was begun by Boulton. He made some fine
astronomical and valuable ornamental clocks, which were better
appreciated on the Continent than in England. The business of the Soho
manufactory in a few years became so extensive, that its goods were
known to every civilized nation, and its growth, under the management
of the enterprising, conscientious, and ingenious Boulton, more than
kept pace with the accumulation of capital; and the proprietor found
himself, by his very prosperity, often driven to the most careful
manipulation of his assets, and to making free use of his credit.

Boulton had a remarkable talent for making valuable acquaintances, and
for making the most of advantages accruing thereby. In 1758 he made
the acquaintance of Benjamin Franklin, who then visited Soho; and in
1766 these distinguished men, who were then unaware of the existence
of James Watt, were corresponding, and, in their letters, discussing
the applicability of steam-power to various useful purposes. Between
the two a new steam-engine was designed, and a model was constructed
by Boulton, which was sent to Franklin and exhibited by him in London.

Dr. Darwin seems to have had something to do with this scheme, and the
enthusiasm awakened by the promise of success given by this model may
have been the origin of the now celebrated prophetic rhymes so often
quoted from the works of that eccentric physician and poet. Franklin
contributed, as his share in the plan, an idea of so arranging the
grate as to prevent the production of smoke. He says: "All that is
necessary is to make the smoke of fresh coals pass descending through
those that are already ignited." His idea has been, by more recent
schemers, repeatedly brought forward as new. Nothing resulted from
these experiments of Boulton, Franklin, and Darwin, and the plan of
Watt soon superseded all less well-developed plans.

In 1767, Watt visited Soho and carefully inspected Boulton's
establishment. He was very favorably impressed by the admirable
arrangement of the workshops and the completeness of their outfit, as
well as by the perfection of the organization and administration of
the business. In the following year he again visited Soho, and this
time met Boulton, who had been absent at the previous visit. The two
great mechanics were mutually gratified by the meeting, and each at
once acquired for the other the greatest respect and esteem. They
discussed Watt's plans, and Boulton then definitely decided not to
continue his own experiments, although he had actually commenced the
construction of a pumping-engine. With Dr. Small, who was also at
Soho, Watt discussed the possibility of applying his engine to the
propulsion of carriages, and to other purposes. On his return home,
Watt continued his desultory labors on his engines, as already
described; and the final completion of the arrangement with Boulton,
which immediately followed the failure of Dr. Roebuck, took place some
time later.

Before Watt could leave Scotland to join his partner at Soho, it was
necessary that he should finish the work which he had in hand,
including the surveys of the Caledonian canal, and other smaller
works, which he had had in progress some months. He reached Birmingham
in the spring of 1774, and was at once domiciled at Soho, where he set
at work upon the partly-made engines which had been sent from Scotland
some time previously. They had laid, unused and exposed to the
weather, at Kinneil three years, and were not in as good order as
might have been desired. The _block-tin_ steam-cylinder was probably
in good condition, but the iron parts were, as Watt said, "perishing,"
while he had been engaged in his civil engineering work. At leisure
moments, during this period, Watt had not entirely neglected his plans
for the utilization of steam. He had given much thought, and had
expended some time, in experiments upon the plan of using it in a
rotary or "wheel" engine. He did not succeed in contriving any plan
which seemed to promise success.

It was in November, 1774, that Watt finally announced to his old
partner, Dr. Roebuck, the successful trial of the Kinneil engine. He
did not write with the usual enthusiasm and extravagance of the
inventor, for his frequent disappointments and prolonged suspense had
very thoroughly extinguished his vivacity. He simply wrote: "The
fire-engine I have invented is now going, and answers much better than
any other that has yet been made; and I expect that the invention will
be very beneficial to me."

The change of the "atmospheric engine" of Newcomen into the modern
steam-engine was now completed in its essential details. The first
engine which was erected at Kinneil, near Boroughstoness, had a
steam-cylinder 18 inches in diameter. It is seen in the accompanying
sketch.

[Illustration: FIG. 26.--Watt's Engine, 1774.]

In Fig. 26, the steam passes from the boiler through the pipe _d_ and
the valve _c_ to the cylinder-casing or steam-jacket, _Y Y_, and above
the piston, _b_, which it follows in its descent in the cylinder,
_a_, the valve _f_ being at this time open, to allow the exhaust into
the condenser, _h_.

The piston now being at the lower end of the cylinder, and the
pump-rods at the opposite end of the beam, _y_, being thus raised and
the pumps filled with water, the valves _c_ and _f_ close, while _e_
opens, allowing the steam which remains above the piston to flow
beneath it, until, the pressures becoming equal above and below, the
weight of the pump-rods overbalancing that of the piston, the latter
is rapidly drawn to the top of the cylinder, while the steam is
displaced above, passing to the under-side of the piston.

The valve _e_ is next closed, and _c_ and _f_ are again opened; the
down-stroke is repeated. The water and air entering the condenser are
removed at each stroke by the air-pump, _i_, which communicates with
the condenser by the passage _s_. The pump _q_ supplies
condensing-water, and the pump _A_ takes away a part of the water of
condensation, which is thrown by the air-pump into the "hot-well,"
_k_, and from it the feed-pump supplies the boiler. The valves are
moved by valve-gear very similar to Beighton's and Smeaton's, by the
pins, _m m_, in the "plug-frame" or "tappet-rod," _n n_.

The engine is mounted upon a substantial foundation, _B B_. _F_ is an
opening out of which, before starting the engine, the air is driven
from the cylinder and condenser.

The inventions covered by the patent of 1769 were described as
follows:

"My method of lessening the consumption of steam, and consequently
fuel, in fire-engines, consists in the following principles:

"1st. That the vessel in which the powers of steam are to be employed
to work the engine--which is called 'the cylinder' in common
fire-engines, and which I call 'the steam-vessel'--must, during the
whole time that the engine is at work, be kept as hot as the steam
which enters it; first, by inclosing it in a case of wood, or any
other materials that transmit heat slowly; secondly, by surrounding
it with steam or other heated bodies; and thirdly, by suffering
neither water nor other substances colder than the steam to enter or
touch it during that time.

"2dly. In engines that are to be worked, wholly or partially, by
condensation of steam, the steam is to be condensed in vessels
distinct from the steam-vessel or cylinder, though occasionally
communicating with them. These vessels I call condensers; and while
the engines are working, these _condensers_ ought at least to be kept
as cold as the air in the neighborhood of the engines, by application
of water or other cold bodies.

"3dly. Whatever air or other elastic vapor is not condensed by the
cold of the condenser, and may impede the working of the engine, is to
be drawn out of the steam-vessels or condensers by means of pumps,
wrought by the engines themselves, or otherwise.

"4thly. I intend in many cases to employ the expansive force of steam
to press on the pistons, or whatever may be used instead of them, in
the same manner as the pressure of the atmosphere is now employed in
common fire-engines. In cases where cold water cannot be had in
plenty, the engines may be wrought by this force of steam only, by
discharging the steam into the open air after it has done its office.

"5thly. Where motions round an axis are required, I make the
steam-vessels in form of hollow rings or circular channels, with
proper inlets and outlets for the steam, mounted on horizontal axles
like the wheels of a water-mill. Within them are placed a number of
valves that suffer any body to go round the channel in one direction
only. In these steam-vessels are placed weights, so fitted to them as
to fill up a part or portion of their channels, yet rendered capable
of moving freely in them by the means hereinafter mentioned or
specified. When the steam is admitted in these engines between these
weights and the valves, it acts equally on both, so as to raise the
weight on one side of the wheel, and, by the reaction of the valves
successively, to give a circular motion to the wheel, the valves
opening in the direction in which the weights are pressed, but not in
the contrary. As the vessel moves round, it is supplied with steam
from the boiler, and that which has performed its office may either be
discharged by means of condensers, or into the open air.

"6thly. I intend in some cases to apply a degree of cold not capable
of reducing the steam to water, but of contracting it considerably, so
that the engines shall be worked by the alternate expansion and
contraction of the steam.

"Lastly, instead of using water to render the piston or other parts of
the engine air or steam-tight, I employ oils, wax, resinous bodies,
fat of animals, quicksilver, and other metals, in their fluid state."

In the construction and erection of his engines, Watt still had great
difficulty in finding skillful workmen to make the parts with
accuracy, to fit them with care, and to erect them properly when once
finished. And the fact that both Newcomen and Watt met with such
serious trouble, indicates that, even had the engine been designed
earlier, it is quite unlikely that the world would have seen the
steam-engine a success until this time, when mechanics were just
acquiring the skill requisite for its construction. But, on the other
hand, it is not at all improbable that, had the mechanics of an
earlier period been as skillful and as well-educated in the manual
niceties of their business, the steam-engine might have been much
earlier brought into use.

In the time of the Marquis of Worcester it would have probably been
found impossible to obtain workmen to construct the steam-engine of
Watt, had it been then invented. Indeed, Watt, upon one occasion,
congratulated himself that one of his steam-cylinders only lacked
_three-eighths_ of an inch of being truly cylindrical.

The history of the steam-engine is from this time a history of the
work of the firm of Boulton & Watt. Newcomen engines continued to be
built for years after Watt went to Soho, and by many builders. A host
of inventors still worked on the most attractive of all mechanical
combinations, seeking to effect further improvements. Some inventions
were made by contemporaries of Watt, as will be seen hereafter, which
were important as being the germs of later growths; but these were
nearly all too far in advance of the time, and nearly every successful
and important invention which marked the history of steam-power for
many years originated in the fertile brain of James Watt.

The defects of the Newcomen engine were so serious, that it was no
sooner known that Boulton of Soho had become interested in a new
machine for raising water by steam-power, than inquiries came to him
from all sides, from mine-owners who were on the point of being
drowned out, and from proprietors whose profits were absorbed by the
expense of pumping, and who were glad to pay the £5 per horse-power
per year finally settled upon as royalty. The London municipal
water-works authorities were also ready to negotiate for
pumping-engines for raising water to supply the metropolis. The firm
was therefore at once driven to make preparations for a large
business.

The first and most important matter, however, was to secure an
extension of the patent, which was soon to expire. If not renewed, the
15 years of study and toil, of poverty and anxiety, through which Watt
had toiled, would prove profitless to the inventor, and the fruits of
his genius would have become the unearned property of others. Watt
saw, at one time, little hope of securing the necessary act of
Parliament, and was greatly tempted to accept a position tendered him
by the Russian Government, upon the solicitation of his old friend,
Dr. Robison, then a Professor of Mathematics at the Naval School at
Cronstadt. The salary was £1,000--a princely income for a man in
Watt's circumstances, and a peculiar temptation to the needy
mechanic.

Watt, however, went to London, and, with the help of his own and of
Boulton's influential friends, succeeded in getting his bill through.
His patent was extended 24 years, and Boulton & Watt set about the
work of introducing their engines with the industry and enterprise
which characterized their every act.

In the new firm, Boulton took charge of the general business, and Watt
superintended the design, construction, and erection of their engines.
Boulton's business capacity, with Watt's wonderful mechanical
ability--Boulton's physical health, and his vigor and courage,
offsetting Watt's feeble health and depression of spirits--and, more
than all, Boulton's pecuniary resources, both in his own purse and in
those of his friends, enabled the firm to conquer all difficulties,
whether in finance, in litigation, or in engineering.

It was only after the successful erection and operation of several
engines that Boulton and Watt became legally partners. The understood
terms were explicitly stated by Watt to include an assignment to
Boulton of two-thirds the patent-right; Boulton paying all expenses,
advancing stock in trade at an appraised valuation, on which it was to
draw interest; Watt making all drawings and designs, and drawing
one-third net profits.

As soon as Watt was relieved of the uncertainties regarding his
business connections, he married a second wife, who, as Arago says, by
"her various talent, soundness of judgment, and strength of
character," made a worthy companion to the large-hearted and
large-brained engineer. Thenceforward his cares were only such as
every business-man expects to be compelled to sustain, and the next
ten years were the most prolific in inventions of any period in Watt's
life.

From 1775 to 1785 the partners acquired five patents, covering a large
number of valuable improvements upon the steam-engine, and several
independent inventions. The first of these patents covered the now
familiar and universally-used copying-press for letters, and a
machine for drying cloth by passing it between copper rollers filled
with steam of sufficiently high temperature to rapidly evaporate the
moisture. This patent was issued February 14, 1780.

[Illustration: FIG. 27.--Watt's Engine, 1781.]

In the following year, October 25, 1781, Watt patented five devices by
which he obtained the rotary motion of the engine-shaft without the
use of a crank. One of these was the arrangement shown in Fig. 27, and
known as the "sun-and-planet" wheels. The crank-shaft carries a
gear-wheel, which is engaged by another securely fixed upon the end of
the connecting-rod. As the latter is compelled to revolve about the
axis of the shaft by a tie which confines the connecting-rod end at a
fixed distance from the shaft, the shaft-gear is compelled to revolve,
and the shaft with it. Any desired velocity-ratio was secured by
giving the two gears the necessary relative diameters. A fly-wheel was
used to regulate the motion of the shaft.[39] Boulton & Watt used the
sun-and-planet device on many engines, but finally adopted the crank,
when the expiration of the patent held by Matthew Wasborough, and
which had earlier date than Watt's patent of 1781, permitted them.
Watt had proposed the use of a crank, it is said, as early as 1771,
but Wasborough anticipated him in securing the patent. Watt had made a
model of an engine with a crank and fly-wheel, and he has stated that
one of his workmen, who had seen the model, described it to
Wasborough, thus enabling the latter to deprive Watt of his own
property. The proceeding excited great indignation on the part of
Watt; but no legal action was taken by Boulton & Watt, as the
overthrow of the patent was thought likely to do them injury by
permitting its use by more active competitors and more ingenious men.

  [39] For the privilege of using the fly-wheel to regulate the motion
  of the engine, Boulton & Watt paid a royalty to Matthew Wasborough,
  who had patented it, and who held also the patent for its
  combination with a crank, as invented by Pickard and Steed.

The next patent issued to Watt was an exceedingly important one, and
of especial interest in a history of the development of the economical
application of steam. This patent included:

1. The expansion of steam, and six methods of applying the principle
and of equalizing the expansive power.

2. The double-acting steam-engine, in which the steam acts on each
side of the piston alternately, the opposite side being in
communication with the condenser.

3. The double or coupled steam-engine--two engines capable of working
together, or independently, as may be desired.

4. The use of a rack on the piston-rod, working into a sector on the
end of the beam, thus securing a perfect rectilinear motion of the
rod.

5. A rotary engine, or "steam-wheel."

The efficiency to be secured by the expansion of steam had long been
known to Watt, and he had conceived the idea of economizing some of
that power, the waste of which was so plainly indicated by the violent
rushing of the exhaust-steam into the condenser, as early as 1769.
This was described in a letter to Dr. Small, of Birmingham, in May of
that year. When experimenting at Kinneil, he had tried to determine
the real value of the principle by trial on his small engine.

Boulton had also recognized the importance of this improved method of
working steam, and their earlier Soho engines were, as Watt said, made
with cylinders "double the size wanted, and cut off the steam at
half-stroke." But, though "this was a great saving of steam, so long
as the valves remained as at first," the builders were so constantly
annoyed by alterations of the valves by proprietors and their
engineers, that they finally gave up that method of working, hoping
ultimately to be able to resume it when workmen of greater
intelligence and reliability could be found. The patent was issued
July 17, 1782.

Watt specified a cut-off at one-quarter stroke as usually best.

Watt's explanation of the method of economizing by expansive working,
as given to Dr. Small,[40] is worthy of reproduction. He says: "I
mentioned to you a method of still doubling the effect of steam, and
that tolerably easy, by using the power of steam rushing into a
vacuum, at present lost. This would do a little more than double the
effect, but it would too much enlarge the vessels to use it all. It is
peculiarly applicable to wheel-engines, and may supply the want of a
condenser where force of steam is only used; for, open one of the
steam-valves and admit steam, until one-fourth of the distance between
it and the next valve is filled with steam, shut the valve, and the
steam will continue to expand and to pass round the wheel with a
diminishing power, ending in one-fourth its first exertion. The sum of
this series you will find greater than one-half, though only
one-fourth steam was used. The power will indeed be unequal, but this
can be remedied by a fly, or in several other ways."

  [40] "Lives of Boulton and Watt," Smiles.

It will be noticed that Watt suggests, above, the now well-known
non-condensing engine. He had already, as has been seen, described it
in his patent of 1769, as also the rotary engine.

Watt illustrates and explains his idea very neatly, by a sketch
similar to that here given (Fig. 28).

Steam, entering the cylinder at _a_, is admitted until one-fourth the
stroke has been made, when the steam-valve is closed, and the
remainder of the stroke is performed without further addition of
steam. The variation of steam-pressure is approximately inversely
proportional to the variation of its volume. Thus, at half-stroke, the
pressure becomes one-half that at which the steam was supplied to the
cylinder. At the end of the stroke it has fallen to one-fourth the
initial pressure. The pressure is always nearly equal to the product
of the initial pressure and volume divided by the volume at the given
instant. In symbols,

         _PV_
  _P´_ = ----.
         _V´_

It is true that the condensation of steam doing work changes this law
in a marked manner; but the condensation and reëvaporation of steam,
due to the transfer of heat to and from the metal of the cylinder,
tends to compensate the first variation by a reverse change of
pressure with change of volume.

[Illustration: FIG. 28.--Expansion of Steam.]

The sketch shows this progressive variation of pressure as expansion
proceeds. It is seen that the work done per unit of volume of steam as
taken from the boiler is much greater than when working without
expansion. The product of the mean pressure by the volume of the
cylinder is less, but the quotient obtained by dividing this quantity
by the volume or weight of steam taken from the boiler, is much
greater with than without expansion. For the case assumed and
illustrated, the work done during expansion is one and two-fifths
times that done previous to cutting off the steam, and the work done
per pound of steam is 2.4 times that done without expansion.

Were there no losses to be met with and to be exaggerated by the use
of steam expansively, the gain would become very great with moderate
expansion, amounting to twice the work done when "following" full
stroke, when the steam is cut off at one-seventh. The estimated gain
is, however, never realized. Losses by friction, by conduction and
radiation of heat, and by condensation and reëvaporation in the
cylinder--of which losses the latter are most serious--after passing a
point which is variable, and which is determined by the special
conditions in each case, augment with greater rapidity than the gain
by expansion.

In actual practice, it is rarely found, except where special
precautions are taken to reduce these losses, that economy follows
expansion to a greater number of volumes than about one-half the
square root of the steam-pressure; i. e., about twice for 15 or 20
pounds pressure, three times for about 30 pounds, and four and five
times for 60 or 65 and for 100 to 125 pounds respectively. Watt very
soon learned this general principle; but neither he, nor even many
modern engineers, seem to have learned that too great expansion often
gives greatly-reduced economy.

The inequality of pressure due to expansion, to which he refers, was a
source of much perplexity to Watt, as he was for a long time convinced
that he must find some method of "equalizing" the consequent irregular
effort of the steam upon the piston. The several methods of
"equalizing the expansive power" which are referred to in the patent
were attempts to secure this result. By one method, he shifted the
centre as the beam vibrated, thus changing the lengths of the arms of
that great lever, to compensate the change of moment consequent upon
the change of pressure. He finally concluded that a fly-wheel, as
first proposed by Fitzgerald, who advised its use on Papin's engine,
would be the best device on engines driving a crank, and trusted to
the inertia of a balance-weight in his pumping-engines, or to the
weight of the pump-rods, and permitted the piston to take its own
speed so far as it was not thus controlled.

The double-acting engine was a modification of the single-acting
engine, and was very soon determined upon after the successful working
of the latter had become assured.

Watt had covered in the top of his single-acting engine, to prevent
cooling the interior of the cylinder by contact with the comparatively
cold atmosphere. When this had been done, there was but a single step
required to convert the machine into the double-acting engine. This
alteration, by which the steam was permitted to act upon the upper and
the lower sides of the piston alternately, had been proposed by Watt
as early as 1767, and a drawing of the engine was laid before a
committee of the House of Commons in 1774-'75. By this simple change
Watt doubled the power of his engine. Although invented much earlier,
the plan was not patented until he was, as he states, driven to take
out the patent by the "plagiarists and pirates" who were always ready
to profit by his ingenuity. This form of engine is now almost
universally used. The single-acting pumping-engine remains in use in
Cornwall, and in a few other localities, and now and then an engine is
built for other purposes, in which steam acts only on one side of the
piston; but these are rare exceptions to the general rule.

The subject of his next invention was not less interesting. The
double-cylinder or "compound" engine has now, after the lapse of
nearly a century, become an important and usual type of engine. It is
impossible to determine precisely to whom to award the credit of its
first conception. Dr. Falk, in 1779, had proposed a double-acting
engine, in which there were two single-acting cylinders, acting in
opposite directions and alternately on opposite sides of a wheel, with
which a rack on the piston-rod of each geared.

Watt claimed that Hornblower, the patentee of the "compound engine,"
was an infringer upon his patents; and, holding the patent on the
separate condenser, he was able to prevent the engine of his
competitor taking such form as to be successfully introduced. The
Hornblower engine was soon given up.

Watt stated that this form of engine had been invented by him as early
as 1767, and that he had explained its peculiarities to Smeaton and
others several years before Hornblower attempted to use it. He wrote
to Boulton: "It is no less than our double-cylinder engine, worked
upon our principle of expansion." He never made use of the plan,
however; and the principal object sought, apparently, in patenting
this, as well as many other devices, was to secure himself against
competition.

The rack and sector patented at this time was soon superseded by the
parallel-motion; and the last claim, the "steam-wheel" or rotary
engine, although one was built of considerable size, was not
introduced.

After the patent of 1782 had been secured, Watt turned his attention,
when not too hard-pressed by business, to other schemes, and to
experimenting with still other modifications and applications of his
engine. He had, as early as 1777, proposed to make a steam-hammer for
Wilkinson's forge; but he was too closely engaged with more important
matters to take hold of the project with much earnestness until late
in the year 1782, when, after some preliminary trials, he reported,
December 13th: "We have tried our little tilting-forge hammer at Soho
with success. The following are some of the particulars: Cylinder, 15
inches in diameter; 4 feet stroke; strokes per minute, 20. The
hammer-head, 120 pounds weight, rises 8 inches, and strikes 240 blows
per minute. The machine goes quite regularly, and can be managed as
easily as a water-mill. It requires a very small quantity of
steam--not above half the contents of the cylinder per stroke. The
power employed is not more than one-fourth of what would be required
to raise the quantity of water which would enable a water-wheel to
work the same hammer with the same velocity."

He immediately set about making a much heavier hammer, and on April
26, 1783, he wrote that he had done "a thing never done
before"--making his hammer strike 300 blows a minute. This hammer
weighed 7-1/2 hundredweight, and had a drop of 2 feet. The
steam-cylinder had a diameter of 42 inches and 6 feet stroke of
piston, and was calculated to have sufficient power to drive four
hammers weighing 7 hundredweight each. The engine made 20 strokes per
minute, the hammer giving 90 blows in the same time.

This new application of steam-power proving successful, Watt next
began to develop a series of minor inventions, which were finally
secured by his patent of April 27, 1784, together with the steam
tilt-hammer, and a steam-carriage, or "locomotive engine."

The contrivance previously used for guiding the head of the
piston-rod--the sectors and chains, or rack--had never given
satisfaction. The rudeness of design of the contrivance was only
equalled by its insecurity. Watt therefore contrived a number of
methods of accomplishing the purpose, the most beautiful and
widely-known of which is the "parallel-motion," although it has now
been generally superseded by one of the other devices patented at the
same time--the cross-head and guides. As originally proposed, a rod
was attached to the head of the piston-rod, standing vertically when
the latter was at quarter-stroke. The upper end of this rod was
pivoted to the end of the beam, and the lower end to the extremity of
a horizontal rod having a length equal to one-half the length of the
beam. The other end of the horizontal rod was coupled to the frame of
the engine. As the piston rose and fell, the upper and lower ends of
the vertical rod were swayed in opposite directions, and to an equal
extent, by the beam and the lower horizontal rod, the middle point at
which the piston-rod was attached preserving its position in the
vertical line. This form was objectionable, as the whole effort of the
engine was transmitted through the parallel-motion rods. Another form
is shown in the sketch given of the double-acting engine in Fig. 31,
which was free from this defect. The head of the piston-rod, _g_, was
guided by rods connecting it with the frame at _c_, and forming a
"parallelogram," _g d e b_, with the beam. Many varieties of
"parallel-motion" have been devised since Watt's invention was
attached to his engines at Soho. They usually are more or less
imperfect, guiding the piston-rod in a line only approximately
straight.

The cross-head and guides are now generally used, very much as
described by Watt in this patent as his "second principle." This
device will be seen in the engravings given hereafter of more modern
engines. The head of the piston-rod is fitted into a transverse bar,
or cross-head, which carries properly-shaped pieces at its
extremities, to which are bolted "gibs," so made as to fit upon guides
secured to the engine-frame. These guides are adjusted to precise
parallelism with the centre line of the cylinder. The cross-head,
sliding in or on these guides, moves in a perfectly straight line,
and, compelling the piston-rod to move with it, the latter is even
more perfectly guided than by a parallel-motion. This arrangement,
where properly proportioned, is not necessarily subject to great
friction, and is much more easily adjusted and kept in line than the
parallel-motion when wear occurs or maladjustment takes place.

By the same patent, Watt secured the now common "puppet-valve" with
beveled seat, and the application of the steam-engine to driving
rolling-mills and hammers for forges, and to "wheel-carriages for
removing persons or goods, or other matters, from place to place." For
the latter purpose he proposes to use boilers "of wood, or of thin
metal, strongly secured by hoops or otherwise," and containing
"internal fire-boxes." He proposed to use a condenser cooled by
currents of air.

It would require too much space to follow Watt in all his schemes for
the improvement and for the application of the steam-engine. A few of
the more important and more ingenious only can be described. Many of
the contracts of Boulton & Watt gave them, as compensation for their
engines, a fraction--usually one-third--of the value of the fuel saved
by the use of the Watt engine in place of the engine of Newcomen, the
amount due being paid annually or semiannually, with an option of
redemption on the part of the purchaser at ten years' purchase. This
form of agreement compelled a careful determination, often, of the
work done and fuel consumed by both the engine taken out and that put
in its place. It was impossible to rely upon any determination by
personal observation of the number of strokes made by the engine. Watt
therefore made a "counter," like that now familiar to every one as
used on gas-meters. It consists of a train of wheels moving pointers
on several dials, the first dial showing tens, the second hundreds,
the third thousands, etc., strokes or revolutions. Motion was
communicated to the train by means of a pendulum, the whole being
mounted on the beam of the engine, where every vibration produced a
swing of the pendulum. Eight dials were sometimes used, the counter
being set and locked, and only opened once a year, when the time
arrived for determining the work done during the preceding
twelve-month.

The application of his engine to purposes for which careful adjustment
of speed was requisite, or where the load was subject to considerable
variation, led to the use of a controlling-valve in the steam-pipe,
called the "throttle-valve," which was adjustable by hand, and
permitted the supply of steam to the engine to be adjusted at any
instant and altered to any desired extent. It is now given many forms,
but it still is most usually made just as originally designed by Watt.
It consists of a circular disk, which just closes up the steam-pipe
when set directly across it, or of an elliptical disk, which closes
the pipe when standing at an angle of somewhat less than 90° with the
line of the pipe. This disk is carried on a spindle extending through
the pipe at one side, and carrying on its outer end an arm by means
of which it may be turned into any position. When placed with its face
in line with the pipe, it offers very little resistance to the flow of
steam to the engine. When set in the other position, it shuts off
steam entirely and stops the engine. It is placed in such position at
any time, that the speed of the engine is just that required at the
time. In the engraving of the double-acting engine with fly-wheel
(Fig. 31), it is shown at _T_, as controlled by the governor.

[Illustration: FIG. 29.--The Governor.]

The governor, or "fly-ball governor," as it is often distinctively
called, was another of Watt's minor but very essential inventions. Two
heavy iron or brass balls, _B B´_, were suspended from pins, _C C´_,
in a little cross-piece carried on the head of a vertical spindle, _A
A´_, driven by the engine. The speed of the engine varying, that of
the spindle changed correspondingly, and the faster the balls were
swung the farther they separated. When the engine's speed decreased,
the period of revolution of the balls was increased, and they fell
back toward the spindle. Whenever the velocity of the engine was
uniform, the balls preserved their distance from the spindle and
remained at the same height, their altitude being determined by the
relation existing between the force of gravity and centrifugal force
in the temporary position of equilibrium. The distance from the point
of suspension down to the level of the balls is always equal to 9.78
inches divided by the square of the number of revolutions per
second--i. e., _h_ = 9.78 (1/_N_^2) = 0.248 (1/_N_^2) meters.

The arms carrying the balls, or the balls themselves, are pinned to
rods, _M M´_, which are connected to a piece, _N N´_, sliding loosely
on the spindle. A score, _T_, cut in this piece engages a lever, _V_,
and, as the balls rise and fall, a rod, _W_, is moved, closing and
opening the throttle-valve, and thus adjusting the supply of steam in
such a way as to preserve a nearly fixed speed of engine. The
connection with the throttle-valve and with the cut-off valve-gear is
seen not only in the engraving of the double-acting Watt engine, but
also in those of the Greene and the Corliss engines. This contrivance
had previously been used in regulating water-wheels and windmills.
Watt's invention consisted in its application to the regulation of the
steam-engine.

Still another useful invention of Watt's was his "mercury
steam-gauge"--a barometer in which the height of the mercury was
determined by the pressure of the steam instead of that of the
atmosphere. This simple instrument consisted merely of a bent tube
containing a portion of mercury. One leg, _B D_, of this U-tube was
connected with the steam-pipe, or with the boiler by a small
steam-pipe; the other end, _C_, was open to the atmosphere. The
pressure of the steam on the mercury in _B D_ caused it to rise in the
other "leg" to a height exactly proportioned to the pressure, and
causing very nearly two inches difference of level to the pound, or
one inch to the pound actual rise in the outer leg. The rude sketch
from Farey, here given (Fig. 30), indicates sufficiently well the form
of this gauge. It is still considered by engineers the most reliable
of all forms of steam-gauge. Unfortunately, it is not conveniently
applicable at high pressure. The scale, _A_, is marked with numbers
indicating the pressure, which numbers are indicated by the head of a
rod floating up with the mercury.

A similar gauge was used to determine the degree of perfection of
vacuum attained in the condenser, the mercury falling in the outer leg
as the vacuum became more complete. A perfect vacuum would cause a
depression of level in that leg to 30 inches below the level of the
mercury in the leg connected with the condenser. In a more usual form,
it consisted of a simple glass tube having its lower end immersed in a
cistern of mercury, as in the ordinary barometer, the top of the tube
being connected with a pipe leading to the condenser. With a perfect
vacuum in the condenser, the mercury would rise in the tube very
nearly 30 inches. Ordinarily, the vacuum is not nearly perfect, and, a
back pressure remaining in the condenser of one or two pounds per
square inch, the atmospheric pressure remaining unbalanced is only
sufficient to raise the mercury 26 or 28 inches above the level of the
liquid metal in the cistern.

[Illustration: FIG. 30. Mercury Steam Gauge. Glass Water Gauge.]

To determine the height of water in his boiler, Watt added to the
gauge-cocks already long in use the "glass water-gauge," which is
still seen in nearly every well-arranged boiler. This was a glass
tube, _a a´_ (Fig. 30), mounted on a standard attached to the front of
the boiler, and at such a height that its middle point was very little
below the proposed water-level. It was connected by a small pipe, _r_,
at the top to the steam-space, and another little pipe, _r´_, led into
the boiler from its lower end below the water-line. As the water rose
and fell within the boiler, its level changed correspondingly in the
glass. This little instrument is especially liked, because the
position of the water is at all times shown to the eye of the
attendant. If carefully protected against sudden changes of
temperature, it answers perfectly well with even very high pressures.

The engines built by Boulton & Watt were finally fitted with the crank
and fly-wheel for application to the driving of mills and machinery.
The accompanying engraving (Fig. 31) shows the engine as thus made,
combining all of the essential improvements designed by its inventor.

In the engraving, _C_ is the steam-cylinder, _P_ the piston, connected
to the beam by the link, _g_, and guided by the parallel-motion, _g d
c_. At the opposite end of the beam a connecting-rod, _O_, connects
with the crank and fly-wheel shaft. _R_ is the rod of the air-pump, by
means of which the condenser is kept from being flooded by the water
used for condensation, which water-supply is regulated by an
"injection-handle," _E_. A pump-rod, _N_, leads down from the beam to
the cold-water pump, by which water is raised from the well or other
source to supply the needed injection-water. The air-pump rod also
serves as a "plug-rod," to work the valves, the pins at _m_ and _R_
striking the lever, _m_, at either end of the stroke. When the piston
reaches the top of the cylinder, the lever, _m_, is raised, opening
the steam-valve, _B_, at the top, and the exhaust-valve, _E_, at the
bottom, and at the same time closing the exhaust at the top and the
steam at the bottom. When the entrance of steam at the top and the
removal of steam-pressure below the piston has driven the piston to
the bottom, the pin, _R_, strikes the lever, _m_, opening the steam
and closing the exhaust valve at the bottom, and similarly reversing
the position of the valves at the top. The position of the valves is
changed in this manner with every reversal of the motion of the piston
as the crank "turns over the centre."

[Illustration: FIG. 31.--Boulton & Watt's Double-Acting Engine, 1784.]

The earliest engines of the double-acting kind, and of any
considerable size, which were built to turn a shaft, were those which
were set up in the Albion Mills, near Blackfriars' Bridge, London, in
1786, and destroyed when the mills burned down in 1791. There were a
pair of these engines (shown in Fig. 27), of 50 horse-power each, and
geared to drive 20 pairs of stones, making fine flour and meal.
Previous to the erection of this mill the power in all such
establishments had been derived from windmills and water-wheels. This
mill was erected by Boulton & Watt, and capitalists working with
them, not only to secure the profit anticipated from locating a
flour-mill in the city of London, but also with a view to exhibiting
the capacity of the new double-acting "rotating" engine. The plan was
proposed in 1783, and work was commenced in 1784; but the mill was not
set in operation until the spring of 1786. The capacity of the mill
was, in ordinary work, 16,000 bushels of wheat ground into fine flour
per week. On one occasion, the mill turned out 3,000 bushels in 24
hours. In the construction of the machinery of the mill, many
improvements upon the then standard practice were introduced,
including cast-iron gearing with carefully-formed teeth and iron
framing. It was here that John Rennie commenced his work, after
passing through his apprenticeship in Scotland, sending his chief
assistant, Ewart, to superintend the erection of the milling
machinery. The mill was a success as a piece of engineering, but a
serious loss was incurred by the capitalists engaged in the
enterprise, as it was set on fire a few years afterward and entirely
destroyed. Boulton and Watt were the principal losers, the former
losing £6,000, and the latter £3,000.

The valve-gear of this engine, a view of which is given in Fig. 27,
was quite similar to that used on the Watt pumping-engine. The
accompanying illustration (Fig. 32) represents this valve-motion as
attached to the Albion Mills engine.

[Illustration: FIG. 32.--Valve-Gear of the Albion Mills Engine.]

The steam-pipe, _a b d d e_, leads the steam from the boiler to the
chambers, _b_ and _e_. The exhaust-pipe, _g g_, leads from _h_ and _i_
to the condenser. In the sketch, the upper steam and the lower exhaust
valves, _b_ and _f_, are opened, and the steam-valve, _e_, and
exhaust-valve, _c_, are closed, the piston being near the upper end of
the cylinder and descending. _l_ represents the plug-frame, which
carries tappets, 2 and 3, which engage the lever, _s_, at either end
of its throw, and turn the shaft, _u_, thus opening and closing _c_
and _e_ simultaneously by means of the connecting-links, 13 and 14. A
similar pair of tappets on the opposite side of the plug-rod move the
valves, _b_ and _f_, by means of the rods, 10 and 11, the arm, _r_,
when struck by those tappets, turning the shaft, _t_, and thus moving
the arms to which those rods are attached. Counterbalance-weights,
carried on the ends of the arms, 4 and 15, retain the valves on their
seats when closed by the action of the tappets. When the piston nearly
reaches the lower end of the cylinder, the tappet, 1, engages the arm,
_r_, closing the steam-valve, _b_, and the next instant shutting the
exhaust-valve, _f_. At the same time, the tappet, 3, by moving the
arm, _s_, downward, opens the steam-valve, _e_, and the exhaust-valve,
_c_. Steam now no longer issues from the steam-pipe into the space,
_c_, and thence into the engine-cylinder (not shown in the sketch);
but it now enters the engine through the valve, _e_, forcing the
piston upwards. The exhaust is simultaneously made to occur at the
upper end, the rejected steam passing from the engine into the space,
_c_, and thence through _c_ and the pipe, _g_, into the condenser.

This kind of valve-gear was subsequently greatly improved by Murdoch,
Watt's ingenious and efficient foreman, but it is now entirely
superseded on engines of this class by the eccentric, and the various
forms of valve-gear driven by it.

[Illustration: FIG. 33.--Watt's Half-Trunk Engine, 1784.]

The "trunk-engine" was still another of the almost innumerable
inventions of Watt. A half-trunk engine is described in his patent of
1784, as shown in the accompanying sketch (Fig. 33), in which _A_ is
the cylinder, _B_ the piston, and _C_ its rod, encased in the
half-trunk, _D_. The plug-rod, _G_, moves the single pair of valves by
striking the catches, _E_ and _F_, as was usual with Watt's earlier
engines.

Watt's steam-hammer was patented at the same time. It is seen in Fig.
34, in which _A_ is the steam-cylinder and _B_ its rod, the engine
being evidently of the form just described. It works a beam, _C C_,
which in turn, by the rod, _M_, works the hammer-helve, _L J_, and the
hammer, _L_. The beam, _F G_, is a spring, and the block, _N_, the
anvil.

[Illustration: FIG. 34.--The Watt Hammer, 1784.]

Watt found it impossible to determine the duty of his engines at all
times by measurement of the work itself, and endeavored to find a way
of ascertaining the power produced, by ascertaining the pressure of
steam within the cylinder. This pressure was so variable, and subject
to such rapid as well as extreme fluctuations, that he found it
impossible to make use of the steam-gauge constructed for use on the
boiler. He was thus driven to invent a special instrument for this
work, which he called the "steam-engine indicator." This consisted of
a little steam-cylinder containing a nicely-fitting piston, which
moved without noticeable friction through a range which was limited by
the compression of a helical spring, by means of which the piston was
secured to the top of its cylinder. The distance through which the
piston rose was proportional to the pressure exerted upon it, and a
pointer attached to its rod traversed a scale upon which the pressure
per square inch could be read. The lower end of the instrument being
connected with the steam-cylinder of the engine by a small pipe
fitted with a cock, the opening of the latter permitted steam from the
engine-cylinder to fill the indicator-cylinder, and the pressure of
steam was always the same in both cylinders. The indicator-pointer
therefore traversed the pressure-scale, always exhibiting the pressure
existing at the instant in the cylinder of the engine. When the engine
was at rest and steam off, the indicator-piston stood at the same
level as when detached from the engine, and the pointer stood at 0 on
the scale. When steam entered, the piston rose and fell with the
fluctuations of pressure; and when the exhaust-valve opened,
discharging the steam and producing a vacuum in the steam-cylinder,
the pointer of the indicator dropped below 0, showing the degree of
exhaustion. Mr. Southern, one of Watt's assistants, fitted the
instrument with a sliding board, moved horizontally backward and
forward by a cord or link-work connecting directly or indirectly with
the engine-beam, and thus giving it a motion coincident with that of
the piston. This board carried a piece of paper, upon which a pencil
attached to the indicator piston-rod drew a curve. The vertical height
of any point on this curve above the base-line measured the pressure
in the cylinder at the moment when it was made, and the horizontal
distance of the point from either end of the diagram determined the
position, at the same moment, of the engine-piston. The curve thus
inscribed, called the "indicator card," or indicator diagram,
exhibiting every minute change in the pressure of steam in the engine,
not only enabled the mean pressure and the power of the engine to be
determined by its measurement, but, to the eye of the expert engineer,
it was a perfectly legible statement of the position of the valves of
the engine, and revealed almost every defect in the action of the
engine which could not readily be detected by external examination. It
has justly been called the "engineers' stethoscope," opening the
otherwise inaccessible parts of the steam-engine to the inspection of
the engineer even more satisfactorily than the stethoscope of the
physician gives him a knowledge of the condition and working of organs
contained within the human body. This indispensable and now familiar
engineers' instrument has since been modified and greatly improved in
detail.

The Watt engine had, by the construction of the improvements described
in the patents of 1782-'85, been given its distinctive form, and the
great inventor subsequently did little more than improve it by
altering the forms and proportions of its details. As thus practically
completed, it embodied nearly all the essential features of the modern
engine; and, as we have seen, the marked features of our latest
practice--the use of the double cylinder for expansion, the cut-off
valve-gear, and surface-condensation--had all been proposed, and to a
limited extent introduced. The growth of the steam-engine has here
ceased to be rapid, and the changes which followed the completion of
the work of James Watt have been minor improvements, and rarely, if
ever, real developments.

Watt's mind lost none of its activity, however, for many years. He
devised and patented a "smoke-consuming furnace," in which he led the
gases produced on the introduction of fresh fuel over the already
incandescent coal, and thus burned them completely. He used two fires,
which were coaled alternately. Even when busiest, also, he found time
to pursue more purely scientific studies. With Boulton, he induced a
number of well-known scientific men living near Birmingham to join in
the formation of a "Lunar Society," to meet monthly at the houses of
its members, "at the full of the moon." The time was thus fixed in
order that those members who came from a distance should be able to
drive home, after the meetings, by moonlight. Many such societies were
then in existence in England; but that at Birmingham was one of the
largest and most distinguished of them all. Boulton, Watt, Drs. Small,
Darwin, and Priestley, were the leaders, and among their occasional
visitors were Herschel, Smeaton, and Banks. Watt called these meetings
"Philosophers' meetings." It was during the period of most active
discussion at the "philosophers' meetings" that Cavendish and
Priestley were experimenting with mixtures of oxygen and hydrogen, to
determine the nature of their combustion. Watt took much interest in
the subject, and, when informed by Priestley that he and Cavendish had
both noticed a deposit of moisture invariably succeeding the explosion
of the mixed gases, when contained in a cold vessel, and that the
weight of this water was approximately equal to the weight of the
mixed gases, he at once came to the conclusion that the union of
hydrogen with oxygen produced water, the latter being a chemical
compound, of which the former were constituents. He communicated this
reasoning, and the conclusions to which it had led him, to Boulton, in
a letter written in December, 1782, and addressed a letter some time
afterward to Priestley, which was to have been read before the Royal
Society in April, 1783. The letter was not read, however, until a year
later, and, three months after, a paper by Cavendish, making the same
announcement, had been laid before the Society. Watt stated that both
Cavendish and Lavoisier, to whom also the discovery is ascribed,
received the idea from him.

The action of chlorine in bleaching organic coloring-matters, by (as
since shown) decomposing them and combining with their hydrogen, was
made known to Watt by M. Berthollet, the distinguished French chemist,
and the former immediately introduced its use into Great Britain, by
inducing his father-in-law, Mr. Macgregor, to make a trial of it.

The copartnership of Boulton & Watt terminated by limitation, and with
the expiration of the patents under which they had been working, in
the first year of the present century; and both partners, now old and
feeble, withdrew from active business, leaving their sons to renew the
agreement and to carry on the business under the same firm-style.

Boulton, however, still interested himself in some branches of
manufacture, especially in his mint, where he had coined many years
and for several nations.

Watt retired, a little later, to Heathfield, where he passed the
remainder of his life in peaceful enjoyment of the society of his
friends, in studies of all current matters of interest in science, as
well as in engineering. One by one his old friends died--Black in
1799, Priestley, an exile to America, in 1803, and Robison a little
later. Boulton died, at the age of eighty-one, August 17, 1809, and
even the loss of this nearest and dearest of his friends outside the
family was a less severe blow than that of his son Gregory, who died
in 1804.

Yet the great engineer and inventor was not depressed by the
loneliness which was gradually coming upon him. He wrote: "I know that
all men must die, and I submit to the decrees of Nature, I hope, with
due reverence to the Disposer of events;" and neglected no opportunity
to secure amusement or instruction, and kept body and mind constantly
occupied. He still attended the weekly meetings of the club, meeting
Rennie and Telford, and other distinguished men of his own and the
succeeding generation. He lost nothing of his fondness for invention,
and spent many months in devising a machine for copying statuary,
which he had not perfected to his own satisfaction at the time of his
death, ten years later. This machine was a kind of pentagraph, which
could be worked in any plane, and in which the marking-pencil gave
place to a cutting-tool. The tracing-point followed the surface of the
pattern, while the cutting-point, following its motion precisely,
formed a fac-simile in the material operated upon.

In the year 1800 he invented the water-main which was laid down by the
Glasgow Water-Works Company across the Clyde. The joints were
spherical and articulated, like those of the lobster's tail.

His workshop, of which a sketch is hereafter given, as drawn by the
artist Skelton, was in the garret of his house, and was well supplied
with tools and all kinds of laboratory material. His lathe and his
copying-machine were placed before the window, and his writing-desk in
the corner. Here he spent the greater part of his leisure time, often
even taking his meals in the little shop, rather than go to the table
for them. Even when very old, he occasionally made a journey to London
or Glasgow, calling on his old friends and studying the latest
engineering devices and inspecting public works, and was everywhere
welcomed by young and old as the greatest living engineer, or as the
kind and wise friend of earlier days.

He died August 19, 1819, in the eighty-third year of his age, and was
buried in Handsworth Church. The sculptor Chantrey was employed to
place a fitting monument above his grave, and the nation erected a
statue of the great man in Westminster Abbey.

This sketch of the greatest of all the inventors of the steam-engine
has been given no greater length than its subject justifies. Whether
we consider Watt as the inventor of the standard steam-engine of the
nineteenth century, as the scientific investigator of the physical
principles upon which the invention is based, or as the builder and
introducer of the most powerful known instrument by which the "great
sources of power in Nature are converted, adapted, and applied for the
use and convenience of man," he is fully entitled to preëminence. His
character as a man was no less admirable than as an engineer.

Smiles, Watt's most conscientious and indefatigable biographer,
writes:[41]

  [41] "Life of Watt," p. 512.

[Illustration: FIG. 35.--James Watt's Workshop. (From Smiles's "Lives
of Boulton and Watt.")]

"Some months since, we visited the little garret at Heathfield in
which Watt pursued the investigations of his later years. The room had
been carefully locked up since his death, and had only once been swept
out. Everything lay very much as he left it. The piece of iron which
he was last employed in turning, lay on the lathe. The ashes of the
last fire were in the grate; the last bit of coal was in the scuttle.
The Dutch oven was in its place over the stove, and the frying-pan in
which he cooked his meals was hanging on its accustomed nail. Many
objects lay about or in the drawers, indicating the pursuits which had
been interrupted by death--busts, medallions, and figures, waiting to
be copied by the copying-machine--many medallion-moulds, a store of
plaster-of-Paris, and a box of plaster casts from London, the contents
of which do not seem to have been disturbed. Here are Watt's ladles
for melting lead, his foot-rule, his glue-pot, his hammer. Reflecting
mirrors, an extemporized camera with the lenses mounted on pasteboard,
and many camera-glasses laid about, indicate interrupted experiments
in optics. There are quadrant-glasses, compasses, scales, weights, and
sundry boxes of mathematical instruments, once doubtless highly
prized. In one place a model of the governor, in another of the
parallel-motion, and in a little box, fitted with wooden cylinders
mounted with paper and covered with figures, is what we suppose to be
a model of his calculating-machine. On the shelves are minerals and
chemicals in pots and jars, on which the dust of nearly half a century
has settled. The moist substances have long since dried up; the putty
has been turned to stone, and the paste to dust. On one shelf we come
upon a dish in which lies a withered bunch of grapes. On the floor, in
a corner, near to where Watt sat and worked, is a hair-trunk--a
touching memorial of a long-past love and a long-dead sorrow. It
contains all poor Gregory's school-books, his first attempts at
writing, his boy's drawings of battles, his first school-exercises
down to his college-themes, his delectuses, his grammars, his
dictionaries, and his class-books--brought into this retired room,
where the father's eye could rest upon them. Near at hand is the
sculpture-machine, on which he continued working to the last. Its
wooden frame is worm-eaten, and dropping into dust, like the hands
that made it. But though the great workman is gone to rest, with all
his griefs and cares, and his handiwork is fast crumbling to decay,
the spirit of his work, the thought which he put into his inventions,
still survives, and will probably continue to influence the destinies
of his race for all time to come."

The visitor to Westminster Abbey will find neither monarch, nor
warrior, nor statesman, nor poet, honored with a nobler epitaph than
that which is inscribed on the pedestal of Chantrey's monument to
Watt:

                      NOT TO PERPETUATE A NAME,
          WHICH MUST ENDURE WHILE THE PEACEFUL ARTS FLOURISH,
                              BUT TO SHOW
    THAT MANKIND HAVE LEARNT TO HONOR THOSE WHO BEST DESERVE THEIR
                              GRATITUDE,
                              THE KING,
   HIS MINISTERS, AND MANY OF THE NOBLES AND COMMONERS OF THE REALM,
                        RAISED THIS MONUMENT TO
                              JAMES WATT,
            WHO, DIRECTING THE FORCE OF AN ORIGINAL GENIUS,
               EARLY EXERCISED IN PHILOSOPHIC RESEARCH,
                         TO THE IMPROVEMENT OF
                           THE STEAM-ENGINE,
  ENLARGED THE RESOURCES OF HIS COUNTRY, INCREASED THE POWER OF MAN,
                     AND ROSE TO AN EMINENT PLACE
     AMONG THE MOST ILLUSTRIOUS FOLLOWERS OF SCIENCE AND THE REAL
                       BENEFACTORS OF THE WORLD.

                      BORN AT GREENOCK, MDCCXXXVI.

            DIED AT HEATHFIELD, IN STAFFORDSHIRE, MDCCCXIX.

[Illustration: Tomb of James Watt.]


SECTION II.--THE CONTEMPORARIES OF JAMES WATT.

In the chronology of the steam-engine, the contemporaries of Watt have
been so completely overshadowed by the greater and more successful
inventor, as to have been almost forgotten by the biographer and by
the student of history. Yet, among the engineers and engine-builders,
as well as among the inventors of his day, Watt found many
enterprising rivals and keen competitors. Some of these men, had they
not been so completely fettered by Watt's patents, would have probably
done work which would have entitled them to far higher honor than has
been accorded them.

WILLIAM MURDOCH was one of the men to whom Watt, no less than the
world, was greatly indebted. For many years he was the assistant,
friend, and coadjutor of Watt; and it is to his ingenuity that we are
to give credit for not only many independent inventions, but also for
the suggestions and improvements which were often indispensable to the
formation and perfection of some of Watt's own inventions.

Murdoch was employed by Boulton & Watt in 1776, and was made
superintendent of construction in the engine department, and given
general charge of the erection of engines. He was sent into Cornwall,
and spent in that district much of the time during which he served the
firm, erecting pumping-engines, the construction of which for so many
years constituted a large part of the business of the Soho
establishment. He was looked upon by both Boulton and Watt as a
sincere friend, as well as a loyal adherent, and from 1810 to 1830 was
given a partner's share of the income of the firm, and a salary of
£1,000. He retired from business at the last of the two dates named,
and, dying in 1839, was buried near the two partners in Handsworth
Church.

Murdoch made a model, in 1784, of the locomotive patented by Watt in
that year. He devised the arrangement of "sun-and-planet wheels,"
adopted for a time in all of Watt's "rotative" engines, and invented
the oscillating steam-engine (Fig. 36) in 1785, using the "D-slide
valves," _G_, moved by the gear, _E_, which was driven by an eccentric
on the shaft, without regard to the oscillation of the cylinder, _A_.
He was the inventor of a rotary engine and of many minor machines for
special purposes, and of many machine-tools used at Soho in building
engines and machines. He seems, like Watt, to have had special
fondness for the worm-gear, and introduced it wherever it could
properly take the place of ordinary gearing. Some of the machines
designed by Watt and Murdoch, who always worked well together, were
found still in use and in good working condition by the author when
visiting the works at Soho in 1873. The old mint in which, from 1797
to 1805, Boulton had coined 4,000 tons of copper, had then been pulled
down, and a new mint had been erected in 1860. Many old machines
still remained about the establishment as souvenirs of the three great
mechanics.

[Illustration: FIG. 36.--Murdoch's Oscillating Engine, 1785.]

Outside of Soho, Murdoch also found ample employment for his inventive
talent. In 1792, while at Redruth, his residence before finally
returning to Soho, he was led to speculate upon the possibility of
utilizing the illuminating qualities of coal-gas, and, convinced of
its practicability, he laid the subject before the Royal Society in
1808, and was awarded the Rumford gold medal. He had, ten years
earlier, lighted a part of the Soho works with coal-gas, and in 1803
Watt authorized him to extend his pipes throughout all the buildings.
Several manufacturers promptly introduced the new light, and its use
extended very rapidly.

Still another of Murdoch's favorite schemes was the transmission of
power by the use of compressed air. He drove the pattern-shop engine
at Soho by means of air from the blowing-engine in the foundery, and
erected a pneumatic lift to elevate castings from the foundery-floor
to the canal-bank. He made a steam-gun, introduced the heating of
buildings by the circulation of hot water, and invented the method of
transmitting packages through tubes by the impulse of compressed air,
as now practised by the "pneumatic dispatch" companies. He died at the
age of eighty-five years.

Among the most active and formidable of Watt's business rivals was
JONATHAN HORNBLOWER, the patentee of the "compound" or double-cylinder
engine. A sketch of this engine, as patented by Hornblower in 1781, is
here given (Fig. 37). It was first described by the inventor in the
"Encyclopædia Britannica." It consists, as is seen by reference to the
engraving, of two steam-cylinders, _A_ and _B_--_A_ being the low and
_B_ the high pressure cylinder--the steam leaving the latter being
exhausted into the former, and, after doing its work there, passing
into the condenser, as already described. The piston-rods, _C_ and
_D_, are both connected to the same part of the beam by chains, as in
the other early engines. These rods pass through stuffing-boxes in the
cylinder-heads, which are fitted up like those seen on the Watt
engine. Steam is led to the engine through the pipe, _G Y_, and cocks,
_a_, _b_, _c_, and _d_, are adjustable, as required, to lead steam
into and from the cylinders, and are moved by the plug-rod, _W_, which
actuates handles not shown. _K_ is the exhaust-pipe leading to the
condenser. _V_ is the engine feed-pump rod, and _X_ the great rod
carrying the pump-buckets at the bottom of the shaft.

The cocks _c_ and _a_ being open and _b_ and _d_ shut, the steam
passes from the boiler into the upper part of the steam-cylinder, _B_;
and the communication between the lower part of _B_ and the top of _A_
is also open. Before starting, steam being shut off from the engine,
the great weight of the pump-rod, _X_, causes that end of the beam to
preponderate, the pistons standing, as shown, at the top of their
respective steam-cylinders.

The engine being freed from all air by opening all the valves and
permitting the steam to drive it through the engine and out of the
condenser through the "snifting-valve," _O_, the valves _b_ and _d_
are closed, and the cock in the exhaust-pipe opened.

[Illustration: FIG. 37.--Hornblower's Compound Engine, 1781.]

The steam beneath the piston of the large cylinder is immediately
condensed, and the pressure on the upper side of that piston causes it
to descend, carrying that end of the beam with it, and raising the
opposite end with the pump-rods and their attachments. At the same
time, the steam from the lower end of the small high-pressure cylinder
being let into the upper end of the larger cylinder, the completion of
the stroke finds a cylinder full of steam transferred from the one to
the other with corresponding increase of volume and decrease of
pressure. While expanding and diminishing in pressure as it passes
from the smaller into the larger cylinder, this charge of steam
gradually resists less and less the pressure of the steam from the
boiler on the upper side of the piston of the small cylinder, _B_, and
the net result is the movement of the engine by pressures exerted on
the upper sides of both pistons and against pressures of less
intensity on the under sides of both. The pressures in the lower part
of the small cylinder, in the upper part of the large cylinder, and in
the communicating passage, are evidently all equal at any given time.

When the pistons have reached the bottoms of their respective
cylinders, the valves at the top of the small cylinder, _B_, and at
the bottom of the large cylinder, _A_, are closed, and the valves _c_
and _d_ are opened. Steam from the boiler now enters beneath the
piston of the small cylinder; the steam in the larger cylinder is
exhausted into the condenser, and the steam already in the small
cylinder passes over into the large cylinder, following up the piston
as it rises.

Thus, at each stroke a small cylinder full of steam is taken from the
boiler, and the same weight, occupying the volume of the larger
cylinder, is exhausted into the condenser from the latter cylinder.

Referring to the method of operation of this engine, Prof. Robison
demonstrated that the effect produced was the same as in Watt's
single-cylinder engine--a fact which is comprehended in the law
enunciated many years later by Rankine, that, "so far as the
theoretical action of the steam on the piston is concerned, it is
immaterial whether the expansion takes place in one cylinder, or in
two or more cylinders." It was found, in practice, that the Hornblower
engine was no more economical than the Watt engine; and that erected
at the Tin Croft Mine, Cornwall, in 1792, did even less work with the
same fuel than the Watt engines.

Hornblower was prosecuted by Boulton & Watt for infringement. The suit
was decided against him, and he was imprisoned in default of payment
of the royalty, and fine demanded. He died a disappointed and
impoverished man. The plan thus unsuccessfully introduced by
Hornblower was subsequently modified and adopted by others among the
contemporaries of Watt; and, with higher steam and the use of the Watt
condenser, the "compound" gradually became a standard type of
steam-engine.

Arthur Woolf, in 1804, re-introduced the Hornblower or Falck engine,
with its two steam-cylinders, using steam of higher tension. His first
engine was built for a brewery in London, and a considerable number
were subsequently made. Woolf expanded his steam from six to nine
times, and the pumping-engines built from his plans were said to have
raised about 40,000,000 pounds one foot high per bushel of coals, when
the Watt engine was raising but little more than 30,000,000. In one
case, a duty of 57,000,000 was claimed.

The most successful of those competitors of Watt who endeavored to
devise a peculiar form of pumping-engine, which should have the
efficiency of that of Boulton & Watt, and the necessary advantage in
first cost, were WILLIAM BULL and RICHARD TREVITHICK.[42] The
accompanying illustration shows the design, which was then known as
the "Bull Cornish Engine."

  [42] For an exceedingly interesting and very faithful account of
  their work, _see_ "Life of Richard Trevithick," by F. Trevithick,
  London, 1872.

[Illustration: FIG. 88.--Bull's Pumping-Engine, 1798.]

The steam-cylinder, _a_, is carried on wooden beams, _b_, extending
across the engine-house directly over the pump-well. The piston-rod,
_c_, is secured to the pump-rods, _d d_, the cylinder being inverted,
and the pumps, _e_, in the shaft, _f_, are thus operated without the
intervention of the beam invariably seen in Watt's engines. A
connecting-rod, _g_, attached to the pump-rod and to the end of a
balance-beam, _h_, operates the latter, and is counterbalanced by a
weight, _i_. The rod, _j_, serves both as a plug-rod and as an
air-pump connecting-rod. A snifting-valve, _k_, opens when the engine
is blown through, and relieves the condenser and air-pump, _l_, of all
air. The rod, _m_, operates a solid air-pump piston, the valves of the
pump being placed on either side at the base, instead of in the
pump-bucket, as in Watt's engines. The condensing-water cistern was a
wooden tank, _n_. A jet "pipe-condenser," _o_, was used instead of a
jet condenser of the form adopted by other makers, and was supplied
with water through the cock, _p_. The plug-rod, _q_, as it rises and
falls with the pump-rods and balance-beam, operates the
"gear-handles," _r r_, and opens and closes the valves, _s s_, at the
required points in the stroke. The attendant works these valves by
hand, in starting, from the floor, _t_. The operation of the engine is
similar to that of a Watt engine. It is still in use, with a few
modifications and improvements, and is a very economical and durable
machine. It has not been as generally adopted, however, as it would
probably have been had not the legal proscription of Watt's patents so
seriously interfered with its introduction. Its simplicity and
lightness are decided advantages, and its designers are entitled to
great credit for their boldness and ingenuity, as displayed in their
application of the minor devices which distinguish the engine. The
design is probably to be credited to Bull originally; but Trevithick
built some of these engines, and is supposed to have greatly improved
them while working with Edward Bull, the son of the inventor, William
Bull. One of these engines was erected by them at the Herland Mine,
Cornwall, in 1798, which had a steam-cylinder 60 inches in diameter,
and was built on the plan just described.

Another of the contemporaries of James Watt was a clergyman, EDWARD
CARTWRIGHT, the distinguished inventor of the power-loom, and of the
first machine ever used in combing wool, who revived Watt's plan of
surface-condensation in a somewhat modified form. Watt had made a
"pipe-condenser," similar in plan to those now often used, but
had simply immersed it in a tank of water, instead of in a
constantly-flowing stream. Cartwright proposed to use two concentric
cylinders or spheres, between which the steam entered when exhausted
from the cylinder of the engine, and was condensed by contact with
the metal surfaces. Cold water within the smaller and surrounding the
exterior vessel kept the metal cold, and absorbed the heat discharged
by the condensing vapor.

Cartwright's engine is best described in the _Philosophical Magazine_
of June, 1798, from which the accompanying sketch is copied.

[Illustration: FIG. 39.--Cartwright's Engine, 1798.]

The object of the inventor is stated to have been to remedy the
defects of the Watt engine--imperfect vacuum, friction, and
complication.

In the figure, the steam-cylinder takes steam through the pipe, _B_.
The piston, _R_, has a rod extending downward to the smaller
pump-piston, _G_, and upward to the cross-head, which, in turn, drives
the cranks above, by means of connecting-rods. The shafts thus turned
are connected by a pair of gears, _M L_, of which one drives a pinion
on the shaft of the fly-wheel. _D_ is the exhaust-pipe leading to the
condenser, _F_; and the pump, _G_, removes the air and water of
condensation, forcing it into the hot-well, _H_, whence it is returned
to the boiler through the pipe, _I_. A float in _H_ adjusts an
air-valve, so as to keep a supply of air in the chamber, to serve as a
cushion and to make an air-chamber of the reservoir, and permits the
excess to escape. The large tank contains the water supplied for
condensing the steam.

The piston, _R_, is made of metal, and is packed with two sets of cut
metal rings, forced out against the sides of the cylinder by steel
springs, the rings being cut at three points in the circumference, and
kept in place by the springs. The arrangement of the two cranks, with
their shafts and gears, is intended to supersede Watt's plan for
securing a perfectly rectilinear movement of the head of the
piston-rod, without friction.

In the accounts given of this engine, great stress is laid upon the
supposed important advantage here offered, by the introduction of the
surface-condenser, of permitting the employment of a working-fluid
other than steam--as, for example, alcohol, which is too valuable to
be lost. It was proposed to use the engine in connection with a still,
and thus to effect great economy by making the fuel do double duty.
The only part of the plan which proved both novel and valuable was the
metallic packing and piston, which has not yet been superseded. The
engine itself never came into use.

At this point, the history of the steam-engine becomes the story of
its applications in several different directions, the most important
of which are the raising of water--which had hitherto been its only
application--the locomotive-engine, the driving of mill-machinery, and
steam-navigation.

Here we take leave of James Watt and of his contemporaries, of the
former of whom a French author[43] says: "The part which he played in
the mechanical applications of the power of steam can only be compared
to that of Newton in astronomy and of Shakespeare in poetry." Since
the time of Watt, improvements have been made principally in matters
of mere detail, and in the extension of the range of application of
the steam-engine.

  [43] Bataille. "Traité des Machines à Vapeur," Paris, 1847.

[Illustration]




CHAPTER IV.

_THE MODERN STEAM-ENGINE._

  "Those projects which abridge distance have done most for the
  civilization and happiness of our species."--MACAULAY.

THE SECOND PERIOD OF APPLICATION--1800-'40.

STEAM-LOCOMOTION ON RAILROADS.


[Illustration: FIG. 40.--The First Railroad-Car, 1825.]

Introductory.--The commencement of the nineteenth century found the
modern steam-engine fully developed in all its principal features, and
fairly at work in many departments of industry. The genius of
Worcester, and Morland, and Savery, and Desaguliers, had, in the first
period of the application of the power of steam to useful work,
effected a beginning which, looked upon from a point of view which
exhibits its importance as the first step toward the wonderful results
to-day familiar to every one, appears in its true light, and entitles
those great men to even greater honor than has been accorded them. The
results actually accomplished, however, were absolutely insignificant
in comparison with those which marked the period of development just
described. Yet even the work of Watt and of his contemporaries was but
a mere prelude to the marvellous advances made in the succeeding
period, to which we are now come, and, in extent and importance, was
insignificant in comparison with that accomplished by their successors
in the development of all mechanical industries by the application of
the steam-engine to the movement of every kind of machine.

The first of the two periods of application saw the steam-engine
adapted simply to the elevation of water and the drainage of mines;
during the second period it was adapted to every variety of useful
work, and introduced wherever the muscular strength of men and
animals, or the power of wind and of falling water, which had
previously been the only motors, had found application. A history of
the development of industries by the introduction of steam-power
during this period, would be no less extended and hardly less
interesting than that of the steam-engine itself.

The way had been fairly opened by Boulton and Watt; and the year 1800
saw a crowd of engineers and manufacturers entering upon it, eager to
reap the harvest of distinction and of pecuniary returns which seemed
so promising to all. The last year of the eighteenth century was also
the last of the twenty-five years of partnership of Boulton & Watt,
and, with it, the patents under which that firm had held the great
monopoly of steam-engine building expired. The right to manufacture
the modern steam-engine was common to all. Watt had, at the
commencement of the new century, retired from active business-life.
Boulton remained in business; but he was not the inventor of the new
engine, and could not retain, by the exercise of all his remaining
power, the privileges previously held by legal authorization.

The young Boulton and the young Watt were not the Boulton & Watt of
earlier years; and, had they possessed all of the business talent and
all of the inventive genius of their fathers, they could not have
retained control of a business which was now growing far more rapidly
than the facilities for manufacturing could be extended in any single
establishment. All over the country, and even on the Continent of
Europe, and in America, thousands of mechanics, and many men of
mechanical tastes in other professions, were familiar with the
principles of the new machine, and were speculating upon its value for
all the purposes to which it has since been applied; and a multitude
of enthusiastic mechanics, and a larger multitude of visionary and
ignorant schemers, were experimenting with every imaginable device, in
the vain hope of attaining perpetual motion, and other hardly less
absurd results, by its modification and improvement. Steam-engine
building establishments sprang up wherever a mechanic had succeeded in
erecting a workshop and in acquiring a local reputation as a worker in
metal, and many of Watt's workmen went out from Soho to take charge of
the work done in these shops. Nearly all of the great establishments
which are to-day most noted for their extent and for the importance
and magnitude of the work done in them, not only in Great Britain, but
in Europe and the United States, came into existence during this
second period of the application of the steam-engine as a prime mover.

The new establishments usually grew out of older shops of a less
pretentious character, and were managed by men who had been trained by
Watt, or who had had a still more awakening experience with those who
vainly strove to make up, by their ingenuity and by great excellence
of workmanship, the advantages possessed at Soho in a legal monopoly
and greater experience in the business.

It was exceedingly difficult to find expert and conscientious workmen,
and machine-tools had not become as thoroughly perfected as had the
steam-engine itself. These difficulties were gradually overcome,
however, and thenceforward the growth of the business was increasingly
rapid.

Every important form of engine had now been invented. Watt had
perfected, with the aid of Murdoch, both the pumping-engine and the
rotative steam-engine for application to mills. He had invented the
trunk engine, and Murdoch had devised the oscillating engine and the
ordinary slide-valve, and had made a model locomotive-engine, while
Hornblower had introduced the compound engine. The application of
steam to navigation had been often proposed, and had sometimes been
attempted, with sufficient success to indicate to the intelligent
observer an ultimate triumph. It only remained to extend the use of
steam as a motor into all known departments of industry, and to effect
such improvements in details as experience should prove desirable.

The engines of Hero, of Porta, and of Branca were, it will be
remembered, non-condensing; but the first plan of a non-condensing
engine that could be made of any really practical use is given in the
"Theatrum Machinarum" of Leupold, published in 1720. This sketch is
copied in Fig. 41. It is stated by Leupold that this plan was
suggested by Papin. It consists of two single-acting cylinders, _r s_,
receiving steam alternately from the same steam-pipe through a
"four-way cock," _x_, and exhausting into the atmosphere. Steam is
furnished by the boiler, _a_, and the pistons, _c d_, are alternately
raised and depressed, depressing and raising the pump-rods, _k l_, to
which they are attached by the beams, _h g_, vibrating on the centres,
_i i_. The water from the pumps, _o p_, is forced up the stand-pipe,
_q_, and discharged at its top. The alternate action of the
steam-pistons is secured by turning the "four-way cock," _x_, first
into the position shown, and then, at the completion of the stroke,
into the reverse position, by which change the steam from the boiler
is then led into the cylinder, _s_, and the steam in _r_ is discharged
into the atmosphere.[44]

  [44] _Vide_ "Theatrum Machinarum," vol. iii., Tab. 30.

[Illustration: FIG. 41.--Leupold's Engine, 1720.]

Leupold states that he is indebted to Papin for the suggestion of the
peculiar valve here used. He also proposed to use a Savery engine
without condensation in raising water. We have no evidence that this
engine was ever built.

The first rude scheme for applying steam to locomotion on land was
probably that of Isaac Newton, who, in 1680, proposed the machine
shown in the accompanying figure (42), which will be recognized as
representing the scientific toy which is found in nearly every
collection of illustrative philosophical apparatus. As described in
the "Explanation of the Newtonian Philosophy," it consists of a
spherical boiler, _B_, mounted on a carriage. Steam issuing from the
pipe, _C_, seen pointing directly backward, by its reaction upon the
carriage, drives the latter ahead. The driver, sitting at _A_,
controls the steam by the handle, _E_, and cock, _F_. The fire is seen
at _D_.

[Illustration: FIG. 42.--Newton's Steam-Carriage, 1680.]

When, at the end of the eighteenth century, the steam-engine had been
so far perfected that the possibility of its successful application to
locomotion had become fully and very generally recognized, the problem
of adapting it to locomotion on land was attacked by many inventors.

Dr. Robison had, as far back as in 1759, proposed it to James Watt
during one of their conferences, at a time when the latter was even
more ignorant than the former of the principles which were involved in
the construction of the steam-engine, and this suggestion may have had
some influence in determining Watt to pursue his research; thus
setting in operation that train of thoughtful investigation and
experiment which finally earned for him his splendid fame.

In 1765, that singular genius, Dr. Erasmus Darwin, whose celebrity was
acquired by speculations in poetry and philosophy as well as in
medicine, urged Matthew Boulton--subsequently Watt's partner, and just
then corresponding with our own Franklin in relation to the use of
steam-power--to construct a steam-carriage, or "fiery chariot," as he
poetically styled it, and of which he sketched a set of plans. A young
man named Edgeworth became interested in the scheme, and, in 1768,
published a paper which had secured for him a gold medal from the
Society of Arts. In this paper he proposed railroads on which the
carriages were to be drawn by horses, _or by ropes from steam-winding
engines_.

[Illustration: FIG. 43.--Read's Steam-Carriage, 1790.]

Nathan Read, of whom an account will be given hereafter, when
describing his attempt to introduce steam-navigation, planned, and in
1790 obtained a patent for, a steam-carriage, of which the sketch seen
in Fig. 43 is copied from the rough drawing accompanying his
application. In the figure, _A A A A_ are the wheels; _B B_, pinions
on the hubs of the rear wheels, which are driven by a ratchet
arrangement on the racks, _G G_, connected with the piston-rods; _C o_
is the boiler; _D D_, the steam-pipes carrying steam to the
steam-cylinder, _E E_; _F F_ are the engine-frames; _H_ is the
"tongue" or "pole" of the carriage, and is turned by a horizontal
steering-wheel, with which it is connected by the ropes or chains, _I
K_, _I K_; _W W_ are the cocks, which serve to shut off steam from the
engine when necessary, and to determine the amount of steam to be
admitted. The pipes _a a_ are exhaust-pipes, which the inventor
proposed to turn so that they should point backward, in order to
secure the advantage of the effort of reaction of the expelled steam.
(!)

Read made a model steam-carriage, which he exhibited when endeavoring
to secure assistance in furtherance of his schemes, but seems to have
given more attention to steam-navigation, and nothing was ever
accomplished by him in this direction.

These were merely promising schemes, however. The first actual
experiment was made, as is supposed, by a French army-officer,
NICHOLAS JOSEPH CUGNOT, who in 1769 built a steam-carriage, which was
set at work in presence of the French Minister of War, the Duke de
Choiseul. The funds required by him were furnished by the Compte de
Saxe. Encouraged by the partial success of the first locomotive, he,
in 1770, constructed a second (Fig. 44), which is still preserved in
the Conservatoire des Arts et Métiers, Paris.

[Illustration: FIG. 44.--Cugnot's Steam-Carriage, 1770.]

This machine, when recently examined by the author, was still in an
excellent state of preservation. The carriage and its machinery are
substantially built and well-finished, and exceedingly creditable
pieces of work in every respect. It surprises the engineer to find
such evidence of the high character of the work of the mechanic
Brezin a century ago. The steam-cylinders were 13 inches in diameter,
and the engine was evidently of considerable power. This locomotive
was intended for the transportation of artillery. It consists of two
beams of heavy timber extending from end to end, supported by two
strong wheels behind, and one still heavier but smaller wheel in
front. The latter carries on its rim blocks which cut into the soil as
the wheel turns, and thus give greater holding power. The single wheel
is turned by two single-acting engines, one on each side, supplied
with steam by a boiler (seen in the sketch) suspended in front of the
machine. The connection between the engines and the wheels was
effected by means of pawls, as first proposed by Papin, which could be
reversed when it was desired to drive the machine backward. A seat is
mounted on the carriage-body for the driver, who steers the machine by
a train of gearing, which turns the whole frame, carrying the
machinery 15 or 20 degrees either way. This locomotive was found to
have been built on a tolerably satisfactory general plan; but the
boiler was too small, and the steering apparatus was incapable of
handling the carriage with promptness.

The death of one of Cugnot's patrons, and the exile of the other, put
an end to Cugnot's experiments.

Cugnot was a mechanic by choice, and exhibited great talent. He was a
native of Vaud, in Lorraine, where he was born in 1725. He served both
in the French and the German armies. While under the Maréchal de Saxe,
he constructed his first steam locomotive-engine, which only
disappointed him, as he stated, in consequence of the inefficiency of
the feed-pumps. The second was that built under the authority of the
Minister Choiseul, and cost 20,000 livres. Cugnot received from the
French Government a pension of 600 livres. He died in 1804, at the age
of seventy-nine years.

Watt, at a very early period, proposed to apply his own engine to
locomotion, and contemplated using either a non-condensing engine or
an air-surface condenser. He actually included the locomotive-engine
in his patent of 1784; and his assistant, Murdoch, in the same year,
made a working-model locomotive (Fig. 45), which was capable of
running at a rapid rate. This model, now deposited in the Patent
Museum at South Kensington, London, had a flue-boiler, and its
steam-cylinder was three-fourths of an inch in diameter, and the
stroke of piston 2 inches. The driving-wheels were 9-1/2 inches
diameter.

[Illustration: FIG. 45.--Murdoch's Model, 1784.]

Nothing was, however, done on a larger scale by either Watt or
Murdoch, who both found more than enough to claim their attention in
the construction and introduction of other engines. Murdoch's model is
said to have run from 6 to 8 miles an hour, its little driving-wheels
making from 200 to 275 revolutions per minute. As is seen in the
sketch, this model was fitted with the same form of engine, known as
the "grasshopper-engine," which was used in the United States by
Oliver Evans.

"To Oliver Evans," says Dr. Ernest Alban, the distinguished German
engineer, "was it reserved to show the true value of a long-known
principle, and to establish thereon a new and more simple method of
applying the power of steam--a method that will remain an eternal
memorial to its introducer." Dr. Alban here refers to the earliest
permanently successful introduction of the non-condensing
high-pressure steam-engine.

OLIVER EVANS, one of the most ingenious mechanics that America has
ever produced, was born at Newport, Del., in 1755 or 1756, the son of
people in very humble circumstances.

[Illustration: Oliver Evans.]

He was, in his youth, apprenticed to a wheelwright, and soon exhibited
great mechanical talent and a strong desire to acquire knowledge. His
attention was, at an early period, drawn to the possible application
of the power of steam to useful purposes by the boyish pranks of one
of his comrades, who, placing a small quantity of water in a
gun-barrel, and ramming down a tight wad, put the barrel in the fire
of a blacksmith's forge. The loud report which accompanied the
expulsion of the wad was an evidence to young Evans of great and (as
he supposed) previously undiscovered power.

Subsequently meeting with a description of a Newcomen engine, he at
once noticed that the elastic force of confined steam was not there
utilized. He then designed the non-condensing engine, in which the
power was derived exclusively from the tension of high-pressure steam,
and proposed its application to the propulsion of carriages.

About the year 1780, Evans joined his brothers, who were millers by
occupation, and at once employed his inventive talent in improving the
details of mill-work, and with such success as to reduce the cost of
attendance one-half, and also to increase the fineness of the flour
made. He proved himself a very expert millwright.

In 1786 he applied to the Pennsylvania Legislature for a patent for
the application of the steam-engine to driving mills, and to the
steam-carriage, but was refused it. In 1800 or 1801, Evans, after
consultation with Professor Robert Patterson, of the University of
Pennsylvania, and getting his approval of the plans, commenced the
construction of a steam-carriage to be driven by a non-condensing
engine. He soon concluded, however, that it would be a better scheme,
pecuniarily, to adapt his engine, which was novel in form and of small
first cost, to driving mills; and he accordingly changed his plans,
and built an engine of 6 inches diameter of cylinder and 18 inches
stroke of piston, which he applied with perfect success to driving a
plaster-mill.

This engine, which he called the "Columbian Engine," was of a peculiar
form, as seen in Fig. 46. The beam is supported at one end by a
rocking column; at the other, it is attached directly to the
piston-rod, while the crank lies beneath the beam, the connecting-rod,
1, being attached to the latter at the extreme end. The head of the
piston-rod is compelled to rise and fall in a vertical line by the
"Evans's parallelogram"--a kind of parallel-motion very similar to
one of those designed by Watt. In the sketch (Fig. 46), 2 is the
crank, 3 the valve-motion, 4 the steam-pipe from the boiler, _E_, 5 6
7 the feed-pipe leading from the pump, _F_. _A_ is the boiler. The
flame from the fire on the grate, _H_, passes under the boiler between
brick walls, and back through a central flue to the chimney, _I_.

[Illustration: FIG. 46.--Evans's Non-condensing Engine, 1800.]

Subsequently, Evans continued to extend the applications of his engine
and to perfect its details; and, others following in his track, the
non-condensing engine is to-day fulfilling the predictions which he
made 70 years ago, when he said:

"I have no doubt that my engines will propel boats against the current
of the Mississippi, and wagons on turnpike roads, with great
profit...."

"The time will come when people will travel in stages moved by
steam-engines from one city to another, almost as fast as birds can
fly, 15 or 20 miles an hour.... A carriage will start from Washington
in the morning, the passengers will breakfast at Baltimore, dine at
Philadelphia, and sup in New York the same day....

"Engines will drive boats 10 or 12 miles an hour, and there will be
hundreds of steamers running on the Mississippi, as predicted years
ago."[45]

  [45] Evans's prediction is less remarkable than that of Darwin,
  elsewhere quoted.

In 1804, Evans applied one of his engines in the transportation of a
large flat-bottomed craft, built on an order of the Board of Health of
Philadelphia, for use in clearing some of the docks along the
water-front of the city. Mounting it on wheels, he placed in it one of
his 5-horse power engines, and named the odd machine (Fig. 47)
"Oruktor Amphibolis." This steam dredging-machine, weighing about
40,000 pounds, was then propelled very slowly from the works, up
Market Street, around to the Water-Works, and then launched into the
Schuylkill. The engine was then applied to the paddle-wheel at the
stern, and drove the craft down the river to its confluence with the
Delaware.

[Illustration: FIG. 47.--Evans's "Oruktor Amphibolis," 1804.]

In September of the same year, Evans laid before the Lancaster
Turnpike Company a statement of the estimated expenses and profits of
steam-transportation on the common road, assuming the size of the
carriage used to be sufficient for transporting 100 barrels of flour
50 miles in 24 hours, and placed in competition with 10 wagons drawn
by 5 horses each.

In the sketch above given of the "Oruktor Amphibolis," the engine is
seen to resemble that previously described. The wheel, _A_, is driven
by a rod depending from the end of a beam, _B´ B_, the other end of
which is supported at _E_ by the frame, _E F G_. The body of the
machine is carried on wheels, _K K_, driven by belts, _M M_, from the
pulley on the shaft carrying _A_. The paddle-wheel is seen at _W_.
Evans had some time previously sent Joseph Sampson to England with
copies of his plans, and by him they were shown to Trevithick, Vivian,
and other British engineers.

Among other devices, the now familiar Cornish boiler, having a single
internal flue, and the Lancashire boiler, having a pair of internal
flues, were planned and used by Evans.

At about the time that he was engaged on his steam dredging-machine,
Evans communicated with Messrs. McKeever & Valcourt, who contracted
with him to build an engine for a steam-vessel to ply between New
Orleans and Natchez on the Mississippi, the hull of the vessel to be
built on the river, and the machinery to be sent to the first-named
city to be set up in the boat. Financial difficulties and low water
combined to prevent the completion of the steamer, and the engine was
set at work driving a saw-mill, where, until the mill was destroyed by
fire, it sawed lumber at the rate of 250 feet of boards per hour.

Evans never succeeded in accomplishing in America as great a success
as had rewarded Watt in Great Britain; but he continued to build
steam-engines to the end of his life, April 19, 1819, and was
succeeded by his sons-in-law, James Rush and David Muhlenberg.

He exhibited equal intelligence and ingenuity in perfecting the
processes of milling, and in effecting improvements in his own
business, that of the millwright. When but twenty-four years old, he
invented a machine for making the wire teeth used in cotton and
woolen cards, turning them out at the rate of 3,000 per minute. A
little later he invented a card-setting machine, which cut the wire
from the reel, bent the teeth, and inserted them. In milling, he
invented a whole series of machines and attachments, including the
elevator, the "conveyor," the "hopper-box," the "drill," and the
"descender," and enabled the miller to make finer flour, gaining over
20 pounds to the barrel, and to do this at half the former cost of
attendance. The introduction of his improvements into Ellicott's
mills, near Baltimore, where 325 barrels of flour were made per day,
was calculated to have saved nearly $5,000 per year in cost of labor,
and over $30,000 by increasing the production. He wrote "The Young
Steam-Engineer's Guide," and a work which remained standard many years
after his death, "The Young Millwright's Guide." Less fortunate than
his transatlantic rival, he was nevertheless equally deserving of
fame. He has sometimes been called "The Watt of America."

The application of steam to locomotion on the common road was much
more successful in Great Britain than in the United States. As early
as 1786, William Symmington, subsequently more successful in his
efforts to introduce steam for marine propulsion, assisted by his
father, made a working model of a steam-carriage, which did not,
however, lead to important results.

In 1802, Richard Trevithick, a pupil of Murdoch's, who afterward
became well known in connection with the introduction of railroads,
made a model steam-carriage, which was patented in the same year. The
model may still be seen in the Patent Museum at South Kensington.[46]

  [46] _See_ "Life of Trevithick."

In this engine, high-pressure steam was employed, and the condenser
was dispensed with. The boiler was of the form devised by Evans, and
was subsequently generally used in Cornwall, where it was called the
"Trevithick Boiler." The engine had but one cylinder, and the
piston-rod drove a "cross-tail," working in guides, which was
connected with a "cross-head" on the opposite side of the shaft by two
"side-rods." The connecting-rod was attached to the cross-head and the
crank, "returning" toward the cylinder as the shaft lay between the
latter and the cross-head. This was probably the first example of the
now common "return connecting-rod engine." The connection between the
crank-shaft and the wheels of the carriage was effected by gearing.
The valve-gear and the feed-pumps were worked from the engine-shaft.
The inventor proposed to secure his wheels against slipping by
projecting bolts, when necessary, through the rim of the wheel into
the ground. The first carriage of full size was built by Trevithick
and Vivian at Camborne, in 1803, and, after trial, was taken to
London, where it was exhibited to the public. _En route_, it was
driven by its own engines to Plymouth, 90 miles from Camborne, and
then shipped by water. It is not known whether the inventor lost faith
in his invention; but he very soon dismantled the machine, sold the
engine and carriage separately, and returned to Cornwall, where he
soon began work on a railroad-locomotive.

In 1821, Julius Griffiths, of Brompton, Middlesex, England, patented a
steam-carriage for the transportation of passengers on the highway.
His first road-locomotive was built in the same year by Joseph Bramah,
one of the ablest mechanics of his time. The frame of the carriage
carried a large double coach-body between the two axles, and the
machinery was mounted over and behind the rear axle. One man was
stationed on a rear platform, to manage the engine and to attend to
the fire, and another, stationed in front of the body of the coach,
handled the steering-wheel. The boiler was composed of horizontal
water-tubes and steam-tubes, the latter being so situated as to
receive heat from the furnace-gases _en route_ to the chimney, and
thus to act as a superheater. The wheels were driven, by means of
intermediate gearing, by two steam-engines, which, with their
attachments, were suspended on helical springs, to prevent injury by
jars and shocks. An air-surface condenser was used, consisting of
flattened thin metal tubes, cooled by the contact of the external air,
and discharging the water of condensation, as it accumulated within
them, into a feed-pump, which, in turn, forced it into the lowest row
of tubes in the boiler.

The boiler did not prove large enough for continuous work; but the
carriage was used experimentally, now and then, for a number of years.

During the succeeding ten years the adaptation of the steam-engine to
land-transportation continued to attract more and more attention, and
experimental road-engines were built with steadily-increasing
frequency. The defects of these engines revealing themselves on trial,
they were one by one remedied, and the road-locomotive gradually
assumed a shape which was mechanically satisfactory. Their final
introduction into general use seemed at one time only a matter of
time; their non-success was due to causes over which the legislator
and the general public, and not the engineer, had control, as well as
to the development of steam-transportation on a rival plan.

In 1822, David Gordon patented a road-engine, but it is not known
whether it was ever built. At about the same time, Mr. Goldsworthy
Gurney, who subsequently took an active part in their introduction,
stated, in his lectures, that "elementary power is capable of being
applied to propel carriages along common roads with great political
advantage, and the floating knowledge of the day places the object
within reach." He made an ammonia-engine--probably the first ever
made--and worked it so successfully, that he made use of it in driving
a little locomotive.

Two years later, Gordon patented a curious arrangement, which,
however, had been proposed twelve years earlier by Brunton, and was
again proposed afterward by Gurney, and others. This consisted in
fitting to the engine a set of jointed legs, imitating, as nearly as
the inventor could make them, the action of a horse's legs and feet.
Such an arrangement was actually experimented with until it was found
that they could not be made to work satisfactorily, when it was also
found that they were not needed.

During the same season, Burstall & Hill made a steam-carriage, and
made many unsuccessful attempts to introduce their plan. The engine
used was like that of Evans, except that the steam-cylinder was placed
at the end of the beam, and the crank-shaft under the middle. The
front and rear wheels were connected by a longitudinal shaft and bevel
gearing. The boiler was found to have the usual defect, and would only
supply steam for a speed of three or four miles an hour. The result
was a costly failure. W. H. James, of London, in 1824-'25, proposed
several devices for placing the working parts, as well as the body of
the carriage, on springs, without interfering with their operation,
and the Messrs. Seaward patented similar devices. Samuel Brown, in
1826, introduced a gas-engine, in which the piston was driven by the
pressure produced by the combustion of gas, and a vacuum was secured
by the condensation of the resulting vapor. Brown built a locomotive
which he propelled by this engine. He ascended Shooter's Hill, near
London, and the principal cause of his ultimate failure seems to have
been the cost of operating the engine.

From this date forward, during several years, a number of inventors
and mechanics seem to have devoted their whole time to this promising
scheme. Among them, Burstall & Hill, Gurney, Ogle & Summers, Sir
Charles Dance, and Walter Hancock, were most successful.

Gurney, in the year 1827, built a steam-carriage, which he kept at
work nearly two years in and about London, and sometimes making long
journeys. On one occasion he made the journey from Meksham to Cranford
Bridge, a distance of 85 miles, in 10 hours, including all stops. He
used the mechanical legs previously adopted by Brunton and by Gordon,
but omitted this rude device in those engines subsequently built.

Gurney's engine of 1828 is of interest to the engineer as exhibiting a
very excellent arrangement of machinery, and as having one of the
earliest of "sectional boilers." The latter was of peculiar form, and
differed greatly in design from the sectional boiler invented a
quarter of a century earlier by John Stevens, in the United States.

[Illustration: FIG. 48.--Gurney's Steam-Carriage.]

In the sketch (Fig. 48) this boiler is seen at the right. It was
composed of bent [<]-shaped tubes, _a a_, connected to two cylinders,
_b b_, the upper one of which was a steam-chamber. Vertical tubes
connected these two chambers, and permitted a complete and regular
circulation of the water. A separate reservoir, called a separator,
_d_, was connected with these chambers by pipes, as shown. From the
top of this separator a steam-pipe, _e e e_, conveyed steam to the
engine-cylinders at _f_. The cranks, _g_, on the rear axle were turned
by the engines, and the eccentric, _h_, on the axle drove the
valve-gearing and the valve, _i_. The link, _k l_, being moved by a
line, _l l_, led from the driver's seat, the carriage was started,
stopped, or reversed, by throwing the upper end of the link into gear
with the valve-stem, by setting the link midway between its upper and
lower positions, or by raising it until the lower end, coming into
action on the valve-stem, produced a reverse motion of the valve. The
pin on which this link vibrated is seen at the centre of its
elliptical strap. The throttle-valve, _o_, by which the supply of
steam to the engine was adjusted, was worked by the lever, _n_. The
exhaust-pipe, _p_, led to the tank, _q_, and the uncondensed vapor
passed to the chimney, _s s_, by the pipe, _r r_. The force-pump, _u_,
taking feed-water from the tank, _t_, supplied it to the boiler by the
pipe, _x x x_, which, _en route_, was coiled up to form a "heater"
directly above the boiler. The supply was regulated by the cock, _y_.
The attendant had a seat at _z_. A blast-apparatus, 1, was driven by
an independent engine, 2 3, and produced a forced blast, which was led
to the boiler-furnace through the air-duct, 5 5; 4 4 represents the
steam-pipe to the little blowing-engine. The steering-wheel, 6, was
directed by a lever, 7, and the change of direction of the perch, 8,
which turned about a king-bolt at 9, gave the desired direction to the
forward wheels and to the carriage.

This seems to have been one of the best designs brought out at that
time. The boiler, built to carry 70 pounds, was safe and strong, and
was tested up to 800 pounds pressure. A forced draught was provided.
The engines were well placed, and of good design. The valve was
arranged to work the steam with expansion from half-stroke. The
feed-water was heated, and the steam slightly superheated. The boiler
here used has been since reproduced under new names by later
inventors, and is still used with satisfactory results. Modifications
of the "pipe-boiler" were made by several other makers of
steam-carriages also. Anderson & James made their boilers of
lap-welded iron tubes of one inch internal diameter and one-fifth inch
thick, and claimed for them perfect safety. Such tubes should have
sufficient strength to sustain a pressure of 20,000 pounds per square
inch. If made of such good iron as the makers claimed to have put into
them, "which worked like lead," they would, as was also claimed, when
ruptured, open by tearing, and discharge their contents without
producing the usual disastrous consequences of boiler explosions.

The primary principle of the sectional boiler was then well
understood. The boilers of Ogle & Summers were made up of pairs of
upright tubes, set one within the other, the intervening space being
filled with water and steam, and the flame passing through the inner
and around the outer tube of each pair.

One of the engines of Sir James Anderson and W. H. James was built in
1829. It had two 3-1/2-inch steam-cylinders, driving the rear wheels
independently. In James's earlier plan of 1824-'25, a pair of
cylinders was attached to each of the two halves into which the rear
axle was divided, and were arranged to drive cranks set at
right-angles with each other. The later machine weighed 3 tons, and
carried 15 passengers, on a rough graveled road across the Epping
Forest, at the rate of from 12 to 15 miles per hour. Steam was carried
at 300 pounds. Several tubes gave way in the welds, but the carriage
returned, carrying 24 passengers at the rate of 7 miles per hour. On a
later trial, with new boilers, the carriage again made 15 miles per
hour. It was, however, subject to frequent accidents, and was finally
withdrawn.

WALTER HANCOCK was the most successful and persevering of all those
who attempted the introduction of steam on the common road. He had, in
1827, patented a boiler of such peculiar form, that it deserves
description. It consisted of a collection of flat chambers, of which
the walls were of boiler-plate. These chambers were arranged side by
side, and connected laterally by tubes and stays, and all were
connected by short vertical tubes to a horizontal large pipe placed
across the top of the boiler-casing, and serving as a steam-drum or
separator. This earliest of "sheet flue-boilers" did excellent
service on Hancock's steam-carriages, where experience showed that
there was little or no danger of disruptive explosions.

Hancock's first steam-carriage was mounted on three wheels, the
leading-wheel arranged to swivel on a king-bolt, and driven by a pair
of oscillating cylinders connected with its axle, which was "cranked"
for the purpose. The engines turned with the steering-wheel. This
carriage was by no means satisfactory, but it was used for a long
time, and traveled many hundreds of miles without once failing to do
the work assigned it.

By this time there were a half-dozen steam-carriages under
construction for Hancock, for Ogle & Summers, and for Sir Charles
Dance.

In 1831, Hancock placed a new carriage on a route between London and
Stratford, where it ran regularly for hire. Dance, in the same season,
started another on the line between Cheltenham and Gloucester, where
it ran from February 21st to June 22d, traveling 3,500 miles and
carrying 3,000 passengers, running the 9 miles in 55 minutes usually,
and sometimes in three-quarters of an hour, and never meeting with an
accident, except the breakage of an axle in running over heaps of
stones which had been purposely placed on the road by enemies of the
new system of transportation. Ogle & Summers's carriage attained a
speed, as testified by Ogle before a committee of the House of
Commons, of from 32 to 35 miles an hour, and on a rising grade, near
Southampton, at 24-1/2 miles per hour. They carried 250 pounds of
steam, ran 800 miles, and met with no accident. Colonel Macerone, in
1833, ran a steam-carriage of his own design from London to Windsor
and back, with 11 passengers, a distance of 23-1/2 miles, in 2 hours.
Sir Charles Dance, in the same year, ran his carriage 16 miles an
hour, and made long excursions at the rate of 9 miles an hour. Still
another experimenter, Heaton, ascended Lickey Hill, between Worcester
and Birmingham, on gradients of one in eight and one in nine, in
places; this was considered one of the worst pieces of road in
England. The carriage towed a coach containing 20 passengers.

Of all these, and many others, Hancock, however, had most marked
success. His coach, called the "Infant," which was set at work in
February, 1831, was, a year later, plying between London "City" and
Paddington. Another, called the "Era," was built for the London and
Greenwich Steam-Carriage Company, which was mechanically a success.
The company, however, was financially unsuccessful. In October, 1832,
the "Infant" ran to Brighton from London, carrying a party of 11, at
the rate of 9 miles per hour, ascending Redhill at a speed of 5 miles.
They steamed 38 miles the first day, stopping at night at Hazledean,
and reached Brighton next day, running 11 miles per hour. Returning
with 15 passengers, the coach ran 1 mile in less than 4 minutes, and
made 10 miles in 55 minutes. A run from Stratford to Brighton was made
in less than 10 hours, at an average speed of 12 miles an hour running
time, the actual running time being less than 6 hours. The next year
another carriage, the "Enterprise," was put on the road to Paddington
by Hancock for another company, and ran regularly over two weeks; but
this company was also unsuccessful. In the summer of 1833 he brought
out still another steam-coach, the "Autopsy" (Fig. 49), which he ran
to Brighton, and then, returning to London, man[oe]uvred the carriage
in the crowded streets without difficulty or accident. He went about
the streets of London at all times, and without hesitation. The coach
next ran between Finsbury Square and Pentonville regularly for four
weeks, without accident or delay. In the sketch, a part of the side is
broken away to show the machinery. The boiler, _A B_, supplies steam
through the steam-pipe, _H K_, to the steam-engine, _C D_, which is
coupled to the crank-shaft, _F_. _E_ is the feed-pump. The rear axle
is turned by the endless chain seen connecting it with the
engine-shaft, and the rear wheels, _S_, are thus driven. A blower,
_T_, gives a forced draught. The driver sits at _M_, steering by the
wheel, _N_, which is coupled to the larger wheel, _P_, and thus turns
the forward axle into any desired position. In 1834, Hancock built a
steam "drag" on an Austrian order, which, carrying 10 persons and
towing a coach containing 6 passengers, was driven through the city
beyond Islington, making 14 miles an hour on a level, and 8 miles or
more on rising ground. In the same year he built the "Era," and, in
August, put the "Autopsy" on with it, to make a steam-line to
Paddington. These coaches ran until the end of November, carrying
4,000 passengers, at a usual rate of speed of 12 miles per hour. He
then sent the "Era" to Dublin, where, on one occasion, it ran 18 miles
per hour.

[Illustration: FIG. 49.--Hancock's "Autopsy," 1833.]

In 1835 a large carriage, the "Erin," was completed, which was
intended to carry 20 passengers. It towed three omnibuses and a
stage-coach, with 50 passengers, on a level road, at the speed of 10
miles an hour. It drew an omnibus with 18 passengers through
Whitehall, Charing Cross, and Regent Street, and out to Brentford,
running 14 miles an hour. It ran also to Reading, making 38 miles,
with the same load, in 3 hours and 8 minutes running time. The stops
_en route_ occupied a half-hour. The same carriage made 75 miles to
Marlborough in 7-1/2 hours running time, stopping 4-1/2 hours on the
road, in consequence of having left the tender and supplies behind.

In May, 1836, Hancock put all his carriages on the Paddington road,
and ran regularly for over five months, running 4,200 miles in 525
trips to Islington, 143 to Paddington, and 44 to Stratford, passing
through the city over 200 times. The carriages averaged 5 hours and 17
or 18 minutes daily running time. A light steam-phaeton, built in
1838, for his own use, made 20 miles an hour, and was driven about the
city, and among horses and carriages, without causing annoyance or
danger. Its usual speed was about 10 miles an hour. Altogether,
Hancock built nine steam-carriages, capable of carrying 116 passengers
in addition to the regular attendants.[47]

  [47] For a detailed account of the progress of steam on the highway,
  _see_ "Steam on Common Roads," etc., by Young, Holley, & Fisher,
  London, 1861.

In December, 1833, about 20 steam-carriages and traction road-engines
were running, or were in course of construction, in and near London.
In our own country, the roughness of roads discouraged inventors;
and in Great Britain even, the successful introduction of
road-locomotives, which seemed at one time almost an accomplished
fact, finally met with so many obstacles, that even Hancock, the most
ingenious, persistent, and successful constructor, gave up in despair.
Hostile legislation procured by opposing interests, and the rapid
progress of steam-locomotion on railroads, caused this result.

In consequence of this interruption of experiment, almost nothing was
done during the succeeding quarter of a century, and it is only within
a few years that anything like a business success has been founded
upon the construction of road-locomotives, although the scheme seems
to have been at no time entirely given up.

The opposition of coach-proprietors, and of all classes having an
interest in the old lines of coaches, was most determined, and the
feeling evinced by them was intensely bitter; but the advocates of the
new system of transportation were equally determined and persevering,
and, having right on their side, and the pecuniary advantage of the
public as their object, they would probably have succeeded ultimately,
except for the introduction of the still better method of
transportation by rail.

In the summer of 1831, when the war between the two parties was at its
height, a committee of the British House of Commons made a very
complete investigation of the subject. This committee reported that
they had become convinced that "the substitution of inanimate for
animal power, in draught on common roads, is one of the most important
improvements in the means of internal communication ever introduced."
They considered its practicability to have been "fully established,"
and predicted that its introduction would "take place more or less
rapidly, in proportion as the attention of scientific men shall be
drawn, by public encouragement, to further improvement." The success
of the system had, as they stated, been retarded by prejudice, adverse
interests, and prohibitory tolls; and the committee remark: "When we
consider that these trials have been made under the most unfavorable
circumstances, at great expense, in total uncertainty, without any of
those guides which experience has given to other branches of
engineering; that those engaged in making them are persons looking
solely to their own interests, and not theorists attempting the
perfection of ingenious models; when we find them convinced, after
long experience, that they are introducing such a mode of conveyance
as shall tempt the public, by its superior advantages, from the use of
the admirable lines of coaches which have been generally established,
it surely cannot be contended that the introduction of steam-carriages
on common roads is, as yet, an uncertain experiment, unworthy of
legislative attention."

Farey, one of the most distinguished mechanical engineers of the
time, testified that he considered the practicability of such a system
as fully established, and that the result would be its general
adoption. Gurney had run his carriage between 20 and 30 miles an hour;
Hancock could sustain a speed of 10 miles; Ogle had run his coach 32
to 35 miles an hour, and ascended a hill rising 1 in 6 at the speed of
24-1/2 miles. Summers had traveled up a hill having a gradient of 1 in
12, with 19 passengers, at the rate of speed of 15 miles per hour; he
had run 4-1/2 hours at 30 miles an hour. Farey thought that
steam-coaches would be found to cost one-third as much as the
stage-coaches in use. The steam-carriages were reported to be safer
than those drawn by horses, and far more manageable; and the
construction of boilers adopted--the "sectional" boiler, as it is now
called--completely insured against injury by explosion, and the
dangers and inconveniences arising from the frightening of horses had
proved to be largely imaginary. The wear and tear of roads were found
to be less than with horses, while with broad wheel-tires the
carriages acted beneficially as road-rollers. The committee finally
concluded:

"1. That carriages can be propelled by steam on common roads at an
average rate of 10 miles per hour.

"2. That at this rate they have conveyed upward of 14 passengers.

"3. That their weight, including engine, fuel, water, and attendants,
may be under three tons.

"4. That they can ascend and descend hills of considerable inclination
with facility and safety.

"5. That they are perfectly safe for passengers.

"6. That they are not (or need not be, if properly constructed)
nuisances to the public.

"7. That they will become a speedier and cheaper mode of conveyance
than carriages drawn by horses.

"8. That, as they admit of greater breadth of tire than other
carriages, and as the roads are not acted on so injuriously as by the
feet of horses in common draught, such carriages will cause less wear
of roads than coaches drawn by horses.

"9. That rates of toll have been imposed on steam-carriages, which
would prohibit their being used on several lines of road, were such
charges permitted to remain unaltered."

THE RAILROAD, which now, by the adaptation of steam to the propulsion
of its carriages, became the successful rival of the system of
transportation of which an account has just been given, was not a new
device. It, like all other important changes of method and great
inventions, had been growing into form for ages. The ancients were
accustomed to lay down blocks of stone as a way upon which their
heavily-loaded wagons could be drawn with less resistance than on the
common road. This practice was gradually so modified as to result in
the adoption of the now universally-practised methods of paving and
road-making. The old tracks, bearing the marks of heavy traffic, are
still seen in the streets of the unearthed city of Pompeii.

In the early days of mining in Great Britain, the coal or the ore was
carried from the mine to the vessel in which it was to be embarked in
sacks on the backs of horses. Later, the miners laid out wagon-roads,
and used carts and wagons drawn by horses, and the roads were paved
with stone along the lines traversed by the wheels of the vehicles.
Still later (about 1630), heavy planks or squared timber took the
place of the stone, and were introduced into the north of England by a
gentleman of the name of Beaumont, who had transferred his property
there from the south. A half century later, the system had become
generally introduced. By the end of the eighteenth century the
construction of these "tram-ways" had become well-understood, and the
economy which justified the expenditure of considerable amounts of
money in making cuts and in filling, to bring the road to a uniform
grade, had become well-recognized. Arthur Young, writing at this time,
says the coal wagon-roads were "great works, carried over all sorts
of inequalities of ground, so far as the distance of nine or ten
miles," and that, on these tram-ways of timber, "one horse is able to
draw, and that with ease, fifty or sixty bushels of coals." The
wagon-wheels were of cast-iron, and made with grooved rims, which
fitted the rounded tops of the wooden rails. But these wooden rails
were found subject to rapid decay, and at Whitehaven, in 1738, they
were protected from wear by cast-iron plates laid upon them, and this
improvement rapidly became known and adopted. A tram-road, laid down
at Sheffield for the Duke of Norfolk, in 1776, was made by laying
angle-bars of cast-iron on longitudinal sleepers of timber; another,
built by William Jessup in Leicestershire, in 1789, had an edge-rail,
and the wheels were made with flanges, like those used to-day. The
coned "tread" of the wheel, which prevents wear of flanges and reduces
resistance, was the invention of James Wright, of Columbia, Pa., 40
years later. The modern railroad was simply the result of this gradual
improvement of the permanent way, and the adaptation of the
steam-engine to the propulsion of its wagons.

At the beginning of the nineteenth century, therefore, the
steam-engine had been given a form which permitted its use, and the
railroad had been so far perfected that there were no difficulties to
be anticipated in the construction of the permanent way, and inventors
were gradually preparing, as has been seen, to combine these two
principal elements into one system. Railroads had been introduced in
all parts of Great Britain, some of them of considerable length, and
involving the interests of so many private individuals that they were
necessarily constructed under the authorization of legal enactments.
In the year 1805 the Merstham Railway was opened to traffic, and it is
stated that on that occasion one horse drew a train of 12 wagons,
carrying 38 tons of stone, on a "down gradient" of 1 in 120, at the
rate of 6 miles per hour.

[Illustration: Richard Trevithick.]

[Illustration: FIG. 50.--Trevithick's Locomotive, 1804.]

RICHARD TREVITHICK was the first engineer to apply steam-power to the
haulage of loads on the railroad. Trevithick was a Cornishman by
birth, a native of Redruth. He was naturally a skillful mechanic, and
was placed by his father with Watt's assistant, Murdoch, who was
superintending the erection of pumping-engines in Cornwall; and from
that ingenious and accomplished engineer young Trevithick probably
acquired both the skill and the knowledge which, with his native
talent, enterprise, and industry, enabled him to accomplish the work
which has made him famous. He was soon intrusted with the erection and
management of large pumping-engines, and subsequently went into the
business of constructing steam-engines with another engineer, Edward
Bull, who took an active part, with the Hornblowers and others, in
opposing the Boulton & Watt patents. The termination of the suits
which established the validity of Watt's patent put an end to their
business, and Trevithick looked about for other work, and, not long
after, entered into partnership with a relative, Andrew Vivian, who
was also a skillful mechanic; they together designed and patented the
steam-carriage already referred to. Its success was sufficiently
satisfactory to awaken strong confidence of a perfect success on the
now common tram-roads; and Trevithick, in February, 1804, had
completed a "locomotive" engine to work on the Welsh Pen-y-darran
road. This engine (Fig. 50) had a cylindrical flue-boiler, _A_, like
that designed by Oliver Evans, and a single steam-cylinder, _B_, set
vertically into the steam-space of the boiler, and driving the
outside cranks, _L_, on the rear axle of the engine by very long
connecting-rods, _D_, attached to its cross-head at _E_. The
guide-bars, _I_, were stayed by braces leading to the opposite end of
the boiler. No attempt was made to condense the exhaust-steam, which
was discharged into the smoke-pipe. The pressure of steam adopted was
40 pounds per square inch; but Trevithick had already made a number of
non-condensing engines on which he carried from 50 to 145 pounds
pressure.

In the year 1808, Trevithick built a railroad in London, on what was
known later as Torrington Square, or Euston Square, and set at work a
steam-carriage, which he called "Catch-me-who-can." This was a very
plain and simple machine. The steam-cylinder was set vertically in the
after-end of the boiler, and the cross-head was connected to two rods,
one on either side, driving the hind pair of wheels. The exhaust-steam
entered the chimney, aiding the draught. This engine, weighing about
10 tons, made from 12 to 15 miles an hour on the circular railway in
London, and was said by its builder to be capable of making 20 miles
an hour. The engine was finally thrown from the track, after some
weeks of work, by the breaking of a rail, and, Trevithick's funds
having been expended, it was never replaced. This engine had a
steam-cylinder 14-1/2 inches in diameter, and a stroke of piston of 4
feet. Trevithick used no device to aid the friction of the wheels on
the rails in giving pulling-power, and seems to have understood that
none was needed. This plan of working a locomotive-engine without such
complications as had been proposed by other engineers was, however,
subsequently patented, in 1813, by Blackett & Hedley. The latter was
at one time Trevithick's agent, and was director of Wylam Colliery, of
which Mr. Blackett was proprietor.

Trevithick applied his high-pressure non-conducting engine not only to
locomotives, but to every purpose that opportunity offered him. He put
one into the Tredegar Iron-Works, to drive the puddle-train, in 1801.
This engine had a steam-cylinder 28 inches in diameter, and 6 feet
stroke of piston; a boiler of cast-iron, 6-3/4 feet in diameter and 20
feet long, with a wrought-iron internal tube, 3 feet in diameter at
the furnace-end and 24 inches beyond the furnace. The steam-pressure
ranged from 50 to 100 pounds per square inch. The valve was a four-way
cock. The exhaust-steam was carried into the chimney, passing through
a feed-water heater _en route_. This engine was taken down in
1856.[48]

  [48] "Life of Trevithick."

In 1803, Trevithick applied his engine to driving rock-drills, and
three years later made a large contract with the Trinity Board for
dredging in the Thames, and constructed steam dredging-machines for
the work, of the form which is still most generally used in Great
Britain, although rarely seen in the United States--the
"chain-and-bucket dredger."

A little later, Trevithick was engaged upon the first and unsuccessful
attempt to carry a tunnel under the Thames, at London; but no sooner
had that costly scheme been given up, than he returned to his favorite
pursuits, and continued his work on interrupted schemes for
ship-propulsion. Trevithick at last left England, spent some years in
South America, and finally returned home and died in extreme poverty,
April, 1833, at the age of sixty-two, without having succeeded in
accomplishing the general introduction of any of his inventions.

Trevithick was characteristically an inventor of the typical sort. He
invented many valuable devices, but brought but few into even
experimental use, and reaped little advantage from any of them. He was
ingenious, a thorough mechanic, bold, active, and indefatigable; but
his lack of persistence made his whole life, as Smiles has said, "but
a series of beginnings."

It is at about this period that we find evidence of the intelligent
labors of another of our own countrymen--one who, in consequence of
the unobtrusive manner in which his work was done, has never received
the full credit to which he is entitled.

COLONEL JOHN STEVENS, of Hoboken, as he is generally called, was born
in the city of New York, in 1749; but throughout his business-life he
was a resident of New Jersey.

[Illustration: Colonel John Stevens.]

His attention is said to have been first called to the application of
steam-power by seeing the experiments of John Fitch with his steamer
on the Delaware, and he at once devoted himself to the introduction of
steam-navigation with characteristic energy, and with a success that
will be indicated when we come to the consideration of that subject.

But this far-sighted engineer and statesman saw plainly the
importance of applying the steam-engine to land-transportation as well
as to navigation; and not only that, but he saw with equal
distinctness the importance of a well-devised and carefully-prosecuted
scheme of internal communication by a complete system of railroads. In
1812 he published a pamphlet containing "Documents tending to prove
the superior advantages of Railways and Steam-Carriages over
Canal-Navigation."[49] At this time, the only locomotive in the world
was that of Trevithick and Vivian, at Merthyr Tydvil, and the railroad
itself had not grown beyond the old wooden tram-roads of the
collieries. Yet Colonel Stevens says, in this paper: "I can see
nothing to hinder a steam-carriage moving on its ways with a velocity
of 100 miles an hour;" adding, in a foot-note: "This astonishing
velocity is considered here merely possible. It is probable that it
may not, in practise, be convenient to exceed 20 or 30 miles per hour.
Actual experiment can only determine this matter, and I should not be
surprised at seeing steam-carriages propelled at the rate of 40 or 50
miles an hour."

  [49] Printed by T. & J. Swords, 160 Pearl Street, New York, 1812.

At a yet earlier date he had addressed a memoir to the proper
authorities, urging his plans for railroads. He proposed rails of
timber, protected, when necessary, by iron plates, or to be made
wholly of iron; the car-wheels were to be of cast-iron, with inside
flanges to keep them on the track. The steam-engine was to be driven
by steam of 50 pounds pressure and upward, and to be non-condensing.

Answering the objections of Robert R. Livingston and of the State
Commissioners of New York, he goes further into details. He gives 500
to 1,000 pounds as the maximum weight to be placed on each wheel;
shows that the trains, or "suits of carriages," as he calls them, will
make their journeys with as much certainty and celerity in the darkest
night as in the light of day; shows that the grades of proposed roads
would offer but little resistance; and places the whole subject before
the public with such accuracy of statement and such evident
appreciation of its true value, that every one who reads this
remarkable document will agree fully with President Charles King, who
said[50] that "whosoever shall attentively read this pamphlet, will
perceive that the political, financial, commercial, and military
aspects of this great question were all present to Colonel Stevens's
mind, and that he felt that he was fulfilling a patriotic duty when he
placed at the disposal of his native country these fruits of his
genius. The offering was not then accepted. The 'Thinker' was ahead of
his age; but it is grateful to know that he lived to see his projects
carried out, though not by the Government, and that, before he
finally, in 1838, closed his eyes in death, at the great age of
eighty-nine, he could justly feel assured that the name of Stevens, in
his own person and in that of his sons, was imperishably enrolled
among those which a grateful country will cherish."

  [50] "Progress of the City of New York."

Without having made any one superlatively great improvement in the
mechanism of the steam-engine, like that which gave Watt his
fame--without having the honor even of being the first to
propose the propulsion of vessels by the modern steam-engine, or
steam-transportation on land--he exhibited a far better knowledge of
the science and the art of engineering than any man of his time; and
he entertained and urged more advanced opinions and more statesmanlike
views in relation to the economical importance of the improvement and
the application of the steam-engine, both on land and water, than seem
to be attributable to any other leading engineer of that time.

Says Dr. King: "Who can estimate if, at that day, acting upon the
well-considered suggestion of President Madison, 'of the signal
advantages to be derived to the United States from a general system of
internal communication and conveyance,' Congress had entertained
Colonel Stevens's proposal, and, after verifying by actual experiment
upon a small scale the accuracy of his plan, had organized such a
'general system of internal communication and conveyance;' who can
begin to estimate the inappreciable benefits that would have resulted
therefrom to the comfort, the wealth, the power, and, above all, to
the absolutely impregnable union of our great Republic and all its
component parts? All this Colonel Stevens embraced in his views, for
he was a statesman as well as an experimental philosopher; and whoever
shall attentively read his pamphlet, will perceive that the political,
financial, commercial, and military aspects of this great question
were all present to his mind, and he felt that he was fulfilling a
patriotic duty when he placed at the disposal of his native country
these fruits of his genius."

WILLIAM HEDLEY, who has already been referred to, seems to have been
the first to show, by carefully-conducted experiment, how far the
adhesion of the wheels of the locomotive-engine could be relied upon
for hauling-power in the transportation of loads.

His employer, Blackett, had applied to Trevithick for a
locomotive-engine to haul coal-trains at the Wylam collieries; but
Trevithick was unable, or was disinclined, to build him one, and in
October, 1812, Hedley was authorized to attempt the construction of an
engine. It was at about this time that Blenkinsop (1811) was trying
the toothed rail or rack, the Messrs. Chapman (December, 1812) were
experimenting with a towing-chain, and (May, 1813) Brunton with
movable legs.

Hedley, who had known of the success met with in the experiments of
Trevithick with smooth wheels hauling loads of considerable weight, in
Cornwall, was confident that equal success might be expected in the
north-country, and built a carriage to be moved by men stationed at
four handles, by which its wheels were turned.

This carriage was loaded with heavy masses of iron, and attached to
trains of coal-wagons on the railway. By repeated experiment, varying
the weight of the traction-carriage and the load hauled, Hedley
ascertained the proportion of the weight required for adhesion to that
of the loads drawn. It was thus conclusively proven that the weight of
his proposed locomotive-engine would be sufficient to give the
pulling-power necessary for the propulsion of the coal-trains which it
was to haul.

When the wheels slipped in consequence of the presence of grease,
frost, or moisture on the rail, Hedley proposed to sprinkle ashes on
the track, as sand is now distributed from the sand-box of the modern
engine. This was in October, 1812.

Hedley now went to work building an engine with smooth wheels, and
patented his design March 13, 1813, a month after he had put his
engine at work. The locomotive had a cast-iron boiler, and a single
steam-cylinder 6 inches in diameter, with a small fly-wheel. This
engine had too small a boiler, and he soon after built a larger
engine, with a return-flue boiler made of wrought-iron. This hauled 8
loaded coal-wagons 5 miles an hour at first, and a little later 10,
doing the work of 10 horses. The steam-pressure was carried at about
50 pounds, and the exhaust, led into the chimney, where the pipe was
turned upward, thus secured a blast of considerable intensity in its
small chimney. Hedley also contracted the opening of the exhaust-pipe
to intensify the blast, and was subjected to some annoyance by
proprietors of lands along his railway, who were irritated by the
burning of their grass and hedges, which were set on fire by the
sparks thrown out of the chimney of the locomotive. The cost of
Hedley's experiment was defrayed by Mr. Blackett.

Subsequently, Hedley mounted his engine on eight wheels, the
four-wheeled engines having been frequently stopped by breaking the
light rails then in use. Hedley's engines continued in use at the
Wylam collieries many years. The second engine was removed in 1862,
and is now preserved at the South Kensington Museum, London.

GEORGE STEPHENSON, to whom is generally accorded the honor of having
first made the locomotive-engine a success, built his first engine at
Killingworth, England, in 1814.

[Illustration: George Stephenson.]

At this time Stephenson was by no means alone in the field, for the
idea of applying the steam-engine to driving carriages on common roads
and on railroads was beginning, as has been seen, to attract
considerable attention. Stephenson, however, combined, in a very
fortunate degree, the advantages of great natural inventive talent and
an excellent mechanical training, reminding one strongly of James
Watt. Indeed, Stephenson's portrait bears some resemblance to that of
the earlier great inventor.

George Stephenson was born June 9, 1781, at Wylam, near
Newcastle-upon-Tyne, and was the son of a "north-country miner." When
still a child, he exhibited great mechanical talent and unusual love
of study. When set at work about the mines, his attention to duty and
his intelligence obtained for him rapid promotion, until, when but
seventeen years of age, he was made engineer, and took charge of the
pumping-engine at which his father was fireman.

When a mere child, and employed as a herd-boy, he amused himself
making model engines in clay, and, as he grew older, never lost an
opportunity to learn the construction and management of machinery.
After having been employed at Newburn and Callerton, where he first
became "engine-man," he began to study with greater interest than ever
the various steam-engines which were then in use; and both the
Newcomen engine and the Watt pumping-engine were soon thoroughly
understood by him. After having become a brakeman, he removed to
Willington Quay, where he married, and commenced his wedded life on 18
or 20 shillings per week. It was here that he became an intimate
friend of the distinguished William Fairbairn, who was then working as
an apprentice at the Percy Main Colliery, near by. The "father of the
railroad" and the future President of the British Association were
accustomed, at times, to "change works," and were frequently seen in
consultation over their numerous projects. It was at Willington Quay
that his son Robert, who afterward became a distinguished civil
engineer, was born, October 16, 1803.

In the following year Stephenson removed to Killingworth, and became
brakeman at that colliery; but his wife soon died, and he gladly
accepted an invitation to become engine-driver at a spinning-mill near
Montrose, Scotland. At the end of a year he returned, on foot, to
Killingworth with his savings (about £28), expended over one-half of
the amount in paying his father's debts and in making his parents
comfortable, and then returned to his old station as brakeman at the
pit.

Here he made some useful improvements in the arrangement of the
machinery, and spent his spare hours in studying his engine and
planning new machines. He a little later distinguished himself by
altering and repairing an old Newcomen engine at the High Pit, which
had failed to give satisfaction, making it thoroughly successful after
three days' work. The engine cleared the pit, at which it had been
vainly laboring a long time, in two days after Stephenson started it
up.

In the year 1812, Stephenson was made engine-wright of the
Killingworth High Pit, receiving £100 a year, and it was made his duty
to supervise the machinery of all the collieries under lease by the
so-called "Grand Allies." It was here, and at this period, that he
commenced a systematic course of self-improvement and the education of
his son, and here he first began to be recognized as an inventor. He
was full of life and something of a wag, and often made most amusing
applications of his inventive powers: as when he placed the watch,
which a comrade had brought him as out of repairs, in the oven "to
cook," his quick eye having noted the fact that the difficulty arose
simply from the clogging of the wheels by the oil, which had been
congealed by cold.

Smiles,[51] his biographer, describes his cottage as a perfect
curiosity-shop, filled with models of engines, machines of various
kinds, and novel apparatus. He connected the cradles of his neighbors'
wives with the smoke-jacks in their chimneys, and thus relieved them
from constant attendance upon their infants; he fished at night with a
submarine lamp, which attracted the fish from all sides, and gave him
wonderful luck; he also found time to give colloquial instruction to
his fellow-workmen.

  [51] "Lives of George and Robert Stephenson," by Samuel Smiles. New
  York and London, 1868.

He built a self-acting inclined plane for his pit, on which the
wagons, descending loaded, drew up the empty trains; and made so many
improvements at the Killingworth pit, that the number of horses
employed underground was reduced from 100 to 16.

Stephenson now had more liberty than when employed at the brakes, and,
hearing of the experiments of Blackett and Hedley at Wylam, went over
to their colliery to study their engine. He also went to Leeds to see
the Blenkinsop engine draw, at a trial, 70 tons at the rate of 3 miles
an hour, and expressed his opinion in the characteristic remark, "I
think I could make a better engine than that to go upon legs." He very
soon made the attempt.

Having laid the subject before the proprietors of the lease under
which the collieries were worked, and convinced Lord Ravensworth, the
principal owner, of the advantages to be secured by the use of a
"traveling engine," that nobleman advanced the money required.
Stephenson at once commenced his first locomotive-engine, building it
in the workshops at West Moor, assisted mainly by John Thirlwall, the
colliery blacksmith, during the years 1813 and 1814, completing it in
July of the latter year.

This engine had a wrought-iron boiler 8 feet long and 2 feet 10 inches
in diameter, with a single flue 20 inches in diameter. The cylinders
were vertical, 8 inches in diameter and of 2 feet stroke of piston,
set in the boiler, and driving a set of wheels which geared with each
other and with other cogged wheels on the two driving-axles. A
feed-water heater surrounded the base of the chimney. This engine drew
30 tons on a rising gradient of 10 or 12 feet to the mile at the rate
of 4 miles an hour. This engine proved in many respects defective, and
the cost of its operation was found to be about as great as that of
employing horse-power.

Stephenson determined to build another engine on a somewhat different
plan, and patented its design in February, 1815. It proved a much
more efficient machine than the "Blücher," the first engine.

[Illustration: FIG. 51.--Stephenson's Locomotive of 1815. Section.]

This second engine (Fig. 51) was also fitted with two vertical
cylinders, _C c_, but the connecting-rods were attached directly to
the four driving-wheels, _W W´_. To permit the necessary freedom of
motion, "ball-and-socket" joints were adopted, to unite the rods with
the cross-heads, _R r_, and with the cranks, _R´ Y´_; and the two
driving-axles were connected by an endless chain, _T t´_. The cranked
axle and the outside connection of the wheels, as specified in the
patent, were not used until afterward, it having been found impossible
to get the cranked axles made. In this engine the forced draught
obtained by the impulse of the exhaust-steam was adopted, doubling the
power of the machine and permitting the use of coke as a fuel, and
making it possible to adopt the multi-tubular boiler. Small
steam-cylinders, _S S S_, took the weight of the engine and served as
springs.

It was at about this time that George Stephenson and Sir Humphry
Davy, independently and almost simultaneously, invented the
"safety-lamp," without which few mines of bituminous coal could to-day
be worked. The former used small tubes, the latter fine wire gauze, to
intercept the flame. Stephenson proved the efficiency of his lamp by
going with it directly into the inflammable atmosphere of a dangerous
mine, and repeatedly permitting the light to be extinguished when the
lamp became surcharged with the explosive mixture which had so
frequently proved fatal to the miners. This was in October and
November, 1815, and Stephenson's work antedates that of the great
philosopher.[52] The controversy which arose between the supporters of
the rival claims of the two inventors was very earnest, and sometimes
bitter. The friends of the young engineer raised a subscription,
amounting to above £1,000, and presented it to him as a token of their
appreciation of the value of his simple yet important contrivance. Of
the two forms of lamp, that of Stephenson is claimed to be safest, the
Davy lamp being liable to produce explosions by igniting the explosive
gas when, by its combustion within the gauze cylinder, the latter is
made red-hot. Under similar conditions, the Stephenson lamp is simply
extinguished, as was seen at Barnsley, in 1857, at the Oaks Colliery,
where both kinds of lamp were in use, and elsewhere.

  [52] _Vide_ "A Description of the Safety-Lamp invented by George
  Stephenson," etc., London, 1817.

Stephenson continued to study and experiment, with a view to the
improvement of his locomotive and the railroad. He introduced better
methods of track-laying and of jointing the rails, adopting a
half-lap, or peculiar scarf-joint, in place of the then usual
square-butt joint. He patented, with these modifications of the
permanent way, several of his improvements of the engine. He had
substituted forged for the rude cast wheels previously used,[53] and
had made many minor changes of detail. The engines built at this time
(1816) continued in use many years. Two years later, with a
dynamometer which he designed for the purpose, he made experimental
determinations of the resistance of trains, and showed that it was
made up of several kinds, as the sliding friction of the axle-journals
in their bearings, the rolling friction of the wheels on the rails,
the resistance due to gravity on gradients, and that due to the
resistance of the air.

  [53] The American chilled wheel of cast-iron, a better wheel than
  that above described, has never been generally and successfully
  introduced in Europe.

These experiments seemed to him conclusive against the possibility of
the competition of engines on the common highway with locomotives
hauling trains on the rail. Finding that the resistance, with his
rolling-stock, and at all the speeds at which he made his experiments,
was approximately invariable, and equivalent to about 10 pounds per
ton, and estimating that a gradient rising but 1 foot in 100 would
decrease the hauling power of the engine 50 per cent., he saw at once
the necessity of making all railroads as nearly absolutely level as
possible, and, consequently, the radically distinctive character of
this branch of civil engineering work. He persistently condemned the
"folly" of attempting the general introduction of steam on the common
road, where great changes of level and an impressible road-bed were
certain to prove fatal to success, and was most strenuous in his
advocacy of the policy of securing level tracks, even at very great
expense.

Taking part in the contest, which now became a serious one, between
the advocates of steam on the common road and those urging the
introduction of locomotives and their trains on an iron track, he
calculated that a road-engine capable of carrying 20 or 30 passengers
at 10 miles per hour, could, on the rail, carry ten times as many
people at three or four times that speed. The railway-engine finally
superseded its predecessor--the engine of the common road--almost
completely.

In 1817, Stephenson built an engine for the Duke of Portland, to haul
coal from Kilmarnock to Troon, which cost £750, and, with some
interruptions, this engine worked on that line until 1848, when it was
broken up. On November 18, 1822, the Hetton Railway, near Sunderland,
was opened. George Stephenson was the engineer of the line--a short
track, 8 miles long, built from the Hetton Colliery to the docks on
the bank of the river Wear. On this line he put in five of the
"self-acting inclines"--two inclines worked by stationary engines, the
gradients being too heavy for locomotives--and used five
locomotive-engines of his own design, which were called by the people
of the neighborhood, possibly for the first time, "the iron horses."
These engines were quite similar to the Killingworth engine. They drew
a train of 17 coal-cars--a total load of 64 tons--about 4 miles an
hour. Meantime, also, in 1823, Stephenson had been made engineer of
the Stockton & Darlington Railroad, which had been projected for the
purpose of securing transportation to tide-water for the valuable
coal-lands of Durham. This road was built without an expectation on
the part of any of its promoters, Stephenson excepted, that steam
would be used as a motor to the exclusion of horses.

Mr. Edward Pearse, however, one of the largest holders of stock in the
road, and one of its most earnest advocates, became so convinced, by
an examination of the Killingworth engines and their work, of the
immense advantage to be derived by their use, that he not only
supported Stephenson's arguments, but, with Thomas Richardson,
advanced £1,000 for the purpose of assisting Stephenson to commence
the business of locomotive-engine construction at Newcastle. This
workshop, which subsequently became a great and famous establishment,
was commenced in 1824.

For this road Stephenson recommended wrought-iron rails, which were
then costing £12 per ton--double the price of cast rails. The
directors, however, stipulated that he should only buy one-half the
rails required from the dealers in "malleable" iron. These rails
weighed 20 pounds to the yard. After long hesitation, in the face of a
serious opposition, the directors finally concluded to order three
locomotives of Stephenson. The first, or "No. 1," engine (Fig. 52) was
delivered in time for the opening of the road, September 27, 1825. It
weighed 8 tons. Its boiler contained a single straight flue, one end
of which was the furnace. The cylinders were vertical, like those of
the earlier engines, and coupled directly to the driving-wheels. The
crank-pins were set in the wheels at right angles, in order that,
while one engine was "turning the centre," the other might exert its
maximum power. The two pairs of drivers were coupled by horizontal
rods, as seen in the figure, which represents this engine as
subsequently mounted on a pedestal at the Darlington station. A
steam-blast in the chimney gave the requisite strength of draught.
These engines were built for slow and heavy work, but were capable of
making what was then thought the satisfactorily high speed of 16 miles
per hour. The inclines on the road were worked by fixed engines.

[Illustration: FIG. 52.--Stephenson's No. 1 Engine, 1825.]

On the opening day, which was celebrated as a holiday by the people
far and near, the No. 1 engine drew 90 tons at the rate of 12, and at
times 15, miles an hour.

[Illustration: FIG. 58.--Opening of the Stockton and Darlington
Railroad, 1815. (After an old engraving.)]

Stephenson's engines were kept at work hauling coal-trains, but the
passenger-coaches were all drawn for some time by horses, and the
latter system was a rude forerunner, in most respects, of modern
street-railway transportation. Mixed passenger and freight trains were
next introduced, and, soon after, separate passenger-trains drawn by
faster engines were placed on the line, and the present system of
railroad transportation was now fairly inaugurated.

A railroad between Manchester and Liverpool had been projected at
about the time that the Stockton & Darlington road was commenced. The
preliminary surveys had been made in the face of strong opposition,
which did not always stop at legal action and verbal attack, but in
some instances led to the display of force. The surveyors were
sometimes driven from their work by a mob armed with sticks and
stones, urged on by land-proprietors and those interested in the lines
of coaches on the highway. Before the opening of the Stockton &
Darlington Railroad, the Liverpool & Manchester bill had been carried
through Parliament, after a very determined effort on the part of
coach-proprietors and landholders to defeat it, and Stephenson urged
the adoption of the locomotive to the exclusion of horses. It was his
assertion, made at this time, that he could build a locomotive to run
20 miles an hour, that provoked the celebrated rejoinder of a writer
in the _Quarterly Review_, who was, however, in favor of the
construction of the road and of the use of the locomotive upon it:
"What can be more palpably absurd and ridiculous, than the prospect
held out of locomotives traveling _twice as fast_ as stage-coaches? We
would as soon expect the people of Woolwich to suffer themselves to be
fired off upon one of Congreve's ricochet-rockets, as trust themselves
to the mercy of such a machine going at such a rate."

It was during his examination before a committee of the House of
Commons, during this contest, that Stephenson, when asked, "Suppose,
now, one of your engines to be going at the rate of 9 or 10 miles an
hour, and that a cow were to stray upon the line and get in the way
of the engine, would not that be a very awkward circumstance?"
replied, "Yes, _very_ awkward--_for the coo!_" And when asked if men
and animals would not be frightened by the red-hot smoke-pipe,
answered, "But how would they know that it was not _painted?_" The
line was finally built, with George Rennie as consulting, and
Stephenson as principal constructing engineer.

His work on this road became one of the important elements of the
success, and one of the great causes of the distinction, which marked
the life of these rising engineers. The successful construction of
that part of the line which lay across "Chat Moss," an unfathomable
swampy deposit of peat, extending over an area of 12 square miles, and
the building of which had been repeatedly declared an impossibility,
was in itself sufficient to prove that the engineer who had
accomplished it was no common man. Stephenson adopted the very simple
yet bold expedient of using, as a filling, compacted turf and peat,
and building a road-bed of materials lighter than water, or the
substance composing the bog, and thus forming a _floating_ embankment,
on which he laid his rails. To the surprise of every one but
Stephenson himself, the plan proved perfectly successful, and even
surprisingly economical, costing but little more than one-tenth the
estimate of at least one engineer. Among the other great works on this
remarkable pioneer-line were the tunnel, a mile and a half long, from
the station at Liverpool to Edgehill; the Olive Mount deep-cut, two
miles long, and in some places 100 feet deep, through red sandstone,
of which nearly 500,000 yards were removed; the Sankey Viaduct, a
brick structure of nine arches, of 50 feet span each, costing £45,000;
and a number of other pieces of work which are noteworthy in even
these days of great works.

Stephenson planned all details of the line, and even designed the
bridges, machinery, engines, turn-tables, switches, and crossings,
and was responsible for every part of the work of their construction.

Finally, the work of building the line approached completion, and it
became necessary promptly to settle the long-deferred question of a
method of applying motive-power. Some of the directors and their
advisers still advocated the use of horses; many thought stationary
hauling-engines preferable; and the remainder were, almost to a man,
undecided. The locomotive had no outspoken advocate, and few had the
slightest faith in it. George Stephenson was almost alone, and the
opponents of steam had secured a provision in the Newcastle & Carlisle
Railroad concession, stipulating expressly that horses should there be
exclusively employed. The directors did, however, in 1828, permit
Stephenson to put on the line a locomotive, to be used, during its
construction, in hauling gravel-trains. A committee was sent, at
Stephenson's request, to see the Stockton & Darlington engines, but no
decided expression of opinion seems to have been made by them. Two
well-known professional engineers reported in favor of fixed engines,
and advised the division of the line into 19 stages of about a mile
and a half each, and the use of 21 fixed engines, although they
admitted the excessive first-cost of that system. The board was
naturally strongly inclined to adopt their plan. Stephenson, however,
earnestly and persistently opposed such action, and, after long
debate, it was finally determined "to give the traveling engine a
chance." The board decided to offer a reward of £500 for the best
locomotive-engine, and prescribed the following conditions:

  1. The engine must consume its own smoke.

  2. The engine, if of 6 tons weight, must be able to draw after it,
  day by day, 20 tons weight (including the tender and water-tank) at
  10 miles an hour, with a pressure of steam on the boiler not
  exceeding 50 pounds to the square inch.

  3. The boiler must have two safety-valves, neither of which must be
  fastened down, and one of them completely out of the control of the
  engine-man.

  4. The engine and boiler must be supported on springs, and rest on 6
  wheels, the height of the whole not exceeding 15 feet to the top of
  the chimney.

  5. The engine, with water, must not weigh more than 6 tons; but an
  engine of less weight would be preferred, on its drawing a
  proportionate load behind it; if of only 4-1/2 tons, then it might
  be put only on 4 wheels. The company to be at liberty to test the
  boiler, etc., by a pressure of 150 pounds to the square inch.

  6. A mercurial gauge must be affixed to the machine, showing the
  steam-pressure above 45 pounds to the square inch.

  7. The engine must be delivered, complete and ready for trial, at
  the Liverpool end of the railway, not later than the 1st of October,
  1829.

  8. The price of the engine must not exceed £550.

This circular was printed and published throughout the kingdom, and a
considerable number of engines were constructed to compete at the
trial, which was proposed to take place October 1, 1829, but which was
deferred to the 6th of that month. Only four engines, however, were
finally entered on the day of the trial. These were the "Novelty,"
constructed by Messrs. Braithwaite & Ericsson, the latter being the
distinguished engineer who subsequently came to the United States to
introduce screw-propulsion, and, later, the monitor system of
iron-clads; the "Rocket," built from Stephenson's plans; and the
"Sanspareil" and the "Perseverance," built by Hackworth and Burstall,
respectively.

The "Sanspareil," which was built under the direction of Timothy
Hackworth, one of Stephenson's earlier foremen, resembled the engine
built by the latter for the Stockton & Darlington road, but was
heavier than had been stipulated, was not ready for work when called,
and, when finally set at work, proved to be very extravagant in its
use of fuel, partly in consequence of the extreme intensity of its
blast, which caused the expulsion of unconsumed coals from the
furnace.

The "Perseverance" could not attain the specified speed, and was
withdrawn.

[Illustration: FIG. 54.--The "Novelty," 1829.]

The "Novelty" was apparently a well-designed and for that time a
remarkably well-proportioned machine. _A_, in Fig. 54, is the boiler,
_D_ the steam-cylinders, _E_ a heater. Its weight but slightly
exceeded three tons, and it was a "tank engine," carrying its own fuel
and water at _B_. A forced draught was obtained by means of the
bellows, _C_. This engine was run over the line at the rate of about
28 miles an hour at times, but its blowing apparatus failed, and the
"Rocket" held the track alone. A later trial still left the "Rocket"
alone in the field.

The "Rocket" (Fig. 55) was built at the works of Robert Stephenson &
Co., at Newcastle-upon-Tyne. The boiler was given considerable
heating-surface by the introduction of 25 3-inch copper tubes, at the
suggestion of Henry Booth, secretary of the railroad company. The
blast was altered by gradually closing in the opening at the extremity
of the exhaust-pipe, and thus "sharpening" it until it was found to
have the requisite intensity. The effect of this modification of the
shape of the pipe was observed carefully by means of syphon
water-gauges attached to the chimney. The draft was finally given such
an intensity as to raise the water 3 inches in the tube of the
draught-gauge. The total length of the boiler was 6 feet, its
diameter 40 inches. The fire-box was attached to the rear of the
boiler, and was 3 feet high and 2 feet wide, with water-legs to
protect its side-sheets from injury by overheating. The cylinders, as
seen in the sketch, were inclined, and coupled to a single pair of
driving-wheels. A tender, attached to the engine, carried the fuel and
water. The engine weighed less than 4-1/2 tons.

[Illustration: FIG. 55.--The "Rocket," 1829.]

The little engine does not seem to have been very prepossessing in
appearance, and the "Novelty" is said to have been the general
favorite, the Stephenson engine having few, if any, backers among the
spectators. On its first trial, it ran 12 miles in less than an hour.

After the accident which disabled the "Novelty," the "Rocket" came
forward again, and ran at the rate of from 25 to 30 miles an hour,
drawing a single carriage carrying 30 passengers. Two days later, on
the 8th of October, steam was raised in a little less than an hour
from cold water, and it then, with 13 tons of freight in the train,
ran 35 miles in 1 hour and 48 minutes, including stops, and attained a
speed of 29 miles an hour. The average of all runs for the trial was
15 miles an hour.

This success, far exceeding the expectation of the most sanguine of
the advocates of the system, and greatly exceeding what had been
asserted by opponents to be the bounds of possibility, settled
completely the whole question, and the Manchester & Liverpool road was
at once equipped with locomotive engines.

The "Rocket" remained on the line until 1837, when it was sold, and
set at work by the purchasers on the Midgeholme Railway, near
Carlisle. On one occasion, on this road, it was driven 4 miles in
4-1/2 minutes. It is now in the Patent Museum at South Kensington,
London.

In January, 1830, a single line of rails had been carried across Chat
Moss, and, six months later, the first train, drawn by the "Arrow,"
ran through, June 14th, from Liverpool to Manchester, making the trip
in an hour and a half, and attaining a maximum speed of over 27 miles
an hour. The line was formally opened to traffic September 15, 1830.

This was one of the most notable occasions in the history of the
railroad, and the successful termination of the great work was
celebrated, as so important an event should be, by impressive
ceremonies. Among the distinguished spectators were Sir Robert Peel
and the Duke of Wellington. Mr. Huskisson, a Member of Parliament for
Liverpool, was also present. There had been built for the line, by
Robert Stephenson & Co., 7 locomotives besides the "Rocket," and a
large number of carriages. These were all brought out in procession,
and 600 passengers entered the train, which started for Manchester,
and ran at times, on smooth portions of the road, at the rate of 20
and 25 miles an hour. Crowds of people along the line cheered at this
strange and to them incomprehensible spectacle, and the story of the
wonderful performances of that day on the new railroad was repeated in
every corner of the land. A sad accident, the precursor of thousands
to follow the introduction of the new method of transportation, while
it repressed the rising enthusiasm of the people and dampened the
ardor of the most earnest of the advocates of the railroad, occurring
during this trip, assisted in making known the power of the new motor
and the danger attending its use as well. The trains stopped for water
at Parkside, and occasion was taken to send the "Northumbrian," an
engine driven by George Stephenson himself, on a side track, with the
carriage containing the Duke of Wellington, and the other engines and
trains were all directed to be sent along the main track in view of
the Duke and his party. While this movement was in process of
execution, Mr. Huskisson, who had carelessly stood on the main line
until the "Rocket," which led the column, had nearly reached him,
attempted to enter the carriage of the Duke. He was too late, and was
struck by the "Rocket," thrown down across the rail, and the advancing
engine crushed a leg so seriously that he died the same evening.
Immediately after the accident, he was placed on the "Northumbrian,"
and Stephenson made the 15 miles to the destination of the wounded man
in 25 minutes--a speed of 36 miles an hour. The news of this accident,
and the statement of the velocity of the engine, were published
throughout the kingdom and Europe; and the misfortune of this first
victim of a railroad accident was one of the causes of the immediate
adoption and rapid spread of the modern railway system.

This road, which was built in the hope of securing 400 passengers per
day, almost immediately averaged 1,200, and in five years reported
500,000 passengers for the year.[54] The success of this road insured
the general introduction of railroads, and from this time forward
there was never a doubt of their ultimate adoption to the exclusion
of every other system of general internal communication and
transportation.

  [54] Smiles.

For some years after this his first great triumph, George Stephenson
gave his whole time to the building of railroads and the improvement
of the engine. He was assisted by his son Robert, to whom he gradually
surrendered his business, and retired to Tapton House, on the Midland
Railway, and led a busy but pleasant life during the remaining years
of his existence.

Even as early as 1840, he seems to have projected many improvements
which were only generally adopted many years later. He proposed
self-acting and continuous systems of brake, and considered a good
system of brake of so great importance, that he advocated their
compulsory introduction by State legislation. He advised moderate
speeds, from considerations both of safety and of expense.

A few years after the opening of the Liverpool & Manchester road,
great numbers of schemes were proposed by ignorant or designing men,
which had for their object the filling of the pockets of their
proposers rather than the benefit of the stockholders and the public;
and the Stephensons were often called upon to combat these crude and
ill-digested plans. Among these was the pneumatic system of
propulsion, already referred to as first proposed by Papin, in
combination with his double-acting air-pump, in 1687. It had been
again proposed in the early part of the present century by Medhurst,
who proposed a method of pneumatic transmission of small parcels and
of letters, which is now in use, and, 15 years later, a railroad to
take the place of that of Stephenson and his coadjutors. The most
successful of several attempts to introduce this method was that of
Clegg & Samuda, at West London, and on the London & Croydon road, and
again in Ireland, between Kingstown and Dalkey. A line of pipe, _B B_,
seen in Fig. 56, two feet in diameter, was laid between the rails, _A
A_, of the road. This pipe was fitted with a nicely-packed piston,
carrying a strong arm, which rose through a slit made along the top of
the pipe, and covered by a flexible strip of leather, _E E_. This arm
was attached to the carriage, _C C_, to be propelled. The pressure of
the atmosphere being removed, by the action of a powerful pump, from
the side toward which the train was to advance, the pressure of the
atmosphere on the opposite side drove the piston forward, carrying the
train with it. Stephenson was convinced, after examining the plans of
the projectors, that the scheme would fail, and so expressed himself.
Those who favored it, however, had sufficient influence with
capitalists to secure repeated trials, although each was followed by
failure, and it was several years before the last was heard of this
system.

[Illustration: FIG. 56.--The Atmospheric Railroad.]

A considerable portion of several of the later years of Stephenson's
life was spent in traveling in Europe, partly on business and partly
for pleasure. During a visit to Belgium in 1845, he was received
everywhere, and by all classes, from the king down to the humblest of
his subjects, with such distinction as is rarely accorded even to the
greatest men. He soon after visited Spain with Sir Joshua Walmsley, to
report on a proposed railway from the capital to the Bay of Biscay. On
this journey he was taken ill, and his health was permanently
impaired. Thenceforward he devoted himself principally to the
direction of his own property, which had become very considerable, and
spent much of his time at the collieries and other works in which he
had invested it. His son had now entirely relieved him of all business
connected with railroads, and he had leisure to devote to
self-improvement and social amusement. Among his friends he claimed
Sir Robert Peel, his old acquaintance, now Sir William, Fairbairn, Dr.
Buckland, and many others of the distinguished men of that time.

In August, 1848, Stephenson was attacked with intermittent fever,
succeeded by hæmorrhage from the lungs, and died on the 12th of that
month, at the age of sixty-six years, honored of all men, and secure
of an undying fame. Soon after his death, statues were erected at
Liverpool, London, and Newcastle, the cost of the second of which was
defrayed by private subscriptions, including a contribution of about
$1,500 by 3,150 workingmen--one of the finest tributes ever offered to
the memory of a great man.

But the noblest monument is that which he himself erected by the
establishment of a system of education and protection of his
working-people at Clay Cross. He made it a condition of employment
that every employé should contribute from five to twelve pence each
fortnight to a fund, to which the works also made liberal
contributions. From that fund it was directed that the expenses of
free education of the children of the work-people, night-schools for
those employed in the works, a reading-room and library, medical
treatment, and a benevolent fund were to be defrayed. Music and
cricket-clubs, and prize funds for the best garden, were also founded.
The school, public hall, and the church of Clay Cross, and this noble
system of support, are together a nobler monument than any statue or
similar structure could be.

The character of George Stephenson was in every way admirable. Simple,
earnest, and honorable; courageous, indomitable, and industrious;
humorous, kind, and philanthropic, his memory will long be cherished,
and will long prove an incentive to earnest effort and to the pursuit
of an honorable fame with hundreds of the youth who, reading his
simple yet absorbing story, as told by his biographer, shall in later
years learn to know him.

[Illustration: FIG. 57.--Stephenson's Locomotive, 1833.]

After the death of his father, Robert Stephenson continued, as he had
already done for several years, to conduct the business of building
locomotives, as well as of constructing railroads. The work of
locomotive engine-building was done at Newcastle, and for many years
those works were the principal engine-building establishment of the
world.

After their introduction on the Liverpool & Manchester road, the
engines of the firm of Robert Stephenson & Co. were rapidly modified,
until they assumed the form shown in Fig. 57, which remained standard
until their gradual increase in weight compelled the builders to place
a larger number of wheels beneath them, and make those other changes
which finally resulted in the creation of distinct types for special
kinds of work. In the engine of 1833, as shown above, the cylinders,
_A_, are carried at the extreme forward end of the boiler, and the
driving-wheels, _B_, are coupled directly to the connecting-rod of the
engine and to each other. A buffer, _C_, extends in front, and the
rear end of the boiler is formed into a rectangular fire-box, _D_,
continuous with the shell, _E_, and the flame and gases pass to the
connection and smoke-pipe, _F_, _G_, through a large number of small
tubes, _a_. Steam is led to the cylinders by a steam-pipe, _H H_, to
which it is admitted by the throttle-valve, _b_. A steam-dome, _I_,
from which the steam is taken, assists by giving more steam-space far
above the water-line, and thus furnishing dry steam. The exhaust steam
issues with great velocity into the chimney from the pipe, _J_, giving
great intensity of draught. The engine-driver stands on the platform,
_K_, from which all the valves and handles are accessible. Feed-pumps,
_L_, supply the boiler with water, which is drawn from the tender
through the pipes, _e_, _f_.

The valve-gear was then substantially what it is to-day, the
"Stephenson link" (Fig. 58). On the driving-axle were keyed two
eccentrics, _E_, so set that the motion of the one was adapted to
driving the valve when the engine was moving forward, and the other
was arranged to move the valve when running backward. The former was
connected, through its strap and the rod, _B_, to the upper end of a
"strap-link," _A_, while the second was similarly connected with the
lower end. By means of a handle, _L_, and the link, _n_, and its
connections, including the counterweighted bell-crank, _M_, this link
could be raised or depressed, thus bringing the pin on the link-block,
to which the valve-stem was connected, into action with either
eccentric. Or, the link being set in mid-gear, the valve would cover
both steam-ports of the cylinder, and the engine could move neither
way. As shown, the engine is in position to run backward. A series of
notches, _Z_, into either of which a catch on _L_ could be dropped,
enabled the driver to place the link where he chose. In intermediate
positions, between mid-gear and full-gear, the motion of the valve is
such as to produce expansion of the steam, and some gain in economy of
working, although reducing the power of the engine.

[Illustration: FIG. 58.--The Stephenson Valve-Gear, 1833.]

The success of the railroad and the locomotive in Great Britain led to
its rapid introduction in other countries. In France, as early as
1823, M. Beaunier was authorized to construct a line of rails from the
coal-mines of St. Étienne to the Loire, using horses for the traction
of his trains; and in 1826, MM. Seguin began a road from St. Étienne
to Lyons. In 1832, engines built at Lyons were substituted for horses
on these roads, but internal agitations interrupted the progress of
the new system in France, and, for 10 years after the opening
of the Manchester & Liverpool road, France remained without
steam-transportation on land.

In Belgium the introduction of the locomotive was more promptly
accomplished. Under the direction of Pierre Simon, an enterprising and
well-informed young engineer, who had become known principally as an
advocate of the even then familiar project of a canal across the
Isthmus of Darien, very complete plans of railroad communication for
the kingdom were prepared, in compliance with a decree dated July 31,
1834, and were promptly authorized. The road between Brussels and
Mechlin was opened May 6, 1837, and other roads were soon built; and
the railway system of Belgium was the first on the Continent of
Europe.

The first German railroad worked with locomotive steam-engines was
that between Nuremberg and Fürth, built under the direction of M.
Denis. The other European countries soon followed in this rapid march
of improvement.

In the United States, public attention had been directed to this
subject, as has already been stated, very early in the present
century, by Evans and Stevens. At that time the people of the United
States, as was natural, closely watched every important series of
events in the mother-country; and so remarkable and striking a change
as that which was taking place in the time of Stephenson, in methods
of communication and transportation, could not fail to attract general
attention and awaken universal interest.

Notwithstanding the success of the early experiments of Evans and
others, and in spite of the statesmanlike arguments of Stevens and
Dearborn, and the earnest advocacy of the plan by all who were
familiar with the revelations which were daily made of the power and
capabilities of the steam-engine, it was not until after the opening
of the Manchester & Liverpool road that any action was taken looking
to the introduction of the locomotive. Colonel John Stevens, in 1825,
had built a small locomotive, which he had placed on a circular
railway before his house--now Hudson Terrace--at Hoboken, to prove
that his statements had a basis of fact. This engine had two "lantern"
tubular boilers, each composed of small iron tubes, arranged
vertically in circles about the furnaces.[55] This exhibition had no
other effect, however, than to create some interest in the subject,
which aided in securing a rapid adoption of the railroad when once
introduced.

  [55] One of these sectional boilers is still preserved in the
  lecture-room of the author, at the Stevens Institute of Technology.

The first line of rails in the New England States is said to have been
laid down at Quincy, Mass., from the granite quarry to the Neponset
River, three miles away, in 1826 and 1827. That between the coal-mines
of Mauch Chunk, Pa., and the river Lehigh, nine miles distant, was
built in 1827. In the following year the Delaware & Hudson Canal
Company built a railroad from their mines to the termination of the
canal at Honesdale. These roads were worked either by gravity or by
horses and mules.

The competition at Rainhill, on the Liverpool and Manchester Railroad,
had been so widely advertised, and promised to afford such conclusive
evidence relative to the value of the locomotive steam-engine and the
railroad, that engineers and others interested in the subject came
from all parts of the world to witness the trial. Among the strangers
present were Mr. Horatio Allen, then chief-engineer of the Delaware &
Hudson Canal Company, and Mr. E. L. Miller, a resident of Charleston,
S. C., who went from the United States for the express purpose of
seeing the new machines tested.

Mr. Allen had been authorized to purchase, for the company with which
he was connected, three locomotives and the iron for the road, and had
already shipped one engine to the United States, and had set it at
work on the road. This engine was received in New York in May, 1829,
and its trial took place in August at Honesdale, Mr. Allen himself
driving the engine. But the track proved too light for the locomotive,
and it was laid up and never set at regular work. This engine was
called the "Stourbridge Lion"; it was built by Foster, Rastrick & Co.,
of Stourbridge, England. During the summer of the next year, a small
experimental engine, which was built in 1829 by Peter Cooper, of New
York, was successfully tried on the Baltimore & Ohio Railroad, at
Baltimore, making 13 miles in less than an hour, and moving, at some
points on the road, at the rate of 18 miles an hour. One carriage
carrying 36 passengers was attached. This was considered a
working-model only, and was rated at one horse-power.

Ross Winans, writing of this trial of Cooper's engine, makes a
comparison with the work done by Stephenson's "Rocket," and claims a
decided superiority for the former. He concluded that the trial
established fully the practicability of using locomotives on the
Baltimore & Ohio road at high speeds, and on all its curves and heavy
gradients, without inconvenience or danger.

This engine had a vertical tubular boiler, and the draught was urged,
like that of the "Novelty" at Liverpool, by mechanical means--a
revolving fan. The single steam-cylinder was 3-1/4 inches in diameter,
and the stroke of piston 14-1/2 inches. The wheels were 30 inches in
diameter, and connected to the crank-shaft by gearing. The engine, on
the trial, worked up to 1.43 horse-power, and drew a gross weight of
4-1/2 tons. Mr. Cooper, unable to find such tubes as he needed for his
boiler, used gun-barrels. The whole machine weighed less than a ton.

Messrs. Davis & Gartner, a little later, built the "York" for this
road--a locomotive having also a vertical boiler, of very similar form
to the modern steam fire-engine boiler, 51 inches in diameter, and
containing 282 fire-tubes, 16 inches long, and tapering from 1-1/2
inches diameter at the bottom to 1-1/4 at the top, where the gases
were discharged through a combustion-chamber into a steam-chimney.
This engine weighed 3-1/2 tons.

They subsequently built several "grasshopper" engines (Fig. 59), some
of which ran many years, doing good work, and one or two of which are
still in existence. The first--the "Atlantic"--was set at work in
September, 1832, and hauled 50 tons from Baltimore 40 miles, over
gradients having a maximum rise of 37 feet to the mile, and on curves
having a minimum radius of 400 feet, at the rate of 12 to 15 miles an
hour. This engine weighed 6-1/2 tons, carried 50 pounds of steam--a
pressure then common on both continents --and burned a ton of
anthracite coal on the round trip. The blast was secured by a fan, and
the valve-gear was worked by cams instead of eccentrics. This engine
made the round trip at a cost of $16, doing the work of 42 horses,
which had cost $33 per trip. The engine cost $4,500, and was designed
by Phineas Davis, assisted by Ross Winans.

[Illustration: FIG. 59.--The "Atlantic," 1882.]

Mr. Miller, on his return from the Liverpool & Manchester trial,
ordered a locomotive for the Charleston & Hamburg Railroad from the
West Point Foundery. This engine was guaranteed by Mr. Miller to draw
three times its weight at the rate of 10 miles an hour. It was built
during the summer of 1830, from the plans of Mr. Miller, and reached
Charleston in October. The trials were made in November and December.

[Illustration: FIG. 60.--The "Best Friend," 1830.]

This engine (Fig. 60) had a vertical tubular boiler, in which the
gases rose through a very high fire-box, into which large numbers of
rods projected from the sides and top, and passed out through tubes
leading them laterally outward into an outside jacket, through which
they rose to the chimney. The steam-cylinders were two in number, 8
inches in diameter and of 16 inches stroke, inclined so as to connect
with the driving-axle. The four wheels were all of the same size,
4-1/2 feet in diameter, and connected by coupling-rods. The engine
weighed 4-1/2 tons. The "Best Friend," as it was called, did excellent
work until June, 1831, when the explosion of the boiler, in
consequence of the recklessness of the fireman, unexpectedly closed
its career.

A second engine (Fig. 61) was built for this road, at the West Point
Foundery, from plans furnished by Horatio Allen, and was received and
set at work early in the spring of 1831. The engine, called the "West
Point," had a horizontal tubular boiler, but was in other respects
very similar to the "Best Friend." It is said to have done very good
work.

[Illustration: FIG. 61.--The "West Point," 1831.]

The Mohawk & Hudson Railroad ordered an engine at about this time,
also, of the West Point Foundery, and the trials, made in July and
August, 1831, proved thoroughly successful.

This engine, the "De Witt Clinton," was contracted for by John B.
Jervis, and fitted up by David Matthew. It had two steam-cylinders,
each 5-1/2 inches in diameter and 16 inches stroke of piston. The
connecting-rods were directly attached to a cranked axle, and turned
four coupled wheels 4-1/2 feet in diameter. These wheels had cast-iron
hubs and wrought-iron spokes and tires. The tubes were of copper,
2-1/2 inches in diameter and 6 feet long. The engine weighed 3-1/2
tons, and hauled 5 cars at the rate of 30 miles an hour.

Another engine, the "South Carolina" (Fig. 62), was designed by
Horatio Allen for the South Carolina Railroad, and completed late in
the year 1831. This was the first eight-wheeled engine, and the
prototype, also, of a peculiar and lately-revived form of engine.

In the summer of 1832, an engine built by Messrs. Davis & Gartner, of
York, Pa., was put on the Baltimore & Ohio road, which at times
attained a speed, unloaded, of 30 miles an hour. The engine weighed
3-1/2 tons, and drew, usually, 4 cars, weighing altogether 14 tons,
from Baltimore to Ellicott's Mills, a distance of 13 miles, in the
schedule-time, one hour.

[Illustration: FIG. 62.--The "South Carolina," 1831.]

Horatio Allen's engine on the South Carolina Railroad is said to have
been the first eight-wheeled engine ever built.

It was at about the time of which we are now writing that the first
locomotive was built of what is now distinctively known as the
American type--an engine with a "truck" or "bogie" under the forward
end of the boiler. This was the "American" No. 1, built at the West
Point Foundery, from plans furnished by John B. Jervis, Chief
Engineer, for the Mohawk & Hudson Railroad. Ross Winans had already
(1831) introduced the passenger-car with swiveling trucks.[56] It was
completed in August, 1832, and is said by Mr. Matthew to have been an
extremely fast and smooth-running engine. A mile a minute was
repeatedly attained, and it is stated by the same authority,[57] that
a speed of 80 miles an hour was sometimes made over a single mile.
This engine had cylinders 9-1/2 inches diameter, 16 inches stroke of
piston, two pairs of driving-wheels, coupled, 5 feet in diameter each;
and the truck had four 33-inch wheels. The boiler contained tubes 3
inches in diameter, and its fire-box was 5 feet long and 2 feet 10
inches wide. Robert Stephenson & Co. subsequently built a similar
engine, from the plans of Mr. Jervis, and for the same road. It was
set at work in 1833. In both engines the driving-wheels were behind
the fire-box. This engine is another illustration of the fact--shown
by the description already given of other and earlier engines--that
the independence of the American mechanic, and the boldness and
self-confidence which have to the present time distinguished him, were
among the earliest of the fruits of our political independence and
freedom.

  [56] "History of the First Locomotives in America," Brown.

  [57] "Ross Winans _vs._ The Eastern Railroad Company--Evidence."
  Boston, 1854.

These American engines were all designed to burn anthracite coal. The
English locomotives all burned bituminous coal.

Robert L. Stevens, the President and Engineer of the Camden & Amboy
Railroad, and a distinguished son of Colonel John Stevens, of Hoboken,
was engaged, at the time of the opening of the Liverpool & Manchester
Railroad, in the construction of the Camden & Amboy Railroad. It was
here that the first of the now standard form of _T_-rail was laid
down. It was of malleable iron, and of the form shown in the
accompanying figure. It was designed by Mr. Stevens, and is known in
the United States as the "Stevens" rail. In Europe, where it was
introduced some years afterward, it is sometimes called the
"Vignolles" rail. He purchased an engine of the Stephensons soon after
the trial at Rainhill, and this engine, the "John Bull," was set up on
the then uncompleted road at Bordentown, in the year 1831. Its first
public trial was made in November of that year. The road was opened
for traffic, from end to end, two years later. This engine had
steam-cylinders 9 inches in diameter, 2 feet stroke of piston, one
pair of drivers 4-1/2 feet in diameter, and weighed 10 tons. This
engine, and that built by Phineas Davis for the Baltimore & Ohio
Railroad, were exhibited at the Centennial Exhibition at Philadelphia,
in the year 1876.

[Illustration: FIG. 63.--The "Stevens" Rail. Enlarged Section.]

[Illustration: FIG. 64.--"Old Ironsides," 1832.]

Engines supplied to the Camden & Amboy Railroad subsequent to 1831
were built from the designs of Robert L. Stevens, in the shop of the
Messrs. Stevens, at Hoboken. The other principal roads of the country,
at first, very generally purchased their engines of the Baldwin
Locomotive Works, then a small shop owned by Matthias W. Baldwin.
Baldwin's first engine was a little model built for Peale's Museum, to
illustrate to the visitors of that then well-known place of
entertainment the character of the new motor, the success of which,
at Rainhill, had just then excited the attention of the world. This
was in 1831, and the successful working of this little model led to
his receiving an order for an engine from the Philadelphia &
Germantown Railroad. Mr. Baldwin, after studying the new engine of the
Camden & Amboy road, made his plans, and built an engine (Fig. 64),
completing it in the autumn of 1832, and setting it in operation
November 23d of that year. It was kept at work on that line of road
for a period of 20 years or more. This engine was of Stephenson's
"Planet" class, mounted on two driving-wheels 4-1/2 feet in diameter
each, and two separate wheels of the same size, uncoupled. The
steam-cylinders were 9-1/2 inches in diameter, 18 inches stroke of
piston, and were placed horizontally on each side of the smoke-box.
The boiler, 2-1/2 feet in diameter, contained 72 copper tubes 1-1/2
inches in diameter and 7 feet long. The engine cost the railroad
company $3,500. On the trial, steam was raised in 20 minutes, and the
maximum speed noted was 28 miles an hour. The engine subsequently
attained a speed of over 30 miles. In 1834, Mr. Baldwin completed for
Mr. E. L. Miller, of Charleston, a six-wheeled engine, the "E. L.
Miller" (Fig. 65), with cylinders 10 inches in diameter and 16 inches
stroke of piston. He made the boiler of this engine of a form which
remained standard many years, with a high dome over the fire-box. At
about the same time, he built the "Lancaster," an engine resembling
the "Miller," for the State road to Columbia, and several others were
soon contracted for and built. By the end of 1834, 5 engines had been
built by him, and the construction of locomotive-engines had become
one of the leading and most promising industries of the United States.
Mr. William Norris established a shop in Philadelphia in 1832, which
he gradually enlarged until it, like the Baldwin Works, became a large
establishment. He usually built a six-wheeled engine, with a
leading-truck or bogie, and placed his driving-wheels in front of the
fire-box.

[Illustration: FIG. 65.--The "E. L. Miller," 1834.]

At this time the English locomotives were built to carry 60 pounds of
steam. The American builders adopted pressures of 120 to 130 pounds
per square inch, the now generally standard pressures throughout the
world. In the years 1836 and 1837, Baldwin built 80 engines. They were
of three classes: 1st, with cylinders 12-1/2 inches in diameter and of
16 inches stroke, weighing 12 tons; 2d, with cylinders 12 by 16, and
a weight of 10-1/2 tons; and 3d, engines weighing 9 tons, and having
steam-cylinders of 10-1/2 inches diameter and of the same stroke. The
driving-wheels were usually 4-1/2 feet in diameter, and the cylinder
"inside-connected" to cranked axles. A few "outside-connected" engines
were made, this plan becoming generally adopted at a later period.

The railroads of the United States were very soon supplied with
locomotive-engines built in America. In the year 1836, William Norris,
who had two years before purchased the interest of Colonel Stephen H.
Long, an army-officer who patented and built locomotives of his own
design, built the "George Washington," and set it at work. This
engine, weighing 14,400 pounds, drew 19,200 pounds up an incline 2,800
feet long, rising 369 feet to the mile, at the speed of 15-1/2 miles
an hour. This showed an adhesion not far from one-third the weight on
the driving-wheels. This was considered a very wonderful performance,
and it produced such an impression at the time, that several copies of
the "George Washington" were made, on orders from British railroads,
and the result was the establishment of the reputation of the
locomotive-engine builders of the United States upon a foundation
which has never since failed them. The engine had Jervis's
forward-truck, now always seen under standard engines, which had
already been placed under railroad-cars by Ross Winans.

In New England, the Locks & Canals Company, of Lowell, began building
engines as early as 1834, copying the Stephenson engine. Hinckley &
Drury, of Boston, commenced building an outside-connected engine in
1840, and their successors, the Boston Locomotive Works, became the
largest manufacturing establishment of the kind in New England. Two
years later, Ross Winans, the Baltimore builder, introduced some of
his engines upon Eastern railroads, fitting them with upright boilers,
and burning anthracite coal.

The changes which have been outlined produced the now typical American
locomotive. It was necessarily given such form that it would work
safely and efficiently on rough, ill-ballasted, and often
sharply-winding tracks; and thus it soon became evident that the two
pairs of coupled driving-wheels, carrying two-thirds the weight of the
whole engine, the forward-truck, and the system of "equalizing"
suspension-bars, by which the weight is distributed fairly among all
the wheels, whatever the position of the engine, or whatever the
irregularity of the track, made it the very best of all known types of
locomotive for the railroads of a new country. Experience has shown it
equally excellent on the smoothest and best of roads. The
"cow-catcher," placed in front to remove obstacles from the track, the
bell, and the heavy whistle, are characteristics of the American
engine also. The severity of winter-storms compelled the adoption of
the "cab," or house, and the use of wood for fuel led to the invention
of the "spark-arrester" for that class of engines. The heavy grades on
many roads led to the use of the "sand-box," from which sand was
sprinkled on the track, to prevent the slipping of the wheels.

In the year 1836, the now standard chilled wheel was introduced for
cars and trucks; the single eccentric, which had been, until then,
used on Baldwin engines, was displaced by the double eccentric, with
hooks in place of the link; and, a year later, the iron frame took the
place of the previously-used wooden frame on all engines.

The year 1837 introduced a period of great depression in all branches
of industry, which continued until the year 1840, or later, and
seriously checked all kinds of manufacturing, including the building
of locomotives. On the revival of business, numbers of new
locomotive-works were started, and in these establishments originated
many new types of engine, each of the more successful of which was
adapted to some peculiar set of conditions. This variety of type is
still seen on nearly all of the principal roads.

The direction of change in the construction of locomotive-engines at
the period at which this division of the subject terminates is very
well indicated in a letter from Robert Stephenson to Robert L.
Stevens, dated 1833, which is now preserved at the Stevens Institute
of Technology. He writes: "I am sorry that the feeling in the United
States in favor of light railways is so general. In England we are
making every succeeding railway stronger and more substantial." He
adds: "Small engines are losing ground, and large ones are daily
demonstrating that powerful engines are the most economical." He gives
a sketch of his latest engine, weighing _nine tons_, and capable, as
he states, of "taking 100 tons, gross load, at the rate of 16 or 17
miles an hour on a level." To-day there are engines built weighing 70
tons, and our locomotive-builders have standard sizes guaranteed to
draw over 2,000 tons on a good and level track.

[Illustration]




CHAPTER V.

_THE MODERN STEAM-ENGINE._

  "Voilà la plus merveilleuse de toutes les Machines; le Mécanisme
  ressemble à celui des animaux. La chaleur est le principe de son
  mouvement; il se fait dans ses différens tuyaux une circulation,
  comme celle du sang dans les veines, ayant des valvules qui
  s'ouvrent et se ferment à propos; elles se nourrit, s'évacue d'elle
  même dans les temps réglés, et tire de son travail tout ce qu'il lui
  faut pour subsister. Cette Machine a pris sa naissance en
  Angleterre, et toutes les Machines à feu qu'on a construites
  ailleurs que dans la Grande Brétagne ont été exécutées par des
  Anglais."--BELIDOR.

THE SECOND PERIOD OF APPLICATION--1800-1850 (CONTINUED). THE
STEAM-ENGINE APPLIED TO SHIP-PROPULSION.


Among the most obviously important and most inconceivably fruitful of
all the applications of steam which marked the period we are now
studying, is that of the steam-engine to the propulsion of vessels.
This direction of application has been that which has, from the
earliest period in the history of the steam-engine, attracted the
attention of the political economist and the historian, as well as the
mechanician, whenever a new improvement, or the revival of an old
device, has awakened a faint conception of the possibilities attendant
upon the introduction of a machine capable of making so great a force
available. The realization of the hopes, the prophecies, and the
aspirations of earlier times, in the modern marine steam-engine, may
be justly regarded as the greatest of all the triumphs of mechanical
engineering. Although, as has already been stated, attempts were made
at a very early period to effect this application of steam-power, they
were not successful, and the steamship is a product of the present
century. No such attempts were commercially successful until after the
time of Newcomen and Watt, and at the commencement of the nineteenth
century. It is, indeed, but a few years since the passage across the
Atlantic was frequently made in sailing-vessels, and the dangers, the
discomforts, and the irregularities of their trips were most serious.
Now, hardly a day passes that does not see several large and powerful
steamers leaving the ports of New York and Liverpool to make the same
voyages, and their passages are made with such regularity and safety,
that travelers can anticipate with confidence the time of their
arrival at the termination of their voyage to a day, and can cross
with safety and with comparative comfort even amid the storms of
winter. Yet all that we to-day see of the extent and the efficiency of
steam-navigation has been the work of the present century, and it may
well excite our wonder and our admiration.

The history of this development of the use of steam-power illustrates
most perfectly that process of growth of this invention which has been
already referred to; and we can here trace it, step by step, from the
earliest and rudest devices up to those most recent and most perfect
designs which represent the most successful existing types of the
heat-engine--whether considered with reference to its design and
construction, or as the highest application of known scientific
principles--that have yet been seen in even the present advanced state
of the mechanic arts.

The paddle-wheel was used as a substitute for oars at a very early
date, and a description of paddle-wheels applied to vessels, curiously
illustrated by a large wood-cut, may be found in the work of Fammelli,
"De l'artificioses machines," published in old French in 1588.
Clark[58] quotes from Ogilby's edition of the "Odyssey" a stanza
which reads like a prophecy, and almost awakens a belief that the
great poet had a knowledge of steam-vessels in those early times--a
thousand years before the Christian era. The prince thus addresses
Ulysses:

  [58] "Steam and the Steam-Engine."

    "We use nor Helm nor Helms-man. Our tall ships
    Have Souls, and plow with Reason up the deeps;
    All cities, Countries know, and where they list,
    Through billows glide, veiled in obscuring Mist;
    Nor fear they Rocks, nor Dangers on the way."

Pope's translation[59] furnishes the following rendering of Homer's
prophecy:

  [59] "Odyssey," Book VIII., p. 175.

    "So shalt thou instant reach the realm assigned,
    In wondrous ships, self-moved, instinct with mind;

    ...

    Though clouds and darkness veil the encumbered sky,
    Fearless, through darkness and through clouds they fly.
    Though tempests rage, though rolls the swelling main,
    The seas may roll, the tempests swell in vain;
    E'en the stern god that o'er the waves presides,
    Safe as they pass and safe repass the tide,
    With fury burns; while, careless, they convey
    Promiscuous every guest to every bay."

It is stated that the Roman army under Claudius Caudex was taken
across to Sicily in boats propelled by paddle-wheels turned by oxen.
Vulturius gives pictures of such vessels.

This application of the force of steam was very possibly anticipated
600 years ago by Roger Bacon, the learned Franciscan monk, who, in an
age of ignorance and intellectual torpor, wrote:

"I will now mention some wonderful works of art and nature, in which
there is nothing of magic, and which magic could not perform.
Instruments may be made by which the largest ships, with only one man
guiding them, will be carried with greater velocity than if they were
full of sailors," etc., etc.

Darwin's poetical prophecy was published long years before Watt's
engine rendered its partial fulfillment a possibility; and thus, for
many years before even the first promising effort had been made, the
minds of the more intelligent had been prepared to appreciate the
invention when it should finally be brought forward.

The earliest attempt to propel a vessel by steam is claimed by Spanish
authorities, as has been stated, to have been made by Blasco de Garay,
in the harbor of Barcelona, Spain, in 1543. The record, claimed as
having been extracted from the Spanish archives at Simancas, states
the vessel to have been of 200 tons burden, and to have been moved by
paddle-wheels; and it is added that the spectators saw, although not
allowed closely to inspect the apparatus, that one part of it was a
"vessel of boiling water"; and it is also stated that objection was
made to the use of this part of the machine, because of the danger of
explosion.

The account seems somewhat apocryphal, and it certainly led to no
useful results.

In an anonymous English pamphlet, published in 1651, which is supposed
by Stuart to have been written by the Marquis of Worcester, an
indefinite reference to what may probably have been the steam-engine
is made, and it is there stated to be capable of successful
application to propelling boats.

In 1690, Papin proposed to use his piston-engine to drive
paddle-wheels to propel vessels; and in 1707 he applied the
steam-engine, which he had proposed as a pumping-engine, to driving a
model boat on the Fulda at Cassel. In this trial he used the
arrangement of which a sketch has been shown, his pumping-engine
forcing up water to turn a water-wheel, which, in turn, was made to
drive the paddles. An account of his experiments is to be found in
manuscript in the correspondence between Leibnitz and Papin, preserved
in the Royal Library at Hanover. Professor Joy found there the
following letter:[60]

  "Dionysius Papin, Councillor and Physician to his Royal Highness the
  Elector of Cassel, also Professor of Mathematics at Marburg, is
  about to dispatch a vessel of singular construction down the river
  Weser to Bremen. As he learns that all ships coming from Cassel, or
  any point on the Fulda, are not permitted to enter the Weser, but
  are required to unload at Münden, and as he anticipates some
  difficulty, although those vessels have a different object, his own
  not being intended for freight, he begs most humbly that a gracious
  order be granted that his ship may be allowed to pass unmolested
  through the Electoral domain; which petition I most humbly support.

                                                        G. W. LEIBNITZ.
  "HANOVER, _July 13, 1707_."

This letter was returned to Leibnitz, with the following indorsement:

  "The Electoral Councillors have found serious obstacles in the way of
  granting the above petition, and, without giving their reasons, have
  directed me to inform you of their decision, and that, in consequence,
  the request is not granted by his Electoral Highness.

                                                             H. REICHE.
  "HANOVER, _July 25, 1707_."

  [60] _Scientific American_, February 24, 1877.

This failure of Papin's petition was the death-blow to his effort to
establish steam-navigation. A mob of boatmen, who thought they saw in
the embryo steamship the ruin of their business, attacked the vessel
at night, and utterly destroyed it. Papin narrowly escaped with his
life, and fled to England.

In the year 1736, Jonathan Hulls took out an English patent for the
use of a steam-engine for ship-propulsion, proposing to employ his
steamboat in towing. In 1737 he published a well-written pamphlet,
describing this apparatus, which is shown in Fig. 66, a reduced
fac-simile of the plate accompanying his paper.

[Illustration: FIG. 66.--Hulls's Steamboat, 1736.]

He proposed using the Newcomen engine, fitted with a
counterpoise-weight and a system of ropes and grooved wheels, which,
by a peculiar ratchet-like action, gave a continuous rotary motion.
His vessel was to have been used as a tow-boat. He says, in his
description: "In some convenient part of the Tow-boat there is placed
a Vessel about two-3rds full of water, with the Top closed; and this
Vessel being kept Boiling, rarifies the Water into a Steam, this Steam
being convey'd thro' a large pipe into a cylindrical Vessel, and there
condensed, makes a Vacuum, which causes the weight of the atmosphere
to press down on this Vessel, and so presses down a Piston that is
fitted into this Cylindrical Vessel, in the same manner as in Mr.
Newcomen's Engine, with which he raises Water by Fire.

"_P_, the Pipe coming from the Furnace to the Cylinder. _Q_, the
Cylinder wherein the steam is condensed. _R_, the Valve that stops the
Steam from coming into the Cylinder, whilst the Steam within the same
is condensed. _S_, the Pipe to convey the condensing Water into the
Cylinder. _T_, a cock to let in the condensing Water when the Cylinder
is full of Steam and the Valve, _P_, is shut. _U_, a Rope fixed to the
Piston that slides up and down in the Cylinder.

"_Note._ This Rope, _U_, is the same Rope that goes round the wheel,
_D_, in the machine."

In the large division of his plate, _A_ is the chimney; _B_ is the
tow-boat; _C C_ is the frame carrying the engine; _Da_, _D_, and _Db_
are three wheels carrying the ropes _M_, _Fb_, and _Fa_, _M_ being the
rope _U_ of his smaller figure, 30. _Ha_ and _Hb_ are two wheels on
the paddle-shafts, _I I_, arranged with pawls so that the
paddle-wheel, _I I_, always turns the same way, though the wheels _Ha_
and _Hb_ are given a reciprocating motion; _Fb_ is a rope connecting
the wheels in the vessel, _Db_, with the wheels at the stern. Hulls
says:

"When the Weight, _G_, is so raised, while the wheels _Da_, _D_, and
_Db_ are moving backward, the Rope _Fa_ gives way, and the Power of
the Weight, _G_, brings the Wheel _Ha_ forward, and the Fans with it,
so that the Fans always keep going forward, notwithstanding the Wheels
_Da_, _D_, and _Db_ move backward and forward as the Piston moves up
and down in the Cylinder. _L L_ are Teeth for a Catch to drop in from
the Axis, and are so contrived that they catch in an alternate manner,
to cause the Fan to move always forward, for the Wheel _Ha_, by the
power of the weight, _G_, is performing his Office while the other
wheel, _Hb_, goes back in order to fetch another stroke.

"_Note._ The weight, _G_, must contain but half the weight of the
Pillar of Air pressing on the Piston, because the weight, _G_, is
raised at the same time as the Wheel _Hb_ performs its Office, so that
it is in effect two Machines acting alternately, by the weight of one
Pillar of Air, of such a Diameter as the Diameter of the Cylinder is."

The inventor suggests the use of timber guards to protect the wheels
from injury, and, in shallow water, the attachment to the
paddle-shafts of cranks "to strike a Shaft to the Bottom of the River,
which will drive the Vessel forward with the greater Force." He
concludes: "Thus I have endeavoured to give a clear and satisfactory
Account of my New-invented Machine, for carrying Vessels out of and
into any Port, Harbour, or River, against Wind and Tide, or in a Calm;
and I doubt not but whoever shall give himself the Trouble to peruse
this Essay, will be so candid as to excuse or overlook any
Imperfections in the diction or manner of writing, considering the
Hand it comes from, if what I have imagined may only appear as plain
to others as it has done to me, viz., That the Scheme I now offer is
Practicable, and if encouraged will be Useful."

There is no positive evidence that Hulls ever put his scheme to the
test of experiment, although tradition does say that he made a model,
which he tried with such ill success as to prevent his prosecution of
the experiment further; and doggerel rhymes are still extant which
were sung by his neighbors in derision of his folly, as they
considered it.

A prize was awarded by the French Academy of Sciences, in 1752, for
the best essay on the manner of impelling vessels without wind. It was
given to Bernouilli, who, in his paper, proposed a set of vanes like
those of a windmill--a screw, in fact--one to be placed on each side
of the vessel, and two more behind. For a vessel of 100 tons, he
proposed a shaft 14 feet long and 2 inches in diameter, carrying
"eight wheels, for acting on the water, to each of which it" (the
shaft) "is perpendicular, and forms an axis for them all; the wheels
should be at equal distances from each other. Each wheel consists of 8
arms of iron, each 3 feet long, so that the whole diameter of the
wheel is 6 feet. Each of these arms, at the distance of 20 inches from
the centre, carries a sheet-iron plane (or paddle) 16 inches square,
which is inclined so as to form an angle of 60 degrees, both with the
arbor and keel of the vessel, to which the arbor is placed parallel.
To sustain this arbor and the wheels, two strong bars of iron, between
2 and 3 inches thick, proceed from the side of the vessel at right
angles to it, about 2-1/2 feet below the surface of the water." He
proposed similar screw-propellers at the stern, and suggested that
they could be driven by animal or by steam-power.

But a more remarkable essay is quoted by Figuier[61]--the paper of
l'Abbé Gauthier, published in the "Mémoires de la Société Royale des
Sciences et Lettres de Nancy." Bernouilli had expressed the belief
that the best steam-engine then known--that of Newcomen--was not
superior to some other motors. Gauthier proposed to use that engine in
the propulsion of paddle-wheels placed at the side of the vessel. His
plan was not brought into use, but his paper embodied a glowing
description of the advantages to be secured by its adoption. He states
that a galley urged by 26 oars on a side made but 4,320 toises (8,420
meters), or about 5 miles, an hour, and required a crew of 260 men. A
steam-engine, doing the same work, would be ready for action at all
times, could be applied, when not driving the vessel, to raising the
anchor, working the pumps, and to ventilating the ship, while the fire
would also serve to cook with. The engine would occupy less space and
weight than the men, would require less aliment, and that of a less
expensive kind, etc. He would make the boiler safe against explosions
by bands of iron; would make the fire-box of iron, with a water-filled
ash-pit and base-plate. His injection-water was to come from the sea,
and return by a delivery-pipe placed above the water-line. The chains,
usually leading from the end of the beam to the pump-rods, were to be
carried around wheels on the paddle-shaft, which were to be provided
with pawls entering a ratchet, and thus the paddles, having been given
several revolutions by the descent of the piston and the unwinding of
the chain, were to revolve freely while the return-stroke was made,
the chain being hauled down and rewound by the wheel on the shaft, the
latter being moved by a weight. The engine was proposed to be of 6
feet stroke, and to make 15 strokes per minute, with a force of 11,000
pounds.

  [61] "Les Merveilles de la Science."

A little later (1760), a Swiss clergyman, J. A. Genevois, published
in London a paper relating to the improvement of navigation,[62] in
which his plan was proposed of compressing springs by steam or other
power, and applying their effort while recovering their form to
ship-propulsion.

  [62] "Some New Enquiries tending to the Improvement of Navigation."
  London, 1760.

It was at this time that the first attempts were made in the United
States to solve this problem, which had begun to be recognized as one
of the greatest which had presented itself to the mechanic and the
engineer.

WILLIAM HENRY was a prominent citizen of the then little village of
Lancaster, Pa., and was noted as an ingenious and successful
mechanic.[63] He was still living at the beginning of the present
century. Mr. Henry was the first to make the "rag" carpet, and was the
inventor of the screw-auger. He was of a Scotch and North-of-Ireland
family, his father, John Henry, and his two older brothers, Robert and
James, having come to the United States about 1720. Robert settled,
finally, in Virginia, and it is said that Patrick Henry, the patriot
and orator, was of his family. The others remained in Chester County,
Pa., where William was born, in 1729. He learned the trade of a
gunsmith, and, driven from his home during the Indian war (1755 to
1760), settled in Lancaster.

  [63] _Lancaster Daily Express_, December 10, 1872. This account is
  collated from various manuscripts and letters in the possession of
  the author.

In the year 1760 he went to England on business, where his attention
was attracted to the invention--then new, and the subject of
discussion in every circle--of James Watt. He saw the possibility of
its application to navigation and to driving carriages, and, on his
return home, commenced the construction of a steam-engine, and
finished it in 1763.

Placing it in a boat fitted with paddle-wheels, he made a trial of the
new machine on the Conestoga River, near Lancaster, where the craft,
by some accident, sank,[64] and was lost. He was not discouraged by
this failure, but made a second model, adding some improvements. Among
the records of the Pennsylvania Philosophical Society is, or was, a
design, presented by Henry in 1782, of one of his steamboats. The
German traveler Schöpff visited the United States in 1783, and at Mr.
Henry's house, at Lancaster, was shown "a machine by Mr. Henry,
intended for the propelling of boats, etc.; 'but,' said Mr. Henry, 'I
am doubtful whether such a machine would find favor with the public,
as every one considers it impracticable against wind and tide;' but
that such a Boat _will_ come into use and navigate on the waters of
the Ohio and Mississippi, he had not the least doubt of, but the time
had not yet arrived of its being appreciated and applied."

  [64] Bowen's "Sketches," p. 56.

John Fitch, whose experiments will presently be referred to, was an
acquaintance and frequent visitor to the house of Mr. Henry, and may
probably have there received the earliest suggestions of the
importance of this application of steam. About 1777, when Henry was
engaged in making mathematical and philosophical instruments, and the
screw-auger, which at that time could only be obtained of him, Robert
Fulton, then twelve years old, visited him, to study the paintings of
Benjamin West, who had long been a friend and protégé of Henry. He,
too, not improbably received there the first suggestion which
afterward led him to desert the art to which he at first devoted
himself, and which made of the young portrait-painter a successful
inventor and engineer. West's acquaintance with Henry had no such
result. The young painter was led by his patron and friend to attempt
historical pictures,[65] and probably owes his fame greatly to the
kindly and discerning mechanic. Says Galt, in his "Memoirs of Sir
Benjamin West" (London, 1816): "Towards his old friend, William Henry,
of Lancaster City, he always cherished the most grateful affection;
he was the first who urged him to attempt historical composition."

  [65] Some of West's portraits, including those of Mr. and Mrs.
  Henry, were lately in the possession of Mr. John Jordan, of
  Philadelphia.

When, after the invention of Watt, the steam-engine had taken such
shape that it could really work the propelling apparatus of a paddle
or screw vessel, a new impetus was given to the work of its
adaptation. In France, the Marquis de Jouffroy was one of the earliest
to perceive that the improvements of Watt, rendering the engine more
compact, more powerful, and, at the same time, more regular and
positive in its action, had made it, at last, readily applicable to
the propulsion of vessels. The brothers Périer had imported a Watt
engine from Soho, and this was attentively studied by the marquis,[66]
and its application to the paddle-wheels of a steam-vessel seemed to
him a simple problem. Comte d'Auxiron and Chevalier Charles Mounin, of
Follenai, friends and companions of Jouffroy, were similarly
interested, and the three are said to have often discussed the scheme
together, and to have united in devising methods of applying the new
motor.

  [66] Figuier.

In the year 1770, D'Auxiron determined to attempt the realization of
the plans which he had conceived. He resigned his position in the
army, prepared his plans and drawings, and presented them to M.
Bertin, the Prime Minister, in the year 1771 or 1772. The Minister was
favorably impressed, and the King (May 22, 1772) granted D'Auxiron a
monopoly of the use of steam in river-navigation for 15 years,
provided he should prove his plans practicable, and they should be so
adjudged by the Academy.

A company had been formed, the day previous, consisting of D'Auxiron,
Jouffroy, Comte de Dijon, the Marquis d'Yonne, and Follenai, which
advanced the requisite funds. The first vessel was commenced in
December, 1772. When nearly completed, in September, 1774, the boat
sprung a leak, and, one night, foundered at the wharf. After some
angry discussion, during which D'Auxiron was rudely, and probably
unjustly, accused of bad faith, the company declined to advance the
money needed to recover and complete the vessel. They were, however,
compelled by the court to furnish it; but, meantime, D'Auxiron died of
apoplexy, the matter dropped, and the company dissolved. The cost of
the experiment had been something more than 15,000 francs.

The heirs of D'Auxiron turned the papers of the deceased inventor over
to Jouffroy, and the King transferred to him the monopoly held by the
former. Follenai retained all his interest in the project, and the two
friends soon enlisted a powerful adherent and patron, the Marquis
Ducrest, a well-known soldier, courtier, and member of the Academy,
who took an active part in the prosecution of the scheme. M. Jacques
Périer, the then distinguished mechanic, was consulted, and prepared
plans, which were adopted in place of those of Jouffroy. The boat was
built by Périer, and a trial took place in 1774, on the Seine. The
result was unsatisfactory. The little craft could hardly stem the
sluggish current of the river, and the failure caused the immediate
abandonment of the scheme by Périer.

Still undiscouraged, Jouffroy retired to his country home, at
Baume-les-Dames, on the river Doubs. There he carried on his
experiments, getting his work done as best he could, with the rude
tools and insufficient apparatus of a village blacksmith. A Watt
engine and a chain carrying "duck-foot" paddles were his propelling
apparatus. The boat, which was about 14 feet long and 6 wide, was
started in June, 1776. The duck's-foot system of paddles proved
unsatisfactory, and Jouffroy gave it up, and renewed his experiments
with a new arrangement. He placed on the paddle-wheel shaft a
ratchet-wheel, and on the piston-rod of his engine, which was placed
horizontally in the boat, a double rack, into the upper and the lower
parts of which the ratchet-wheel geared. Thus the wheels turned in
the same direction, whichever way the piston was moving. The new
engine was built at Lyons in 1780, by Messrs. Frères-Jean. The new
boat was about 140 feet long and 14 feet wide; the wheels were 14 feet
in diameter, their floats 6 feet long, and the "dip," or depth to
which they reached, was about 2 feet. The boat drew 3 feet of water,
and had a total weight of about 150 tons.

At a public trial of the vessel at Lyons, July 15, 1783, the little
steamer was so successful as to justify the publication of the fact by
a report and a proclamation. The fact that the experiment was not made
at Paris was made an excuse on the part of the Academy for withholding
its indorsement, and on the part of the Government for declining to
confirm to Jouffroy the guaranteed monopoly. Impoverished and
discouraged, Jouffroy gave up all hope of prosecuting his plans
successfully, and reëntered the army. Thus France lost an honor which
was already within her grasp, as she had already lost that of the
introduction of the steam-engine, in the time of Papin.

About 1785, John Fitch and James Rumsey were engaged in experiments
having in view the application of steam to navigation.

Rumsey's experiments began in 1774, and in 1786 he succeeded in
driving a boat at the rate of four miles an hour against the current
of the Potomac at Shepherdstown, W. Va., in presence of General
Washington. His method of propulsion has often been reinvented since,
and its adoption urged with that enthusiasm and persistence which is a
peculiar characteristic of inventors.

Rumsey employed his engine to drive a great pump which forced a stream
of water aft, thus propelling the boat forward, as proposed earlier by
Bernouilli. This same method has been recently tried again by the
British Admiralty, in a gunboat of moderate size, using a centrifugal
pump to set in motion the propelling stream, and with some other
modifications which are decided improvements upon Rumsey's rude
arrangements, but which have not done much more than his toward the
introduction of "Hydraulic or Jet Propulsion," as it is now called.

In 1787 he obtained a patent from the State of Virginia for
steam-navigation. He wrote a treatise "On the Application of Steam,"
which was printed at Philadelphia, where a Rumsey society was
organized for the encouragement of attempts at steam-navigation.

Rumsey died of apoplexy, while explaining some of his schemes before a
London society a short time later, December 23, 1793, at the age of
fifty years. A boat, then in process of construction from his plans,
was afterward tried on the Thames, in 1793, and steamed at the rate of
four miles an hour. The State of Kentucky, in 1839, presented his son
with a gold medal, commemorative of his father's services "in giving
to the world the benefit of the steamboat."

JOHN FITCH was an unfortunate and eccentric, but very ingenious,
Connecticut mechanic. After roaming about until forty years of age, he
finally settled on the banks of the Delaware, where he built his first
steamboat.

In April, 1785, as Fitch himself states, at Neshamony, Bucks County,
Pa., he suddenly conceived the idea that a carriage might be driven by
steam. After considering the subject a few days, his attention was led
to the plan of using steam to propel vessels, and from that time to
the day of his death he was a persistent advocate of the introduction
of the steamboat. At this time, Fitch says, "I did not know that there
was a steam-engine on the earth;" and he was somewhat disappointed
when his friend, the Rev. Mr. Irwin, of Neshamony, showed him a sketch
of one in "Martin's Philosophy."

Fitch's first model was at once built, and was soon after tried on a
small stream near Davisville. The machinery was made of brass, and the
boat was impelled by paddle-wheels. A rough model of his steamboat was
shown to Dr. John Ewing, Provost of the University of Pennsylvania,
who, August 20, 1785, addressed a commendatory letter to an ex-Member
of Congress, William C. Houston, asking him to assist Fitch in
securing the aid of the General Government. The latter referred the
inventor, by a letter of recommendation, to a delegate from New
Jersey, Mr. Lambert Cadwalader. With this, and other letters, Fitch
proceeded to New York, where Congress then met, and made his
application in proper form. He was unsuccessful, and equally so in
attempting to secure aid from the Spanish minister, who desired that
the profits should be secured, by a monopoly of the invention, to the
King of Spain. Fitch declined further negotiation, determined that, if
successful at all, the benefit should accrue to his own countrymen.

In September, 1785, Fitch presented to the American Philosophical
Society, at Philadelphia, a model in which he had substituted an
endless chain and floats for the paddle-wheels, with drawings and a
descriptive account of his scheme. This model is shown in the
accompanying figure.

[Illustration: FIG. 67.--Fitch's Model, 1785.]

In March, 1786, Fitch was granted a patent by the State of New Jersey,
for the exclusive right to the navigation of the waters of the State
by steam, for 14 years. A month later, he was in Philadelphia, seeking
a similar patent from the State of Pennsylvania. He did not at once
succeed, but in a few days he had formed a company, raised $300, and
set about finding a place in which to construct his engine. Henry
Voight, a Dutch watchmaker, a good mechanic, and a very ingenious man,
took an interest in the company, and with him Fitch set about his
work with great enthusiasm. After making a little model, having a
steam-cylinder but one inch in diameter, they built a model boat and
engine, the latter having a diameter of cylinder of three inches. They
tried the endless chain, and other methods of propulsion, without
success, and finally succeeded with a set of oars worked by the
engine. In August, 1786, it was determined by the company to authorize
the construction of a larger vessel; but the money was not readily
obtained. Meantime, Fitch continued his efforts to secure a patent
from the State, and was finally, March 28, 1787, successful. He also
obtained a similar grant from the State of Delaware, in February of
the same year, and from New York, March 19.

Money was now subscribed more freely, and the work on the boat
continued uninterruptedly until May, 1787, when a trial was made,
which revealed many defects in the machinery. The cylinder-heads were
of wood, and leaked badly; the piston leaked; the condenser was
imperfect; the valves were not tight. All these defects were remedied,
and a condenser invented by Voight--the "pipe-condenser"--was
substituted for that defective detail as previously made.

The steamboat was finally placed in working order, and was found
capable, on trial, of making three or four miles an hour. But now the
boiler proved to be too small to furnish steam steadily in sufficient
quantity to sustain the higher speed. After some delay, and much
distress on the part of the sanguine inventor, who feared that he
might be at last defeated when on the very verge of success, the
necessary changes were finally made, and a trial took place at
Philadelphia, in presence of the members of the Convention--then in
session at Philadelphia framing the Federal Constitution--August 22,
1787. Many of the distinguished spectators gave letters to Fitch
certifying his success. Fitch now went to Virginia, where he succeeded
in obtaining a patent, November 7, 1787, and then returned to ask a
patent of the General Government.

A controversy with Rumsey now followed, in which Fitch asserted his
claims to the invention of the steamboat, and denied that Rumsey had
done more than to revive the scheme which Bernouilli, Franklin, Henry,
Paine, and others, had previously proposed, and that Rumsey's
_steamboat_ was not made until 1786.

The boiler adopted in Fitch's boat of 1787 was a "pipe-boiler," which
he had described in a communication to the Philosophical Society, in
September, 1785. It consisted (Fig. 68) of a small water-pipe, winding
backward and forward in the furnace, and terminating at one end at the
point at which the feed-water was introduced, and at the other uniting
with the steam-pipe leading to the engine. Voight's condenser was
similarly constructed. Rumsey claimed that this boiler was copied from
his designs. Fitch brought evidence to prove that Rumsey had not built
such a boiler until after his own.

[Illustration: FIG. 68.--Fitch and Voight's Boiler, 1787.]

[Illustration: FIG. 69.--Fitch's First Boat, 1787.]

Fitch's first boat-engine had a steam-cylinder 12 inches in diameter.
A second engine was now built (1788) with a cylinder 18 inches in
diameter, and a new boat. The first vessel was 45 feet long and 12
feet wide; the new boat was 60 feet long and of but 8 feet breadth of
beam. The first boat (Fig. 69) had paddles worked at the sides, with
the motion given the Indian paddle in propelling a canoe; in the
second boat (Fig. 70) they were similarly worked, but were placed at
the stern. There were three of these paddles. The boat was finally
finished in July, 1788, and made a trip to Burlington, 20 miles from
Philadelphia. When just reaching their destination, their boiler gave
out, and they made their return-trip to Philadelphia floating with the
tide. Subsequently, the boat made a number of excursions on the
Delaware River, making three or four miles an hour.

[Illustration: FIG. 70.--John Fitch, 1788.]

Another of Fitch's boats, in April, 1790, made seven miles an hour.
Fitch, writing of this boat, says that "on the 16th of April we got
our work completed, and tried our boat again; and, although the wind
blew very fresh at the east, we reigned lord high admirals of the
Delaware, and no boat on the river could hold way with us." In June
of that year it was placed as a passenger-boat on a line from
Philadelphia to Burlington, Bristol, Bordentown, and Trenton,
occasionally leaving that route to take excursions to Wilmington and
Chester. During this period, the boat probably ran between 2,000 and
3,000 miles,[67] and with no serious accident. During the winter of
1790-'91, Fitch commenced another steamboat, the "Perseverance," and
gave considerable time to the prosecution of his claim for a patent
from the United States. The boat was never completed, although he
received his patent, after a long and spirited contest with other
claimants, on the 26th of August, 1791, and Fitch lost all hope of
success. He went to France in 1793, hoping to obtain the privilege of
building steam-vessels there, but was again disappointed, and worked
his passage home in the following year.

  [67] "Life of John Fitch," Westcott.

[Illustration: FIG. 71.--John Fitch, 1796.]

In the year 1796, Fitch was again in New York City, experimenting with
a little _screw_ steamboat on the "Collect" Pond, which then covered
that part of the city now occupied by the "Tombs," the city prison.
This little boat was a ship's yawl fitted with a screw, like that
adopted later by Woodcroft, and driven by a rudely-made engine.

Fitch, while in the city of Philadelphia at about this time, met
Oliver Evans, and discussed with him the probable future of
steam-navigation, and proposed to form a company in the West, to
promote the introduction of steam on the great rivers of that part of
the country. He settled at last in Kentucky, on his land-grant, and
there amused himself with a model steamboat, which he placed in a
small stream near Bardstown. His death occurred there in July, 1798,
and his body still lies in the village cemetery, with only a rough
stone to mark the spot.

Both Rumsey and Fitch endeavored to introduce their methods in Great
Britain; and Fitch, while urging the importance and the advantages of
his plan, confidently stated his belief that the ocean would soon be
crossed by steam-vessels, and that the navigation of the Mississippi
would also become exclusively a steam-navigation. His reiterated
assertion, "The day will come when some more powerful man will get
fame and riches from my invention; but no one will believe that poor
John Fitch can do anything worthy of attention," now almost sounds
like a prophecy.

During this period, an interest which had never diminished in Great
Britain had led to the introduction of experimental steamboats in that
country. PATRICK MILLER, of Dalswinton, had commenced experimenting,
in 1786-'87, with boats having double or triple hulls, and propelled
by paddle-wheels placed between the parts of the compound vessel.
James Taylor, a young man who had been engaged as tutor for Mr.
Miller's sons, suggested, in 1787, the substitution of steam for the
manual power which had been, up to that time, relied upon in their
propulsion. Mr. Miller, in 1787, printed a description of his plan of
propelling apparatus, and in it stated that he had "reason to believe
that the power of the Steam-Engine may be applied to work the wheels."

In the winter of 1787-'88, William Symmington, who had planned a new
form of steam-engine, and made a successful working-model, was
employed by Mr. Miller to construct an engine for a new boat. This was
built; the little engine, having two cylinders of but four inches in
diameter, was placed on board, and a trial was made October 14, 1788.
The vessel (Fig. 72) was 25 feet long, of 7 feet beam, and made 5
miles an hour.

[Illustration: FIG. 72.--Miller, Taylor, and Symmington, 1788.]

In the year 1789, a large vessel was built, with an engine having a
steam-cylinder 18 inches in diameter, and this vessel was ready for
trial in November of that year. On the first trial, the paddle-wheels
proved too slight, and broke down; they were replaced by stronger
wheels, and, in December, the boat, on trial, made seven miles an
hour.

Miller, like many other inventors, seems to have lost his interest in
the matter as soon as success seemed assured, and dropped it to take
up other incomplete plans. More than a quarter of a century later, the
British Government gave Taylor a pension of £50 per annum, and, in
1837, his four daughters were each given a similar annuity. Mr.
Miller received no reward, although he is said to have expended over
£30,000. The engine of Symmington was condemned by Miller as "the most
improper of all steam-engines for giving motion to a vessel." Nothing
more was done in Great Britain until early in the succeeding century.

In the United States, several mechanics were now at work besides
Fitch. Samuel Morey and Nathan Read were among these. Nicholas
Roosevelt was another. It had just been found that American mechanics
were able to do the required shop-work. The first experimental
steam-engine built in America is stated to have been made in 1773 by
Christopher Colles, a lecturer before the American Philosophical
Society at Philadelphia. The first steam-cylinder of any considerable
size is said[68] to have been made by Sharpe & Curtenius, of New York
City.

  [68] _Rivington's Gazette_, February 16, 1775.

SAMUEL MOREY was the son of one of the first settlers of Orford, N. H.
He was naturally fond of science and mechanics, and became something
of an inventor. He began experimenting with the steamboat in 1790 or
earlier, building a small vessel, and fitting it with paddle-wheels
driven by a steam-engine of his own design, and constructed by
himself.[69] He made a trial-trip one Sunday morning in the summer of
1790, a friend to accompany him, from Oxford, up the Connecticut
River, to Fairlee, Vt., a distance of several miles, and returned
safely. He then went to New York, and spent the summer of each year
until 1793 in experimenting with his boat and modifications of his
engine. In 1793 he made a trip to Hartford, returning to New York the
next summer. His boat was a "stern-wheeler," and is stated to have
been capable of steaming five miles an hour. He next went to
Bordentown, N. J., where he built a larger boat, which is said to have
been a side-wheel boat, and to have worked satisfactorily. His funds
finally gave out, and he gave up his project after having, in 1797,
made a trip to Philadelphia. Fulton, Livingston, and Stevens met Morey
at New York, inspected his boat, and made an excursion to Greenwich
with him.[70] Livingston is said[71] to have offered to assist Morey
if he should succeed in attaining a speed of eight miles an hour.

  [69] _Providence Journal_, May 7, 1874. Coll., N. H. Antiquar. Soc.,
  No. 1; "Who invented the Steamboat?" William A. Mowry, 1874.

  [70] Rev. Cyrus Mann, in the _Boston Recorder_, 1858.

  [71] Westcott.

Morey's experiments seem to have been conducted very quietly, however,
and almost nothing is known of them. The author has not been able to
learn any particulars of the engines used by him, and nothing definite
is known of the dimensions of either boat or machinery. Morey never,
like Fitch and Rumsey, sought publicity for his plans or notoriety for
himself.

NATHAN READ, who has already been mentioned, a native of Warren,
Mass., where he was born in the year 1759, and a graduate of Harvard
College, was a student of medicine, and subsequently a manufacturer of
chain-cables and other iron-work for ships. He invented, and in 1798
patented, a nail-making machine. He was at one time (1800-1803) a
Member of Congress, and, later, a Justice of the Court of Common
Pleas, and Chief Justice in Hancock County, Me., after his removal to
that State in 1807. He died in Belfast, Me., in 1849, at the age of
ninety years.

In the year 1788 he became interested in the problem of
steam-navigation, and learned something of the work of Fitch. He first
attempted to design a boiler that should be strong, light, and
compact, as well as safe. His first plan was that of the "Portable
Furnace-Boiler," as he called it; it was patented August 26, 1791. As
designed, it consisted, as seen in Figs. 73 and 74, which are reduced
from his patent drawings, of a shell of cylindrical form, like the now
common vertical tubular boiler. _A_ is the furnace-door, _B_ a heater
and feed-water reservoir, _D_ a pipe leading the feed-water into the
boiler,[72] _E_ the smoke-pipe, and _F_ the steam-pipe leading to the
engine. _G_ is the "shell" of the boiler, and _H_ the fire-box. The
crown-sheet, _I I_, has depending from it, in the furnace, a set of
water-tubes, _b b_, closed at their lower ends, and another set, _a
a_, which connect the water-space above the furnace with the
water-bottom, _K K_. _L_ is the furnace, and _M_ the draught-space
between the boiler and the ash-pit, in which the grates are set.

  [72] This is substantially an arrangement that has recently become
  common. It has been repatented by later inventors.

[Illustration: FIG. 73.--Read's Boiler in Section, 1788.]

[Illustration: FIG. 74.--Read's Multi-Tubular Boiler, 1788.]

This boiler was intended to be used in both steamboats and
steam-carriages. The first drawings were made in 1788 or 1789, as were
those of a peculiar form of steam-engine which also resembled very
closely that afterward constructed in Great Britain by Trevithick.[73]
He built a boat in 1789, which he fitted with paddle-wheels and a
crank, which was turned by hand, and, by trial, satisfied himself that
the system would work satisfactorily.

  [73] "Nathan Read and the Steam-Engine."

He then applied for his patent, and spent the greater part of the
winter of 1789-'90 in New York, where Congress then met, endeavoring
to secure it. In January, 1791, Read withdrew his petitions for
patents, proposing to incorporate accounts of new devices, and renewed
them a few months later. His patents were finally issued, dated August
26, 1791. John Fitch, James Rumsey, and John Stevens, also, all
received patents at the same date, for various methods of applying
steam to the propulsion of vessels.

Read appears to have never succeeded in even experimentally making his
plans successful. He deserves credit for his early and intelligent
perception of the importance of the subject, and for the ingenuity of
his devices. As the inventor of the vertical multi-tubular fire-box
boiler, he has also entitled himself to great distinction. This boiler
is now in very general use, and is a standard form.

In 1792, Elijah Ormsbee, a Rhode Island mechanic, assisted pecuniarily
by David Wilkinson, built a small steamboat at Winsor's Cove,
Narragansett Bay, and made a successful trial-trip on the Seekonk
River. Ormsbee used an "atmospheric engine" and "duck's-foot" paddles.
His boat attained a speed of from three to four miles an hour.

In Great Britain, Lord Dundas and William Symmington, the former as
the purveyor of funds and the latter as engineer, followed by Henry
Bell, were the first to make the introduction of the steam-engine for
the propulsion of ships so completely successful that no interruption
subsequently took place in the growth of the new system of
water-transportation.

Thomas, Lord Dundas, of Kerse, had taken great interest in the
experiments of Miller, and had hoped to be able to apply the new motor
on the Forth and Clyde Canal, in which he held a large interest.
After the failure of the earlier experiments, he did not forget the
matter; but subsequently, meeting with Symmington, who had been
Miller's constructing engineer, he engaged him to continue the
experiments, and furnished all required capital, about £7,000. This
was ten years after Miller had abandoned his scheme.

Symmington commenced work in 1801. The first boat built for Lord
Dundas, which has been claimed to have been the "first practical
steamboat," was finished ready for trial early in 1802. The vessel was
called the "Charlotte Dundas," in honor of a daughter of Lord Dundas,
who became Lady Milton.

[Illustration: FIG. 75.--The "Charlotte Dundas," 1801.]

The vessel (Fig. 75) was driven by a Watt double-acting engine,
turning a crank on the paddle-wheel shaft. The sectional sketch below
exhibits the arrangement of the machinery. _A_ is the steam-cylinder,
driving, by means of the connecting-rod, _B C_, a stern-wheel, _E E_.
_F_ is the boiler, and _G_ the tall smoke-pipe. An air-pump and
condenser, _H_, is seen under the steam-cylinder.

In March, 1802, the boat was brought to Lock No. 20 on the Forth and
Clyde Canal, and two vessels of 70 tons burden each taken in tow. Lord
Dundas, William Symmington, and a party of invited guests, were taken
on board, and the boat steamed down to Port Glasgow, a distance of
about 20 miles, against a strong head-wind, in six hours.

The proprietors of the canal were now urged to adopt the new plan of
towing; but, fearing injury to the banks of the canal, they declined
to do so. Lord Dundas then laid the matter before the Duke of
Bridgewater, who gave Symmington an order for eight boats like the
Charlotte Dundas, to be used on his canal. The death of the Duke,
however, prevented the contract from being carried into effect, and
Symmington again gave up the project in despair. A quarter of a
century later, Symmington received from the British Government £100,
and, a little later, £50 additional, as an acknowledgment of his
services. The Charlotte Dundas was laid up, and we hear nothing more
of that vessel.

[Illustration: FIG. 76.--The "Comet," 1812.]

Among those who saw the Charlotte Dundas, and who appreciated the
importance of the success achieved by Symmington, was HENRY BELL, who,
10 years afterward, constructed the Comet (Fig. 76), the first
passenger-vessel built in Europe. This vessel was built in 1811, and
completed January 18, 1812. The craft was of 30 tons burden, 40 feet
in length, and 10-1/2 feet breadth of beam. There were _two_
paddle-wheels on each side, driven by engines rated at three
horse-power.

Bell had, it is said, been an enthusiastic believer in the advantages
to be secured by this application of steam, from about 1786. In 1800,
and again in 1803, he applied to the British Admiralty for aid in
securing those advantages by experimentally determining the proper
form and proportions of machinery and vessel; but was not able to
convince the Admiralty of "the practicability and great utility of
applying steam to the propelling of vessels against winds and tides,
and every obstruction on rivers and seas where there was depth of
water." He also wrote to the United States Government, urging his
views in a similar strain.

Bell's boat was, when finished, advertised as a passenger-boat, to
leave Greenock, where the vessel was built, on Mondays, Wednesdays,
and Fridays, for Glasgow, 24 miles distant, returning Tuesdays,
Thursdays, and Saturdays. The fare was made "four shillings for the
best cabin, and three shillings for the second." It was some months
before the vessel became considered a trustworthy means of conveyance.
Bell, on the whole, was at first a heavy loser by his venture,
although his boat proved itself a safe, stanch vessel.

Bell constructed several other boats in 1815, and with his success
steam-navigation in Great Britain was fairly inaugurated. In 1814
there were five steamers, all Scotch, regularly working in British
waters; in 1820 there were 34, one-half of which were in England, 14
in Scotland, and the remainder in Ireland. Twenty years later, at the
close of the period to which this chapter is especially devoted, there
were about 1,325 steam-vessels in that kingdom, of which 1,000 were
English and 250 Scotch.

But we must return to America, to witness the first and most complete
success, commercially, in the introduction of the steamboat.

The Messrs. Stevens, Livingston, Fulton, and Roosevelt were there the
most successful pioneers. The latter is said to have built the
"Polacca," a small steamboat launched on the Passaic River in 1798.
The vessel was 60 feet long, and had an engine of 20 inches diameter
of cylinder and 2 feet stroke, which drove the boat 8 miles an hour,
carrying a party of invited guests, which included the Spanish
Minister. Livingston and John Stevens had induced Roosevelt to try
their plans still earlier,[74] paying the expense of the experiments.
The former adopted the plan of Bernouilli and Rumsey, using a
centrifugal pump to force a jet of water from the stern; the latter
used the screw. Livingston going to France as United States Minister,
Barlow carried over the plans of the "Polacca," and Roosevelt's
friends state that a boat built by them, in conjunction with Fulton,
was a "sister-ship" to that vessel. In 1798, Roosevelt patented a
double engine, having cranks set at right angles. As late as 1814 he
received a patent for a steam-vessel, fitted with paddle-wheels having
adjustable floats. His boat of 1798 is stated by some writers to have
been made by him on joint account of himself, Livingston, and Stevens.
Roosevelt, some years later, was again at work, associating himself
with Fulton in the introduction of steam-navigation of the rivers of
the West.[75]

  [74] "Encyclopædia Americana."

  [75] "A Lost Chapter in the History of the Steamboat," J. H. B.
  Latrobe, 1871.

In 1798, the Legislature of New York passed a law giving Chancellor
Livingston the exclusive right to steam-navigation in the waters of
the State for a period of 20 years, _provided_ that he should succeed,
within a twelve-month, in producing a boat that should steam four
miles an hour.

Livingston did not succeed in complying with the terms of the act,
but, in 1803, he procured the reënactment of the law in favor of
himself and Robert Fulton, who was then experimenting in France, after
having, in England, watched the progress of steam-navigation there,
and then taken a patent in this country.

[Illustration: Robert Fulton.]

ROBERT FULTON was a native of Little Britain, Lancaster County, Pa.,
born 1765. He commenced experimenting with paddle-wheels when a mere
boy, in 1779, visiting an aunt living on the bank of the
Conestoga.[76] During his youth he spent much of his time in the
workshops of his neighborhood, and learned the trade of a watchmaker;
but he adopted, finally, the profession of an artist, and exhibited
great skill in portrait-painting. While his tastes were at this time
taking a decided bent, he is said to have visited frequently the house
of William Henry, already mentioned, to see the paintings of Benjamin
West, who in his youth had been a kind of protégé of Mr. Henry; and he
may probably have seen there the model steamboats which Mr. Henry
exhibited, in 1783 or 1784, to the German traveler Schöpff. In later
years, Thomas Paine, the author of "Common Sense," at one time lived
with Mr. Henry, and afterward, in 1788, proposed that Congress take up
the subject for the benefit of the country.

  [76] _Vide_ "Life of Fulton," Reigart.

Fulton went to England when he came of age, and studied painting with
Benjamin West. He afterward spent two years in Devonshire, where he
met the Duke of Bridgewater, who afterward so promptly took advantage
of the success of the "Charlotte Dundas."

While in England and in France--where he went in 1797, and resided
some time--he may have seen something of the attempts which were
beginning to be made to introduce steam-navigation in both of those
countries.

At about this time--perhaps in 1793--Fulton gave up painting as a
profession, and became a civil engineer. In 1797 he went to Paris, and
commenced experimenting with submarine torpedoes and torpedo-boats. In
1801 he had succeeded so well with them as to create much anxiety in
the minds of the English, then at war with France.

He had, as early as 1793, proposed plans for steam-vessels, both to
the United States and the British Governments, and seems never
entirely to have lost sight of the subject.[77] While in France he
lived with Joel Barlow, who subsequently became known as a poet, and
as Embassador to France from the United States, but who was then
engaged in business in Paris.

  [77] _Vide_ "Life of Fulton," Colden.

When about leaving the country, Fulton met Robert Livingston
(Chancellor Livingston, as he is often called), who was then (1801)
Embassador of the United States at the court of France. Together they
discussed the project of applying steam to navigation, and determined
to attempt the construction of a steamboat on the Seine; and in the
early spring of the year 1802, Fulton having attended Mrs. Barlow to
Plombières, where she had been sent by her physician, he there made
drawings and models, which were sent or described to Livingston. In
the following winter Fulton completed a model side-wheel boat.

[Illustration: FIG. 77.--Fulton's Experiments.]

January 24, 1803, he delivered this model to MM. Molar, Bordel, and
Montgolfier, with a descriptive memoir, in which he stated that he
had, by experiment, proven that side-wheels were better than the
"chaplet" (paddle-floats set on an endless chain).[78] These gentlemen
were then building for Fulton and Livingston their first boat, on
L'Isle des Cygnes, in the Seine. In planning this boat, Fulton had
devised many different methods of applying steam to its propulsion,
and had made some experiments to determine the resistance of fluids.
He therefore had been able to calculate, more accurately than had any
earlier inventor, the relative size and proportions of boat and
machinery.

  [78] A French inventor, a watchmaker of Trévoux, named Desblancs,
  had already deposited at the Conservatoire a model fitted with
  "chaplets."

[Illustration: FIG. 78.--Fulton's Table of Resistances.]

The author has examined a large collection of Fulton's drawings, among
which are sketches, very neatly executed, of many of these plans,
including the chaplet, side-wheel, and stern-wheel boats, driven by
various forms of steam-engine, some working direct, and some geared to
the paddle-wheel shaft. Figs. 77 and 78 are engraved from two of these
sheets. The first represents the method adopted by Fulton to determine
the resistance of masses of wood of various forms and proportions,
when towed through water. The other is "A Table of the resistance of
bodies moved through water, taken from experiments made in England by
a society for improving Naval architecture, between the years 1793 and
1798" (Fig. 78). This latter is from a certified copy of "The Original
Drawing on file in the Office of the Clerk of the New York District,
making a part of the Demonstration of the patent granted to Robert
Fulton, Esqr., on the 11th day of February, 1809. Dated this 3rd
March, 1814," and is signed by Theron Rudd, Clerk of the New York
District. Resistances are given in pounds per square foot.

Guided by these experiments and calculations, therefore, Fulton
directed the construction of his vessel. It was completed in the
spring of 1803. But, unfortunately, the hull of the little vessel was
too weak for its heavy machinery, and it broke in two and sank to the
bottom of the Seine. Undiscouraged, Fulton at once set about repairing
damages. He was compelled to direct the rebuilding of the hull. The
machinery was little injured. In June, 1803, the reconstruction was
completed, and the vessel was set afloat in July. The hull was 66 feet
long, of 8 feet beam, and of light draught.

August 9, 1803, this boat was cast loose, and steamed up the Seine, in
presence of an immense concourse of spectators. A committee of the
National Academy, consisting of Bougainville, Bossuet, Carnot, and
Périer, were present to witness the experiment. The boat moved but
slowly, making only between 3 and 4 miles an hour against the current,
the speed through the water being about 4-1/2 miles; but this was, all
things considered, a great success.

The experiment was successful, but it attracted little attention,
notwithstanding the fact that its success had been witnessed by the
committee of the Academy and by many well-known savants and mechanics,
and by officers on Napoleon's staff. The boat remained a long time on
the Seine, near the palace. The water-tube boiler of this vessel (Fig.
79) is still preserved at the Conservatoire des Arts et Métiers at
Paris, where it is known as Barlow's boiler. Barlow patented it in
France as early as 1793, as a steamboat-boiler, and states that the
object of his construction was to obtain the greatest possible extent
of heating-surface.

Fulton endeavored to secure the pecuniary aid and the countenance of
the First Consul, but in vain.

Livingston wrote home, describing the trial of this steamboat and its
results, and procured the passage of an act by the Legislature of the
State of New York, extending a monopoly granted him in 1798 for the
term of 20 years from April 5, 1803, the date of the new law, and
extending the time allowed for proving the practicability of driving a
boat four miles an hour by steam to two years from the same date. A
later act further extended the time to April, 1807.

[Illustration: FIG. 79.--Barlow's Water-Tube Boiler, 1793.]

In May, 1804, Fulton went to England, giving up all hope of success in
France with either his steamboats or his torpedoes. Fulton had already
written to Boulton & Watt, ordering an engine to be built from plans
which he furnished them; but he had not informed them of the purpose
to which it was to be applied. This engine was to have a
steam-cylinder 2 feet in diameter and of 4 feet stroke. The engine of
the Charlotte Dundas was of very nearly the same size; and this fact,
and the visit of Fulton to Symmington in 1801, as described by the
latter, have been made the basis of a claim that Fulton was a copyist
of the plans of others. The general accordance of the dimensions of
his boat on the Seine with those of the "Polacca" of Roosevelt is also
made the basis of similar claims by the friends of the latter. It
would appear, however, that Symmington's statement is incorrect, as
Fulton was in France, experimenting with torpedoes, at the time (July,
1801[79]) when he is accused of having obtained from the English
engineer the dimensions and a statement of the performance of his
vessel. Yet a fireman employed by Symmington has made an affidavit to
the same statement. It is evident, however, from what has preceded,
that those inventors and builders who were at that time working with
the object of introducing the steamboat were usually well acquainted
with what had been done by others, and with what was being done by
their contemporaries; and it is undoubtedly the fact that each
profited, so far as he was able, by the experience of others.

  [79] Woodcroft, p. 64.

While in England, however, Fulton was certainly not so entirely
absorbed in the torpedo experiments with which he was occupied in the
years 1804-'6 as to forget his plans for a steamboat; and he saw the
engine ordered by him in 1804 completed in the latter year, and
preceded it to New York, sailing from Falmouth in October, 1806, and
reaching the United States December 13, 1806.

The engine was soon received, and Fulton immediately contracted for a
hull in which to set it up. Meantime, Livingston had also returned to
the United States, and the two enthusiasts worked together on a larger
steamer than any which had yet been constructed.

In the spring of 1807, the "Clermont" (Fig. 80), as the new boat was
christened, was launched from the ship-yard of Charles Brown, on the
East River, New York. In August the machinery was on board and in
successful operation. The hull of this boat was 133 feet long, 18
wide, and 9 deep. The boat soon made a trip to Albany, running the
distance of 150 miles in 32 hours running time, and returning in 30
hours. The sails were not used on either occasion.

[Illustration: FIG. 80.--The Clermont, 1807.]

This was the first voyage of considerable length ever made by a
steam-vessel; and Fulton, though not to be classed with James Watt as
an inventor, is entitled to the great honor of having been the first
to make steam-navigation an every-day commercial success, and of
having thus made the first application of the steam-engine to
ship-propulsion, which was not followed by the retirement of the
experimenter from the field of his labors before success was
permanently insured.

[Illustration: FIG. 81.--Engine of the Clermont, 1808.]

The engine of the Clermont (Fig. 81) was of rather peculiar form, the
piston, _E_, being coupled to the crank-shaft, _O_, by a bell-crank,
_I H P_, and a connecting-rod, _P Q_, the paddle-wheel shaft, _M N_,
being separate from the crank-shaft, and connected with the latter by
gearing, _O O_. The cylinders were 24 inches in diameter by 4 feet
stroke. The paddle-wheels had buckets 4 feet long, with a dip of 2
feet. Old drawings, made by Fulton's own hand, and showing the engine
as it was in 1808, and the engine of a later steamer, the Chancellor
Livingston, are in the lecture-room of the author at the Stevens
Institute of Technology.

The voyage of the Clermont to Albany was attended by some ludicrous
incidents, which found their counterparts wherever, subsequently,
steamers were for the first time introduced. Mr. Colden, the
biographer of Fulton, says that she was described, by persons who had
seen her passing by night, "as a monster moving on the waters, defying
wind and tide, and breathing flames and smoke."

This first steamboat used dry pine wood for fuel, and the flames rose
to a considerable distance above the smoke-pipe. When the fires were
disturbed, mingled smoke and sparks would rise high in the air. "This
uncommon light," says Colden, "first attracted the attention of the
crews of other vessels. Notwithstanding the wind and tide were averse
to its approach, they saw with astonishment that it was rapidly coming
toward them; and when it came so near that the noise of the machinery
and paddles was heard, the crews (if what was said in the newspapers
of the time be true), in some instances, shrank beneath their decks
from the terrific sight, and left their vessels to go on shore; while
others prostrated themselves, and besought Providence to protect them
from the approach of the horrible monster which was marching on the
tides, and lighting its path by the fires which it vomited."

In the Clermont, Fulton used several of the now characteristic
features of the American river steamboat, and subsequently introduced
others. His most important and creditable work, aside from that of
the introduction of the steamboat into every-day use, was the
experimental determination of the magnitude and the laws of
ship-resistance, and the systematic proportioning of vessel and
machinery to the work to be done by them.

The success of the Clermont on the trial-trip was such that Fulton
soon after advertised the vessel as a regular passenger-boat between
New York and Albany.[80]

  [80] A newspaper-slip in the scrap-book of the author has the
  following:

  "The traveler of today, as he goes on board the great steamboats St.
  John or Drew, can scarcely imagine the difference between such
  floating palaces and the wee-bit punts on which our fathers were
  wafted 60 years ago. We may, however, get some idea of the sort of
  thing then in use by a perusal of the steamboat announcements of
  that time, two of which are as follows:

  ["_Copy of an Advertisement taken from the Albany Gazette, dated
  September, 1807._]

  "The North River Steamboat will leave Pauler's Hook Ferry [now
  Jersey City] on Friday, the 4th of September, at 9 in the morning,
  and arrive at Albany on Saturday, at 9 in the afternoon. Provisions,
  good berths, and accommodations are provided.

  "The charge to each passenger is as follows:

  "To Newburg        dols. 3,    time 14 hours.
   "  Poughkeepsie     "   4,      "  17   "
   "  Esopus           "   5,      "  20   "
   "  Hudson           "   5-1/2,  "  30   "
   "  Albany           "   7,      "  36   "

  "For places, apply to William Vandervoort, No. 48 Courtlandt Street,
  on the corner of Greenwich Street.

  "_September 2, 1807._

  ["_Extract from the New York Evening Post, dated October 2, 1807._]

  "Mr. Fulton's new-invented _Steamboat_, which is fitted up in a neat
  style for passengers, and is intended to run from New York to Albany
  as a Packet, left here this morning with 90 passengers, against a
  strong head-wind. Notwithstanding which, it was judged she moved
  through the waters at the rate of six miles an hour."

During the next winter the Clermont was repaired and enlarged, and in
the summer of 1808 was again on the route to Albany; and, meantime,
two new steamboats--the Raritan and the Car of Neptune--had been built
by Fulton. In the year 1811 he built the Paragon. Both of the two
vessels last named were of nearly double the size of the Clermont. A
steam ferry-boat was built to ply between New York and Jersey City in
1812, and the next year two others, to connect the metropolis with
Brooklyn. These were "twin-boats," the two parallel hulls being
connected by a "bridge" or deck common to both. The Jersey ferry was
crossed in fifteen minutes, the distance being a mile and a half.
To-day, the time occupied at the same ferry is about ten minutes.
Fulton's ferry-boat carried, at one load, 8 carriages, and about 30
horses, and still had room for 300 or 400 foot-passengers. Fulton also
designed steam-vessels for use on the Western rivers, and, in 1815,
some of his boats were started as "packets" on the line between New
York and Providence, R. I.

Meantime, the War of 1812 was in progress, and Fulton designed a steam
vessel-of-war, which was then considered a wonderfully formidable
craft. His plans were submitted to a commission of experienced naval
officers, among whom were Commodores Decatur and Perry, Captain John
Paul Jones, Captain Evans, and others whose names are still familiar,
and were favorably commended. Fulton proposed to build a steam-vessel
capable of carrying a heavy battery, and of steaming four miles an
hour. The ship was to be fitted with furnaces for red-hot shot. Some
of her guns were to be discharged below the water-line. The estimated
cost was $320,000.

The construction of the vessel was authorized by Congress in March,
1814; the keel was laid June 20, 1814, and the vessel was launched
October 29th of the same year.

[Illustration: FIG. 82.--Launch of the "Fulton the First," 1804.]

The "Fulton the First," as she was called, was considered an enormous
vessel at that time. The hull was double, 156 feet long, 56 feet wide,
and 20 feet deep, measuring 2,475 tons. In the following May the ship
was ready for her engine, and in July was so far completed as to
steam, on a trial-trip, to the ocean at Sandy Hook and back--53
miles--in 8 hours and 20 minutes. In September of the same year, with
armament and stores on board, the same route was traversed again, the
vessel making 5-1/2 miles an hour. The vessel, as thus completed, had
a double hull, each about 20 feet longer than the Clermont, and
separated by a space 15 feet across. Her engine, having a
steam-cylinder 48 inches in diameter and of 5 feet stroke of piston,
was furnished with steam by a copper boiler 22 feet long, 12 feet
wide, and 8 feet high, and turned a wheel between the two hulls which
was 16 feet in diameter, and carried "floats" or "buckets" 14 feet
long, and with a dip of 4 feet. The engine was in one of the two
hulls, and the boiler in the other. The sides, at the gun-deck, were 4
feet 10 inches thick, and her spar-deck was surrounded by heavy
musket-proof bulwarks. The armament consisted of 30 32-pounders, which
were intended to discharge red-hot shot. There was one heavy mast for
each hull, fitted with large latteen sails. Each end of each hull was
fitted with a rudder. Large pumps were carried, which were intended to
throw heavy streams of water upon the decks of the enemy, with a view
to disabling the foe by wetting his ordnance and ammunition. A
submarine gun was to have been carried at each bow, to discharge shot
weighing 100 pounds, at a depth of 10 feet below the water-line.

This was the first application of the steam-engine to naval purposes,
and, for the time, it was an exceedingly creditable one. Fulton,
however, did not live to see the ship completed. He was engaged in a
contest with Livingston, who was then endeavoring to obtain permission
from the State of New Jersey to operate a line of steamboats in the
waters of the Hudson River and New York Bay, and, while returning from
attending a session of the Legislature at Trenton, in January, 1815,
was exposed to the weather on the bay at a time when he was ill
prepared to withstand it. He was taken ill, and died February 24th of
that year. His death was mourned as a national calamity.

From the above brief sketch of this distinguished man and his work, it
is seen that, although Robert Fulton is not entitled to distinction as
an inventor, he was one of the ablest, most persistent, and most
successful of those who have done so much for the world by the
introduction of the inventions of others. He was an intelligent
engineer and an enterprising business-man, whose skill, acuteness, and
energy have given the world the fruits of the inventive genius of all
who preceded him, and have thus justly earned for him a fame that can
never be lost.

Fulton had some active and enterprising rivals.

Oliver Evans had, in 1801 or 1802, sent one of his engines, of about
150 horse-power, to New Orleans, for the purpose of using it to propel
a vessel owned by Messrs. McKeever and Valcourt, which was there
awaiting it. The engine was actually set up in the boat, but at a low
stage of the river, and no trial could be made until the river should
again rise, some months later. Having no funds to carry them through
so long a period, Evans's agents were induced to remove the engine
again, and to set it up in a saw-mill, where it created great
astonishment by its extraordinary performance in sawing lumber.

Livingston and Roosevelt were also engaged in experiments quite as
early as Fulton, and perhaps earlier.

The prize gained by Fulton was, however, most closely contested by
Colonel JOHN STEVENS, of Hoboken, who has been already mentioned in
connection with the early history of railroads, and who had been since
1791 engaged in similar experiments. In 1789 he had petitioned the
Legislature of the State of New York for a grant similar to that
accorded to Livingston, and he then stated that his plans were
complete, and on paper.

[Illustration: FIG. 83.--Section of Steam-Boiler, 1804.]

In 1804, while Fulton was in Europe, Stevens had completed a
steamboat, 68 feet long and of 14 feet beam, which combined novelties
and merits of design in a manner that exhibited the best possible
evidence of remarkable inventive talent, as well as of the most
perfect appreciation of the nature of the problem which he had
proposed to himself to solve. Its boiler (Fig. 83) was of what is now
known as the water-tubular variety. It was quite similar to some now
known as sectional boilers, and contained 100 tubes 2 inches in
diameter and 18 inches long, each fastened at one end to a central
water-leg and steam-drum, and plugged at the other end. The flames
from the furnace passed around and among the tubes, the water being
inside them. The engine (Fig. 84) was a _direct-acting high-pressure_
condensing engine, having a 10-inch cylinder, 2 feet stroke of piston,
and drove a _screw_ having four blades, and of a form which, even
to-day, appears quite good. The whole is a most remarkable piece of
early engineering.

[Illustration: FIG. 84.--Engine, Boiler, and Screw-Propellers used by
Stevens, 1804.]

A model of this little steamer, built in 1804, is preserved in the
lecture-room of the Department of Mechanical Engineering at the
Stevens Institute of Technology; and the machinery itself, consisting
of the high-pressure "sectional" or "safety" tubular boiler, as it
would be called to-day, the high-pressure condensing engine, with
rotating valves, and twin screw-propellers, as just described, is
given a place of honor in the model-room, or museum, where it
contrasts singularly with the mechanism contributed to the collection
by manufacturers and inventors of our own time. The hub and blade of a
single screw, also used with the same machinery, is likewise to be
seen there.

[Illustration: FIG. 85.--Stevens's Screw Steamer, 1804.]

Stevens seems to have been the first to fully recognize the importance
of the principle involved in the construction of the sectional
steam-boiler. His eldest son, John Cox Stevens, was in Great Britain
in the year 1805, and, while there, patented another modification of
this type of boiler. In his specification, he details both the method
of construction and the principles which determine its form. He says
that he describes this invention as it was made known to him by his
father, and adds:

"From a series of experiments made in France, in 1790, by M. Belamour,
under the auspices of the Royal Academy of Sciences, it has been found
that, within a certain range the elasticity of steam is nearly doubled
by every addition of temperature equal to 30° of Fahrenheit's
thermometer. These experiments were carried no higher than 280°, at
which temperature the elasticity of steam was found equal to about
four times the pressure of the atmosphere. By experiments which have
lately been made by myself, the elasticity of steam at the temperature
of boiling oil, which has been estimated at about 600°, was found to
equal 40 times the pressure of the atmosphere.

"To the discovery of this principle or law, which obtains when water
assumes a state of vapor, I certainly can lay no claim; but to the
application of it, upon certain principles, to the improvement of the
steam-engine, I do claim exclusive right.

"It is obvious that, to derive advantage from an application of this
principle, it is absolutely necessary that the vessel or vessels for
generating steam should have strength sufficient to withstand the
great pressure from an increase of elasticity in the steam; but this
pressure is increased or diminished in proportion to the capacity of
the containing vessel. The principle, then, of this invention consists
in forming a boiler by means of a system, or combination of a number
of small vessels, instead of using, as in the usual mode, one large
one; the relative strength of the materials of which these vessels
are composed increasing in proportion to the diminution of capacity.
It will readily occur that there are an infinite variety of possible
modes of effecting such combinations; but, from the nature of the
case, there are certain limits beyond which it becomes impracticable
to carry on improvement. In the boiler I am about to describe, I
apprehend that the improvement is carried to the utmost extent of
which the principle is capable. Suppose a plate of brass of one foot
square, in which a number of holes are perforated; into each of which
holes is fixed one end of a copper tube, of about an inch in diameter
and two feet long; and the other ends of these tubes inserted in like
manner into a similar piece of brass; the tubes, to insure their
tightness, to be cast in the plates; these plates are to be inclosed
at each end of the pipes by a strong cap of cast-iron or brass, so as
to leave a space of an inch or two between the plates or ends of the
pipes and the cast-iron cap at each end; the caps at each end are to
be fastened by screw-bolts passing through them into the plates; the
necessary supply of water is to be injected by means of a forcing-pump
into the cap at one end, and through a tube inserted into the cap at
the other end the steam is to be conveyed to the cylinder of the
steam-engine; the whole is then to be encircled in brickwork or
masonry in the usual manner, placed either horizontally or
perpendicularly, at option.

"I conceive that the boiler above described embraces the most eligible
mode of applying the principle before mentioned, and that it is
unnecessary to give descriptions of the variations in form and
construction that may be adopted, especially as these forms may be
diversified in many different modes."

Boilers of the character of those described in the specification given
above were used on the locomotive built by John Stevens in 1824-'25,
and one of them remains in the collections of the Stevens Institute of
Technology.

The use of such a boiler 70 years ago is even more remarkable than the
adoption of the screw-propeller, in such excellent proportions, 30
years before the labors of Smith and of Ericsson brought the screw
into general use; and we have, in this strikingly original
combination, as good evidence of the existence of unusual engineering
talent in this great engineer as we found of his political and
statesmanlike ability in his efforts to forward the introduction of
railways.

Colonel John Stevens designed a peculiar form of iron-clad in the year
1812, which has been since reproduced by no less distinguished and
successful an engineer than the late John Elder, of Glasgow, Scotland.
It consisted of a saucer-shaped hull, carrying a heavy battery, and
plated with iron of ample thickness to resist the shot fired from the
heaviest ordnance then known. This vessel was secured to a swivel, and
was anchored in the channel to be defended. A set of screw-propellers,
driven by steam-engines, and situated beneath the vessel, where they
were safe against injury by shot, were so arranged as to permit the
vessel to be rapidly revolved about its centre. As each gun was
brought into line of fire, it was discharged, and was then reloaded
before coming around again. This was probably the earliest embodiment
of the now well-established "Monitor" principle. It was probably the
first iron-clad ever designed. It has recently been again brought out
and introduced into the Russian navy, and is there called the
"Popoffka."

The first of Stevens's boats performed so well, that he immediately
built another one, using the same engine as before, but employing a
larger boiler, and propelling the vessel by _twin screws_, the latter
being another instance of his use of a device brought forward long
afterward as new, and frequently adopted. This boat was sufficiently
successful to prove the practicability of making steam-navigation a
commercial success; and Stevens, assisted by his sons, built a boat
which he named the "Ph[oe]nix," and made the first trial in 1807, but
just too late to anticipate Fulton. This boat was driven by
paddle-wheels.

[Illustration: FIG. 86.--Stevens's Twin-Screw Steamer, 1805.]

The Ph[oe]nix, being shut out of the waters of the State of New York
by the monopoly held by Fulton and Livingston, was used for a time
between New York and New Brunswick, and then, anticipating a better
pecuniary return, it was concluded to send her to Philadelphia, to ply
on the Delaware.

At that time no canal offered the opportunity to make an inland
passage; and in June, 1808, Robert L. Stevens, a son of John, started
with her to make the passage by sea. Although meeting a gale of wind,
he arrived at Philadelphia safely, having been the first to trust
himself on the open sea in a vessel relying entirely upon steam-power.

From this time forward the Stevenses, father and sons, continued to
construct steam-vessels; and, after the breaking down of the Fulton
monopoly by the courts, they built the most successful steamboats that
ran on the Hudson River.

After Fulton and Stevens had thus led the way, steam-navigation was
introduced very rapidly on both sides of the ocean; and on the
Mississippi the number of boats set afloat was soon large enough to
fulfill Evans's prediction that the navigation of that river would
ultimately be effected by steam-vessels.

The changes and improvements which, during the 20 years succeeding the
time of Fulton and of John Stevens, gradually led to the adoption of
the now recognized type of "American river-boat" and its steam-engine,
were principally made by that son of the senior Stevens, who has
already been mentioned--ROBERT L. STEVENS--and who became known later
as the designer and builder of the first well-planned iron-clad ever
constructed, the Stevens Battery. Much of his best work was done
during his father's lifetime.

[Illustration: Robert L. Stevens.]

He made many extended and most valuable, as well as interesting,
experiments on ship-propulsion, expending much time and large sums of
money upon them; and many years before they became generally
understood, he had arrived at a knowledge not only of the laws
governing the variation of resistance at excessive speeds, but he had
determined, and had introduced into his practice, those forms of least
resistance and those graceful water-lines which have only recently
distinguished the practice of other successful naval architects.

Referring to his invaluable services, President King, who seems to
have been the first to thoroughly appreciate the immense amount of
original invention and the surprising excellence of the engineering of
this family, in a lecture delivered in New York in 1851, gave, for the
first time, a connected and probably accurate description of their
work, upon which nearly all later accounts have been based.

Young Stevens began working in his father's machine-shop in 1804 or
1805, when a mere boy, and thus acquired at a very early age that
familiarity with practical details of work and of business which is
essential to perfect success. It was he who introduced the now common
"hollow water-line" in the Ph[oe]nix, and thus anticipated the claims
of the builders of the once famous "Baltimore clippers," and of the
inventors of the "wave-line" form of vessels. In the same vessel he
adopted a feathering paddle-wheel and the guard-beam now universally
seen in our river steamboats.

As usually constructed, this arrangement of float is as shown in Fig.
87. The rods, _F F_, connect the eccentrically-set collar, _G_,
carried on _H_, a pin mounted on the paddle-beam outside the wheel, or
an eccentric secured to the vessel, with the short arms, _D D_, by
which the paddles are turned upon the pins, _E E_. _A_ is the centre
of the paddle-wheel, and _C C_ are arms. Circular hoops, or bands,
connect all of the arms, each of which carries a float. They are all
thus tied together, forming a very firm and powerful combination to
resist external forces.

[Illustration: FIG. 87.--The Feathering Paddle-Wheel.]

The steamboat Philadelphia was built in the year 1813, and the young
naval architect took advantage of the opportunity to introduce several
new devices, including screw-bolts in place of tree-nails, and
diagonal knees of wood and of iron. Two years later he altered the
engines of this boat, and arranged them to work steam expansively. A
little later he commenced using anthracite coal, which had been
discovered in 1791 by Philip Ginter, and introduced at Wilkesbarre,
Pa., in the smith-shops, some years before the Revolution. It had been
used in a peculiar grate devised by Judge Fell, of that town, in 1808.
Oliver Evans also had used it in stoves even earlier than the latter
date, and at about the same time it had been used in the
blast-furnace[81] at Kingston. Stevens was the first of whom we have
record who was thoroughly successful in using, as a steam-coal, the
new and almost unmanageable fuel. He fitted up the boiler of the
steamboat Passaic for it in 1818, and adopted anthracite as a
steaming-coal. He used it in a cupola-furnace in the same year, and
its use then rapidly became general in the Eastern States.

  [81] Bishop.

Stevens continued his work of improving the beam-engine for many
years. He designed the now universally-used "skeleton-beam," which is
one of the characteristic features of the American engine, and placed
the first example of this light and elegant, yet strong, construction
on the steamer Hoboken in the year 1822. He built the Trenton, which
was then considered an extraordinarily powerful, fast, and handsome
vessel, two years afterward, and placed the two boilers on the
guards--a custom which is still general on the river steamboats of the
Eastern States. In this vessel he also adopted the plan of making the
paddle-wheel floats in two parts, placing one above the other, and
securing the upper half on the forward and the lower half on the after
side of the arm, thus obtaining a smoother action of the wheel, and
less loss by oblique pressures.

In 1827 he built the North America (Fig. 88), one of his largest and
most successful steamers, a vessel fitted with a pair of engines each
44-1/2 inches in diameter of cylinder and 8 feet stroke of piston,
making 24 revolutions per minute, driving the boat 15 to 16 miles an
hour. Anticipating difficulty in keeping the long, light, shallow
vessel in shape when irregularly laden, and when steaming at the high
speed expected to be obtained when her powerful engine was exerting
its maximum effort, he adopted the expedient of stiffening the hull by
means of a truss of simple form. This proved thoroughly satisfactory,
and the "hog-frame," as it has since been inelegantly but universally
called, is still one of the peculiar features of every American
river-steamer of any considerable size. It was in the North America,
also, that he first introduced the artificial blast for forcing the
fires, which is still another detail of now usual practice.

[Illustration: FIG. 88.--The North America and Albany, 1827-'30.]

Stevens next turned his attention to the engine again, and adopted
spring bearings under the paddle-shaft of the New Philadelphia in
1828, and fitted the steam-cylinder with the "double-poppet" valve,
which is now universally used on beam-engines. This consists of two
disk-valves, connected by the valve-spindle. The disks are of unequal
sizes, the smaller passing through the seat of the larger. When
seated, the pressure of the steam is, in the steam-valve, taken on the
upper side of the larger and the lower side of the smaller disk, thus
producing a partial balancing of the valve, and rendering it easy to
work the heaviest engine by the hand-gear. The two valve-seats are
formed in the top and the bottom, respectively, of the steam-passage
leading to the cylinder; and when the valve is raised, the steam
enters at the top and the bottom at the same time, and the two
currents, uniting, flow together into the steam-cylinder. The same
form of valve is used as an exhaust-valve.

At about the same time he built the now standard form of return
tubular boilers for moderate pressures. In the figure, _S_ is the
steam and _W_ the water space, and _F_ the furnace. The direction of
the currents of smoke and gas are shown by the arrows.

[Illustration: FIG. 89.--Stevens's Return Tubular Boiler, 1832.]

Some years later (1840), Stevens commenced using steam-packed pistons
on the Trenton, in which steam was admitted by self-adjusting valves
behind the metallic packing-rings, setting them out more effectively
than did the steel springs then (and still) usually employed.

His pistons, thus fitted, worked well for many years. A set of the
small brass check-valves used in a piston of this kind, built by
Stevens, and preserved in the cabinets of the Stevens Institute of
Technology, are good evidence of the ingenuity and excellent
workmanship which distinguished the machinery constructed under the
direction of this great engineer.

[Illustration: FIG. 90.--Stevens's Valve-Motion.]

The now familiar "Stevens cut-off," a peculiar device for securing the
expansion of steam in the steam-cylinder, was the invention (1841) of
Robert L. Stevens and a nephew, who inherited the same constructive
talent which distinguished the first of these great men--Mr. Francis
B. Stevens. In this form of valve-gear, the steam and exhaust valves
are independently worked by separate eccentrics, the latter being set
in the usual manner, opening and closing the exhaust-passages just
before the crank passes its centre. The steam-eccentric is so placed
that the steam-valve is opened as usual, but closed when but about
one-half the stroke has been made. This result is accomplished by
giving the eccentric a greater throw than is required by the motion of
the valve, and permitting it to move through a portion of its path
without moving the valve. Thus, in Fig. 90, if _A B_ be the direction
of motion of the eccentric-rod, the valve would ordinarily open the
steam-port when the eccentric assumes the position _O C_, closing when
the eccentric has passed around to _O D_. With the Stevens valve-gear,
the valve is opened when the eccentric reaches _O E_, and closes when
it arrives at _O F_. The steam-valve of the opposite end of the
cylinder is open while the eccentric is moving from _O M_ to _O K_.
Between _K_ and _E_, and between _F_ and _M_, both valves are seated.
_H B_ is proportional to the lift of the valve, and _O H_ to the
motion of the valve-gear when out of contact with the valve-lifters.
While the crank is moving through an arc, _E F_, steam is entering the
cylinder; from _F_ to _M_ the steam is expanding. At _M_ the stroke is
completed, and the other steam-valve opens. The ratio (E M)/(E L) is
the ratio of expansion.

This form of cut-off motion is still a very usual one, and can be seen
in nearly all steamers in the United States not using the device of
Sickles. It was at about this time, also, that Stevens, having
succeeded his father in the business of introducing the steam-engine
in land-transportation, as well as on the water, adopted the use of
steam expansively on the locomotives of the Camden & Amboy Railroad,
which was controlled and built by capital furnished principally by the
Messrs. Stevens. He at the same time constructed eight-wheeled engines
for heavy work, and adopted anthracite coal as fuel. In the latter
change he was thoroughly successful, and the same improvement was made
with engines built for fast traffic in 1848.

The most remarkable of all the applications of steam-power proposed by
Robert L. Stevens was that known as the Stevens Steam Iron-Clad
Battery. As has already been stated, Colonel John Stevens had
proposed, as early as 1812, to build a circular or saucer-shaped
iron-clad, like those built 60 years later for the Russian Navy.
Nothing was done, however, although the son revived the idea in a
modified form 20 years afterward. In the years 1813-'14, the war with
England being then in progress, he invented, after numerous and
hazardous experiments, an _elongated shell_, to be fired from ordinary
smooth-bored cannon. Having perfected this invention, he sold the
secret to the United States, after making experiments to prove their
destructiveness so decisive as to leave no doubt of the efficacy of
such projectiles.

As early as 1837 he had perfected a plan of an iron-clad war-vessel,
and in August, 1841, his brothers, James C. and Edwin A. Stevens,
representing Robert L., addressed a letter to the Secretary of the
Navy, proposing to build an iron-clad vessel of high speed, with all
its machinery below the water-line, and having submerged
screw-propellers. The armament was to consist of the most powerful
rifled guns, loading at the breech, and provided with elongated shot
and shell. In the year 1842, having contracted to build for the United
States Government a large war-steamer on this plan, which should be
shot and shell proof, Robert L. Stevens built a steamboat at
Bordentown, for the sole purpose of experimenting on the forms and
curves of propeller-blades, as compared with side-wheels, and
continued his experiments for many months. After some delay, during
which Mr. Stevens and his brothers were engaged with their experiments
and in perfecting their plans, the keel of an iron-clad was laid down
in a dry-dock which had been constructed for the purpose at great
cost. This vessel was to have been 250 feet long, of 40 feet beam, and
28 feet deep. The machinery was designed to furnish 700 indicated
horse-power. The plating was proposed to be 4-1/2 inches thick--the
same thickness of armor as was adopted 10 years later by the French
for their comparatively rude constructions.

In 1854, such marked progress had been made in the construction of
ordnance that Mr. Stevens was no longer willing to proceed with the
original plans, fearing that, were the ship completed, it might prove
not invulnerable, and might throw some discredit upon its designer, as
well as upon the navy of which it was to form a part. The work, which
had, in those years of peace, progressed very slowly and
intermittently, was therefore stopped entirely, the vessel given up,
and in 1854 the keel of a ship of vastly greater size and power was
laid down. The new design was 415 feet long, of 45 feet beam, and of
something over 5,000 tons displacement. The thickness of armor
proposed was 6-3/4 inches--2-1/4 inches thicker than that of the
first French and British iron-clads--and the machinery was designed by
Mr. Stevens to be of 8,624 indicated horse-power, driving twin-screws,
and propelling the vessel 20 miles or more an hour. As with the
preceding design, the progress of construction was intermittent and
very slow. Government advanced funds, and then refused to continue the
work; successive administrations alternately encouraged and
discouraged the engineer; and he finally, cutting loose entirely from
all official connections, went on with the work at his own expense.

The remarkable genius of the elder Stevens was well reflected in the
character of his son, and is in no way better exemplified than by the
accuracy with which, in this great ship, those forms and proportions,
both of hull and machinery, were adopted which are now, twenty-five
years later, recognized as most correct under similar conditions. The
lines of the vessel are beautifully fair and fine, and are what J.
Scott Russell has called "wave-lines," or trochoidal lines, such as
Rankine has shown to be the best possible for easy propulsion. The
proportion of length to midship dimensions is such as to secure the
speed proposed with a minimum resistance, and to accord closely with
the proportions arrived at and adopted by common consent in present
transoceanic navigation by the best--not to say radical--builders.

The death of Robert L. Stevens occurred in April, 1856, when this
larger vessel had advanced so far toward completion that the hull and
machinery were practically finished, and it only remained to add the
armor-plating, and to decide upon the form of fighting-house and upon
the number and size of guns. The construction of the vessel, which had
proceeded slowly and intermittently during the years of peace, as
successive administrations had considered it necessary to continue the
payment of appropriations, or had stopped temporarily in the absence
of any apparent immediate necessity for continuance of the work, was
again interrupted by his death.

The name of Robert L. Stevens will be long remembered as that of one
of the greatest of American mechanics, the most intelligent of naval
architects, and as the first, and one of the greatest, of those to
whom we are indebted for the commencement of the mightiest of
revolutions in the methods and implements of modern naval warfare.
American mechanical genius and engineering skill have rarely been too
promptly recognized, and no excuse will be required for an attempt
(which it is hoped may yet be made) to place such splendid work as
that of the Messrs. Stevens in a light which shall reveal both its
variety and extent and its immense importance.

While Fulton was introducing the steamboat upon the waters of New York
Bay and the Hudson River, and while the Stevenses, father and sons,
were rapidly bringing out a fleet of steamers on the Delaware River
and Bay, other mechanics were preparing to contest the field with them
as opportunity offered, and as legislative acts authorizing monopoly
expired by limitation or were repealed.

About 1821, Robert L. Thurston, John Babcock, and Captain Stephen T.
Northam, of Newport, R. I., commenced building steamboats, beginning
with a small craft intended for use at Slade's Ferry, on an arm of
Narragansett Bay, near Fall River. They afterward built vessels to ply
on Long Island Sound. One of their earliest boats was the Babcock,
built at Newport in 1826. The engine was built by Thurston and
Babcock, at Portsmouth, R. I. They were assisted in their work by
Richard Sanford, and with funds by Northam. The engine was of 10 or 12
inches diameter of cylinder, and 3 or 4 feet stroke of piston. The
boiler was a form of "pipe-boiler," subsequently (1824) patented by
Babcock. The water used was injected into the hot boiler as fast as
required to furnish steam, no water being retained in the
steam-generator. This boat was succeeded, in 1827-'28, by a larger
vessel, the Rushlight, for which the engine was built by James P.
Allaire, at New York, while the boat was built at Newport. The boilers
of both vessels had tubes of cast-iron. The smaller of these boats was
of 80 tons burden; it steamed from Newport to Providence, 30 miles, in
3-1/2 hours, and to New York, a distance of 175 miles, in 25 hours,
using 1-3/4 cord of wood.[82] Thurston and Babcock subsequently
removed to Providence, where the latter soon died. Thurston continued
to build steam-engines at this place until nearly a half-century
later, dying in 1874.[83] The establishment founded by him, after
various changes, became the Providence Steam-Engine Works.

  [82] _American Journal of Science_, March, 1827; _London Mechanics'
  Magazine_, June 16, 1827.

  [83] "New Universal Cyclopædia," vol. iv., 1878.

James P. Allaire, of New York, the West Point Iron Foundery, at West
Point, on the Hudson River, and Daniel Copeland and his son, Charles
W. Copeland, on the Connecticut River, were also early builders of
engines for steam-vessels. Daniel Copeland was probably the first
(1850) to adopt a slide-valve working with a lap to secure the
expansion of steam. His steamboats were then usually stern-wheel
vessels, and were built to ply on several routes on the Connecticut
River and Long Island Sound. The son, Charles W. Copeland,
went to West Point, and while there designed some heavy marine
steam-machinery, and subsequently designed several steam
vessels-of-war for the United States Navy. He was the earliest
designer of iron steamers in the United States, building the Siamese
in 1838. This steamer was intended for use on Lake Pontchartrain and
the canal to New Orleans. It had two hulls, was 110 feet long, and
drew but 22 inches of water, loaded. The two horizontal non-condensing
engines turned a single paddle-wheel placed between the two hulls,
driving the boat 10 miles an hour. The hull was constructed of plates
of iron 10 feet long, formed on blocks after having been heated in a
furnace constructed especially for the purpose. The frames were of
T-iron, which was probably here used for the first time. The same
engineer, associated with Samuel Hart, a well-known naval constructor,
built, in 1841, for the United States Navy, the iron steamer Michigan,
a war-vessel intended for service on the great northern lakes. This
vessel is still in service, and in good order. The hull is 162-1/2
feet in length, 27 feet in breadth, and 12-1/2 feet in depth,
measuring 500 tons. The frames were made of T-iron, stiffened by
reverse bars of L-iron. The keel-plate was 5/8 inch thick, the bottom
plates 3/8, and the sides 3/16 inch. The deck-beams were of iron, and
the vessel, as a whole, was a good specimen of iron-ship building.

During the period from 1830 to 1840, a considerable number of the now
standard details of steam-engine and steamboat construction were
devised or introduced by Copeland. He was probably the first to use
(on the Fulton, 1840) an independent engine to drive the blowing-fans
where an artificial draught was required. He made a practice of
fitting his steamers with a "bilge-injection," by means of which the
vessel could be freed of water, through the condenser and air-pump,
when leaking seriously; the condensing-water is, in such a case, taken
from inside the vessel, instead of from the sea. This is probably an
American device. It was in use in the United States previously to
1835, as was the use of anthracite coal on steamers, which was
continued by Copeland in manufacturing and in air-furnaces, as well as
on steamboats. He also modified the form of Stevens's double-poppet
valve, giving it such shape that it was comparatively easy to grind it
tight and to keep it in order.

In 1825, James P. Allaire, of New York, built compound engines for the
Henry Eckford, and subsequently constructed similar engines for
several other steamers, one of which, the Sun, made the trip from New
York to Albany in 12 hours 18 minutes. He used steam at 100 pounds
pressure. Erastus W. Smith afterward introduced this form of engine on
the Great Lakes, and still later they were introduced into British
steamers. The machinery of the steamer Buckeye State was constructed
at the Allaire Works, New York, in 1850, from the designs of John
Baird and Erastus W. Smith, the latter being the designing and
constructing engineer. The steamer was placed on the route between
Buffalo, Cleveland, and Detroit, in 1851, and gave most satisfactory
results, consuming less than two-thirds the fuel required by a similar
vessel of the same line fitted with the single-cylinder engine. The
steam-cylinders of this engine were placed one within the other, the
low-pressure exterior cylinder being annular. They were 37 and 80
inches in diameter respectively, and the stroke was 11 feet. Both
pistons were connected to one cross-head, and the general arrangement
of the engine was similar to that of the common form of beam-engine.
The steam-pressure was from 70 to 75 pounds--about the maximum
pressure adopted a quarter of a century later on transatlantic lines.
This steamer was of high speed, as well as economical of fuel.

In the year 1830, there were 86 steamers on the Hudson River and in
Long Island Sound.

During the early part of the nineteenth century, the introduction of
the steamboat upon the waters of the great rivers of the interior of
the United States was one of the most notable details of its history.
Inaugurated by the unsuccessful experiment of Evans, the building of
steamboats on those waters, once commenced, never ceased; and a
generation after Fitch's burial on the shore of the Ohio, his last
wish--that he might lie "where the song of the boatman would enliven
the stillness of his resting-place, and the music of the steam-engine
soothe his spirit"--was fulfilled day by day unceasingly.

Nicholas J. Roosevelt was, as has been already stated, the first to
take a steamboat down the great rivers. His boat was built at
Pittsburgh in 1811, under an arrangement with Fulton and Livingston,
from Fulton's plans. It was called the "New Orleans," was of about 200
tons burden, and was propelled by a stern-wheel, assisted, when the
winds were favorable, by sails carried on two masts. The hull was 138
feet long, 30 feet beam, and the cost of the whole, including engines,
was about $40,000. The builder, with his family, an engineer, a pilot,
and six "deck-hands," left Pittsburgh in October, 1811, reaching
Louisville in 70 hours (steaming about 10 miles an hour), and New
Orleans in 14 days, steaming from Natchez.

The next steamers built on Western waters were probably the Comet and
the Vesuvius, both of which were in service some time. The Comet was
finally laid aside, and the engine used to drive a mill, and the
Vesuvius was destroyed by the explosion of her boilers. As early as
1813 there were two shops at Pittsburgh building steam-engines.
Steamboat-building now became an important and lucrative business in
the West; and it is stated that as early as 1840 there were a thousand
steamers on the Mississippi and its tributaries.

In the Washington, built at Wheeling, Va., in 1816, under the
direction of Captain Henry M. Shreve, the boilers, which had
previously been placed in the hold, were carried on the main-deck, and
a "hurricane-deck" was built over them. Shreve substituted two
horizontal direct-acting engines for the single upright engine used by
Fulton, drove them by high-pressure steam without condensation, and
attached them, one on each side the boat, to cranks placed at right
angles. He adopted a cam cut-off expanding the steam considerably, and
the flue-boiler of Evans. At that time the voyage from New Orleans to
Louisville occupied three weeks, and Shreve was made the subject of
many witticisms when he predicted that the time would ultimately be
shortened to ten days. It is now made in four days. The Washington was
seized at New Orleans, in 1817, by order of Livingston, who claimed
that his rights included the monopoly of the navigation of the
Mississippi and its tributaries. The courts decided adversely on this
claim, and the release of the Washington was the act which removed
every obstacle to the introduction of steam-navigation throughout the
United States.

The first steamer on the Great Lakes was the Ontario, built in 1816,
at Sackett's Harbor. Fifteen years later, Western steamboats had taken
the peculiar form which has since usually distinguished them.

The use of the steam-engine for ocean-navigation kept pace with its
introduction on inland waters. Begun by Robert L. Stevens in the
United States, in the year 1808, and by his contemporaries, Bell and
Dodd, in Great Britain, it steadily and rapidly advanced in
effectiveness and importance, and has now nearly driven the sailing
fleet from the ocean. Transatlantic steam-navigation began with the
voyage of the American steamer Savannah from Savannah, Ga., to St.
Petersburg, Russia, _via_ Great Britain and the North-European ports,
in the year 1819. Fulton, not long before his death, planned a vessel,
which it was proposed to place in service in the Baltic Sea; but
circumstances compelled a change of plan finally, and the steamer was
placed on a line between Newport, R. I., and the city of New York; and
the Savannah, several years later, made the voyage then proposed for
Fulton's ship. The Savannah measured 350 tons, and was constructed by
Crocker & Fickett, at Corlears Hook, N. Y. She was purchased by Mr.
Scarborough, of Savannah, who placed Captain Moses Rogers, previously
in command of the Clermont and of Stevens's boat, the Ph[oe]nix, in
charge. The ship was fitted with steam-machinery and paddle-wheels,
and sailed for Savannah April 27, 1819, making the voyage successfully
in seven days. From Savannah, the vessel sailed for Liverpool May
26th, and arrived at that port June 20th. During this trip the engines
were used 18 days, and the remainder of the voyage was made under
sail. From Liverpool the Savannah sailed, July 23d, for the Baltic,
touching at Copenhagen, Stockholm, St. Petersburg, and other ports. At
St. Petersburg, Lord Lyndock, who had been a passenger, was landed;
and, on taking leave of the commander of the steamer, the
distinguished guest presented him with a silver tea-kettle, suitably
inscribed with a legend referring to the importance of the event which
afforded him the opportunity. The Savannah left St. Petersburg in
November, passing New York December 9th, and reaching Savannah in 50
days from the date of departure, stopping four days at Copenhagen,
Denmark, and an equal length of time at Arundel, Norway. Several
severe gales were met in the Atlantic, but no serious injury was done
to the ship.

The Savannah was a full-rigged ship. The wheels were turned by an
inclined direct-acting low-pressure engine, having a steam-cylinder 40
inches in diameter and 6 feet stroke of piston. The paddle-wheels were
of wrought-iron, and were so attached that they could be detached and
hoisted on board when it was desired. After the return of the ship to
the United States, the machinery was removed and was sold to the
Allaire Works, of New York. The steam-cylinder was exhibited by the
purchasers at the "World's Fair" at New York thirty years later. The
vessel was employed, as a sailing-vessel, on a line between New York
and Savannah, and was finally lost in the year 1822. Under sail, with
a moderate breeze, this ship is said to have sailed about three knots,
and to have steamed five knots. Pine-wood was used as the fuel, which
fact accounts for the necessity of making the transatlantic voyage
partly under sail.

Renwick states that another vessel, ship-rigged and fitted with a
steam-engine, was built at New York in 1819, to ply between New York
and Charleston, and to New Orleans and Havana, and that it proved
perfectly successful as a steamer, having good speed, and proving an
excellent sea-boat. The enterprise was, however, pecuniarily a
failure, and the vessel was sold to the Brazilian Government after the
removal of the engine. In 1825 the steamer Enterprise made a voyage to
India, sailing and steaming as the weather and the supply of fuel
permitted. The voyage occupied 47 days.

Notwithstanding these successful passages across the ocean, and the
complete success of the steamboat in rivers and harbors, it was
asserted, as late as 1838, by many who were regarded as authority,
that the passage of the ocean by steamers was quite impracticable,
unless possibly they could steam from the coasts of Europe to
Newfoundland or to the Azores, and, replenishing their coal-bunkers,
resume their voyages to the larger American ports. The voyage was,
however, actually accomplished by two steamers in the year just
mentioned. These were the Sirius, a ship of 700 tons and of 250
horse-power, and the Great Western, of 1,340 tons and 450 horse-power.
The latter was built for this service, and was a large ship for that
time, measuring 236 feet in length. Her wheels were 28 feet in
diameter, and 10 feet in breadth of face. The Sirius sailed from Cork
April 4, 1838, and the Great Western from Bristol April 8th, both
arriving at New York on the same day--April 23d--the Sirius in the
morning, and the Great Western in the afternoon.

The Great Western carried out of Bristol 660 tons of coal. Seven
passengers chose to take advantage of the opportunity, and made the
voyage in one-half the time usually occupied by the sailing-packets of
that day. Throughout the voyage the wind and sea were nearly ahead,
and the two vessels pursued the same course, under very similar
conditions. Arriving at New York, they were received with the greatest
possible enthusiasm. They were saluted by the forts and the men-of-war
in the harbor; the merchant-vessels dipped their flags, and the
citizens assembled on the Battery, and, coming to meet them in boats
of all kinds and sizes, cheered heartily. The newspapers of the time
were filled with the story of the voyage and with descriptions of the
steamers themselves and of their machinery.

A few days later the two steamers started on their return to Great
Britain, the Sirius reaching Falmouth safely in 18 days, and the Great
Western making the voyage to Bristol in 15 days, the latter meeting
with head-winds and working, during a part of the time, against a
heavy gale and in a high sea, at the rate of but two knots an hour.
The Sirius was thought too small for this long and boisterous route,
and was withdrawn and replaced on the line between London and Cork,
where the ship had previously been employed. The Great Western
continued several years in the transatlantic trade.

Thus these two voyages inaugurated a transoceanic steam-service, which
has steadily grown in extent and in importance. The use of steam-power
for this work of extended ocean-transportation has never since been
interrupted. During the succeeding six years the Great Western made 70
passages across the Atlantic, occupying on the voyages to the westward
an average of 15-1/2 days, and eastward 13-1/2. The quickest passage
to New York was made in May, 1843, in 12 days and 18 hours, and the
fastest steaming was logged 12 months earlier, when the voyage from
New York was made in 12 days and 7 hours.

Meantime, several other steamers were built and placed in the
transatlantic trade. Among these were the Royal William, the British
Queen, the President, the Liverpool, and the Great Britain. The
latter, the finest of the fleet, was launched in 1843. This steamer
was 300 feet long, 50 feet beam, and of 1,000 horse-power. The hull
was of iron, and the whole ship was an example of the very best work
of that time. After several voyages, this vessel went ashore on the
coast of Ireland, and there remained several weeks, but was finally
got off, without having suffered serious injury--a remarkable
illustration of the stanchness of an iron hull when well built and of
good material. The vessel was repaired, and many years afterward was
still afloat, and engaged in the transportation of passengers and
merchandise to Australia.

The "Cunard Line" of transatlantic steamers was established in the
year 1840. The first of the line--the Britannia--sailed from Liverpool
for New York, July 4th of that year, and was followed, on regular
sailing-days, by the other three of the four ships with which the
company commenced business. These four vessels had an aggregate
tonnage of 4,600 tons, and their speed was less than eight knots.
To-day, the tonnage of a single vessel of the fleet exceeds that of
the four; the total tonnage has risen to many times that above given.
There are 50 steamers in the line, aggregating nearly 50,000
horse-power. The speed of the steamships of the present time is double
that of the vessels of that date, and passages are not infrequently
made in eight days.

The form of steam-engine in most general use at this time, on
transatlantic steamers, was that known as the "side-lever engine." It
was first given the standard form by Messrs. Maudsley & Co., of
London, about 1835, and was built by them for steamers supplied to the
British Government for general mail service.

The steam-vessels of the time are well represented in the accompanying
engraving (Fig. 91) of the steamship Atlantic--a vessel which was
shortly afterward (1851) built as the pioneer steamer of the American
"Collins Line." This steamship was one of several which formed the
earliest of American steamship-lines, and is one of the finest
examples of the type of paddle-steamers which was finally superseded
by the later screw-fleets. The "Collins Line" existed but a very few
years, and its failure was probably determined as much by the evident
and inevitable success of screw-propulsion as by the difficulty of
securing ample capital, complete organization, and efficient general
management. This steamer was built at New York--the hull by William
Brown, and the machinery by the Novelty Iron-Works. The length of the
hull was 276 feet, its breadth 45 feet, and the depth of hold 31-1/2
feet. The width over the paddle-boxes was 75 feet. The ship measured
2,860 tons. The form of the hull was then peculiar in the fineness of
its lines; the bow was sharp, and the stern fine and smooth, and the
general outline such as best adapted the ship for high speed. The main
saloon was about 70 feet long, and the dining-room was 60 feet in
length and 20 feet wide. The state-rooms were arranged on each side
the dining "saloon," and accommodated 150 passengers. These vessels
were beautifully fitted up, and with them was inaugurated that
wonderful system of passenger-transportation which has since always
been distinguished by those comforts and conveniences which the
American traveler has learned to consider his by right.

[Illustration: FIG. 91.--The Atlantic, 1851.]

The machinery of these ships was, for that time, remarkably powerful
and efficient. The engines were of the side-lever type, as
illustrated in Fig. 92, which represents the engine of the Pacific,
designed by Mr. Charles W. Copeland, and built by the Allaire Works.

[Illustration: FIG. 92.--The Side-Lever Engine, 1849.]

In this type of engine, as is seen, the piston-rod was attached to a
cross-head working vertically, from which, at each side, links, _B C_,
connected with the "side-lever," _D E F_. The latter vibrated about a
"main centre" at _E_, like the overhead beam of the more common form
of engine; from its other end, a "connecting-rod," _H_, led to the
"cross-tail," _W_, which was, in turn, connected to the crank-pin,
_I_. The condenser, _M_, and air-pump, _Q_, were constructed in the
same manner as those of other engines, their only peculiarities being
such as were incident to their location between the cylinder, _A_, and
the crank, _I J_. The paddle-wheels were of the common "radial" form,
covered in by paddle-boxes so strongly built that they were rarely
injured by the heaviest seas.

These vessels surpassed, for a time, all other sea-going steamers in
speed and comfort, and made their passages with great regularity. The
minimum length of voyage of the Baltic and Pacific, of this line, was
9 days 19 hours.

During the latter part of the period the history of which has been
here given, the marine steam-engine became subject to very marked
changes in type and in details, and a complete revolution was effected
in the method of propulsion. This change has finally resulted in the
universal adoption of a new propelling instrument, and in driving the
whole fleet of paddle-steamers from the ocean. The Great Britain was a
screw-steamer.

The screw-propeller, which, as has been stated, was probably first
proposed by Dr. Hooke in 1681, and by Dr. Bernouilli, of Groningen, at
about the middle of the eighteenth century, and by Watt in 1784, was,
at the end of the century, tried experimentally in the United States
by David Bushnell, an ingenious American, who was then conducting the
experiments with torpedoes which were the cause of the incident which
originated that celebrated song by Francis Hopkinson, the "Battle of
the Kegs," using the screw to propel one of his submarine boats, and
by John Fitch, and by Dallery in France.

Joseph Bramah, of Great Britain, May 9, 1785, patented a
screw-propeller identical in general arrangement with those used
to-day. His sketch exhibits a screw, apparently of very fair shape,
carried on an horizontal shaft, which passes out of the vessel through
a stuffing-box, the screw being wholly submerged. Bramah does not seem
to have put his plan in practice. It was patented again in England,
also, by Littleton in 1794, and by Shorter in 1800.

John Stevens, however, first gave the screw a practically useful
form, and used it successfully, in 1804 and 1805, on the single and
the twin screw boats which he built at that time. This propelling
instrument was also tried by Trevithick, who planned a vessel to be
propelled by a steam-engine driving a screw, at about this time, and
his scheme was laid before the Navy Board in the year 1812. His plans
included an iron hull. Francis Pettit Smith tried the screw also in
the year 1808, and subsequently.

Joseph Ressel, a Bohemian, proposed to use a screw in the propulsion
of balloons, about 1812, and in the year 1826 proposed its use for
marine propulsion. He is said to have built a screw-boat in the year
1829, at Trieste, which he named the Civetta. The little craft met
with an accident on the trial-trip, and nothing more was done.

The screw was finally brought into general use through the exertions
of John Ericsson, a skillful Swedish engineer, who was residing in
England in the year 1836, and of Mr. F. P. Smith, an English farmer.
Ericsson patented a peculiar form of screw-propeller, and designed a
steamer 40 feet in length, of 8 feet beam, and drawing 3 feet of
water. The screw was double, two shafts being placed the one within
the other, revolving in opposite directions, and carrying the one a
right-hand and the other a left-hand screw. These screws were 5-1/4
feet in diameter. On her trial-trip this little steamer attained a
speed of 10 miles an hour. Its power as a "tug" was found to be very
satisfactory; it towed a schooner of 140 tons burden at the rate of 7
miles, and the large American packet-ship Toronto was towed on the
Thames at a speed of 5 miles an hour.

Ericsson endeavored to interest the British Admiralty in his
improvements, and succeeded only so far as to induce the Lords of the
Admiralty to make an excursion with him on the river. No interest was
awakened in the new system, and nothing was done by the naval
authorities. A note to the inventor from Captain Beaufort--one of the
party--was received shortly afterward, in which it was stated that
the excursionists had not found the performance of the little vessel
to equal their hopes and expectations. All the interests of the then
existing engine-building establishments were opposed to the
innovation, and the proverbial conservatism of naval men and naval
administrations aided in procuring the rejection of Ericsson's plans.

Fortunately for the United States, it happened, at that time, that we
had in Great Britain both civil and naval representatives of greater
intelligence, or of greater boldness and enterprise. The consul at
Liverpool was Mr. Francis B. Ogden, of New Jersey, a gentleman who was
somewhat familiar with the steam-engine and with steam-navigation. He
had seen Ericsson's plans at an earlier period, and had at once seen
their probable value. He was sufficiently confident of success to
place capital at the disposal of the inventor. The little screw-boat
just described was built with funds of which he furnished a part, and
was named, in his honor, the Francis B. Ogden.

Captain Robert F. Stockton, an officer of the United States Navy, and
also a resident of New Jersey, was in London at the time, and made an
excursion with Ericsson on the Ogden. He was also at once convinced of
the value of the new method of application of steam-power to
ship-propulsion, and gave the engineer an order to build two iron
screw-steamboats for use in the United States. Ericsson was induced,
by Messrs. Ogden and Stockton, to take up his residence in the United
States.[84] The Stockton was sent over to the United States in April,
1839, under sail, and was sold to the Delaware & Raritan Canal
Company. Her name was changed, and, as the New Jersey, she remained in
service many years.

  [84] This distinguished inventor is still a resident of New York
  (1878).

The success of the boat built by Ericsson was so evident that,
although the naval authorities remained inactive, a private company
was formed, in 1839, to work the patents of F. P. Smith, and this
"Ship-Propeller Company" built an experimental craft called the
Archimedes, and its trial-trip was made October 14th of the same year.
The speed attained was 9.64 miles an hour. The result was in every
respect satisfactory, and the vessel, subsequently, made many voyages
from port to port, and finally circumnavigated the island of Great
Britain. The proprietors of the ship were not pecuniarily successful
in their venture, however, and the sale of the vessel left the company
a heavy loser. The Archimedes was 125 feet long, of 21 feet 10 inches
beam, and 10 feet draught, registering 232 tons. The engines were
rated at 80 horse-power. Smith's earlier experiments (1837) were made
with a little craft of 6 tons burden, driven by an engine having a
steam-cylinder 6 inches in diameter and 15 inches stroke of piston.
The funds needed were furnished by a London banker--Mr. Wright.

Bennett Woodcroft had also used the screw experimentally as early as
1832, on the Irwell, near Manchester, England, in a boat of 55 tons
burden. Twin-screws were used, right and left handed respectively;
they were each two feet in diameter, and were given an expanding
pitch. The boat attained a speed of four miles an hour.

Experiments made subsequently (1843) with this form of screw, and in
competition with the "true" screw of Smith, brought out very
distinctly the superiority of the former, and gave some knowledge of
the proper proportions for maximum efficiency. In later examples of
the Woodcroft screw, the blades were made detachable and adjustable--a
plan which is still a usual one, and which has proved to be, in some
respects, very convenient.

When Ericsson reached the United States, he was almost
immediately given an opportunity to build the Princeton--a large
screw-steamer--and at about the same time the English and French
Governments also had screw-steamers built from his plans, or from
those of his agent in England, the Count de Rosen. In these latter
ships--the Amphion and the Pomona--the first horizontal direct-acting
engines ever built were used, and they were fitted with double-acting
air-pumps, having canvas valves and other novel features. The great
advantages exhibited by these vessels over the paddle-steamers of the
time did for screw-propulsion what Stephenson's locomotive--the
Rocket--did for railroad locomotion ten years earlier.

Congress, in 1839, had authorized the construction of three
war-vessels, and the Secretary of the Navy ordered that two be at once
built in the succeeding year. Of these, one was the Princeton, the
screw-steamer of which the machinery was designed by Ericsson. The
length of this vessel was 164 feet, beam 30-1/2 feet, and depth 21-1/2
feet. The ship drew from 16-1/2 to 18 feet of water, displacing at
those draughts 950 and 1,050 tons. The hull had a broad, flat floor,
with sharp entrance and fine run, and the lines were considered at
that time remarkably fine.

The screw was of gun-bronze, six-bladed, and was 14 feet in diameter
and of 35 feet pitch; i. e., were there no slip, the screw working as
if in a solid nut, the ship would have been driven forward 35 feet at
each revolution.

The engines were two in number, and very peculiar in form; the
cylinder was, in fact, a _semi_-cylinder, and the place of the
piston-rod, as usually built, was taken by a vibrating shaft, or
"rock-shaft," which carried a piston of rectangular form, and which
vibrated like a door on its hinges as the steam was alternately let
into and exhausted from each side of it. The great rock-shaft carried,
at the outer end, an arm from which a connecting-rod led to the crank,
thus forming a "direct-acting engine."

The draught in the boilers was urged by blowers. Ericsson had adopted
this method of securing an artificial draught ten years before, in one
of his earlier vessels, the Corsair. The Princeton carried a XII-inch
wrought-iron gun. This gun exploded after a few trials, with terribly
disastrous results, causing the death of several distinguished men,
including members of the President's cabinet.

The Princeton proved very successful as a screw-steamer, attaining a
speed of 13 knots, and was then considered very remarkably fast.
Captain Stockton, who commanded the vessel, was most enthusiastic in
praise of her.

Immediately there began a revolution in both civil and naval
ship-building, which progressed with great rapidity. The Princeton was
the first of the screw-propelled navy which has now entirely displaced
the older type of steam-vessel. The introduction of the screw now took
place with great rapidity. Six steamers were fitted with Ericsson's
screw in 1841, 9 in 1842, and nearly 30 in the year 1843.

In Great Britain, France, Germany, and other European countries, the
revolution was also finally effected, and was equally complete. Nearly
all sea-going vessels built toward the close of the period here
considered were screw-steamers, fitted with direct-acting,
quick-working engines. It was, however, many years before the
experience of engineers in the designing and in the construction and
management of this new machinery enabled them to properly proportion
it for the various kinds of service to which they were called upon to
adapt it. Among other modifications of earlier practice introduced by
Ericsson was the surface-condenser with a circulating pump driven by a
small independent engine.

The screw was found to possess many advantages over the paddle-wheel
as an instrument for ship-propulsion. The cost of machinery was
greatly reduced by its use; the expense of maintenance in working
order was, however, somewhat increased. The latter disadvantage was,
nevertheless, much more than compensated by an immense increase in the
economy of ship-propulsion, which marked the substitution of the new
instrument and its impelling machinery.

When a ship is propelled by paddles, the motion of the vessel creates,
in consequence of the friction of the fluid against the sides and
bottom, a current of water which flows in the direction in which the
ship is moving, and forms a current following the ship for a time, and
finally losing all motion by contact with the surrounding mass of
water. All the power expended in the production of this great stream
is, in the case of the paddle-steamer, entirely lost. In
screw-steamers, however, the propelling instrument works in this
following current, and the tendency of its action is to bring the
agitated fluid to rest, taking up and thus restoring, usefully, a
large part of that energy which would otherwise have been lost. The
screw is also completely covered by the water, and acts with
comparative efficiency in consequence of its submersion. The rotation
of the screw is comparatively rapid and smooth, also, and this permits
the use of small, light, fast-running engines. The latter condition
leads to economy of weight and space, and consequently saves not only
the cost of transportation of the excess of weight of the larger kind
of engine, but, leaving so much more room for paying cargo, the gain
is found to be a double one. Still further, the quick-running engine
is, other things being equal, the most economical of steam; and thus
some expense is saved not only in the purchase of fuel, but in its
transportation, and some still additional gain is derived from the
increased amount of paying cargo which the vessel is thus enabled to
carry. The change here described was thus found to be productive of
enormous direct gain. Indirectly, also, some advantage was derived
from the greater convenience of a deck clear from machinery and the
great paddle-shaft, in the better storage of the lading, the greater
facility with which the masts and sails could be fitted and used; and
directly, again, in clear sides unencumbered by great paddle-boxes
which impeded the vessel by catching both sea and wind.

The screw was, for some years, generally regarded as simply auxiliary
in large vessels, assisting the sails. Ultimately the screw became
the essential feature, and vessels were lightly sparred and were given
smaller areas of sail, the latter becoming the auxiliary power.

In November of the year 1843, the screw-steamer Midas, Captain Poor, a
small schooner-rigged craft, left New York for China, on probably the
first voyage of such length ever undertaken by a steamer; and in the
following January the Edith, Captain Lewis, a bark-rigged
screw-vessel, sailed from the same port for India and China. The
Massachusetts, Captain Forbes, a screw-steamship of about 800 tons,
sailed for Liverpool September 15, 1845, the first voyage of an
American transatlantic passenger-steamer since the Savannah's pioneer
adventure a quarter of a century before. Two years later, American
enterprise had placed both screw and paddle steamers on the rivers of
China--principally through the exertions of Captain R. B. Forbes--and
steam-navigation was fairly established throughout the world.

On comparing the screw-steamer of the present time with the best
examples of steamers propelled by paddle-wheels, the superiority of
the former is so marked that it may cause some surprise that the
revolution just described should have progressed no more rapidly. The
reason of this slow progress, however, was probably that the
introduction of the rapidly-revolving screw, in place of the
slow-moving paddle-wheel, necessitated a complete revolution in the
design of their steam-engines; and the unavoidable change from the
heavy, long-stroked, low-speed engines previously in use, to the light
engines, with small cylinders and high piston-speed, called for by the
new system of propulsion, was one that necessarily occurred slowly,
and was accompanied by its share of those engineering blunders and
accidents that invariably take place during such periods of
transition. Engineers had first to learn to design such engines
as should be reliable under the then novel conditions of
screw-propulsion, and their experience could only be gained through
the occurrence of many mishaps and costly failures. The best
proportions of engines and screws, for a given ship, were determined
only by long experience, although great assistance was derived from
the extensive series of experiments made with the French steamer
Pelican. It also became necessary to train up a body of engine-drivers
who should be capable of managing these new engines; for they required
the exercise of a then unprecedented amount of care and skill.
Finally, with the accomplishment of these two requisites to success
must simultaneously occur the enlightenment of the public,
professional as well as non-professional, in regard to their
advantages. Thus it happens that it is only after a considerable time
that the screw attained its proper place as an instrument of
propulsion, and finally drove the paddle-wheel quite out of use,
except in shoal water.

Now our large screw-steamers are of higher speed than any
paddle-steamers on the ocean, and develop their power at far less
cost. This increased economy is due not only to the use of a more
efficient propelling instrument, and to changes already described, but
also, in a great degree, to the economy which has followed as a
consequence of other changes in the steam-engine driving it. The
earliest days of screw-propulsion witnessed the use of steam of from 5
to 15 pounds pressure, in a geared engine using jet-condensation, and
giving a horse-power at an expense of perhaps 7 to 10, or even more,
pounds of coal per hour. A little later came direct-acting engines
with jet-condensation and steam at 20 pounds pressure, costing about 5
or 6 pounds per horse-power per hour. The steam-pressure rose a little
higher with the use of greater expansion, and the economy of fuel was
further improved. The introduction of the surface-condenser, which
began to be generally adopted some ten years ago, brought down the
cost of power to from 3 to 4 pounds in the better class of engines. At
about the same time, this change to surface-condensation helping
greatly to overcome those troubles arising from boiler-incrustation
which had prevented the rise of steam-pressure above about 25 pounds
per square inch, and as, at the same time, it was learned by engineers
that the deposit of lime-scale in the marine boiler was determined by
temperature rather than by the degree of concentration, and that all
the lime entering the boiler was deposited at the pressure just
mentioned, a sudden advance took place. Careful design, good
workmanship, and skillful management, made the surface-condenser an
efficient apparatus; and, the dangers of incrustation being thus
lessened, the movement toward higher pressures recommenced, and
progressed so rapidly that now 75 pounds per square inch is very
usual, and more than 125 pounds has since been attained.

The close of this period was marked by the construction of the most
successful types of paddle-steamers, the complete success of
transoceanic steam-transportation, the introduction of the
screw-propeller and the peculiar engine appropriate to it, and,
finally, a general improvement, which had finally become marked both
in direction and in rapidity of movement, leading toward the use of
higher steam-pressure, greater expansion, lighter and more
rapidly-working machinery, and decidedly better design and
construction, and the use of better material. The result of these
changes was seen in economy of first cost and maintenance, and the
ability to attain greater speed, and to assure greater safety to
passengers and less risk to cargo.

The introduction of the changes just noted finally led to the last
great change in the form of the marine steam-engine, and a revolution
was inaugurated, which, however, only became complete in the
succeeding period. The non-success of Hornblower and of Wolff, and
others who had attempted to introduce the "compound" or
double-cylinder engine on land, had not convinced all engineers that
it might not yet be made a successful rival of the then standard type;
and the three or four steamers which were built for the Hudson River
at the end of the first quarter of the nineteenth century are said to
have been very successful vessels. Carrying 75 to 100 pounds of steam
in their boilers, the Swiftsure and her contemporaries were by that
circumstance well fitted to make that form of engine economically a
success. This form of engine was built occasionally during the
succeeding quarter of a century, but only became a recognized standard
type after the close of the epoch to the history of which this chapter
is devoted. That latest and greatest advance in the direction of
increased efficiency in the marine steam-engine was, however,
commenced very soon after Watt's death, and its completion was the
work of nearly a half-century.

[Illustration]




CHAPTER VI.

_THE STEAM-ENGINE OF TO-DAY._

  ... "And, last of all, with inimitable power, and 'with whirlwind
  sound,' comes the potent agency of steam. In comparison with the
  past, what centuries of improvement has this single agent comprised
  in the short compass of fifty years! Everywhere practicable,
  everywhere efficient, it has an arm a thousand times stronger than
  that of Hercules, and to which human ingenuity is capable of fitting
  a thousand times as many hands as belonged to Briareus. Steam is
  found in triumphant operation on the seas; and, under the influence
  of its strong propulsion, the gallant ship--

    'Against the wind, against the tide,
    Still steadies with an upright keel.'

  It is on the rivers, and the boatman may repose on his oars; it is
  on highways, and exerts itself along the courses of land-conveyance;
  it is at the bottom of mines, a thousand feet below the earth's
  surface; it is in the mills, and in the workshops of the trades. It
  rows, it pumps, it excavates, it carries, it draws, it lifts, it
  hammers, it spins, it weaves, it prints. It seems to say to men, at
  least to the class of artisans: 'Leave off your manual labor; give
  over your bodily toil; bestow but your skill and reason to the
  directing of my power, and I will bear the toil, with no muscle to
  grow weary, no nerve to relax, no breast to feel faintness!' What
  further improvement may still be made in the use of this astonishing
  power it is impossible to know, and it were vain to conjecture. What
  we do know is, that it has most essentially altered the face of
  affairs, and that no visible limit yet appears beyond which its
  progress is seen to be impossible."--DANIEL WEBSTER.


THE PERIOD OF REFINEMENT--1850 TO DATE.

By the middle of the present century, as we have now seen, the
steam-engine had been applied, and successfully, to every great
purpose for which it was fitted. Its first application was to the
elevation of water; it next was applied to the driving of mills and
machinery; and it finally became the great propelling power in
transportation by land and by sea.

At the beginning of the period to which we are now come, these
applications of steam-power had become familiar both to the engineer
and to the public. The forms of engine adapted to each purpose had
been determined, and had become usually standard. Every type of the
modern steam-engine had assumed, more or less closely, the form and
proportions which are now familiar; and the most intelligent designers
and builders had been taught--by experience rather than by theory, for
the theory of the steam-engine had then been but little investigated,
and the principles and laws of thermo-dynamics had not been traced in
their application to this engine--the principles of construction
essential to successful practice, and were gradually learning the
relative standing of the many forms of steam-engine, from among which
have been preserved a few specially fitted for certain specific
methods of utilization of power.

During the years succeeding the date 1850, therefore, the growth of
the steam-engine had been, not a change of standard type, or the
addition of new parts, but a gradual improvement in forms,
proportions, and arrangements of details; and this period has been
marked by the dying out of the forms of engine least fitted to succeed
in competition with others, and the retention of the latter has been
an example of "the survival of the fittest." This has therefore been a
Period of Refinement.

During this period invention has been confined to details; it has
produced new forms of parts, new arrangements of details; it has
devised an immense variety of valves, valve-motions, regulating
apparatus, and a still greater variety of steam-boilers and of
attachments, essential and non-essential, to both engines and boilers.
The great majority of these peculiar devices have been of no value,
and very many of the best of them have been found to have about equal
value. All the well-known and successful forms of engine, when equally
well designed and constructed and equally well managed, are of very
nearly equal efficiency; all of the best-known types of steam-boiler,
where given equal proportions of grate to heating-surface and equally
well designed, with a view to securing a good draught and a good
circulation of water, have been found to give very nearly equally good
results; and it has become evident that a good knowledge of principles
and of practice, on the part of the designer, the constructor, and the
manager of the boiler, is essential in the endeavor to achieve
economical success; that good engineering is demanded, rather than
great ingenuity. The inventor has been superseded here by the
engineer.

The knowledge acquired in the time of Watt, of the essential
principles of steam-engine construction, has since become generally
familiar to the better class of engineers. It has led to the selection
of simple, strong, and durable forms of engine and boiler, to the
introduction of various kinds of valves and of valve-gearing, capable
of adjustment to any desired range of expansive working, and to the
attachment of efficient forms of governor to regulate the speed of the
engine, by determining automatically the point of cut-off which will,
at any instant, best adjust the energy exerted by the expanding steam
to the demand made by the work to be done.

The value of high pressures and considerable expansion was recognized
as long ago as in the early part of the present century, and Watt, by
combining skillfully the several principal parts of the steam-engine,
gave it very nearly the shape which it has to-day. The compound
engine, even, as has been seen, was invented by contemporaries of
Watt, and the only important modifications since his time have
occurred in details. The introduction of the "drop cut-off," the
attachment of the governor to the expansion-apparatus in such a manner
as to determine the degree of expansion, the improvement of
proportions, the introduction of higher steam and greater expansion,
the improvement of the marine engine by the adoption of
surface-condensation, in addition to these other changes, and the
introduction of the double-cylinder engine, after the elevation of
steam-pressure and increase of expansion had gone so far as to justify
its use, are the changes, therefore, which have taken place during
this last quarter-century. It began then to be generally understood
that expansion of steam produced economy, and mechanics and inventors
vied with each other in the effort to obtain a form of valve-gear
which should secure the immense saving which an abstract consideration
of the expansion of gases according to Marriotte's law would seem to
promise. The counteracting phenomena of internal condensation and
reëvaporation, of the losses of heat externally and internally, and of
the effect of defective vacuum, defective distribution of steam, and
of back-pressure, were either unobserved or were entirely overlooked.

It was many years, therefore, before engine-builders became convinced
that no improvement upon existing forms of expansion-gear could secure
even an approximation to theoretical efficiency.

The fact thus learned, that the benefit of expansive working has a
limit which is very soon reached in ordinary practice, was not then,
and has only recently become, generally known among our steam-engine
builders, and for several years, during the period upon which we now
enter, there continued the keenest competition between makers of rival
forms of expansion-gear, and inventors were continually endeavoring to
produce something which should far excel any previously-existing
device.

In Europe, as in the United States, efforts to "improve" standard
designs have usually resulted in injuring their efficiency, and in
simply adding to the first cost and running expense of the engines,
without securing a marked increase in economy in the consumption of
steam.


SECTION I.--STATIONARY ENGINES.

"STATIONARY ENGINES" had been applied to the operation of
mill-machinery, as has been seen, by Watt and by Murdoch, his
assistant and pupil; and Watt's competitors, in Great Britain and
abroad, had made considerable progress before the death of the great
engineer, in its adaptation to its work. In the United States, Oliver
Evans had introduced the non-condensing high-pressure stationary
engine, which was the progenitor of the standard engine of that type
which is now used far more generally than any other form. These
engines were at first rude in design, badly proportioned, rough and
inaccurate as to workmanship, and uneconomical in their consumption of
fuel. Gradually, however, when made by reputable builders, they
assumed neat and strong shapes, good proportions, and were well made
and of excellent materials, doing their work with comparatively little
waste of heat or of fuel.

One of the neatest and best modern designs of stationary engine for
small powers is seen in Fig. 93, which represents a "vertical
direct-acting engine," with base-plate--a form which is a favorite
with many engineers.

The engine shown in the engraving consists of two principal parts, the
cylinder and the frame, which is a tapering column having openings in
the sides, to allow free access to all the working parts within. The
slides and pillow-blocks are cast with the column, so that they cannot
become loose or out of line; the rubbing surfaces are large and easily
lubricated. Owing to the vertical position, there is no tendency to
side wear of cylinder or piston. The packing-rings are self-adjusting,
and work free but tight. The crank is counterbalanced; the crank-pin,
cross-head pin, piston-rod, valve-stem, etc., are made of steel; all
the bearing surfaces are made extra large, and are accurately fitted;
and the best quality of Babbitt-metal only used for the
journal-bearings.

[Illustration: FIG. 93.--Vertical Stationary Steam-Engine.]

The smaller sizes of these engines, from 2 to 10 horse-power, have
both pillow-blocks cast in the frame, giving a bearing each side of
the double cranks. They are built by some constructors in quantities,
and parts duplicated by special machinery (as in fire-arms and
sewing-machines), which secures great accuracy and uniformity of
workmanship, and allows of any part being quickly and cheaply
replaced, when worn or broken by accident. The next figure is a
vertical section through the same engine.

[Illustration: FIG. 94.--Vertical Stationary Steam-Engine. Section.]

Engines fitted with the ordinary rigid bearings require to be erected
on a firm foundation, and to be kept in perfect line. If, by the
settling of the foundation, or from any other cause, they get out of
line, heating, cutting, and thumping result. To obviate this, modern
engines are often fitted with self-adjusting bearings throughout; this
gives the engine great flexibility and freedom from friction. The
accompanying cuts show clearly how this is accomplished. The
pillow-block has a spherical shell turned and fitted into the
spherically-bored pillow-block, thus allowing a slight angular motion
in any direction. The connecting-rod is forged in a single piece,
without straps, gibs, or key, and is mortised through at each end for
the reception of the brass boxes, which are curved on their backs, and
fit the cheek-pieces, between which they can turn to adjust themselves
to the pins, in the plane of the axis of the rod. The adjustment for
wear is made by wedge-blocks and set screws, as shown, and they are so
constructed that the parts cannot get loose and cause a break-down.
The cross-head has adjustable gibs on each side, turned to fit the
slides, which are cast solidly in the frame, and bored out exactly in
the line with the cylinder. This permits it freely to turn on its
axis, and, in connection with the adjustable boxes in the
connecting-rod, allows a perfect self-adjustment to the line of the
crank-pin. The out-board bearing may be moved an inch or more out of
position in any direction, without detriment to the running of the
engine, all bearings accommodating themselves perfectly to whatever
position the shaft may assume.

The ports and valve-passages are proportioned as in locomotive
practice. The valve-seat is adapted to the ordinary plain slide or
D-valve, should it be preferred, but the balanced piston slide-valve
works with equal ease whether the steam-pressure is 10 or 100 pounds,
and at the same time gives double steam and exhaust openings, which
greatly facilitates the entrance of the steam to, and its escape from,
the cylinder, thus securing a nearer approach to boiler-pressure and a
less back-pressure, saving the power required to work an ordinary
valve, and reducing the wear of valve-gear.

This is a type of engine frequently seen in the United States, but
more rarely in Europe. It is an excellent form of engine. The vertical
direct-acting engine is sometimes, though rarely, built of very
considerable size, and these large engines are more frequently seen in
rolling-mills than elsewhere.

Where much power is required, the stationary engine is usually an
horizontal direct-acting engine, having a more or less effective
cut-off valve-gear, according to the size of engine and the cost of
fuel. A good example of the simpler form of this kind of engine is the
small horizontal slide-valve engine, with independent cut-off valve
riding on the back of the main valve--a combination generally known
among engineers as the Meyer system of valve-gear. This form of
steam-engine is a very effective machine, and does excellent work when
properly proportioned to yield the required amount of power. It is
well adapted to an expansion of from four to five times. Its
disadvantages are the difficulty which it presents in the attachment
of the regulator, to determine the point of cut-off by the heavy work
which it throws upon the governor when attached, and the rather
inflexible character of the device as an expansive valve-gear. The
best examples of this class of engine have neat heavy bed-plates,
well-designed cylinders and details, smooth-working valve-gear, the
expansion-valve adjusted by a right and left hand screw, and
regulation secured by the attachment of the governor to the
throttle-valve.

The engine shown in the accompanying illustration (Fig. 95) is an
example of an excellent British stationary steam-engine. It is simple,
strong, and efficient. The frame, front cylinder-head, cross-head
guides, and crank-shaft "plumber-block," are cast in one piece, as has
so generally been done in the United States for a long time by some of
our manufacturers. The cylinder is secured against the end of the
bed-plate, as was first done by Corliss. The crank-pin is set in a
counterbalanced disk. The valve-gear is simple, and the governor
effective, and provided with a safety-device to prevent injury by the
breaking of the governor-belt. An engine of this kind of 10 inches
diameter of cylinder, 20 inches stroke of piston, is rated by the
builders at about 25 horse-power; a similar engine 30 inches in
diameter of cylinder would yield from 225 to 250 horse-power. In
this example, all parts are made to exact size by gauges standardized
to Whitworth's sizes.

[Illustration: FIG. 95.--Horizontal Stationary Steam-Engine.]

[Illustration: FIG. 96.--Horizontal Stationary Steam-Engine.]

In American engines (as is seen in Fig. 96), usually, two supports are
placed--the one under the latter bearing, and the other under the
cylinder--to take the weight of the engine; and through them it is
secured to the foundation. As in the vertical engine already
described, a valve is sometimes used, consisting of two pistons
connected by a rod, and worked by an ordinary eccentric. By a simple
arrangement these pistons have always the same pressure inside as out,
which prevents any leakage or blowing through; and they are said
always to work equally as well and free from friction under 150 pounds
pressure as under 10 pounds per square inch, and to require no
adjustment. It is more usual, however, to adopt the three-ported valve
used on locomotives, with (frequently) a cut-off valve on the back of
this main valve, which cut-off valve is adjusted either by hand or by
the governor.

Engines of the class just described are especially well fitted, by
their simplicity, compactness, and solidity, to work at the high
piston-speeds which are gradually becoming generally adopted in the
effort to attain increased economy of fuel by the reduction of the
immense losses of heat which occur in the expansion of steam in the
metallic cylinders through which we are now compelled to work it.

One of the best known of recent engines is the Allen engine, a
steam-engine having the same general arrangement of parts seen in the
above illustration, but fitted with a peculiar valve-gear, and having
proportions of parts which are especially calculated to secure
smoothness of motion and uniformity of pressure on crank-pin and
journals, at speeds so high that the inertia of the reciprocating
parts becomes a seriously-important element in the calculation of the
distribution of stresses and their effect on the dynamics of the
machine.

In the Allen engine,[85] the cylinder and frame are connected as in
the engine seen above, and the crank-disk, shaft-bearings, and other
principal details, are not essentially different. The valve-gear[86]
differs in having four valves, one at each end on the steam as well as
on the exhaust side, all of which are balanced and work with very
little resistance. These valves are not detachable, but are driven by
a link attached to and moved by an eccentric on the main shaft, the
position of the valve-rod attachment to which link is determined by
the governor, and the degree of expansion is thus adjusted to the work
of the engine. The engine has usually a short stroke, not exceeding
twice the diameter of cylinder, and is driven at very high speed,
generally averaging from 600 to 800 feet per minute.[87] This high
piston-speed and short stroke give very great velocity of rotation.
The effect is, therefore, to produce an exceptional smoothness of
motion, while permitting the use of small fly-wheels. Its short stroke
enables entire solidity to be attained in a bed of rigid form, making
it a very completely self-contained engine, adapted to the heaviest
work, and requiring only a small foundation.

  [85] The invention of Messrs. Charles T. Porter and John F. Allen.

  [86] Invented by Mr. John F. Allen.

  [87] Or not far from 600 times the cube root of the length of
  stroke, measured in feet.

The journals of the shaft, and all cylindrical wearing surfaces, are
finished by grinding in a manner that leaves them perfectly round. The
crank-pin and cross-head pin are hardened before being ground. The
joints of the valve-gear consist of pins turning in solid ferrules in
the rod-ends, both hardened and ground. After years of constant use
thus, no wear occasioning lost time in the valve-movements has been
detected.

High speed and short strokes are essential elements of economy. It is
now well understood that all the surfaces with which the steam comes
in contact condense it.

Obviously, one way to diminish this loss is to reduce the extent of
surface to which the steam is exposed. In engines of high speed and
short stroke, the surfaces with which the steam comes in contact,
while doing a given amount of work, present less area than in ordinary
engines running at low speed. Where great steadiness of motion is
desired, the expense of coupled engines is often incurred.
Quick-running engines do not require to be coupled; a single engine
may give greater uniformity of motion than is usually obtained with
coupled engines at ordinary speeds. The ports and valve-movements, the
weight of the reciprocating parts, and the size and weight of the
fly-wheels, should be calculated expressly for the speeds chosen.

The economy of the engine here described is unexcelled by the best of
the more familiar "drop cut-off" engines.

An engine reported upon by a committee of the American Institute, of
which Dr. Barnard was chairman, was non-condensing, 16 inches in
diameter of cylinder, 30 inches stroke, making 125 revolutions per
minute, and developed over 125 horse-power with 75 pounds of steam in
the boiler, using 25-3/4 pounds of steam per indicated horse-power,
and 2.87 pounds of coal--an extraordinarily good performance for an
engine of such small power.

The governor used on this engine is known as the Porter governor. It
is given great power and delicacy by weighting it down, and thus
obtaining a high velocity of rotation, and by suspending the balls
from forked arms, which are given each two bearing-pins separated
laterally so far as to permit considerable force to be exerted in
changing speeds without cramping those bearings sufficiently to
seriously impair the sensitiveness of the governor. This engine as a
whole may be regarded as a good representative of the high-speed
engine of to-day.

Since this change in the direction of high speeds has already gone so
far that the "drop cut-off" is sometimes inapplicable, in consequence
of the fact that the piston would, were such a valve-gear adopted,
reach the end of its stroke before the detached valve could reach its
seat; and since this progress is only limited by our attainments in
mechanical skill and accuracy, it seems probable that the
"positive-motion expansion-gear" type of engine will ultimately
supersede the now standard "drop cut-off engine."

The best known and most generally used class of stationary engines at
the present time is, however, that which has the so-called "drop
cut-off," or "detachable valve-gear." The oldest well-known form of
valve-motion of this description now in use is that known as the
Sickels cut-off, patented by Frederick E. Sickels, an American
mechanic, about the year 1841, and also built by Hogg, of New York,
who placed it upon the engine of the steamer South America. The
invention is claimed for both Hogg and Sickels. It was introduced by
the inventor in a form which especially adapted it to use with the
beam-engine used on the Eastern waters of the United States, and was
adapted to stationary engines by Messrs. Thurston, Greene & Co., of
Providence, R. I., who made use of it for some years before any other
form of "drop cut-off" came into general use. The Sickels cut-off
consisted of a set of steam-valves, usually independent of the
exhaust-valves, and each raised by a catch, which could be thrown out,
at the proper moment, by a wedge with which it came in contact as it
rose with the opening valve. This wedge, or other equivalent device,
was so adjusted that the valve should be detached and fall to its seat
when the piston reached that point in its movement, after taking
steam, at which expansion was to commence. From this point, no steam
entering the cylinder, the piston was impelled by the expanding vapor.
The valve was usually the double-poppet. Sickels subsequently invented
what was called the "beam-motion," to detach the valve at any point in
the stroke. As at first arranged, the valve could only be detached
during the earlier half-stroke, since at mid-stroke the direction of
motion of the eccentric rod was reversed and the valve began to
descend. By introducing a "wiper" having a motion transverse to that
of the valve and its catch, and by giving this wiper a motion
coincident with that of the piston by connecting it with the beam or
other part of the engine moving with the piston, he obtained a
kinematic combination which permitted the valve to be detached at any
point in the stroke, adding a very simple contrivance which enabled
the attendant to set the wiper so that it should strike the catch at
any time during the forward movement of the "beam-motion."

On stationary engines, the point of cut-off was afterward determined
by the governor, which was made to operate the detaching mechanism,
the combination forming what is sometimes called an "automatic"
cut-off. The attachment of the governor so as to determine the degree
of expansion had been proposed before Sickels's time. One of the
earliest of these contrivances was that of Zachariah Allen, in 1834,
using a cut-off valve independent of the steam-valve. The first to so
attach the governor to a _drop cut-off_ valve-motion was George H.
Corliss, who made it a feature of the Corliss valve-gear in 1849. In
the year 1855, N. T. Greene introduced a form of expansion-gear, in
which he combined the range of the Sickels beam-motion device with the
expansion-adjustment gained by the attachment of the governor, and
with the advantages of flat slide-valves at all ports--both steam and
exhaust.

Many other ingenious forms of expansion valve-gear have been invented,
and several have been introduced, which, properly designed and
proportioned to well-planned engines, and with good construction and
management, should give economical results little if at all inferior
to those just named. Among the most ingenious of these later devices
is that of Babcock & Wilcox, in which a very small auxiliary
steam-cylinder and piston is employed to throw the cut-off valve over
its port at the instant at which the steam is to be cut off. A very
beautiful form of isochronous governor is used on this engine, to
regulate the speed of the engine by determining the point of cut-off.

In Wright's engine, the expansion is adjusted by the movement, by the
regulator, of cams which operate the steam-valves so that they shall
hold the valve open a longer or shorter time, as required.

Since compactness and lightness are not as essential as in portable,
locomotive, and marine engines, the parts are arranged, in stationary
engines, with a view simply to securing efficiency, and the design is
determined by circumstances. It was formerly usual to adopt the
condensing engine in mills, and wherever a stationary engine was
required. In Europe generally, and to some extent in the United
States, where a supply of condensing water is obtainable, condensing
engines and moderate steam-pressures are still employed. But this type
of engine is gradually becoming superseded by the high-pressure
condensing engine, with considerable expansion, and with an
expansion-gear in which the point of cut-off is determined by the
governor.

[Illustration: FIG. 97.--Corliss Engine.]

[Illustration: FIG. 98--Corliss Engine Valve-Motion.]

The best-known engine of this class is the Corliss engine, which is
very extensively used in the United States, and which has been copied
very generally by European builders. Fig. 97 represents the Corliss
engine. The horizontal steam-cylinder is bolted firmly to the end of
the frame, which is so formed as to transmit the strain to the main
journal with the greatest directness. The frame carries the guides for
the cross-head, which are both in the same vertical plane. The valves
are four in number, a steam and an exhaust valve being placed at each
end of the steam-cylinder. Short steam-passages are thus secured, and
this diminution of clearance is a source of some economy. Both sets of
valves are driven by an eccentric operating a disk or wrist-plate, _E_
(Fig. 98), which vibrates on a pin projecting from the cylinder. Short
links reaching from this wrist-plate to the several valves, _D D_, _F
F_, move them with a peculiarly varying motion, opening and closing
them rapidly, and moving them quite slowly when the port is either
nearly open or almost closed. This effect is ingeniously secured by so
placing the pins on the wrist-plate that their line of motion becomes
nearly transverse to the direction of the valve-links when the limit
of movement is approached. The links connecting the wrist-plate with
the arms moving the steam-valves have catches at their extremities,
which are disengaged by coming in contact, as the arm swings around
with the valve-stem, with a cam adjusted by the governor. This
adjustment permits the steam to follow the piston farther when the
engine is caused to "slow down," and thus tends to restore the proper
speed. It disengages the steam-valve earlier, and expands the steam to
a greater extent, when the engine begins to run above the proper
speed. When the catch is thrown out, the valve is closed by a weight
or a strong spring. To prevent jar when the motion of the valve is
checked, a "dash-pot" is used, invented originally by F. E. Sickels.
This is a vessel having a nicely-fitted piston, which is received by a
"cushion" of water or air when the piston suddenly enters the cylinder
at the end of the valve-movement. In the original water dash-pot of
Sickels, the cylinder is vertical, and the plunger or piston descends
upon a small body of water confined in the base of the dash-pot.
Corliss's air dash-pot is now often set horizontally.

[Illustration: FIG. 99.--Greene Engine.]

In the Greene steam-engine (Fig. 99), the valves are four in number,
as in the Corliss. The cut-off gear consists of a bar, _A_, moved by
the steam-eccentric in a direction parallel with the centre-line of
the cylinder and nearly coincident as to time with the piston. On this
bar are tappets, _C C_, supported by springs and adjustable in height
by the governor, _G_. These tappets engage the arms _B B_, on the ends
of rock-shafts, _E E_, which move the steam-valves and remain in
contact with them a longer or shorter time, and holding the valve open
during a greater or less part of the piston-stroke, as the governor
permits the tappets to rise with diminishing engine-speed, or forces
them down as speed increases. The exhaust-valves are moved by an
independent eccentric rod, which is itself moved by an eccentric set,
as is usual with the Corliss and with other engines generally, at
right angles with the crank. This engine, in consequence of the
independence of the steam-eccentric, and of the contemporary movement
of steam valve-motion and steam-piston, is capable of cutting off at
any point from beginning to nearly the end of the stroke. The usual
arrangement, by which steam and exhaust valves are moved by the same
eccentric, only permits expansion with the range from the beginning to
half-stroke. In the Corliss engine the latter construction is
retained, with the object, in part, of securing a means of closing the
valve by a "positive motion," should, by any accident, the closing not
be effected by the weight or spring usually relied upon.

[Illustration: FIG. 100.--Thurston's Greene-Engine Valve-Gear.]

The steam-valve of the Greene engine, as designed by the author, is
seen in Fig. 100, where the valve, _G H_, covering the port, _D_, in
the steam-cylinder, _A B_, is moved by the rod, _J J_, connected to
the rock-shaft, _M_, by the arm, _L K_. The line, _K I_, should, when
carried out, intersect the valve-face at its middle point, under _G_.

The characteristics of the American stationary engine, therefore, are
high steam-pressure without condensation, an expansion valve-gear with
drop cut-off adjustable by the governor, high piston-speed, and
lightness combined with strength of construction. The pressure most
commonly adopted in the boilers which furnish steam to this type of
engine is from 75 to 80 pounds per square inch; but a pressure of 100
pounds is not infrequently carried, and the latter pressure may be
regarded as a "mean maximum," corresponding to a pressure of 60 pounds
at about the commencement of the period here considered--1850.

Very much greater pressures have, however, been adopted by some
makers, and immensely "higher steam" has been experimented with by
several engineers. As early as 1823, Jacob Perkins[88] commenced
experimenting with steam of very great tension. As has already been
stated, the usual pressure at the time of Watt was but a few pounds--5
or 7--in excess of that of the atmosphere. Evans, Trevithick, and
Stevens, had previously worked steam at pressures of from 50 to 75
pounds per square inch, and pressures on the Western rivers and
elsewhere in the United States had already been raised to 100 or 150
pounds, and explosions were becoming alarmingly frequent.

  [88] Perkins was a native of Newburyport, Mass. He was born July 9,
  1766, and died in London, July 30, 1849. He went to England when
  fifty-two years of age, to introduce his inventions.

Perkins's experimental apparatus consisted of a copper boiler, of a
capacity of about one cubic foot, having sides 3 inches in thickness.
It was closed at the bottom and top, and had five small pipes leading
from the upper head. This was placed in a furnace kept at a high
temperature by a forced combustion. Safety-valves loaded respectively
to 425 and 550 pounds per square inch were placed on each of two of
the steam-pipes.

Perkins used the steam generated under these great pressures in a
little engine having a piston 2 inches in diameter and a stroke of 1
foot. It was rated at 10 horse-power.[89]

  [89] It was when writing of this engine that Stuart wrote, in 1824:
  "Judging from the rapid strides the steam-engine has made _during
  the last forty years_ to become a universal first-mover, and from
  the experience that has arisen from that extension, we feel
  convinced that every invention which diminishes its size without
  impairing its power brings it a step nearer to the assistance of the
  'world's great laborers,' the husbandman and the peasant, for whom,
  as yet, it performs but little. At present, it is made occasionally
  to tread out the corn. What honors await not that man who may yet
  direct its mighty power to plough, to sow, to harrow, and to reap!"
  The progress of the steam-engine during those forty years does not
  to-day appear so astounding. The sentiment here expressed has lost
  none of its truth, nevertheless.

In the year 1827, Perkins had attained working pressures, in a
single-acting, single-cylinder engine, of upward of 800 pounds per
square inch. At pressures exceeding 200 pounds, he had much trouble in
securing effective lubrication, as all oils charred and decomposed at
the high temperatures then unavoidably encountered, and he finally
succeeded in evading this seemingly insurmountable obstacle by using
for rubbing parts a peculiar alloy which required no lubrication, and
which became so beautifully polished, after some wear, that the
friction was less than where lubricants were used. At these high
pressures Perkins seems to have met with no other serious difficulty.
He condensed the exhaust-steam and returned it to the boiler, but did
not attempt to create a vacuum in his condenser, and therefore needed
no air-pump. Steam was cut off at one-eighth stroke.

In the same year, Perkins made a compound engine on the Woolf plan,
and adopted a pressure of 1,400 pounds, expanding eight times. In
still another engine, intended for a steam-vessel, Perkins adopted, or
proposed to adopt, 2,000 pounds pressure, cutting off the admission at
one-sixteenth, in single-acting engines of 6 inches diameter of
cylinder and 20 inches stroke of piston. The steam did not retain
boiler-pressure at the cylinder, and this engine was only rated at 30
horse-power.[90]

  [90] Galloway and Hebert, on the Steam-Engine. London, 1836.

Stuart follows a description of Perkins's work in the improvement of
the steam-engine and the introduction of steam-artillery by the
remark:

" ... No other mechanic of the day has done more to illustrate an
obscure branch of philosophy by a series of difficult, dangerous,
and expensive experiments; no one's labors have been more deserving
of cheering encouragement, and no one has received less. Even in
their present state, his experiments are opening new fields for
philosophical research, and his mechanism bids fair to introduce
a new style into the proportions, construction, and form, of
steam-machinery."

Perkins's experience was no exception to the general rule, which
denies to nearly all inventors a fair return for the benefits which
they confer upon mankind.

Another engineer, a few years later, was also successful in
controlling and working steam under much higher pressures than are
even now in use. This was Dr. Ernst Alban, a distinguished German
engine-builder, of Plau, Mecklenburg, and an admirer of Oliver Evans,
in whose path he, a generation later, advanced far beyond that great
pioneer. Writing in 1843, he describes a system of engine and boiler
construction, with which he used steam under pressures about equal to
those experimentally worked by Jacob Perkins, Evans's American
successor. Alban's treatise was translated and printed in Great
Britain,[91] four years later.

  [91] "The High-Pressure Steam-Engine," etc. By Dr. Ernst Alban.
  Translated by William Pole, F. R. A. S. London, 1847.

Alban, on one occasion, used steam of 1,000 pounds pressure. His
boilers were similar in general form to the boiler patented by Stevens
in 1805, but the tubes were horizontal instead of vertical. He
evaporated from 8 to 10 pounds of water into steam of 600 to 800
pounds pressure with each pound of coal. He states that the
difficulty met by Perkins--the decomposition of lubricants in the
steam-cylinder--did not present itself in his experiments, even when
working steam at a pressure of 600 pounds on the square inch, and he
found that less lubrication was needed at such high pressures than in
ordinary practice. Alban expanded his steam about as much as Evans, in
his usual practice, carrying a pressure of 150 pounds, and cutting off
at one-third; he adopted greatly increased piston-speed, attaining 300
feet per minute, at a time when common practice had only reached 200
feet. He usually built an oscillating engine, and rarely attached a
condenser. The valve was the locomotive-slide.[92] The stroke was made
short to secure strength, compactness, cheapness, and high speed of
rotation; but Alban does not seem to have understood the principles
controlling the form and proportions of the expansive engine, or the
necessity of adopting considerable expansion in order to secure
economy in working steam of great tension, and therefore was,
apparently, not aware of the advantages of a long stroke in reducing
losses by "dead-space," in reducing risk of annoyance by hot journals,
or in enabling high piston-speeds to be adopted. He seems never to
have attained a sufficiently high speed of piston to become aware that
the oscillating cylinder cannot be used at speeds perfectly
practicable with the fixed cylinder.

  [92] Invented by Joseph Maudsley, of London, 1827.

Alban states that one of his smallest engines, having a cylinder 4-1/2
inches in diameter and 1 foot stroke of piston, with a piston-speed of
but 140 to 160 feet per minute, developed 4 horse-power, with a
consumption of 5.3 pounds of coal per hour. This is a good result for
so small an amount of work, and for an engine working at so low a
speed of piston. An engine of 30 horse-power, also working very
slowly, required but 4.1 pounds of coal per hour per horse-power.

The work of Perkins and of Alban, like that of their predecessors,
Evans, Stevens, and Trevithick, was, however, the work of engineers
who were far ahead of their time. The general practice, up to the time
which marked the beginning of the modern "period of refinement," had
been but gradually approximating that just described. Higher pressures
were slowly approached; higher piston-speeds came slowly into use;
greater expansion was gradually adopted; the causes of losses of heat
were finally discovered, and steam-jacketing and external
non-conducting coverings were more and more generally applied as
builders became more familiar with their work. The "compound engine"
was now and then adopted; and each experiment, made with higher steam
and greater expansion, was more nearly successful than the last.

Finally, all these methods of securing economy became recognized, and
the reasons for their adoption became known. It then remained, as the
final step in this progression, to combine all these requisites of
economical working in a double-cylinder engine, steam-jacketed, well
protected by non-conducting coverings, working steam of high pressure,
and with considerable expansion at high piston-speed. This is now done
by the best builders.

One of the best examples of this type of engine is that constructed by
the sons of Jacob Perkins, who continued the work of their father
after his death. Their engines are single-acting, and the small or
high-pressure cylinder is placed on the top of the larger or
low-pressure cylinder. The valves are worked by rotating stems, and
the loss of heat and burning of packing incident to the use of the
common method are thus avoided. The stuffing-boxes are placed at the
end of long sleeves, closely surrounding the vertical valve-stems
also, and the water of condensation which collects in these sleeves is
an additional and thorough protection against excessively high
temperature at the packing. The piston-rings are made of the alloy
which has been found to require no lubrication.

Steam is usually worked at from 250 to 450 pounds, and is generated in
boilers composed of small tubes three inches in diameter and
three-eighths of an inch thick, which are tested under a pressure of
2,500 pounds per square inch. The safety-valve is usually loaded to
400 pounds. The boiler is fed with distilled water, obtained
principally by condensation of the exhaust-steam, any deficiency being
made up by the addition of water from a distilling apparatus. Under
these conditions, but 1-1/4 pound of coal is consumed per hour and per
horse-power.

THE PUMPING-ENGINE in use at the present time has passed through a
series of changes not differing much from that which has been traced
with the stationary mill-engine. The Cornish engine is still used to
some extent for supplying water to towns, and is retained at deep
mines. The modern Cornish engine differs very little from that of the
time of Watt, except in the proportions of parts and the form of its
details. Steam-pressures are carried which were never reached during
the preceding period, and, by careful adjustment of well-set and
well-proportioned valves and gearing, the engine has been made to work
rather more rapidly, and to do considerably more work. It still
remains, however, a large, costly, and awkward contrivance, requiring
expensive foundations, and demanding exceptional care, skill, and
experience in management. It is gradually going out of use. This
engine, as now constructed by good builders, is shown in section in
Fig. 101.

A comparison with the Watt engine of a century earlier will at once
enable any one to appreciate the extent to which changes may be made
in perfecting a machine, even after it has become complete, so far as
supplying it with all essential parts can complete it.

[Illustration: FIG. 101.--Cornish Pumping-Engine, 1880.]

In the figure, _A_ is the cylinder, taking steam from the boiler
through the steam-passage, _M_. The steam is first admitted above the
piston, _B_, driving it rapidly downward and raising the pump-rod,
_E_. At an early period in the stroke the admission of steam is
checked by the sudden closing of the induction-valve at _M_, and the
stroke is completed under the action of expanding steam assisted by
the inertia of the heavy parts already in motion. The necessary weight
and inertia is afforded, in many cases, where the engine is applied to
the pumping of deep mines, by the immensely long and heavy pump-rods.
Where this weight is too great, it is counterbalanced, and where too
small, weights are added. When the stroke is completed, the
"equilibrium valve" is opened, and the steam passes from above to the
space below the piston, and an equilibrium of pressure being thus
produced, the pump-rods descend, forcing the water from the pumps and
raising the steam-piston. The absence of the crank, or other device
which might determine absolutely the length of stroke, compels a very
careful adjustment of steam-admission to the amount of load. Should
the stroke be allowed to exceed the proper length, and should danger
thus arise of the piston striking the cylinder-head, _N_, the movement
is checked by buffer-beams. The valve-motion is actuated by a
plug-rod, _J K_, as in Watt's engine. The regulation is effected by a
"cataract," a kind of hydraulic governor, consisting of a
plunger-pump, with a reservoir attached. The plunger is raised by the
engine, and then automatically detached. It falls with greater or less
rapidity, its velocity being determined by the size of the
eduction-orifice, which is adjustable by hand. When the plunger
reaches the bottom of the pump-barrel, it disengages a catch, a weight
is allowed to act upon the steam-valve, opening it, and the engine is
caused to make a stroke. When the outlet of the cataract is nearly
closed, the engine stands still a considerable time while the plunger
is descending, and the strokes succeed each other at long intervals.
When the opening is greater, the cataract acts more rapidly, and the
engine works faster. This has been regarded until recently as the most
economical of pumping-engines, and it is still generally used in
freeing mines of water, and in situations where existing heavy
pump-rods may be utilized in counterbalancing the steam-pressure, and,
by their inertia, in continuing the motion after the steam, by its
expansion, has become greatly reduced in pressure.

In this engine a gracefully-shaped and strong beam, _D_, has taken
the place of the ruder beam of the earlier period, and is carried on a
well-built wall of masonry, _R_. _F_ is the exhaust-valve, by which
the steam passes to the condenser, _G_, beside which is the air-pump,
_H_, and the hot-well, _I_. The cylinder is steam-jacketed, _P_, and
protected against losses of heat by radiation by a brick wall, _O_,
the whole resting on a heavy foundation, _Q_.

The Bull Cornish engine is also still not infrequently seen in use.
The Cornish engine of Great Britain averages a duty of about
45,000,000 pounds raised one foot high per 100 pounds of coal. More
than double this economy has sometimes been attained.

[Illustration: FIG. 102.--Steam-Pump.]

A vastly simpler form of pumping-engine without fly-wheel is the now
common "direct-acting steam-pump." This engine is generally made use
of in feeding steam-boilers, as a forcing and fire pump, and wherever
the amount of water to be moved is not large, and where the pressure
is comparatively great. The steam-cylinder, _A R_, and feed-pump, _B
Q_ (Fig. 102), are in line, and the two pistons have usually one rod,
_D_, in common. The two cylinders are connected by a strong frame,
_N_, and two standards fitted with lugs carry the whole, and serve as
a means of bolting the pump to the floor or to its foundation.

The method of working the steam-valve of the modern steam-pump is
ingenious and peculiar. As shown, the pistons are moving toward the
left; when they reach the end of their stroke, the face of the piston
strikes a pin or other contrivance, and thus moves a small auxiliary
valve, _I_, which opens a port, _E_, and causes steam to be admitted
behind a piston, or permits steam to be exhausted, as in the figure,
from before the auxiliary piston, _F_, and the pressure within the
main steam-chest then forces that piston over, moving the main
steam-valve, _G_, to which it is attached, admitting steam to the
left-hand side of the main piston, and exhausting on the right-hand
side, _A_. Thus the motion of the engine operates its own valves in
such a manner that it is never liable to stop working at the end of
the stroke, notwithstanding the absence of the crank and fly-wheel, or
of independent mechanism, like the cataract of the Cornish engine.
There is a very considerable variety of pumps of this class, all
differing in detail, but all presenting the distinguishing feature of
auxiliary valve and piston, and a connection by which it and the main
engine each works the valve of the other combination.

[Illustration: FIG. 103.--The Worthington Pumping-Engine, 1876.
Section.]

[Illustration: FIG. 104.--The Worthington Pumping-Engine.]

In some cases these pumps are made of considerable size, and are
applied to the elevation of water in situations to which the Cornish
engine was formerly considered exclusively applicable. The
accompanying figure illustrates such a pumping-engine, as built for
supplying cities with water. This is a "compound" direct-acting
pumping-engine. The cylinders, _A B_, are placed in line, working one
pump, _F_, and operating their own air-pumps, _D D_, by a bell-crank
lever, _L H_, connected to the pump-buckets by links, _I K_. Steam
exhausted from the small cylinder, _A_, is further expanded in the
large cylinder, _B_, and thence goes to the condenser, _C_. The
valves, _N M_, are moved by the valve-gear, _L_, which is actuated by
the piston-rod of a similar pair of cylinders placed by the side of
the first. These valves are balanced, and the balance-plates, _R Q_,
are suspended from the rods, _O P_, which allow them to move with the
valves. By connecting the valves of each engine with the piston-rod
of the other, it is seen that the two engines must work alternately,
the one making a stroke while the other is still, and then itself
stopping a moment while the latter makes its stroke.

Water enters the pump through the induction-pipe, _E_, passes into the
pump-barrel through the valves, _V V_, and issues through the
eduction-valves, _T T_, and goes on to the "mains" by the pipe, _G_,
above which is seen an air-chamber, which assists to preserve a
uniform pressure on that side the pump. This engine works very
smoothly and quietly, is cheap and durable, and has done excellent
duty.

Beam pumping-engines are now almost invariably built with crank and
fly-wheel, and very frequently are compound engines. The accompanying
illustration represents an engine of the latter form.

[Illustration: FIG. 105.--Double-Cylinder Pumping-Engine, 1878.]

[Illustration: FIG. 106.--The Lawrence Water-Works Engine.]

_A_ and _B_ are the two steam-cylinders, connected by links and
parallel motion, _C D_, to the great cast-iron beam, _E F_. At the
opposite end of the beam, the connecting-rod, _G_, turns a crank,
_H_, and fly-wheel, _L M_, which regulates the motion of the engine
and controls the length of stroke, averting all danger of accident
occurring in consequence of the piston striking either cylinder-head.
The beam is carried on handsomely-shaped iron columns, which, with
cylinders, pump, and fly-wheel, are supported by a substantial stone
foundation. The pump-rod, _I_, works a double-acting pump, _J_, and
the resistance to the issuing water is rendered uniform by an
air-chamber, _K_, within which the water rises and falls when
pressures tend to vary greatly. A revolving shaft, _N_, driven from
the fly-wheel shaft, carries cams, _O P_, which move the lifting-rods
seen directly over them and the valves which they actuate. Between the
steam-cylinders and the columns which carry the beams is a well, in
which are placed the condenser and air-pump. Steam is carried at 60 or
80 pounds pressure, and expanded from 6 to 10 times.

[Illustration: FIG. 107.--The Leavitt Pumping-Engine.]

A later form of double-cylinder beam pumping-engine is that invented
and designed by E. D. Leavitt, Jr., for the Lawrence Water-Works, and
shown in Figs. 106 and 107. The two cylinders are placed one on each
side the centre of the beam, and are so inclined that they may be
coupled to opposite ends of it, while their lower ends are placed
close together. At their upper ends a valve is placed at each end of
the connecting steam-pipe. At their lower ends a single valve serves
as exhaust-valve to the high-pressure and as steam-valve to the
low-pressure cylinder. The pistons move in opposite directions, and
steam is exhausted from the high-pressure cylinder directly into the
nearer end of the low-pressure cylinder. The pump, of the
"Thames-Ditton" or "bucket-and-plunger" variety, takes a full supply
of water on the down-stroke, and discharges half when rising and half
when descending again. The duty of this engine is reported by a board
of engineers as 103,923,215 foot-pounds for every 100 pounds of coal
burned. The duty of a moderately good engine is usually considered to
be from 60 to 70 millions. This engine has steam-cylinders of 17-1/2
and 36 inches diameter respectively, with a stroke of 7 feet. The pump
had a capacity of about 195 gallons, and delivered 96 per cent. Steam
was carried at a pressure of 75 pounds above the atmosphere, and was
expanded about 10 times. Plain horizontal tubular boilers were used,
evaporating 8.58 pounds of water from 98° Fahr. per pound of coal.

STEAM-BOILERS.--The steam supplied to the forms of stationary engine
which have been described is generated in steam-boilers of exceedingly
varied forms. The type used is determined by the extent to which their
cost is increased in the endeavor to economize fuel by the pressure of
steam carried, by the greater or less necessity of providing against
risk of explosion, by the character of the feed-water to be used, by
the facilities which may exist for keeping in good repair, and even by
the character of the men in whose hands the apparatus is likely to be
placed.

As has been seen, the changes which have marked the growth and
development of the steam-engine have been accompanied by equally
marked changes in the forms of the steam-boiler. At first, the same
vessel served the distinct purposes of steam-generator and
steam-engine. Later, it became separated from the engine, and was then
specially fitted to perform its own peculiar functions; and its form
went through a series of modifications under the action of the causes
already stated.

When steam began to be usefully applied, and considerable pressures
became necessary, the forms given to boilers were approximately
spherical, ellipsoidal, or cylindrical. Thus the boilers of De Caus
(1615) and of the Marquis of Worcester (1663) were spherical and
cylindrical; those of Savery (1698) were ellipsoidal and cylindrical.
After the invention of the steam-engine of Newcomen, the pressures
adopted were again very low, and steam-boilers were given irregular
forms until, at the beginning of the present century, they were again
of necessity given stronger shapes. The material was at first
frequently copper; it is now usually wrought-iron, and sometimes
steel.

The present forms of steam-boilers may be classified as plain, flue,
and tubular boilers. The plain cylindrical or common cylinder boiler
is the only representative of the first class in common use. It is
perfectly cylindrical, with heads either flat or hemispherical. There
is usually attached to the boiler a "steam-drum" (a small cylindrical
vessel), from which the steam is taken by the steam-pipe. This
enlargement of the steam-space permits the mist, held in suspension by
the steam when it first rises from the surface of the water, to
separate more or less completely before the steam is taken from the
boiler.

[Illustration: FIG. 108.--Babcock & Wilcox's Vertical Boiler.]

Flue-boilers are frequently cylindrical, and contain one or more
cylindrical flues, which pass through from end to end, beneath the
water-line, conducting the furnace-gases, and affording a greater area
of heating-surface than can be obtained in the plain boiler. They are
usually from 30 to 48 inches in diameter, and one foot or less in
length for each inch of diameter. Some are, however, made 100 feet and
more in length. The boiler is made of iron 1/4 to 3/8 of an inch in
thickness, with hemispherical or carefully stayed flat heads, and
without flues. The whole is placed in a brickwork setting. These
boilers are used where fuel is inexpensive, where the cost of
repairing would be great, or where the feed-water is impure. A
cylindrical boiler, having one flue traversing it longitudinally, is
called a Cornish boiler, as it is generally supposed to have been
first used in Cornwall. It was probably first invented by Oliver Evans
in the United States, previous to 1786, at which time he had it in
use. The flue has usually a diameter 0.5 or 0.6 the diameter of the
boiler. A boiler containing two longitudinal flues is called the
Lancashire boiler. This form was also introduced by Oliver Evans. The
flues have one-third the diameter of the boiler. Several flues of
smaller diameter are often used, and when a still greater proportional
area of heating-surface is required, tubes of from 1-1/4 inch to 4 or
5 inches in diameter are substituted for flues. The flues are usually
constructed by riveting sheets together, as in making the shell or
outer portion. They are sometimes welded by British manufacturers, but
rarely if ever in the United States. Tubes are always "lap-welded" in
the process of rolling them. Small tubes were first used in the United
States, about 1785. In portable, locomotive, and marine steam-boilers,
the fire must be built within the boiler itself, instead of (as in the
above described stationary boilers) in a furnace of brickwork exterior
to the boiler. The flame and gases from the furnace or fire-box in
these kinds of boiler are never led through brick passages en route to
the chimney, as often in the preceding case, but are invariably
conducted through flues or tubes, or both, to the smoke-stack. These
boilers are also sometimes used as stationary boilers. Fig. 108
represents such a steam-boiler in section, as it is usually exhibited
in working drawings. Provision is made to secure a good circulation of
water in these boilers by means of the "baffle-plates," seen in the
sketch, which compel the water to flow as indicated by the arrows.
The tubes are frequently made of brass or of copper, to secure rapid
transmission of heat to the water, and thus to permit the use of a
smaller area of heating-surface and a smaller boiler. The steam-space
is made as large as possible, to secure immunity from "priming" or the
"entrainment" of water with the steam. This type of steam-boiler,
invented by Nathan Read, of Salem, Mass., in 1791, and patented in
April of that year, was the earliest of the tubular boilers. In the
locomotive boiler (Fig. 109), as in the preceding, the characteristics
are a fire-box at one end of the shell and a set of tubes through
which the gases pass directly to the smoke-stack. Strength,
compactness, great steaming capacity, fair economy, moderate cost, and
convenience of combination with the running parts, are secured by the
adoption of this form. It is frequently used also for portable and
stationary engines. It was invented in France by M. Seguin, and in
England by Booth, and used by George Stephenson at about the same
time--1828 or 1829.

[Illustration: FIG. 109.--Stationary "Locomotive" Boiler.]

Since the efficiency of a steam-boiler depends upon the extent of
effective heating-surface per unit of weight of fuel burned in any
given time--or, ordinarily, upon the ratio of the areas of heating and
grate surface--peculiar expedients are sometimes adopted, having for
their object the increase of heating-surface, without change of form
of boiler and without proportionate increase of cost.

One of these methods is that of the use of Galloway conical tubes
(Fig. 110). These are very largely used in Great Britain, but are
seldom if ever seen in the United States. The Cornish boiler, to which
they are usually applied, consists of a large cylindrical shell, 6
feet or more in diameter, containing one tube of about one-half as
great dimensions, or sometimes two of one-third the diameter of the
shell each. Such boilers have a very small ratio of heating to grate
surface, and their large tubes are peculiarly liable to collapse. To
remove these objections, the Messrs. Galloway introduced stay-tubes
into the flues, which tubes are conical in form, and are set in either
a vertical or an inclined position, the larger end uppermost. The area
of heating-surface is thus greatly increased, and, at the same time,
the liability to collapse is reduced. The same results are obtained by
another device of Galloway, which is sometimes combined with that just
described in the same boiler. Several sheets in the flue have
"pockets" worked into them, which pockets project into the
flue-passage.

[Illustration: FIG. 110.]

Another device is that of an American engineer, Miller, who surrounds
the furnace of cylindrical and other boilers with water-tubes. The
"fuel-economizers" of Greene and others consist of similar collections
of tubes set in the flues, between the boiler and the chimney.

"_Sectional_" boilers are gradually coming into use with high
pressures, on account of their greater safety against disastrous
explosions. The earliest practicable example of a boiler of this class
was probably that of Colonel John Stevens, of Hoboken, N. J. Dr.
Alban, who, forty years later, attempted to bring this type into
general use, and constructed a number of such boilers, did not
succeed. Their introduction, like that of all radical changes in
engineering, has been but slow, and it has been only recently that
their manufacture has become an important branch of industry.

A committee of the American Institute, of which the author was
chairman, in 1871, examined several boilers of this and the ordinary
type, and tested them very carefully. They reported that they felt
"confident that the introduction of this class of steam-boilers will
do much toward the removal of the cause of that universal feeling of
distrust which renders the presence of a steam-boiler so objectionable
in every locality. The difficulties in thoroughly inspecting these
boilers, in regulating their action, and other faults of the class,
are gradually being overcome, and the committee look forward with
confidence to the time when their use will become general, to the
exclusion of older and more dangerous forms of steam-boilers."

The economical performance of these boilers with a similar ratio of
heating to grate surface is equal to that of other kinds. In fact,
they are usually given a somewhat higher ratio, and their economy of
fuel frequently exceeds that of the other types. Their principal
defect is their small capacity for steam and water, which makes it
extremely difficult to obtain steady steam-pressure. Where they are
employed, the feed and draught should be, if possible, controlled by
automatic attachments, and the feed-water heated to the highest
attainable temperature. Their satisfactory working depends, more than
in other cases, on the ability of the fireman, and can only be secured
by the exercise of both care and skill.

Many forms of these boilers have been devised. Walter Hancock
constructed boilers for his steam-carriage of flat plates connected by
stay-bolts, several such sections composing the boiler; and about the
same time (1828) Sir Goldsworthy Gurney constructed for a similar
purpose boilers consisting of a steam and a water reservoir, placed
one above the other, and connected by triangularly-bent water-tubes
exposed to the heat of the furnace-gases. Jacob Perkins made many
experiments looking to the employment of very high steam-pressures,
and in 1831 patented a boiler of this class, in which the
heating-surfaces nearest the fire were composed of iron tubes, which
tubes also served as grate-bars. The steam and water space was
principally comprised within a comparatively large chamber, of which
the walls were secured by closely distributed stay-bolts. For
extremely high pressures, boilers composed only of tubes were used.
Dr. Ernst Alban described the boiler already referred to, and its
construction and operation, and stated that he had experimented with
pressures as high as 1,000 pounds to the square inch.

The Harrison steam-boiler, which has been many years in use in the
United States, consists of several sections, each of which is made up
of hollow globes of cast-iron, communicating with each other by necks
cast upon the spheres, and fitted together with faced joints. Long
bolts, extending from end to end of each row, bind the spheres
together. (_See_ Fig. 111.)

[Illustration: FIG. 111.--Harrison's Sectional Boiler.]

An example of another modern type in extensive use is given in Fig.
112, a semi-sectional boiler, which consists of a series of inclined
wrought-iron tubes, connected by T-heads, which form the vertical
water-channels, at each end. The joints are faced by milling them, and
then ground so perfectly tight that a pressure of 500 pounds to the
square inch is insufficient to produce leakage. No packing is used.
The fire is made under the front and higher end of the tubes, and the
products of combustion pass up between the tubes into a
combustion-chamber under the steam and water drum; hence they pass
down between the tubes, then once more up through the space between
the tubes, and off to the chimney. The steam is taken out at the top
of the steam-drum near the back end of the boiler. The rapid
circulation prevents to some extent the formation of deposits or
incrustations upon the heating-surfaces, sweeping them away and
depositing them in the mud-drum, whence they are blown out. Rapid
circulation of water, as has been shown by Prof. Trowbridge, also
assists in the extraction of the heat from the gases, by the
presentation of fresh water continually, as well as by the prevention
of incrustation.

[Illustration: FIG. 112.--Babcock and Wilcox's Sectional Boiler.]

Attempts have been made to adapt sectional boilers to marine engines;
but very little progress has yet been made in their introduction. The
Root sectional boiler (Fig. 113), an American design, which is in
extensive use in the United States and Europe, has also been
experimentally placed in service on shipboard. Its heating-surface
consists wholly of tubes, which are connected by a peculiarly formed
series of caps; the joints are made tight with rubber "grummets."

[Illustration: FIG. 113.--Root Sectional Boiler.]


SECTION II.--PORTABLE AND LOCOMOTIVE ENGINES.

Engines and boilers, when of small size, are now often combined in one
structure which may be readily transported. Where they have a common
base-plate simply, as in Fig. 114, they are called, usually,
"semi-portable engines." These little engines have some decided
advantages. Being attached to one base, the combined engine and boiler
is easily transported, occupies little space, and may very readily be
mounted upon wheels, rendering it peculiarly well adapted for
agricultural purposes.

[Illustration: FIG. 114.--Semi-Portable Engine, 1878.]

The example here shown differs in its design from those usually seen
in the market. The engine is not fastened to or upon the boiler, and
is therefore not affected by expansion, nor are the bearings
overheated by conduction or by ascending heat from the boiler. The
fly-wheel is at the base, which arrangement secures steadiness at the
high speed which is a requisite for economy of fuel. The boilers are
of the upright tubular style, with internal fire-box, and are
intended to be worked at 150 pounds pressure per inch. They are fitted
with a baffle-plate and circulating-pipe, to prevent priming, and also
with a fusible plug, which will melt and prevent the crown-sheet of
the boiler burning, if the water gets low.

[Illustration: FIG. 115.--Semi-Portable Engine, 1878.]

Another illustration of this form of engine, as built in small sizes,
is seen below. The peculiarity of this engine is, that the cylinder is
placed in the top of the boiler, which is upright. By this arrangement
the engine is constantly drawing from the boiler the hottest and
driest steam, and there is thus no liability of serious loss by
condensation, which is rapid, even in a short pipe, when the engine is
separate from the boiler.

The engine illustrated is rated at 10 horse-power, and makers are
always expected to guarantee their machines to work up to the rated
power. The cylinder is 7 by 7 inches, and the main shaft is directly
over it. On this shaft are three eccentrics, one working the pump, one
moving the valves, and the third one operating the cut-off. The
driving-pulley is 20 inches in diameter, and the balance-wheel 30
inches. The boiler has 15 1-1/4-inch flues. It is furnished with a
heater in its lower portion. The boiler of this engine is tested up to
200 pounds, and is calculated to carry 100 pounds working pressure,
though that is not necessary to develop the full power of the engine.
The compactness of the whole machine is exceptional. It can be set up
in a space 5 feet square and 8 feet high. The weight of the 10
horse-power engine is 1,540 pounds, and of the whole machine 4,890
pounds, boxed for shipment. Every part of the mechanism usually fits
and works with the exactness of a gun-lock, as each piece is carefully
made to gauge.

Portable engines are those which are especially intended to be moved
conveniently from place to place. The engine is usually attached to
the boiler, and the feed-pump is generally attached to the engine. The
whole machine is carried on wheels, and is moved from one place to
another, usually by horses, but sometimes by its own engine, which is
coupled by an engaging and disengaging apparatus to the rear-wheels.
English builders have usually excelled in the construction of this
class of steam-engine, although it is probable that the best American
engines are fully equal to them in design, material, and construction.

The later work of the best-known English builders has given economical
results that have surprised engineers. The annual "shows" of the Royal
Agricultural Society have elicited good evidence of skill in
management as well as of excellence of design and construction. Some
little portable engines have exhibited an economical efficiency
superior to that of the largest marine engines of any but the compound
type, and even closely competing with that form. The causes of this
remarkable economy are readily learned by an inspection of these
engines, and by observation of the method of managing them at the
test-trial. The engines are usually very carefully designed. The
cylinders are nicely proportioned to their work, and their pistons
travel at high speed. Their valve-gear consists usually of a plain
slide-valve, supplemented by a separate expansion-slide, driven by an
independent eccentric, and capable of considerable variation
in the point of cut-off. This form of expansion-gear is very
effective--almost as much so as a drop cut-off--at the usual grade of
expansion, which is not far from four times. The governor is usually
attached to a throttle-valve in the steam-pipe, an arrangement which
is not the best possible under variable loads, but which produces no
serious loss of efficiency when the engine is driven, as at
competitive trials, under the very uniform load of a Prony strap-brake
and at very nearly the maximum capacity of the machine. The most
successful engines have had steam-jacketed cylinders--always an
essential to maximum economy--with high steam and a considerable
expansion. The boilers are strongly made, and are, as are also all
other heated surfaces, carefully clothed with non-conducting material,
and well lagged over all. The details are carefully proportioned, the
rods and frames are strong and well secured together, and the bearings
have large rubbing-surfaces. The connecting-rods are long and
easy-working, and every part is capable of doing its work without
straining and with the least friction.

In handling the engines at the competitive trial, most experienced and
skillful drivers are selected. The difference between the performances
of the same engine in different hands has been found to amount to from
10 to 15 per cent., even where the competitors were both considered
exceptionally skillful men. In manipulating the engine, the fires are
attended to with the utmost care; coal is thrown upon them at regular
and frequent intervals, and a uniform depth of fuel and a perfectly
clean fire are secured. The sides and corners of the fire are looked
after with especial care. The fire-doors are kept open the least
possible time; not a square inch of grate-surface is left unutilized,
and every pound of coal gives out its maximum of calorific power, and
in precisely the place where it is needed. Feed-water is supplied as
nearly as possible continuously, and with the utmost regularity. In
some cases the engine-driver stands by his engine constantly, feeding
the fire with coal in handfuls, and supplying the water to the heater
by hand by means of a cup. Heaters are invariably used in such cases.
The exhaust is contracted no more than is absolutely necessary for
draught. The brake is watched carefully, lest irregularity of
lubrication should cause oscillation of speed with the changing
resistance. The load is made the maximum which the engine is designed
to drive with economy. Thus all conditions are made as favorable as
possible to economy, and they are preserved as invariable as the
utmost care on the part of the attendant can make them.

These trials are usually of only three or five hours' duration, and
thus terminate before it becomes necessary to clean fires. The
following are results obtained at the trial of engines which took
place in July, 1870, at the Oxford Agricultural Fair:

  KEY:
  A: Number.
  B: Diameter.
  C: Stroke.
  D: Nominal.
  E: Dynamometric.
  F: Point of cut off.
  G: Revolutions per minute.
  H: Pounds coal per horse-power per hour.

  ---------------+-------------+-----+--------------+------+------+----
  MAKERS' NAME   | CYLINDERS.  |     | HORSE-POWER. |      |      |
      AND        +-----+-------+     +-------+------+      |      |
   RESIDENCE.    |  A  |   B   |  C  |   D   |  E   |  F   |  G   |  H
  ---------------+-----+-------+-----+-------+------+------+------+----
                 |     |Inches.| In. |       |      |      |      |
  Clayton,       |     |       |     |       |      |      |      |
  Shuttleworth   |  1  | 7     |  12 |   4   | 4.42 |  ... |121.65|3.73
  & Co., Lincoln |     |       |     |       |      |      |      |
                 |     |       |     |       |      |      |      |
  Brown & May,   |     |       |     |       |      |      |      |
  Devizes        |  1  | 7-3/16|  12 |   4   | 4.19 | 11.48|125.65|4.44
                 |     |       |     |       |      |      |      |
  Reading Iron-  |     |       |     |       |      |      |      |
  Works Company, |  1  | 5-3/4 |  14 |   4   | 4.16 |  ... |145.7 |4.65
  Reading        |     |       |     |       |      |      |      |
  ---------------+-----+-------+-----+-------+------+------+------+----

These were horizontal engines, attached to locomotive boilers.

At a similar exhibition held at Bury, in 1867, considerably better
results even than these were reported, as below, from engines of
similar size and styles:

  KEY:
  A: Number.
  B: Diameter.
  C: Stroke.
  D: Nominal.
  E: Dynamometric.
  F: Point of cut off.
  G: Revolutions per minute.
  H: Pounds coal per horse-power per hour.

  ---------------+-------------+-----+--------------+------+------+----
  MAKERS' NAME   | CYLINDERS.  |     | HORSE-POWER. |      |      |
      AND        +-----+-------+     +-------+------+      |      |
   RESIDENCE.    |  A  |   B   |  C  |   D   |  E   |  F   |  G   |  H
  ---------------+-----+-------+-----+-------+------+------+------+----
                 |     |Inches.| In. |       |      |      |      |
  Clayton,       |     |       |     |       |      |      |      |
  Shuttleworth   |  1  |10     | 20  |   10  | 11.00| 3.10 | 71.5 | 4.13
  & Co., Lincoln |     |       |     |       |      |      |      |
                 |     |       |     |       |      |      |      |
  Reading Iron-  |     |       |     |       |      |      |      |
  Works Company, |  1  | 8-5/8 | 20  |   10  | 10.43| 1.4  |109.4 | 4.22
  Reading        |     |       |     |       |      |      |      |
  ---------------+-----+-------+-----+-------+------+------+------+----

With all these engines steam-jackets were used; the feed-water was
highly and uniformly heated by exhaust-steam; the coal was selected,
finely broken, and thrown on the fire with the greatest care; the
velocity of the engines, the steam-pressure, and the amount of
feed-water, were very carefully regulated, and all bearings were run
quite loose; the engine-drivers were usually expert "jockeys."

The next illustration represents the portable steam-engine as built by
one of the oldest and most experienced manufacturers of such engines
in the United States.

In the boilers of these engines the heating-surface is given less
extent than in the stationary engine-boiler, but much greater than in
the locomotive, and varies from 10 to 20 square feet per horse-power.
The boilers are made very strong, to enable them to withstand the
strains due to the attached engine, which are estimated as equivalent
to from one-tenth to one-fifth that due to the steam-pressure. The
boiler is sometimes given even double the strength usual with
stationary boilers of similar capacity. The engine is mounted, in this
example, directly over the boiler, and all parts are in sight and
readily accessible to the engineer.

[Illustration: FIG. 116.--The Portable Steam-Engine, 1878.]

One of these engines, of 20 horse-power, has a steam-cylinder 10
inches in diameter and 18 inches stroke of piston, making 125
revolutions per minute, and has 9 square feet of grate-surface and 288
feet of heating-surface. It weighs about 4-1/2 tons. Steam is carried
at 125 pounds.

In the class of engines just described, the draught is obtained by the
blast of the exhaust-steam which is led into the chimney. Such engines
are now sold at from $120 to $150 per horse-power, according to size
and quality, the smaller engines costing most. The usual consumption
of fuel is from 4 to 6 pounds per hour and per horse-power, burning
from 15 to 20 pounds on each square foot of grate, and each pound
evaporating about 8 pounds of water. A usual weight is, for the larger
sizes, 500 pounds per horse-power.

[Illustration: FIG. 117.--The Thrashers' Road-Engine, 1878.]

These engines are sometimes arranged to propel themselves, as in the
Mills "Thrashers'" road-engine or locomotive, of which the
accompanying engraving is a good representation. This engine is
proportioned for hauling a tank containing 10 barrels, or more, of
water and a grain-separator over all ordinary roads, and to drive a
thrashing-machine or saw-mill, developing 20 or 25 horse-power. This
example of the road-engine has a boiler built to work at 250 pounds of
steam; the engine is designed for a maximum power of 30 horses.

This engine has a balanced valve and automatic cut-off, and is fitted
with a reversing-gear for use on the road. The driving-wheels are of
wrought-iron, 56 inches diameter and 8 inches wide, with cast-iron
driving-arms. Both wheels are drivers on curves as well as on straight
lines. The engine is guided and fired by one man, and the total weight
is so small that it will pass safely over any good country bridge. A
brake is attached, to insure safety when going down-hill. Although
designed to move at a speed of about three miles per hour, the
velocity of the piston may be increased so that four miles per hour
may be accomplished when necessary.

[Illustration: FIG. 118.--Fisher's Steam-Carriage.]

This is an excellent example of this kind of engine as constructed at
the present time. The strongly-built boiler, with its heater, the
jacketed cylinder, and light, strong frame of the engine, the steel
running-gear, the carefully-covered surfaces of cylinder and boiler,
and excellent proportions of details, are illustrations of good modern
engineering, and are in curious contrast with the first of the class,
built a century earlier by Smeaton.

Steam-carriages for passengers are now rarely built. Fig. 118
represents that designed by Fisher about 1870 or earlier. It was only
worked experimentally.

[Illustration: FIG. 119.--Road and Farm Locomotive.]

The above is an engraving of a road and farm locomotive as built by
one of the most successful among several British firms engaged in this
work.

The capacity of these engines has been determined by experiment by the
author in the United States, and abroad by several distinguished
engineers.

The author made a trial of one of these engines at South Orange, N.
J., to determine its power, speed, and convenience of working and
man[oe]uvring. The following were the principal dimensions:

  Weight of engine, complete, 5 tons 4 cwt.          11,648 pounds.
  Steam-cylinder--diameter                                7-3/4 inches.
  Stroke of piston                                       10 inches.
  Revolution of crank to one of driving-wheels           17
  Driving-wheels--diameter                               60 inches.
      "           breadth of tire                        10 inches.
      "           weight, each                          450 pounds.
  Boiler--length over all                                 8 feet.
    "     diameter of shell                              30 feet.
    "     thickness of shell                           7/16 inch.
    "     fire-box sheets, outside, thickness           1/2 inch.
  Load on driving-wheels, 4 tons 10 cwt.             10,080 pounds.

The boiler was of the ordinary locomotive type, and the engine was
mounted upon it, as is usual with portable engines.

The steam-cylinder was steam-jacketed, in accordance with the most
advanced practice here and abroad. The crank-shaft and other
wrought-iron parts subjected to heavy strains were strong and plainly
finished. The gearing was of malleableized cast-iron, and all
bearings, from crank-shaft to driving-wheel, on each side, were
carried by a single sheet of half-inch plate, which also formed the
sides of the fire-box exterior.

The following is a summary of the conclusions deduced by the author
from the trial, and published in the _Journal of the Franklin
Institute_: A traction-engine may be so constructed as to be easily
and rapidly man[oe]uvred on the common road; and an engine weighing
over 5 tons may be turned continuously without difficulty on a circle
of 18 feet radius, or even on a road but little wider than the length
of the engine. A locomotive of 5 tons 4 hundredweight has been
constructed, capable of drawing on a good road 23,000 pounds up a
grade of 533 feet to the mile, at the rate of four miles an hour; and
one might be constructed to draw more than 63,000 pounds up a grade of
225 feet to the mile, at the rate of two miles an hour.

It was further shown that the coefficient of traction with
heavily-laden wagons on a good macadamized road is not far from .04;
the traction-power of this engine is equal to that of 20 horses; the
weight, exclusive of the weight of the engine, that could be drawn on
a level road, was 163,452 pounds; and the amount of fuel required is
estimated at 500 pounds a day. The advantages claimed for the
traction-engine over horse-power are: no necessity for a limitation of
working-hours; a difference in first cost in favor of steam; and in
heavy work on a common road the expense by steam is less than 25 per
cent. of the average cost of horse-power, a traction-engine capable of
doing the work of 25 horses being worked at as little expense as 6 or
8 horses. The cost of hauling heavy loads has been estimated at 7
cents per ton per mile.

Such engines are gradually becoming useful in steam-ploughing. Two
systems are adopted. In the one the engine is stationary, and hauls a
"gang" of ploughs by means of a windlass and wire rope; in the other
the engine traverses a field, drawing behind it a plough or a gang of
ploughs. The latter method has been proposed for breaking up
prairie-land.

Thus, thirty years after the defeat of the intelligent, courageous,
and persistent Hancock and his coworkers in the scheme of applying the
steam-engine usefully on the common road, we find strong indications
that, in a new form, the problem has been again attacked, and at least
partially solved.

One of the most important of the prerequisites to ultimate success in
the substitution of steam for animal power on the highway is that our
roads shall be well made. As the greatest care and judgment are
exercised, and an immense outlay of capital is considered justifiable,
in securing easy grades and a smooth track on our railroad routes, we
may readily believe that similar precaution and outlay will be found
advisable in adapting the common road to the road-locomotive. It would
seem to the engineer that the natural obstacles generally supposed to
stand in the way have, after all, no real existence. The principal
inconvenience that may be anticipated will probably arise from the
carelessness or avarice of proprietors, which may sometimes cause them
to appoint ignorant and inefficient engine-drivers, giving them charge
of what are always excellent servants, but terrible masters.
Nevertheless, as the transportation of passengers on railroads is
found to be attended with less liability to loss of life or injury of
person than their carriage by stage-coach, it will be found, very
probably, that the general use of steam in transporting freight on
common roads may be attended with less risk to life or property than
to-day attends the use of horse-power.

The STEAM FIRE-ENGINE is still another form of portable engine. It is
also one of the latest of all applications of steam-power. The steam
fire-engine is peculiarly an American production. Although previously
attempted, their permanently successful introduction has only occurred
within the last fifteen years.

[Illustration: FIG. 120.--The Latta Steam Fire-Engine.]

As early as 1830, Braithwaite and Ericsson, of London, England, built
an engine with steam and pump cylinders of 7 and 6-1/2 inches
diameter, respectively, with 16 inches stroke of piston. This machine
weighed 2-1/2 tons, and is said to have thrown 150 gallons of water
per minute to a height of between 80 and 100 feet. It was ready for
work in about 20 minutes after lighting the fire. Braithwaite
afterward supplied a more powerful engine to the King of Prussia, in
1832. The first attempt made in the United States to construct a steam
fire-engine was probably that of Hodge, who built one in New York in
1841. It was a strong and very effective machine, but was far too
heavy for rapid transportation. The late J. K. Fisher, who throughout
his life persistently urged the use of steam-carriages and
traction-engines, designing and building several, also planned a
steam fire-engine. Two were built from his design by the Novelty
Works, New York, about 1860, for Messrs. Lee & Larned. They were
"self-propellers," and one of them, built for the city of
Philadelphia, was sent to that city over the highway, driven by its
own engines. The other was built for and used by the New York Fire
Department, and did good service for several years. These engines were
heavy, but very powerful, and were found to move at good speed under
steam and to man[oe]uvre well. The Messrs. Latta, of Cincinnati, soon
after succeeded in constructing comparatively light and very effective
engines, and the fire department of that city was the first to adopt
steam fire-engines definitely as their principal reliance. This change
has now become general.

The steam fire-engine has now entirely displaced the old hand-engine
in all large cities. It does its work at a fraction of the cost of the
latter. It can force its water to a height of 225 feet, and to a
distance of more than 300 feet horizontally, while the hand-engine can
seldom throw it one-third these distances; and the "steamer" may be
relied upon to work at full power many hours if necessary, while the
men at the hand-engine soon become fatigued, and require frequent
relief. The city of New York has 40 steam fire-engines. One engine to
every 10,000 inhabitants is a proper proportion.

In the standard steam fire-engine (Fig. 120) reciprocating engines and
pumps are adopted, as seen in section in Fig. 121, in which _A_ is the
furnace, and _B_ the set of closely-set vertical fire-tubes in the
boiler. _C_ is the combustion-chamber, _D_ the smoke-pipe, and _R_ the
steam-space. _E_ is the steam-cylinder, and _F_ the pump, which is
seen to be double-acting. There are two pairs of engines and pumps,
working on cranks, set at right angles, and turning a balance-wheel
seen behind them. _G_ is the feed-pump which supplies water to the
boiler, _H_ the air-chamber which equalizes the water-pressure, which
reaches it through the pipe, _I J_. _K_ is the feed-water tank, under
the driver's seat, _L_, which, with the engines and boiler, are
carried on the frame, _M M_. The fireman stands on the platform, _N_.
When it is necessary to move the machine, an endless chain connects
the crank-shaft with the rear-wheels, and the engine, with pumps shut
off, is thus made to drive the wheels at any desired speed.

[Illustration: FIG. 121.--The Amoskeag Engine. Section.]

[Illustration: FIG. 122.--The Silsby Rotary Steam Fire-Engine.]

A self-propelling engine by the Amoskeag Company had the following
dimensions and performance: Weight, 4 tons; speed, 8 miles per hour;
steam-pressure, 75 pounds per square inch; height of stream from
1-1/4-inch nozzle, 225 feet; 1-3/4-inch nozzle, 150 feet; distance
horizontally, 1-1/4-inch nozzle, 300 feet; 1-3/4-inch, 250 feet--a
performance which contrasts wonderfully with that of the hand-worked
fire-engine which these engines have now superseded.

It has recently become common to construct the steam fire-engine with
rotary engine and pump (Fig. 122). The superiority of a rotary motion
for a steam-engine is apparently so evident that many attempts have
been made to overcome the practical difficulties to which it is
subject. One of these difficulties, and the principal one, has been
the packing of the part which performs the office of the piston in the
straight cylinder. Robert Stephenson once expressed the opinion that a
rotary engine would never be made to work successfully, on account of
this difficulty of packing. The most palpable of the advantages of the
rotary engine are the reduction in the size of the engine, claimed to
result from the great velocity of the piston; the avoidance of great
accidental strains, especially noticed in propelling ships; and a
great saving of the power which is asserted to be expended in the
reciprocating engine in overcoming the inertia while changing the
direction of the motions. These advantages adapt the rotary engine, in
an especial manner, to the driving of a locomotive or steam
fire-engine.

[Illustration: FIG. 123.--Rotary Steam-Engine.]

[Illustration: FIG. 124.--Rotary Pump.]

In the Holly rotary engine, seen in Fig. 123, eccentrics and
sliding-cams, which are frequently used in rotary engines, and which
are objectionable on account of their great friction, are avoided.
Corrugated pistons, or irregular cams, _C D_, are adopted, forming
chambers within the cases. In the engine the steam enters at _A_, at
the bottom of the case, and presses the cams apart. The only packing
used is in the ends of the long metal cogs, which are ground to fit
the case and are kept out by the momentum of the cams, assisted by a
slight spring back of the packing-pieces. The friction on the pump
(Fig. 124) is said to be less than in the engine. This is the reason
given in support of the claim that the rotary engine forces water to a
given distance with from one-fourth to one-third the steam-pressure
necessary to drive all reciprocating engines. The smaller amount of
power necessary to do the work, the less strain and consequent wear
and tear upon the whole machine, are said to make it more durable and
reliable. The pump being chambered, its liability to injury by the use
of dirty or gritty water is lessened, and it is stated that it will
last for years, pumping gritty water that would soon cut out a
piston-pump. The pump used with this engine is, as shown in the above
illustration, somewhat similar to the rotary engine driving it. Each
of the revolving pistons has three long teeth bearing against the
cylinder, and packed, to prevent leakage, like the engine-cams. They
are carried on steel shafts coupled to the engine-shafts. The water
enters at _E_ and is discharged at _F_, and the passages are purposely
made large in order that sand, chips, and dirt, which may enter with
the water, may pass through.

The rotary engine is gradually coming into use for various special
purposes, where small power is called for, and where economy of fuel
is not important; but it has never yet competed, and may perhaps never
in the future compete, with the reciprocating-piston engine where
large engines are required, or where even moderate economy of fuel is
essential. This form of engine has assumed so little importance, in
fact, in the application of the steam-engine, that comparatively
little is known of its history. Watt invented a rotary engine, and
Yule many years afterward (1836) constructed such engines at Glasgow.
Lamb patented another in 1842, Behrens still another in 1847. Napier,
Hall, Massey, Holly, La France, and others, have built engines of this
class in later times. Nearly all consist either of cams rotating in
gear, as in those above sketched, or of a piston set radially in a
cylinder of small diameter, which turns on its axis within a much
larger cylinder set eccentrically, the piston, as the former turns,
sliding in and out of the smaller cylinder as its outer edge slides in
contact with the inner surface of the larger. In some forms of rotary
engine, a piston revolves on a central shaft, and a sliding abutment
in the external cylinder serves to separate the steam from the exhaust
side and to confine the steam expanding while doing work. Nearly all
of these combinations are also used as pumps.

Fire-engines, made by the best-known American builders of engines,
with reciprocating engines and pumps, such as are in general use in
the United States, have become standard in general plan and
arrangement of details. These are probably the best illustrations of
extreme lightness, combined with strength of parts and working power,
which have ever been produced in any branch of mechanical
engineering. By using a small boiler crowded with heating-surface,
very carefully proportioned and arranged, and with small water-spaces;
by adopting steel for running-gear and working parts wherever
possible; by working at high piston-speed and with high
steam-pressure; by selecting fuel with extreme care--by all these
expedients, the steam fire-engine has been brought, in this country,
to a state of efficiency far superior to anything seen elsewhere.
Steam is raised with wonderful promptness, even from cold water, and
water is thrown from the nozzle at the end of long lines of hose to
great distances. But this combination of lightness with power is only
attained at the expense of a certain regularity of action which can
only be secured by greater water and steam capacity in the boiler. The
small quantity of water contained within the boiler makes it necessary
to give constant attention to the feed, and the tendency, almost
invariably observed, to serious foaming and priming not only compels
unintermitted care while running, but even introduces an element of
danger which is not to be despised, even though the machine be in
charge of the most experienced and skillful attendants. Even the
greatest care, directed by the utmost skill, would not avail to
prevent frequent explosions, were it not for the fact that it rarely,
if ever, happens that accidents to such boilers occur from low water,
unless the boiler is actually completely emptied of water. In driving
them at fires, they frequently foam so violently that it is utterly
impossible to obtain any clew to the amount of water present, and the
attendant usually keeps his feed-pump on and allows the foaming to go
on. As long as water is passing into the boiler it is very unlikely
that any portion will become overheated and that accident will occur.
Such management appears very reckless, and yet accident from such a
cause is exceedingly rare.

The changes which have been made in LOCOMOTIVE-CONSTRUCTION during the
past few years have also been in the direction of the refinement of
the earlier designs, and have been accompanied by corresponding
changes in all branches of railroad-work. The adjustment of parts to
each other and proportioning them to their work, the modification of
the minor details to suit changes of general dimensions, the
improvement of workmanship, and the use of better material, have
signalized this latest period. Special forms of engine have been
devised for special kinds of work. Small, light tank-engines (Fig.
125), carrying their own fuel and water without "tenders," are used
for moving cars about terminal stations and for making up trains;
powerful, heavy, slow-moving engines, of large boiler-capacity and
with small wheels, are used on steep gradients and for hauling long
trains laden with coal and heavy merchandise; and hardly less powerful
but quite differently proportioned "express"-engines are used for
passenger and mail service.

[Illustration: FIG. 125.--Tank-Engine, New York Elevated Railroad.]

[Illustration: FIG. 126.--Forney's Tank-Locomotive.]

A peculiar form of engine (Fig. 126) has been designed by Forney, in
which the whole weight of engine, tender, coal, and water, is carried
by one frame and on one set of wheels, the permanent weight falling on
the driving-wheels and the variable load on the truck. These engines
have also a comparatively short wheel-base and high pulling-power. The
lightest tank-engines of the first class mentioned weigh 8 or 10 tons;
but engines much lighter than these, even, are built for mines, where
they are sent into the galleries to bring out the coal-laden wagons.
The heaviest engines of this class attain weights of 20 or 30 tons.
The heaviest engine yet constructed in the United States is said to be
one in use on the Philadelphia & Reading Railroad, having a weight of
about 100,000 pounds, which is carried on 12 driving-wheels.

[Illustration: FIG. 127.--British Express Engine.]

[Illustration: FIG. 128.--The Baldwin Locomotive. Section.]

[Illustration: FIG. 129.--The American Type of Express-Engine, 1878.]

A locomotive has two steam-cylinders, either side by side within the
frame, and immediately beneath the forward end of the boiler, or on
each side and exterior to the frame. The engines are non-condensing,
and of the simplest possible construction. The whole machine is
carried upon strong but flexible steel springs. The steam-pressure is
usually more than 100 pounds. The pulling-power is generally about
one-fifth the weight under most favorable conditions, and becomes as
low as one-tenth on wet rails. The fuel employed is wood in new
countries, coke in bituminous coal districts, and anthracite coal in
the eastern part of the United States. The general arrangement and the
proportions of locomotives differ somewhat in different localities.
In Fig. 127, a British express-engine, _O_ is the boiler, _N_ the
fire-box, _X_ the grate, _G_ the smoke-box, and _P_ the chimney. _S_
is a spring and _R_ a lever safety-valve, _T_ is the whistle, _L_ the
throttle or regulator valve, _E_ the steam-cylinder, and _W_ the
driving-wheel. The force-pump, _B C_, is driven from the cross-head,
_D_. The frame is the base of the whole system, and all other parts
are firmly secured to it. The boiler is made fast at one end, and
provision is made for its expansion when heated. Adhesion is
secured by throwing a proper proportion of the weight upon the
driving-wheel, _W_. This is from about 6,000 pounds on standard
freight-engines, having several pairs of drivers, to 10,000 pounds on
passenger-engines, per axle. The peculiarities of the American type
(Fig. 128) are the truck, _I J_, or bogie, supporting the forward part
of the engine, the system of equalizers, or beams which distribute the
weight of the machine equally over the several axles, and minor
differences of detail. The cab or house, _r_, protecting the
engine-driver and fireman, is an American device, which is gradually
coming into use abroad also. The American locomotive is distinguished
by its flexibility and ease of action upon even roughly-laid roads. In
the sketch, which shows a standard American engine in section, _A B_
is the boiler, _C_ one of the steam-cylinders, _D_ the piston, _E_ the
cross-head, connected to the crank-shaft, _F_, by the connecting-rod,
_G H_ the driving-wheels, _I J_ the truck-wheels, carrying the truck,
_K L_; _N N_ is the fire-box, _O O_ the tubes, of which but four are
shown. The steam-pipe, _R S_, leads the steam to the valve-chest, _T_,
in which is seen the valve, moved by the valve-gear, _U V_, and the
link, _W_. The link is raised or depressed by a lever, _X_, moved from
the cab. The safety-valve is seen at the top of the dome, at _Y_, and
the spring-balance by which the load is adjusted is shown at _Z_. At
_a_ is the cone-shaped exhaust-pipe, by which a good draught is
secured. The attachments _b_, _c_, _d_, _e_, _f_, _g_--whistle,
steam-gauge, sand-box, bell, head-light, and "cow-catcher"--are nearly
all peculiar, either in construction or location, to the American
locomotive. The cost of passenger-locomotives of ordinary size is
about $12,000; heavier engines sometimes cost $20,000. The locomotive
is usually furnished with a tender, which carries its fuel and water.
The standard passenger-engine on the Pennsylvania Railroad has four
driving-wheels, 5-1/2 feet diameter; steam-cylinders, 17 inches
diameter and 2 feet stroke; grate-surface 15-1/2 square feet, and
heating-surface 1,058 square feet. It weighs 63,100 pounds, of which
39,000 pounds are on the drivers and 24,100 on the truck. The
freight-engine has six driving-wheels, 54-5/8 inches in diameter. The
steam-cylinders are 18 inches in diameter, stroke 22 inches,
grate-surface 14.8 square feet, heating-surface 1,096 feet. It weighs
68,500 pounds, of which 48,000 are on the drivers and 20,500 on the
truck. The former takes a train of five cars up an average grade of 90
feet to the mile. The latter is attached to a train of 11 cars. On a
grade of 50 feet to the mile, the former takes 7 and the latter 17
cars. Tank-engines for very heavy work, such as on grades of 320 feet
to the mile, which are found on some of the mountain lines of road,
are made with five pairs of driving-wheels, and with no truck. The
steam-cylinders are 20-1/8 inches in diameter, 2 feet stroke;
grate-area, 15-3/4 feet; heating-surface, 1,380 feet; weight with tank
full, and full supply of wood, 112,000 pounds; average weight, 108,000
pounds. Such an engine has hauled 110 tons up this grade at the speed
of 5 miles an hour, the steam-pressure being 145 pounds. The adhesion
was about 23 per cent. of the weight.

In checking a train in motion, the inertia of the engine itself
absorbs a seriously large portion of the work of the brakes. This is
sometimes reduced by reversing the engine and allowing the
steam-pressure to act in aid of the brakes. To avoid injury by
abrasion of the surfaces of piston, cylinder, and the valves and
valve-seats, M. Le Chatelier introduces a jet of steam into the
exhaust-passages when reversing, and thus prevents the ingress of
dust-laden air and the drying of the rubbing surfaces. This method of
checking a train is rarely resorted to, however, except in case of
danger. The introduction of the "continuous" or "air" brake, which can
be thrown into action in an instant on every car of the train by the
engine-driver, is so efficient that it is now almost universally
adopted. It is one of the most important safeguards which American
ingenuity has yet devised. In drawing a train weighing 150 tons at the
rate of 60 miles an hour, about 800 effective horse-power is required.
A speed of 80 miles an hour has been often attained, and 100 miles has
probably been reached.

The American locomotive-engine has a maximum life which may be stated
at about 30 years. The annual cost of repairs is from 10 to 15 per
cent. of its first cost. On moderately level roads, the engine
requires a pint of oil to each 25 miles, and a ton of coal to each 40
or 50 miles run. One of the best-managed railroads in the United
States reports expenses as follows for one month:

  Number "train-miles" run per ton of coal burned    53.95
    "         "         "   "  quart of oil used     34.44
  Passenger-cars hauled 1 mile per ton of coal      275.7
  Other      "     "      "       "        "        634.8
  Cost repairs per mile run                          $2 43
   "   fuel       "      "                            3 64
   "   oil and waste per mile run                       62
   "   wages of engine-men per mile run               6 22
  All other expenses per mile                         1 91
  Total cost per "train-mile" run                    14 82

Although the above sketch and description represent the construction
and performance of the standard locomotive of the present time, there
are indications that the compound arrangement of engines will
ultimately be adopted. This will involve a considerable change of
proportions, greatly increasing the volume and weight of
steam-cylinders, but enabling the designer to more than proportionally
decrease the weight of boiler and the quantity of fuel carried. There
is no serious objection to their use, however, and no insuperable
difficulty in the construction of the "double-cylinder" type of engine
for the locomotive. A few such engines have already been put in
service. In these engines the high-pressure cylinder is placed on one
side and the larger low-pressure cylinder on the other side of the
locomotive, thus having but two cylinders, as in the older plan. The
valve-gear is the Stephenson link, as in the ordinary engine. At
starting, the steam is allowed to act on both pistons; but after a few
revolutions the course of the steam is changed, and the exhaust from
the smaller cylinder, instead of passing into the chimney, is sent to
the larger cylinder, which is at the same time cut off from the main
steam-pipe. When the engine is ascending a steep gradient the steam
may, if necessary, be taken from the boiler into both cylinders, as
when starting. Compound engines of this kind have been used on the
French line of railroad from Bayonne to Biarritz. They were designed
by Mallet and built at Le Creuzot. The steam-cylinders are of 9-1/2
and 15-3/4 inches diameter, and of 17-3/4 inches stroke of piston. The
four driving-wheels are 4 feet in diameter, and the total weight of
engine is 20 tons. The boiler has 484-1/2 square feet of
heating-surface, and is built to carry 10 atmospheres pressure. When
hauling trains of 50 tons at 25 miles an hour, these engines require
about 15 pounds of good coal per mile.

The total length of the railways in operation in the United States on
the 1st day of January, 1877, was 76,640 miles,[93] being an average
of one mile of railway for every 600 inhabitants. The railways are as
follows:

  [93] January, 1884, over 120,000 miles.

                     Miles.

  Alabama             1,722
  Alaska                  0
  Arizona                 0
  Arkansas              787
  California          1,854
  Colorado              950
  Connecticut           925
  Dakota                290
  Delaware              285
  Florida               484
  Georgia             2,308
  Idaho                   0
  Illinois            6,980
  Indiana             4,072
  Indian Territory      281
  Iowa                3,937
  Kansas              3,226
  Kentucky            1,464
  Louisiana             539
  Maine                 987
  Maryland            1,092
  Massachusetts       1,825
  Michigan            3,437
  Minnesota           2,024
  Mississippi         1,028
  Missouri            3,016
  Montana                 0
  Nebraska            1,181
  Nevada                714
  New Hampshire         942
  New Jersey          1,594
  New Mexico              0
  New York            5,520
  North Carolina      1,371
  Ohio                4,680
  Oregon                251
  Pennsylvania        5,896
  Rhode Island          182
  South Carolina      1,352
  Tennessee           1,638
  Texas               2,072
  Utah                  486
  Vermont               810
  Virginia            1,648
  Washington            110
  West Virginia         576
  Wisconsin           2,575
  Wyoming               459
                     ------
    Total            76,640

In 1873 came the great financial crisis, with its terrible results of
interrupted production, poverty, and starvation, and an almost total
cessation of the work of building new railroads. The largest number of
miles ever built in any one year were constructed in 1872. The
greatest mileage is in Illinois, reaching 6,589; the smallest in Rhode
Island, 136, and in Washington Territory, 110. The State of
Massachusetts has one mile of railroad to 4.86 miles of territory,
this ratio being the greatest in the country. The longest road in
operation is the Chicago & Northwestern, extending 1,500 miles; the
shortest, the Little Saw-Mill Run Road in Pennsylvania, which is but
three miles in length. The total capital of railways in the country is
$6,000,000,000, or an average of $100,000 per mile. The earnings for
the year 1872 amounted to $454,969,000, or $7,500 per mile. The
largest net earnings recorded as made on any road were gained by the
New York Central & Hudson River, $8,260,827; the smallest on several
roads which not only earned nothing, but incurred a loss.

The catastrophe of 1873-'74 revealed the fact that the latter
condition of railroad finances was vastly more common than had been
suspected; and it is still doubtful whether the existing immense
network of railroads which covers the United States can be made, as a
whole, to pay even a moderate return on the money invested in their
construction. At the period of maximum rate of extension of railroads
in the United States--1873--the reported lengths of the railroads of
Europe and America were as follows:[94]

  [94] _Railroad Gazette._

              RAILROADS IN EUROPE AND AMERICA IN 1873.

  ----------------------------+------------+-------------+------------
       COUNTRIES.             | Railroads, | Population. |   Area,
                              |   Miles.   |             | Sq. Miles.
  ----------------------------+------------+-------------+------------
  United States               |  71,565    |  40,232,000 | 2,492,316
  Germany                     |  12,207    |  40,111,265 |   212,091
  Austria                     |   5,865    |  35,943,592 |   227,234
  France                      |  10,333    |  36,469,875 |   201,900
  Russia in Europe            |   7,044    |  71,207,794 | 1,992,574
  Great Britain, 1872         |  15,814    |  31,817,108 |   120,769
  Belgium                     |   1,301    |   4,839,094 |    11,412
  Netherlands                 |     886    |   3,858,055 |    13,464
  Switzerland                 |     820    |   2,669,095 |    15,233
  Italy                       |   3,667    |  26,273,776 |   107,961
  Denmark                     |     420    |   1,784,741 |    14,453
  Spain                       |   3,401    |  16,301,850 |   182,758
  Portugal                    |     453    |   3,987,867 |    36,510
  Sweden and Norway           |   1,049    |   5,860,122 |   188,771
  Greece                      |     100    |   1,332,508 |    19,941
  ----------------------------+------------+-------------+------------

The railroads in Great Britain comprise over 15,000 miles of track now
being worked in the United Kingdom, on which have been expended
$2,800,000,000. This sum is equal to five times the amount of the
annual value of all the real property in Great Britain, and two-thirds
of the national debt. After deducting all the working expenses, the
gross net annual revenue of all the roads exceeds by $110,000,000 the
total revenue from all sources of Belgium, Holland, Portugal, Denmark,
Sweden and Norway. An army of 100,000 officers and servants is in the
employ of the companies, and the value of the rolling-stock exceeds
$150,000,000.


SECTION III.--MARINE ENGINES.

The changes which have now become completed in the marine steam-engine
have been effected at a later date than those which produced the
modern locomotive. On the American rivers the modification of the
beam-engine since the time of Robert L. Stevens has been very slight.
The same general arrangement is retained, and the details are little,
if at all, altered. The pressure of steam is sometimes as high as 60
pounds per square inch.

[Illustration: FIG. 130.--Beam-Engine.]

The valves are of the disk or poppet variety, rising and falling
vertically. They are four in number, two steam and two exhaust valves
being placed at each end of the steam-cylinder. The beam-engine is a
peculiarly American type, seldom if ever seen abroad. Fig. 130 is an
outline sketch of this engine as built for a steamer plying on the
Hudson River. This class of engine is usually adopted in vessels of
great length, light draught, and high speed. But one steam-cylinder is
commonly used. The cross-head is coupled to one end of the beam by
means of a pair of links, and the motion of the opposite end of the
beam is transmitted to the crank by a connecting-rod of moderate
length. The beam has a cast-iron centre surrounded by a wrought-iron
strap of lozenge shape, in which are forged the bosses for the
end-centres, or for the pins to which the connecting-rod and the links
are attached. The main centre of the beam is supported by a
"gallows-frame" of timbers so arranged as to receive all stresses
longitudinally. The crank and shaft are of wrought-iron. The
valve-gear is usually of the form already mentioned as the Stevens
valve-gear, the invention of Robert L. and Francis B. Stevens. The
condenser is placed immediately beneath the steam-cylinder. The
air-pump is placed close beside it, and worked by a rod attached to
the beam. Steam-vessels on the Hudson River have been driven by such
engines at the rate of 20 miles an hour. This form of engine is
remarkable for its smoothness of operation, its economy and
durability, its compactness, and the latitude which it permits in the
change of shape of the long, flexible vessels in which it is generally
used, without injury by "getting out of line."

[Illustration: FIG. 131.--Oscillating Engine and Feathering
Paddle-Wheel.]

For paddle-engines of large vessels, the favorite type, which has been
the side-lever engine, is now rarely built. For smaller vessels, the
oscillating engine with feathering paddle-wheels is still largely
employed in Europe. This style of engine is shown in Fig. 131. It is
very compact, light, and moderately economical, and excels in
simplicity. The usual arrangement is such that the feathering-wheel
has the same action upon the water as a radial wheel of double
diameter. This reduction of the diameter of the wheel, while retaining
maximum effectiveness, permits a high speed of engine, and therefore
less weight, volume, and cost. The smaller wheel-boxes, by offering
less resistance to the wind, retard the progress of the vessel less
than those of radial wheels. Inclined engines are sometimes used for
driving paddle-wheels. In these the steam-cylinder lies in an inclined
position, and its connecting-rod directly connects the crank with the
cross-head. The condenser and air-pump usually lie beneath the
cross-head guides, and are worked by a bell-crank driven by links on
each side the connecting-rod, attached to the cross-head. Such engines
are used to some extent in Europe, and they have been adopted in the
United States navy for side-wheel gunboats. They are also used on the
ferry-boats plying between New York and Brooklyn.

[Illustration: FIG. 132.--The Two Rhode Islands, 1836-1876.]

Among the finest illustrations of recent practice in the construction
of side-wheel steamers are those built for the several routes between
New York and the cities of New England which traverse Long Island
Sound. Our illustration exhibits the form of these vessels, and also
shows well the modifications in structure and size which have been
made during this generation. The later vessel is 325 feet long, 45
feet beam, 80 feet wide over the "guards," and 16 feet deep, drawing
10 feet of water. The "frames" upon which the planking of the hull is
fastened are of white-oak, and the lighter and "top" timbers of cedar
and locust. The engine has a steam-cylinder 90 inches in diameter and
12 feet stroke of piston.[95] On each side the great saloons which
extend from end to end of the upper deck are state-rooms, containing
each two berths and elegantly furnished. The engine of this vessel is
capable of developing about 2,500 horse-power. The great wheels, of
which the paddle-boxes are seen rising nearly to the height of the
hurricane-deck, are 37-1/2 feet in diameter and 12 in breadth. The
hull of this vessel, including all wood-work, weighs over 1,200 tons.
The weight of the machinery is about 625 tons. The steamer makes 16
knots an hour when the engine is at its best speed--about 17
revolutions per minute--and its average speed is about 14 knots on
its route of 160 miles. The coal required to supply the furnaces of
such a vessel and with such machinery would be about 3 tons per hour.
or a little over 2-1/2 pounds per horse-power. The construction of
such a vessel occupies, usually, about a year, and costs a quarter of
a million dollars.

  [95] The steam-cylinders of the engines of steamers Bristol and
  Providence are 110 inches in diameter and of 12 feet stroke.

[Illustration: FIG. 133.--A Mississippi Steamboat.]

The non-condensing direct-acting engine is used principally on the
Western rivers, driven by steam of from 100 to 150 pounds pressure,
and exhausts its steam into the atmosphere. It is the simplest
possible form of direct-acting engine. The valves are usually of the
"poppet" variety, and are operated by cams which act at the ends of
long levers having their fulcra on the opposite side of the valve, the
stem of which latter is attached at an intermediate point. The engine
is horizontal, and the connecting-rod directly attached to cross-head
and crank-pin without intermediate mechanism. The paddle-wheel is
used, sometimes as a stern-wheel, as in the plan of Jonathan Hulls of
one and a half century ago, sometimes as a side-wheel, as is most
usual elsewhere. One of the most noted of these steamers, plying on
the Mississippi, is shown in the preceding sketch.

One of the largest of these steamers was the Grand Republic,[96] a
vessel 340 feet long, 56 feet beam, and 10-1/4 feet depth. The draught
of water of this great craft was 3-1/2 feet forward and 4-1/2 aft. The
two sets of compound engines, 28 and 56 inches diameter and of 10 feet
stroke, drive wheels 38-1/2 feet in diameter and 18 feet wide. The
boilers were steel. A steamer built still later on the Ohio has the
following dimensions: Length, 225 feet; breadth, 35-1/2 feet; depth, 5
feet; cylinders, 17-3/8 inches in diameter, 6 feet stroke; three
boilers. The hull and cabin were built at Jeffersonville, Ind. She has
40 large state-rooms. The cost of the steamer was $40,000.

  [96] Burned in 1877.

These vessels have now opened to commerce the whole extent of the
great Mississippi basin, transporting a large share of the products of
a section of country measuring a million and a half square miles--an
area equal to many times that of New York State, and twelve times that
of the island of Great Britain--an area exceeding that of the whole of
Europe, exclusive of Russia and Turkey, and capable, if as thoroughly
cultivated as the Netherlands, of supporting a population of between
three and four hundred millions of people.

The steam-engine and propelling apparatus of the modern ocean-steamer
have now become almost exclusively the compound or double-cylinder
engine, driving the screw. The form and the location of the machinery
in the vessel vary with the size and character of the ship which it
drives. Very small boats are fitted with machinery of quite a
different kind from that built for large steamers, and war-vessels
have usually been supplied with engines of a design radically
different from that adopted for merchant-steamers.

[Illustration: FIG. 134.--Steam-Launch, New York Steam-Power Company.]

The introduction of _Steam-Launches_ and small pleasure-boats driven
by steam-power is of comparatively recent date, but their use is
rapidly increasing. Those first built were heavy, slow, and
complicated; but, profiting by experience, light and graceful boats
are now built, of remarkable swiftness, and having such improved and
simplified machinery that they require little fuel and can be easily
managed. Such boats have strong, carefully-modeled hulls, light and
strong boilers, capable of making a large amount of dry steam with
little fuel, and a light, quick-running engine, working without shake
or jar, and using steam economically.

[Illustration: FIG. 135.--Launch-Engine.]

The above sketch represents the engine built by a New York firm for
such little craft. This is the smallest size made for the market. It
has a steam-cylinder 3 inches in diameter and a stroke of piston of 5
inches, driving a screw 26 inches in diameter and of 3 feet pitch. The
maximum power of the engine is four or five times the nominal power.
The boiler is of the form shown in the illustrations of semi-portable
engines, and has a heating-surface, in this case, of 75 square feet.
The boat itself is like that seen on page 386, and is 25 feet long, of
5 feet 8 inches beam, and draws 2-1/4 feet of water. These little
machines weigh about 150 pounds per nominal horse-power, and the
boilers about 300.

Some of these little vessels have attained wonderful speed. A British
steam-yacht, the Miranda, 45-1/2 feet in length, 5-3/4 feet wide, and
drawing 2-1/2 feet of water, with a total weight of 3-3/4 tons, has
steamed nearly 18-1/2 miles an hour for short runs. The boat was
driven by an engine of 6 inches diameter of cylinder and 8 inches
stroke of piston, making 600 revolutions per minute, driving a
two-bladed screw 2-1/2 feet in diameter and of 3-1/3 feet pitch. Its
machinery had a total weight of two tons. Another English yacht, the
Firefly, is said to have made 18.94 miles an hour. A little French
yacht, the Hirondelle, has attained a speed of 16 knots, equal to
about 18-1/2 miles, an hour. This was, however, a much larger vessel
than the preceding. One of the most remarkable of these little
steamers is a torpedo-boat built for the United States navy. This
vessel is 60 feet long, 6 feet wide, and 5 feet deep; its screw is 38
inches in diameter and of 5 feet pitch, two-bladed, and is driven, by
a very light engine and boiler, 400 revolutions per minute, the boat
attaining a speed of 19 to 20 miles an hour. Another little vessel,
the Vision, made nearly as great speed, developing 20 horse-power with
engine and boiler weighing but about 400 pounds.

Yachts of high speed require such weight and bulk of engine that but
little space is left for cabins, and they are usually exceedingly
uncomfortable vessels. In the Miranda the weight of machinery is more
than one-half the total weight of the whole. An illustration of the
more comfortable and more generally liked pleasure-yacht is the Day
Dream. The length is 105 feet, and the boat draws 5-1/2 feet of
water. There are two engines, having steam-cylinders 14 inches in
diameter and of the same length of stroke, direct-acting, condensing,
and driving a screw, of 7 feet diameter and of 10-1/2 feet pitch, 135
revolutions a minute, giving the yacht a speed of 13-1/2 knots an
hour.

[Illustration: FIG. 136.--Horizontal, Direct-acting Naval
Screw-Engine.]

In larger vessels, as in yachts, in nearly all cases, the ordinary
screw-engine is direct-acting. Two engines are placed side by side,
with cranks on the shaft at an angle of 90° with each other. In
merchant-steamers the steam-cylinders are usually vertical and
directly over the crank-pins, to which the cross-heads are coupled.
The condenser is placed behind the engine-frame, or, where a
jet-condenser is used, the frame itself is sometimes made hollow, and
serves as a condenser. The air-pump is worked by a beam connected by
links with the cross-head. The general arrangement is like that shown
in Figs. 137 and 138. For naval purposes such a form is objectionable,
since its height is so great that it would be exposed to injury by
shot. In naval engineering the cylinder is placed horizontally, as in
Fig. 136, which is a sectional view, representing an horizontal,
direct-acting naval screw-engine, with jet-condenser and double-acting
air and circulating pumps. _A_ is the steam-cylinder, _B_ the piston,
which is connected to the crank-pin by the piston-rod, _D_, and
connecting-rod, _E_. _F_ is the cross-head guide. The eccentrics,
_G_, operate the valve, which is of the "three-ported variety," by a
Stephenson link. Reversing is effected by the hand-wheel, _C_, which,
by means of a gear, _m_, and a rack, _k_, elevates and depresses the
link, and thus reverses the valve.

[Illustration: FIG. 137.--Compound Marine Engine. Side Elevation.]

The trunk-engine, in which the connecting-rod is attached directly to
the piston and vibrates within a trunk or cylinder secured to the
piston, moving with it, and extending outside the cylinder, like an
immense hollow piston-rod, is frequently used in the British navy. It
has rarely been adopted in the United States.

[Illustration: FIG. 138.--Compound Marine Engine. Front Elevation and
Section.]

In nearly all steam-vessels which have been built for the merchant
service recently, and in some naval vessels, the compound engine has
been adopted. Figs. 137 and 138 represent the usual form of this
engine. Here _A A_, _B B_ are the small and the large, or the
high-pressure and the low-pressure cylinders respectively. _C C_ are
the valve-chests. _G G_ is the condenser, which is invariably a
surface-condenser. The condensing water is sometimes directed around
the tubes contained within the casing, _G G_, while the steam is
exhausted around them and among them, and sometimes the steam is
condensed within the tubes, while the injection-water which is sent
into the condenser to produce condensation passes around the exterior
of the tubes. In either case, the tubes are usually of small diameter,
varying from five-eighths to half an inch, and in length from four to
seven feet. The extent of heating-surface is usually from one-half to
three-fourths that of the heating-surface of the boilers.

The air and circulating pumps are placed on the lower part of the
condenser-casting, and are operated by a crank on the main shaft at
_N_; or they are sometimes placed as in the style of engine last
described, and driven by a beam worked by the cross-head. The
piston-rods, _T S_, are guided by the cross-heads, _V V_, working in
slipper-guides, and to these cross-heads are attached the
connecting-rods, _X X_, driving the cranks, _M M_. The cranks are now
usually set at right angles; in some engines this angle is increased
to 120°, or even 180°. Where it is arranged as here shown, an
intermediate reservoir, _P O_, is placed between the two cylinders to
prevent the excessive variations of pressure that would otherwise
accompany the varying relative motions of the pistons, as the steam
passes from the high-pressure to the low-pressure cylinder. Steam from
the boilers enters the high-pressure steam-chest, _X_, and is admitted
by the steam-valve alternately above and below the piston as usual.
The exhaust steam is conducted through the exhaust passage around into
the reservoir, _P_, whence it it is taken by the low-pressure
cylinder, precisely as the smaller cylinder drew its steam from the
boiler. From the large or low-pressure cylinder the steam is exhausted
into the condenser. The valve-gear is usually a Stephenson link, _g
e_, the position of which is determined, and the reversal of which is
accomplished, by a hand-wheel, _o_, and screw, _m n p_, which, by the
bell-crank, _k i_, are attached to the link, _g e_. The "box-framing"
forms also the hot-well. The surface-condenser is cleared by a
single-acting air-pump, inside the frame, at _T_. The feed-pump and
the bilge-pumps are driven from the cross-head of the air-pump.

[Illustration: John Elder.]

The successful introduction of the double-cylinder engine was finally
accomplished by the exertions of a few engineers, who were at once
intelligent enough to understand its advantages, and energetic and
enterprising enough to push it forward in spite of active opposition,
and powerful enough, pecuniarily and in influence, to succeed. The
most active and earnest of these eminent men was John Elder, of the
firm of Randolph, Elder & Co., subsequently John Elder & Co., of
Glasgow.[97]

  [97] _Vide_ "Memoir of John Elder," W. J. M. Rankine, Glasgow, 1871.

Elder was of Scotch descent. His ancestors had, for generations,
shown great skill and talent in construction, and had always been
known as successful millwrights. John Elder was born at Glasgow, March
8, 1824, and died in London, September 17, 1869. He was educated at
the Glasgow High-School and in the College of Engineering at the
University of Glasgow, where, however, his attendance was but for a
short time. He learned the trade under his father in the workshops of
the Messrs. Napier, and became an unusually expert draughtsman. After
spending three years in charge of the drawing-office at the
engine-building works of Robert Napier, where his father had been
manager, Elder became a partner in the firm which had previously been
known as Randolph, Elliott & Co., in the year 1852. The firm commenced
building iron vessels in 1860.

In the mean time, the experiments of Hornblower and Wolff, of Allaire
and Smith, and of McNaught, Craddock, and Nicholson, together with the
theoretical investigations of Thompson, Rankine, Clausius, and others,
had shown plainly in what direction to look for improvement upon then
standard engines, and what direction practice was taking with all
types. The practical deductions which were becoming evident were
recognized very early by Elder, and he promptly began to put in
practice the principles which his knowledge of thermo-dynamics and of
mechanics enabled him to appreciate. He adopted the compound engine,
and coupled his cranks at angles of 180°, in order to avoid losses due
to the friction of the crank-shaft in its bearings, by effecting a
partial counterbalancing of pressures on the journals. Elder was one
of the first to point out the fact that the compound engine had proved
itself more efficient than the single-cylinder engine, only when the
pressure of steam carried and the extent to which expansion was
adopted exceeded the customary practice of his time. His own practice
was, from the first, successful, and from 1853 to 1867 he and his
partners were continually engaged in the construction of steamers and
fitting them with compound engines.

The engines of their first vessel, the Brandon, required but 3-1/4
pounds of coal per hour and per horse-power, in 1854, when the usual
consumption was a third more. Five years later, they had built engines
which consumed a third less than those of the Brandon; and
thenceforward, for many years, their engines, when of large size,
exhibited what was then thought remarkable economy, running on a
consumption of from 2-1/4 to 2-1/2 pounds.

In the year 1865 the British Government ordered a competitive trial of
three naval vessels, which only differed in the form of their engines.
The Arethusa was fitted with trunk-engines of the ordinary kind; the
Octavia had three steam-cylinders, coupled to three cranks placed at
angles of 120° with each other; and the Constance was fitted with
compound engines, two sets of three cylinders each, and each taking
steam from the boiler into one cylinder, passing it through the other
two with continuous expansion, and finally exhausting from the third
into the condenser. These vessels, during one week's steaming at sea,
averaged, respectively, 3.64, 3.17, and 2.51 pounds of coal per hour
and per horse-power, and the Constance showed a marked superiority in
the efficiency of the mechanism of her engines, when the losses by
friction were compared.

The change from the side-lever single-cylinder engine, with
jet-condenser and paddle-wheels, to the direct-acting compound engine,
with surface-condenser and screw-propellers, has occurred within the
memory and under the observation of even young engineers, and it may
be considered that the revolution has not been completely effected.
This change in the design of engine is not as great as it at first
seemed likely to become. Builders have but slowly learned the
principles stated above in reference to expansion in one or more
cylinders, and the earlier engines were made with a high and low
pressure cylinder working on the same connecting-rod, and each machine
consisted of four steam-cylinders. It was at last discovered that a
high-pressure single-cylinder engine exhausting into a separate
larger low-pressure engine might give good results, and the compound
engine became as simple as the type of engine which it displaced. This
independence of high and low pressure engines is not in itself novel,
for the plan of using the exhaust of a high-pressure engine to drive a
low-pressure condensing engine was one of the earliest of known
combinations.

The advantage of introducing double engines at sea is considerably
greater than on land. The coal carried by a steam-vessel is not only
an item of great importance in consequence of its first cost, but,
displacing its weight or bulk of freight which might otherwise be
carried, it represents so much non-paying cargo, and is to be charged
with the full cost of transportation in addition to first cost. The
best of steam-coal is therefore usually chosen for steamers making
long voyages, and the necessity of obtaining the most economical
engines is at once seen, and is fully appreciated by steamship
proprietors. Again, an economy of one-fourth of a pound per
horse-power per hour gives, on a large transatlantic steamer, a saving
of about 100 tons of coal for a single voyage. To this saving of cost
is to be added the gain in wages and sustenance of the labor required
to handle that coal, and the gain by 100 tons of freight carried in
place of the coal.

For many years the change which has here been outlined, in the forms
of engine and the working of steam expansively, was retarded by the
inefficiency of methods and tools used in construction. With gradual
improvement in tools and in methods of doing work, it became possible
to control higher steam and to work it successfully; and the change in
this direction has been steadily going on up to the present time with
all types of steam-engine. At sea this rise of pressure was for a
considerable time retarded by the serious difficulty encountered in
the tendency of the sulphate of lime to deposit in the boiler. When
steam-pressure had risen to 25 pounds per square inch, it was found
that no amount of "blowing out" would prevent the deposition of
seriously large quantities of this salt, while at the lower pressures
at first carried at sea no troublesome precipitation occurred, and the
only precaution necessary was to blow out sufficient brine to prevent
the precipitation of common salt from a supersaturated solution. The
introduction of surface-condensation was promptly attempted as the
remedy for this evil, but for many years it was extremely doubtful
whether its disadvantages were not greater than its advantages. It was
found very difficult to keep the condensers tight, and boilers were
injured by some singular process of corrosion, evidently due to the
presence of the surface-condenser. The simple expedient of permitting
a very thin scale to form in the boiler was, after a time, hit upon as
a means of overcoming this difficulty, and thenceforward the greatest
obstacle to the general introduction was the conservative disposition
found among those who had charge of marine machinery, which
conservatism regarded with suspicion every innovation. Another trouble
arose from the difficulty of finding men neither too indolent nor too
ignorant to take charge of the new condenser, which, more complicated
and more readily disarranged than the old, demanded a higher class of
attendants. Once introduced, however, the surface-condenser removed
the obstacle to further elevation of steam-pressure, and the rise from
20 to 60 pounds pressure soon occurred. Elder and his competitors on
the Clyde were the first to take advantage of the fact when these
higher pressures became practicable.

The lightness of engine and the smaller weight of boiler secured when
the simpler type of "compound" engine is used are great advantages,
and, when coupled with the fact that by no other satisfactory device
can great expansion and consequent economy of fuel be obtained at sea,
the advantages are such as to make the adoption of this style of
engine imperative for ship-propulsion.

This extreme lightness in machinery has been largely, also, the result
of very careful and skillful designing, of intelligent construction,
and of care in the selection and use of material. British builders
had, until after the introduction of these later types of
vessels-of-war, been distinguished rather by the weight of their
machinery than for nice calculation and proportioning of parts. Now
the engines of the heavy iron-clads are models of good proportions,
excellence in materials, and of workmanship, which are well worthy of
study. The weight per indicated horse-power has been reduced from 400
or 500 pounds to less than half that amount within the last ten years.
This has been accomplished by forcing the boilers--although thus, to
some extent, losing economy--by higher steam-pressure, a very much
higher piston-speed, reduction of friction of parts, reduction of
capacity for coal-stowage, and exceedingly careful proportioning.
The reduction of coal-bunker capacity is largely compensated by
the increase of economy secured by superheating, by increased
expansion, elevation of piston-speed, and the introduction of
surface-condensation.

A good marine steam-engine of the form which was considered standard
15 or 20 years ago, having low-pressure boilers carrying steam at 20
or 25 pounds pressure as a maximum, expanding twice or three times,
and having a jet-condenser, would require about 30 or 35 pounds of
feed-water per horse-power per hour; substituting surface-condensation
for that produced by the jet brought down the weight of steam used to
from 25 to 30 pounds; increasing steam-pressure to 60 pounds,
expanding from five to eight times, and combining the special
advantages of the superheater and the compound engine with
surface-condensation, has reduced the consumption of steam to 20, or
even, in some cases, 15 pounds of steam per horse-power per hour.
Messrs. Perkins, of London, guarantee, as has already been stated, to
furnish engines capable of giving a horse-power with a consumption of
but 1-1/4 pound of coal. Mr. C. E. Emery reports the United States
revenue-steamer Hassler, designed by him, to have given an ordinary
sea-going performance which is probably fully equal to anything yet
accomplished. The Hassler is a small steamer, of but 151 feet in
length, 24-1/2 feet beam, and 10 feet draught. The engines have
steam-cylinders 18.1 and 28 inches diameter, respectively, and of 28
inches stroke of piston, indicating 125 horse-power; with steam at 75
pounds pressure, and at a speed of but 7 knots, the coal consumed was
but 1.87 pound per horse-power per hour.

The committee of the British Admiralty on designs of ships-of-war have
reported recently: "The carrying-power of ships may certainly be to
some extent increased by the adoption of compound engines in her
Majesty's service. Its use has recently become very general in the
mercantile marine, and the weight of evidence in favor of the large
economy of fuel thereby gained is, to our minds, overwhelming and
conclusive. We therefore beg earnestly to recommend that the use of
compound engines may be generally adopted in ships-of-war hereafter to
be constructed, and applied, whenever it can be done with due regard
to economy and to the convenience of the service, to those already
built."

The forms of screws now employed are exceedingly diverse, but those in
common use are not numerous. In naval vessels it is common to apply
screws of two blades, that they may be hoisted above water into a
"well" when the vessel is under sail, or set with the two blades
directly behind the stern-post, when their resistance to the forward
motion of the vessel will be comparatively small. In other vessels,
and in the greater number of full-power naval vessels, screws of three
or four blades are used.

The usual form of screw (Fig. 139) has blades of nearly equal breadth
from the hub to the periphery, or slightly widening toward their
extremities, as is seen in an exaggerated degree in Fig. 140,
representing the form adopted for tug-boats, where large surface near
the extremity is more generally used than in vessels of high speed
running free. In the Griffith screw, which has been much used, the hub
is globular and very large. The blades are secured to the hub by
flanges, and are bolted on in such a manner that their position may be
changed slightly if desired. The blades are shaped like the section of
a pear, the wider part being nearest the hub, and the blades tapering
rapidly toward their extremities. A usual form is intermediate between
the last, and is like that shown in Fig. 141, the hub being
sufficiently enlarged to permit the blades to be attached as in the
Griffith screw, but more nearly cylindrical, and the blades having
nearly uniform width from end to end.

[Illustration: FIG. 139.--Screw-Propeller.]

[Illustration: FIG. 140.--Tug-boat Screw.]

[Illustration: FIG. 141.--Hirsch Screw.]

The pitch of a screw is the distance which would be traversed by the
screw in one revolution were it to move through the water without
slip; i. e., it is double the distance _C D_, Fig. 140. _C D´_
represents the helical path of the extremity of the blade _B_, and _O
E F H K_ is that of the blade _A_. The proportion of diameter to the
pitch of the screw is determined by the speed of the vessel. For low
speed the pitch may be as small as 1-1/4 the diameter. For vessels of
high speed the pitch is frequently double the diameter. The diameter
of the screw is made as great as possible, since the slip decreases
with the increase of the area of screw-disk. Its length is usually
about one-sixth of the diameter. A greater length produces loss by
increase of surface causing too great friction, while a shorter screw
does not fully utilize the resisting power of the cylinder of water
within which it works, and increased slip causes waste of power. An
empirical value for the probable slip in vessels of good shape, which
is closely approximate usually, is _S_ = 4(_M_/_A_), in which _S_ is
the slip per cent., and _M_ and _A_ are the areas of the midship
section and of the screw-disk in square feet.

The most effective screws have slightly greater pitch at the periphery
than at the hub, and an increasing pitch from the forward to the rear
part of the screw. The latter method of increasing pitch is more
generally adopted alone. The thrust of the screw is the pressure which
it exerts in driving the vessel forward. In well-formed vessels, with
good screws, about two-thirds of the power applied to the screw is
utilized in propulsion, the remainder being wasted in slip and other
useless work. Its efficiency is in such a case, therefore, 66 per
cent. Twin screws, one on each side of the stern-post, are sometimes
used in vessels of light draught and considerable breadth, whereby
decreased slip is secured.

As has already been stated, the introduction of the compound engine
has been attempted, but with less success than in Europe, by several
American engineers.

The most radical change in the methods of ship-propulsion which has
been successfully introduced in some localities has been the adoption
of a system of "wire-rope towage." It is only well adapted for cases
in which the steamer traverses the same line constantly, moving
backward and forward between certain points, and is never compelled to
deviate to any considerable extent from the path selected. A similar
system is in use in Canada, but it has not yet come into use in the
United States, notwithstanding the fact that, wherever its adoption is
practicable, it has a marked superiority in economy over the usual
methods of propulsion. With chain or rope traction there is no loss by
slip or oblique action, as in both screw and paddle-wheel propulsion.
In the latter methods these losses amount to an important fraction of
the total power; they rarely, if ever, fall below a total of 25 per
cent., and probably in towage exceed 50 per cent. The objection to the
adoption of chain-propulsion, as it is also often called, is the
necessity of following closely the line along which the chain or the
rope is laid. There is, however, much less difficulty than would be
anticipated in following a sinuous route or in avoiding obstacles in
the channel or passing other vessels. The system is particularly well
adapted for use on canals.

The steam-boilers in use in the later and best marine engineering
practice are of various forms, but the standard types are few in
number. That used on river-steamers in the United States has already
been described.

[Illustration: FIG. 142.--Marine Fire-tubular Boiler. Section.]

Fig. 142 is a type of marine tubular boiler which is in most extensive
use in sea-going steamers for moderate pressure, and particularly for
naval vessels. Here the gases pass directly into the back connection
from the fire, and thence forward again, through horizontal tubes, to
the front connection and up the chimney. In naval vessels the
steam-chimney is omitted, as it is there necessary to keep all parts
of the boiler as far below the water-line as possible. Steam is taken
from the boiler by pipes which are carried from end to end of the
steam-space, near the top of the boiler, the steam entering these
pipes through small holes drilled on the other side. Steam is thus
taken from the boiler "wet," but no large quantity of water can
usually be "entrained" by the steam.

A marine boiler has been quite extensively introduced into the United
States navy, in which the gases are led from the back connection
through a tube-box around and among a set of upright water-tubes,
which are filled with water, circulation taking place freely from the
water-space immediately above the crown-sheet of the furnace up
through these tubes into the water-space above them. These
"water-tubular" boilers have a slight advantage over the
"fire-tubular" boilers already described in compactness, in steaming
capacity, and in economical efficiency. They have a very marked
advantage in the facility with which the tubes may be scraped or freed
from the deposit when a scale of sulphate of lime or other salt has
formed within them by precipitation from the water. The fire-tubular
boiler excels in convenience of access for plugging up leaking tubes,
and is much less costly than the water-tubular. The water-tube class
of boilers still remain in extensive use in the United States naval
steamers. They have never been much used in the merchant service,
although introduced by James Montgomery in the United States and by
Lord Dundonald in Great Britain twenty years earlier. Opinion still
remains divided among engineers in regard to their relative value.
They are gradually reassuming prominence by their introduction in the
modified form of sectional boilers.

[Illustration: FIG. 143.--Marine High-Pressure Boiler. Section.]

Marine boilers are now usually given the form shown in section in Fig.
143. This form of boiler is adopted where steam-pressures of 60
pounds and upward are carried, as in steam-vessels supplied with
compound engines, cylindrical forms being considered the best with
high pressures. The large cylindrical flues, therefore, form the
furnaces as shown in the transverse sectional view. The gases rise, as
shown in the longitudinal section, through the connection, and pass
back to the end of the boiler through the tubes, and thence, instead
of entering a steam-chimney, they are conducted by a smoke-connection,
not shown in the sketch, to the smoke funnel or stack. In
merchant-steamers, a steam-drum is often mounted horizontally above
the boiler. In other cases a separator is attached to the steam-pipe
between boilers and engines. This usually consists of an iron tank,
divided by a vertical partition extending from the top nearly to the
bottom. The steam, entering the top at one side of this partition,
passes underneath it, and up to the top on the opposite side, where it
issues into a steam-pipe leading directly to the engine. The sudden
reversal of its course at the bottom causes it to leave the suspended
water in the bottom of the separator, whence it is drained off by
pipes.

The most interesting illustrations of recent practice in marine
engineering and naval architecture are found in the steamers which are
now seen on transoceanic routes for the merchant service, and, in the
naval service, in the enormous iron-clads which have been built in
Great Britain.

The City of Peking is one of the finest examples of American practice.
This vessel was constructed for the Pacific Mail Company. The hull is
423 feet long, of 48 feet beam, and 38-1/2 feet deep. Accommodations
are furnished for 150 cabin and 1,800 steerage passengers, and the
coal-bunkers "stow" 1,500 tons of coal. The iron plates of which the
sides and bottom are made are from 11/16 to one inch in thickness. The
weight of iron used in construction was about 5,500,000 pounds. The
machinery weighed nearly 2,000,000 pounds, with spare gear and
accessory apparatus. The engines are compound, with two
steam-cylinders of 51 inches and two of 88 inches diameter, and a
stroke of piston of 4-1/2 feet. The condensing water is sent through
the surface-condensers by circulating-pumps driven by their own
engines. Ten boilers furnish steam to these engines, each having a
diameter of 13 feet, a length of 13-1/2 feet, and a thickness of
"shell" of 13/16 inch. Each has three furnaces, and contains 204
tubes of an outside diameter of 3-1/4 inches. All together, they
have 520 square feet of grate-surface and 17,000 square feet of
heating-surface. The area of cooling-surface in the condensers is
10,000 square feet. The City of Rome, a ship of later design, is 590
feet long, "over all," 52 feet beam, 52 feet deep, and measures 8,300
tons. The engines, of 8,500 horse-power, will drive the vessel 18
knots (21 miles) an hour; they have six steam-cylinders (three high
and three low pressure), and are supplied with steam by 8 boilers
heated by 48 furnaces. The hull is of steel, the bottom double, and
the whole divided into ten compartments by transverse bulkheads. Two
longitudinal bulkheads in the engine and boiler compartments add
greatly to the safety of the vessel.

The most successful steam-vessels in general use are these
screw-steamers of transoceanic lines. Those of the transatlantic lines
are now built from 350 to 550 feet long, generally propelled from 12
to 18 knots (14 to 21 miles) an hour, by engines of from 3,000 to
8,000 horse-power, consuming from 70 to 250 tons of coal a day, and
crossing the Atlantic in from eight to ten days. These vessels are now
invariably fitted with the compound engine and surface-condensers. One
of these vessels, the Germanic, has been reported at Sandy Hook, the
entrance to New York Harbor, in 7 days 11 hours 37 minutes from
Queenstown--a distance, as measured by the log and by observation, of
2,830 miles. Another steamer, the Britannic, has crossed the Atlantic
in 7 days 10 hours and 53 minutes. These vessels are of 5,000 tons
burden, of 750 "nominal" horse-power (probably 5,000 actual).

[Illustration: FIG. 144.--The Modern Steamship.]

The modern steamship is as wonderful an illustration of ingenuity and
skill in all interior arrangements as in size, power, and speed. The
size of sea-going steamers has become so great that it is unsafe to
intrust the raising of the anchor or the steering of the vessel to
manual power and skill; and these operations, as well as the loading
and unloading of the vessel, are now the work of the same great
motor--steam.

The now common form of auxiliary engine for controlling the helm is
one of the inventions of the American engineer F. E. Sickels, who
devised the "Sickels cut-off," and was first invented about 1850. It
was exhibited at London at the International Exhibition of 1851. It
consists[98] principally of two cylinders working at right angles upon
a shaft geared into a large wheel fastened by a friction-plate lined
with wood, and set by a screw to any desired pressure on the
steering-apparatus. The wheel turned by the steersman is connected
with the valve-gear of the cylinders, so that the steam, or other
motor, will move the rudder precisely as the helmsman moves the wheel
adjusting the steam-valves. This wheel thus becomes the
steering-wheel. The apparatus is usually so arranged that it may be
connected or disconnected in an instant, and hand-steering adopted if
the smoothness of the sea and the low speed of the vessel make it
desirable or convenient. This method was first adopted in the United
States on the steamship Augusta.

  [98] "Official Catalogue," 1862, vol. iv., Class viii., p. 123.

The same inventor and others have contrived "steam-windlasses," some
of which are in general use on large vessels. The machinery of these
vessels is also often fitted with a steam "reversing-gear," by means
of which the engines are as easily man[oe]uvred as are those of the
smallest vessels, to which hand-gear is always fitted. In one of these
little auxiliary engines, as devised by the author, a small handle
being adjusted to a marked position, as to the point marked "stop" on
an index-plate, the auxiliary engine at once starts, throws the
valve-gear into the proper position--as, if a link-motion, into
"middle-gear"--thus stopping the large engines, and then it itself
stops. Setting the handle so that its pointer shall point to "ahead,"
the little engine starts again, sets the link in position to go ahead,
thus starting the large engines, and again stops itself. If set at
"back," the same series of operations occurs, leaving the main engines
backing and the little "reversing engine" stopped. A number of forms
of reversing engine are in use, each adapted to some one type of
engine.

The hull of the transatlantic steamer is now always of iron, and is
divided into a number of "compartments," each of which is water-tight
and separated from the adjacent compartments by iron "bulkheads," in
which are fitted doors which, when closed, are also water-tight. In
some cases these doors close automatically when the water rises in the
vessel, thus confining it to the leaking portion.

Thus we have already seen a change in transoceanic lines from steamers
like the Great Western (1837), 212 feet in length, of 35-1/2 feet
beam, and 23 feet depth, driven by engines of 450 horse-power, and
requiring 15 days to cross the Atlantic, to steamships over 550 feet
long, 55 feet beam, and 55 feet deep, with engines of 10,000
horse-power, crossing the Atlantic in 7 days; iron substituted for
wood in construction, the cost of fuel reduced one-half, and the speed
raised from 8 to 18 knots and over. In the earlier days of steamships
they were given a proportion of length to breadth of from 5 to 6 to 1;
in forty years the proportion increased until 11 to 1 was reached.

The whole naval establishment of every country has been greatly
modified by the recent changes in methods of attack and defense; but
the several classes of ships which still form the naval marine are all
as dependent upon their steam-machinery as ever.

[Illustration: H. B. M. Iron-Clad Captain. H. B. M. Iron-Clad
Thunderer. U. S. Iron-Clad Dictator. U. S. Iron-Clad Monitor. H. B. M.
Iron-Clad Giatton. French Iron-Clad Dunderberg. FIG. 145.--Modern
Iron-Clads.]

It is only recently that the attempt seems to have been made to
determine a classification of war-vessels and to plan a naval
establishment which shall be likely to meet fully the requirements of
the immediate future. It has hitherto been customary simply to make
each ship a little stronger, faster, or more powerful to resist or to
make attack than was the last. The fact that the direction of
progress in naval science and architecture is plainly perceivable, and
that upon its study may be based a fair estimate of the character and
relative distribution of several classes of vessels, seems to have
been appreciated by very few.

In the year 1870 the writer proposed[99] a classification of vessels
other than torpedo-vessels, which has since been also proposed in a
somewhat modified form by Mr. J. Scott Russell.[100] The author then
remarked that the increase so rapidly occurring in weight of ordnance
and of armor, and in speed of war-vessels, would probably soon compel
a division of the vessels of every navy into three classes of ships,
exclusive of torpedo-vessels, one for general service in time of
peace, the others for use only in time of war.

  [99] _Journal Franklin Institute_, 1870. H. B. M. S. Monarch.

  [100] London _Engineering_, 1875.

"The first class may consist of unarmored vessels of moderate size,
fair speed under steam, armed with a few tolerably heavy guns, and
carrying full sail-power.

"The second class may be vessels of great speed under steam,
unarmored, carrying light batteries and as great spread of canvas as
can readily be given them; very much such vessels as the Wampanoag
class of our own navy were intended to be--calculated expressly to
destroy the commerce of an enemy.

"The third class may consist of ships carrying the heaviest possible
armor and armament, with strongly-built bows, the most powerful
machinery that can be given them, of large coal-carrying capacity, and
unencumbered by sails, everything being made secondary to the one
object of obtaining victory in contending with the most powerful of
possible opponents. Such vessels could never go to sea singly, but
would cruise in couples or in squadrons. It seems hardly doubtful that
attempts to combine the qualities of all classes in a single vessel,
as has hitherto been done, will be necessarily given up, although the
classification indicated will certainly tend largely to restrict naval
operations."

The introduction of the stationary, the floating, and the automatic
classes of torpedoes, and of torpedo-vessels, has now become
accomplished, and this element, which it was predicted by Bushnell and
by Fulton three-quarters of a century ago would at some future time
become important in warfare, is now well recognized by all nations.
How far it may modify future naval establishments cannot be yet
confidently stated, but it seems sufficiently evident that the attack,
by any navy, of stationary defenses protected by torpedoes is now
quite a thing of the past. It may be perhaps looked upon as
exceedingly probable that torpedo-ships of very high speed will yet
drive all heavily-armored vessels from the ocean, thus completing the
historic parallel between the man-in-armor of the middle ages and the
armored man-of-war of our own time.[101]

  [101] _Vide_ "Report on Machinery and Manufactures, etc., at
  Vienna," by the author, Washington, 1875.

Of these classes, the third is of most interest, as exhibiting most
perfectly the importance and variety of the work which the
steam-engine is made to perform. On the later of these vessels, the
anchor is raised by a steam anchor-hoisting apparatus; the heavier
spars and sails are handled by the aid of a steam-windlass; the helm
is controlled by a steering-engine, and the helmsman, with his little
finger, sets in motion a steam-engine, which adjusts the rudder with a
power which is unimpeded by wind or sea, and with an exactness that
could not be exceeded by the hand-steering gear of a yacht; the guns
are loaded by steam, are elevated or depressed, and are given lateral
training, by the same power; the turrets in which the guns are incased
are turned, and the guns are whirled toward every point of the
compass, in less time than is required to sponge and reload them; and
the ship itself is driven through the water by the power of ten
thousand horses, at a speed which is only excelled on land by that of
the railroad-train.

The British Minotaur was one of the earlier iron-clads. The great
length and consequent difficulty of man[oe]uvring, the defect of
speed, and the weakness of armor of these vessels have led to the
substitution of far more effective designs in later constructions. The
Minotaur is a four-masted screw iron-clad, 400 feet long, of 59 feet
beam and 26-1/2 feet draught of water. Her speed at sea is about
12-1/2 knots, and her engines develop, as a maximum, nearly 6,000
indicated horse-power. Her heaviest armor-plates are but 6 inches in
thickness. Her extreme length and her unbalanced rudder make it
difficult to turn rapidly. With _eighteen men at the steering-wheel_
and sixty others on the tackle, the ship, on one occasion, was 7-1/2
minutes in turning completely around. These long iron-clads were
succeeded by the shorter vessels designed by Mr. E. J. Reed, of which
the first, the Bellerophon, was of 4,246 tons burden, 300 feet long by
56 feet beam, and 24-1/2 feet draught, of the 14-knot speed, with
4,600 horse-power; and having the "balanced rudder" used many years
earlier in the United States by Robert L. Stevens,[102] it can turn in
four minutes with eight men at the wheel. The cost of construction was
some $600,000 less than that of the Minotaur. A still later vessel,
the Monarch, was constructed on a system quite similar to that known
in the United States as the Monitor type, or as a turreted iron-clad.
This vessel is 330 feet long, 57-1/2 feet wide, and 36 feet deep,
drawing 24-1/2 feet of water. The total weight of ship and contents is
over 8,000 tons, and the engines are of over 8,500 horse-power. The
armor is 6 and 7 inches thick on the hull, and 8 inches on the two
turrets, over a heavy teak backing. The turrets contain each two
12-inch rifled guns, weighing 25 tons each, and, with a charge of 70
pounds of powder, throwing a shot of 600 pounds weight with a velocity
of 1,200 feet per second, and giving it a _vis viva_ equivalent to the
raising of over 6,100 tons one foot high, and equal to the work of
penetrating an iron plate 13-1/2 inches thick. This immense vessel is
driven by a pair of "single-cylinder" engines having steam-cylinders
_ten feet_ in diameter and of 4-1/2 feet stroke of piston, driving a
two-bladed Griffith screw of 23-1/2 feet diameter and 26-1/2 feet
pitch, 65 revolutions, at the maximum speed of 14.9 knots, or about
17-1/2 miles, an hour. To drive these powerful engines, boilers having
an aggregate of about 25,000 square feet (or more than a half-acre) of
heating-surface are required, with 900 square feet of grate-surface.
The refrigerating surface in the condensers has an area of 16,500
square feet--over one-third of an acre. The cost of these engines and
boilers was £66,500.

  [102] Still in use on the Hoboken ferry-boats.

Were all this vast steam-power developed, giving the vessel a speed of
15 knots, the ship, if used as a "ram," would strike an enemy at rest
with the tremendous "energy" of 48,000 foot-tons--equal to the shock
of the projectiles of eight or nine such guns as are carried by the
iron-clad itself, simultaneously discharged upon one spot.

But even this great vessel is less formidable than later vessels. One
of the latter, the Inflexible, is a shorter but wider and deeper ship
than the Monarch, measuring 320 feet long, 75 feet beam, and 25
draught, displacing over 10,000 tons. The great rifles carried by this
vessel weigh 81 tons each, throwing shot weighing a half-ton from
behind iron-plating two feet in thickness. The steam-engines are of
about the same power as those of the Monarch, and give this enormous
hull a speed of 14 knots an hour.

The navy of the United States does not to-day possess iron-clads of
power even approximating that of either of several classes of British
and other foreign naval vessels.

The largest vessel of any class yet constructed is the Great Eastern
(Fig. 146), begun in 1854 and completed in 1859, by J. Scott Russell,
on the Thames, England. This ship is 680 feet long, 83 feet wide, 58
feet deep, 28 feet draught, and of 24,000 tons measurement. There are
four paddle and four screw engines, the former having steam-cylinders
74 inches in diameter, with 14 feet stroke, the latter 84 inches in
diameter and 4 feet stroke. They are collectively of 10,000 actual
horse-power. The paddle-wheels are 56 feet in diameter, the screw 24
feet. The steam-boilers supplying the paddle-engines have 44,000
square feet (more than an acre) of heating-surface. The boilers
supplying the screw-engines are still larger. At 30 feet draught, this
great vessel displaces 27,000 tons. The engines were designed to
develop 10,000 horse-power, driving the ship at the rate of 16-1/2
statute miles an hour.

[Illustration: FIG. 146.--The Great Eastern.]

The figures quoted in the descriptions of these great steamships do
not enable the non-professional reader to form a conception of the
wonderful power which is concentrated within so small a space as is
occupied by their steam-machinery. The "horse-power" of the engines is
that determined by James Watt as the maximum obtainable for eight
hours a day from the strongest London draught-horses. The ordinary
average draught-horse would hardly be able to exert two-thirds as much
during the eight hours' steady work of a working-day. The working-day
of the steam-engine, on the other hand, is twenty-four hours in
length.

[Illustration: FIG. 147.--The Great Eastern at Sea.]

The work of the 10,000 horse-power engines of the Great Eastern could
be barely equaled by the efforts of 15,000 horses; but to continue
their work uninterruptedly, day in and day out, for weeks together, as
when done by steam, would require at least three relays, or 45,000
horses. Such a stud would weigh 25,000 tons, and if harnessed "tandem"
would extend thirty miles. It is only by such a comparison that the
mind can begin to comprehend the utter impossibility of accomplishing
by means of animal power the work now done for the world by steam.
The cost of the greater power is but about one-tenth that of
horse-power, and by its means tasks are accomplished with ease which
are absolutely impossible of accomplishment by animal power.

It is estimated that the total steam-power of the world is about
15,000,000 horse-power, and that, were horses actually employed to do
the work which these engines would be capable of doing were they kept
constantly in operation, the number required would exceed 60,000,000.

Thus, from the small beginnings of the Comte d'Auxiron and the Marquis
de Jouffroy in France, of Symmington in Great Britain, and of Henry,
Rumsey, and Fitch, and of Fulton and Stevens, in the United States,
steam-navigation has grown into a great and inestimable aid and
blessing to mankind.

We to-day cross the ocean with less risk, and transport ourselves and
our goods at as little cost in either time or money as, at the
beginning of the century, our parents experienced in traveling
one-tenth the distance.

It is largely in consequence of this ingenious application of a power
that reminds one of the fabled genii of Eastern romance, that the
mechanic and the laborer of to-day enjoy comforts and luxuries that
were denied to wealth, and to royalty itself, a century ago.

The magnitude of our modern steamships excites the wonder and
admiration of even the people of our own time; and there is certainly
no creation of art that can be grander in appearance than a
transatlantic steamer a hundred and fifty yards in length, and
weighing, with her stores, five or six thousand tons, as she starts on
her voyage, moved by engines equal in power to the united strength of
thousands of horses; none can more fully awaken a feeling of awe than
an immense structure like the great modern iron-clads (Fig. 145),
vessels having a total weight of 8,000 to 10,000 tons, and propelled
by steam-engines of as many horse-power, carrying guns whose shot
penetrate solid iron 20 inches thick, and having a power of impact,
when steaming at moderate speed, sufficient to raise 35,000 tons a
foot high.

Far more huge than the Monarch among the iron-clads even is that
prematurely-built monster, the Great Eastern (Fig. 147), already
described, an eighth of a mile long, and with steam doing the work of
a stud of 45,000 horses.

Thus we are to-day witnessing the literal fulfillment of the
predictions of Oliver Evans and of John Stevens, and almost that
contained in the couplets written by the poet Darwin, who, more than a
century ago, before even the earliest of Watt's improvements had
become generally known, sang:

    "Soon shall thy arm, unconquered Steam, afar
    Drag the slow barge, or drive the rapid car;
    Or, on wide-waving wings expanded, bear
    The flying chariot through the fields of air."

[Illustration]




CHAPTER VII.

_THE PHILOSOPHY OF THE STEAM-ENGINE._

THE HISTORY OF ITS GROWTH; ENERGETICS AND THERMO-DYNAMICS.

  "Of all the features which characterize this progressive economical
  movement of civilized nations, that which first excites attention,
  through its intimate connection with the phenomena of production, is
  the perpetual and, so far as human foresight can extend, the
  unlimited growth of man's power over Nature. Our knowledge of the
  properties and laws of physical objects shows no sign of approaching
  its ultimate boundaries; it is advancing more rapidly, and in a
  greater number of directions at once, than in any previous age or
  generation, and affording such frequent glimpses of unexplored
  fields beyond as to justify the belief that our acquaintance with
  Nature is still almost in its infancy."--MILL.


The growth of the philosophy of the steam-engine presents as
interesting a study as that of the successive changes which have
occurred in its mechanism.

In the operation of the steam-engine we find illustrated many of the
most important principles and facts which constitute the physical
sciences. The steam-engine is an exceedingly ingenious, but,
unfortunately, still very imperfect, machine for transforming the
heat-energy obtained by the chemical combination of a combustible with
the supporter of combustion into mechanical energy. But the original
source of all this energy is found far back of its first appearance in
the steam-boiler. It had its origin at the beginning, when all Nature
came into existence. After the solar system had been formed from the
nebulous chaos of creation, the glowing mass which is now called the
sun was the depository of a vast store of heat-energy, which was
thence radiated into space and showered upon the attendant worlds in
inconceivable quantity and with unmeasured intensity. During the past
life of the globe, the heat-energy received from the sun upon the
earth's surface was partly expended in the production of great
forests, and the storage, in the trunks, branches, and leaves of the
trees of which they were composed, of an immense quantity of carbon,
which had previously existed in the atmosphere, combined with oxygen,
as carbonic acid. The great geological changes which buried these
forests under superincumbent strata of rock and earth resulted in the
formation of coal-beds, and the storage, during many succeeding ages,
of a vast amount of carbon, of which the affinity for oxygen remained
unsatisfied until finally uncovered by the hand of man. Thus we owe to
the heat and light of the sun, as was pointed out by George
Stephenson, the incalculable store of potential energy upon which the
human race is so dependent for life and all its necessaries, comforts,
and luxuries.

This coal, thrown upon the grate in the steam-boiler, takes fire, and,
uniting again with the oxygen, sets free heat in precisely the same
quantity that it was received from the sun and appropriated during the
growth of the tree. The actual energy thus rendered available is
transferred, by conduction and radiation, to the water in the
steam-boiler, converts it into steam, and its mechanical effect is
seen in the expansion of the liquid into vapor against the
superincumbent pressure. Transferred from the boiler to the engine,
the steam is there permitted to expand, doing work, and the
heat-energy with which it is charged becomes partly converted into
mechanical energy, and is applied to useful work in the mill or to
driving the locomotive or the steamboat.

Thus we may trace the store of energy received from the sun and
contained in our coal through its several changes until it is finally
set at work; and we might go still further and observe how, in each
case, it is again usually re-transformed and again set free as
heat-energy.

The transformation which takes place in the furnace is a chemical
change; the transfer of heat to the water and the subsequent phenomena
accompanying its passage through the engine are physical changes, some
of which require for their investigation abstruse mathematical
operations. A thorough comprehension of the principles governing the
operation of the steam-engine, therefore, can only be attained after
studying the phenomena of physical science with sufficient minuteness
and accuracy to be able to express with precision the laws of which
those sciences are constituted. The study of the philosophy of the
steam-engine involves the study of chemistry and physics, and of the
new science of energetics, of which the now well-grown science of
thermo-dynamics is a branch. This sketch of the growth of the
steam-engine may, therefore, be very properly concluded by an outline
of the growth of the several sciences which together make up its
philosophy, and especially of the science of thermo-dynamics, which is
peculiarly the science of the steam-engine and of the other
heat-engines.

These sciences, like the steam-engine itself, have an origin which
antedates the commencement of the Christian era; but they grew with an
almost imperceptible growth for many centuries, and finally, only a
century ago, started onward suddenly and rapidly, and their progress
has never since been checked. They are now fully-developed and
well-established systems of natural philosophy. Yet, like that of the
steam-engine and of its companion heat-engines, their growth has by no
means ceased; and, while the student of science cannot do more than
indicate the direction of their progress, he can readily believe that
the beginning of the end is not yet reached in their movement toward
completeness, either in the determination of facts or in the
codification of their laws.

When Hero lived at Alexandria, the great "Museum" was a most important
centre, about which gathered the teachers of all then known
philosophies and of all the then recognized but unformed sciences, as
well as of all those technical branches of study which had already
been so far developed as to be capable of being systematically taught.
Astronomical observations had been made regularly and uninterruptedly
by the Chaldean astrologers for two thousand years, and records
extending back many centuries had been secured at Babylon by
Calisthenes and given to Aristotle, the father of our modern
scientific method. Ptolemy had found ready to his hand the records of
Chaldean observers of eclipses extending back nearly 650 years, and
marvelously accurate.[103]

  [103] Their estimate of the length of the Saros, or cycle of
  eclipses--over 19 years--was "within 19-1/2 minutes of the
  truth."--DRAPER.

A rude method of printing with an engraved roller on plastic clay,
afterward baked, thus making up ceramic libraries, was practised long
previous to this time; and in the alcoves in which Hero worked were
many of these books of clay.

This great Library and Museum of Alexandria was founded three
centuries before the birth of Christ, by Ptolemy Soter, who
established as his capital that great Egyptian city when the death of
his brother, the youthful but famous conqueror whose name he gave it,
placed him upon the throne of the colossal successor of the then
fallen Persian Empire. The city itself, embellished with every
ornament and provided with every luxury that the wealth of a conquered
world or the skill, taste, and ingenuity of the Greek painters,
sculptors, architects, and engineers could provide, was full of
wonders; it was a wonder in itself. This rich, populous, and
magnificent city was the metropolis of the then civilized world.
Trade, commerce, manufactures, and the fine arts were all represented
in this splendid exchange, and learning found its most acceptable
home and noblest field within the walls of Ptolemy's Museum; its
disciples found themselves welcomed and protected by its founder and
his successors, Philadelphus and the later Ptolemies.

The Alexandrian Museum was founded with the declared object of
collecting all written works of authority, of promoting the study of
literature and art, and of stimulating and assisting experimental and
mathematical scientific investigation and research. The founders of
modern libraries, colleges, and technical schools have their prototype
in intelligence, public spirit, and liberality, in the first of the
Ptolemies, who not only spent an immense sum in establishing this
great institution, but spared no expense in sustaining it. Agents were
sent out into all parts of the world, purchasing books. A large staff
of scribes was maintained at the museum, whose duty it was to multiply
copies of valuable works, and to copy for the library such works as
could not be purchased.

The faculty of the museum was as carefully organized as was the plan
of its administration. The four principal faculties of astronomy,
literature, mathematics, and medicine were subdivided into sections
devoted to the several branches of each department. The collections of
the museum were as complete as the teachers of the undeveloped
sciences of the time could make them. Lectures were given in all
branches of study, and the number of students was sometimes as great
as twelve or thirteen thousand. The number of books which were
collected here, when the barbarian leaders of the Roman troops under
Cæsar burned the greater part of it, was stated to be 700,000. Of
these, 400,000 were within the museum itself, and were all destroyed;
the rest were in the temple of Serapis, and, for the time, escaped
destruction.

The greatest of all the great men who lived at Alexandria at the time
of the establishment of the museum was Aristotle, the teacher of
Alexander and the friend of Ptolemy. It is to Aristotle that we owe
the systematization of the philosophical ideas of Plato and the
creation of the inductive method, in which has originated all modern
science. It is to the learned men of Alexandria that we are indebted
for so effective an application of the Aristotelian philosophy that
all the then known sciences were given form, and were so thoroughly
established that the work of modern science has been purely one of
development.

The inductive method, which built up all the older sciences, and which
has created all those of recent development, consists, first, in the
discovery and quantitative determination of facts; secondly, when a
sufficient number of facts have been thus observed and defined, in the
grouping of those facts, and the detection, by a study of their mutual
relations, of the natural laws which give rise to or regulate them.
This simple method is that--and the only--method by which science
advances. By this method, and by it only, do we acquire connected and
systematic knowledge of all the phenomena of Nature of which the
physical sciences are cognizant. It is only by the application of this
Aristotelian method and philosophy that we can hope to acquire exact
scientific knowledge of existing phenomena, or to become able to
anticipate the phenomena which are to distinguish the future. The
Aristotelian method of observing facts, and of inductive reasoning
with those facts as a basis, has taught the chemist the properties of
the known elementary substances and their characteristic behavior
under ascertained conditions, and has taught him the laws of
combination and the effects of their union, enabling him to predict
the changes and the phenomena, chemical and physical, which inevitably
follow their contact under any specified set of conditions.

It is this process which has enabled the physicist to ascertain the
methods of molecular motion which give us light, heat, or electricity,
and the range of action and the laws which govern the transfer of
energy from one of these modes of motion to another. It was this
method of study which enabled James Watt to detect and to remedy the
defects of the Newcomen engine, and it is by the Aristotelian
philosophy that the engineer of to-day is taught to construct the
modern steamship, and to predict, before the keel is laid or a blow
struck in the workshop or the ship-yard, what will be the weight of
the vessel, its cargo-carrying capacity, the necessary size and power
of its engines, the quantity of coal which they will require per day
while crossing the ocean, the depth at which the great hull will float
in the water, and the exact speed that the vessel will attain when the
engines are exerting their thousand or their ten thousand horse-power.

It was at Alexandria that this mighty philosophy was first given a
field in which to work effectively. Here Ptolemy studied astronomy and
"natural philosophy;" Archimedes applied himself to the studies which
attract the mathematician and engineer; Euclid taught his royal pupil
those elements of geometry which have remained standard twenty-two
centuries; Eratosthenes and Hipparchus studied and taught astronomy,
and inaugurated the existing system of quantitative investigation,
proving the spherical form of the earth; and Ctesibius and Hero
studied pneumatics and experimented with the germs of the steam-engine
and of less important machines.

When, seven centuries later, the destruction of this splendid
institution was signalized by the death of that brilliant scholar and
heathen teacher of philosophy, Hypatia, at the hands of the more
heathenish fanatics who tore her in pieces at the foot of the cross,
and by the dispersion of the library left by Cæsar's soldiers in the
Serapeum, a true philosophy had been created, and the inductive method
was destined to live and to overcome every obstacle in the path of
enlightenment and civilization. The fall of the Alexandrian Museum,
sad as was the event, could not destroy the new philosophical method.
Its fruits ripened slowly but surely, and we are to-day gathering a
plentiful harvest.

Science, literature, and the arts, all remained dormant for several
centuries after the catastrophe which deprived them of the light in
which they had flourished so many centuries. The armies of the caliphs
made complete the shameful work of destruction begun by the armies of
Cæsar, and the Alexandrian Library, partly destroyed by the Romans,
was completely dispersed by the Patriarchs and their ignorant and
fanatical followers; and finally all the scattered remnants were
burned by the Saracens. But when the thirst for conquest had become
satiated or appeased, the followers of the caliphs turned their
attention to intellectual pursuits, and the ninth century of the
Christian era saw once more such a collection of philosophical
writings, collected at Bagdad, as could only be gathered by the power
and wealth of the later conquerors of the world. Philosophy once again
resumed its empire, and another race commenced the study of the
mathematics of India and of Greece, the astronomy of Chaldea, and of
all the sciences which originated in Greece and in Egypt. By the
conquest of Spain by the Saracens, the new civilization was imported
into Western Europe and libraries were gathered together under the
Moorish rulers, one of which numbered more than a half-million
volumes. Wherever Saracen armies had extended Mohammedan rule,
schools and colleges, libraries and collections of philosophical
apparatus, were scattered in strange profusion; and students,
teachers, philosophers, of all--the speculative as well as the
Aristotelian--schools, gathered together at these intellectual
ganglia, as enthusiastic in their work as were their Alexandrian
predecessors. The endowment of colleges, that truest gauge of the
intelligence of the wealthy classes of any community, became as
common--perhaps more so--as at the present time, and provision was
made for the education of rich and poor alike. The mathematical
sciences, and the wonderful and beautiful phenomena which--but a
thousand years later--were afterward grouped into a science and called
chemistry, were especially attractive to the Arabian scholars, and
technical applications of discovered facts and laws assisted in a
wonderfully rapid development of arts and manufactures.

When, a thousand years after Christ, the centre of intellectual
activity and of material civilization had drifted westward into
Andalusia, the foundation of every modern physical science except that
now just taking shape--the all-grasping science of energetics--had
been laid with experimentally derived facts; and in mathematics there
had been erected a symmetrical and elegant superstructure. Even that
underlying principle of all the sciences, the principle of the
persistence of energy, had been, perhaps unwittingly, enunciated.

Distinguished historians have shown how the progress of civilization
in Europe resulted in the creation, during the middle ages, of the now
great middle class, which, holding the control of political power,
governs every civilized nation, and has come into power so gradually
that it was only after centuries that its influence was seen and felt.
This, which Buckle[104] calls the intellectual class, first became
active, independently of the military and of the clergy, in the
fourteenth century. In the two succeeding centuries this class gained
power and influence; and in the seventeenth century we find a
magnificent advance in all branches of science, literature, and art,
marking the complete emancipation of the intellect from the artificial
conditions which had so long repressed its every effort at
advancement.

  [104] "History of Civilization in England," vol. i., p. 208. London,
  1868.

Another great social revolution thus occurred, following another
period of centuries of intellectual stagnation. The Saracen invaders
were driven from Europe; the Crusaders invaded Palestine, in the vain
effort to recover from the hands of the infidels the Holy Sepulchre
and the Holy Land; and intestine broils and inter-state conflicts, as
well as these greater social movements, withdrew the minds of men once
more from the arts of peace and the pursuits of scholars. It is not,
then, until the beginning of the seventeenth century--the time of
Galileo and of Newton--that we find the nations of Europe sufficiently
quiet and secure to permit general attention to intellectual
vocations, although it was a half-century earlier (1543) that
Copernicus left to the world that legacy which revolutionized the
theories of the astronomers and established as correct the hypothesis
which made the sun the centre of the solar system.

Galileo now began to overturn the speculations of the deductive
philosophers, and to proclaim the still disputed principle that the
book of Nature is a trustworthy commentary in the study of theological
and revealed truths, so far as they affect or are affected by science;
he suffered martyrdom when he proclaimed the fact that God's laws, as
they now stand, had been instituted without deference to the
preconceived notions of the most ignorant of men. Bruno had a few
years earlier (1600) been burned at the stake for a similar offense.

Galileo was perhaps the first, too, to combine invariably in
application the idea of Plato, the philosophy of Aristotle, and the
methods of modern experimentation, to form the now universal
scientific method of experimental philosophy. He showed plainly how
the grouping of ascertained facts, in natural sequence, leads to the
revelation of the law of that sequence, and indicated the existence of
a principle which is now known as the law of continuity--the law that
in all the operations of Nature there is to be seen an unbroken chain
of effect leading from the present back into a known or an unknown
past, toward a cause which may or may not be determinable by science
or known to history.

Galileo, the Italian, was worthily matched by Newton, the prince of
English philosophers. The science of theoretical mechanics was hardly
beginning to assume the position which it was afterward given among
the sciences; and the grand work of collating facts already
ascertained, and of definitely stating principles which had previously
been vaguely recognized, was splendidly done by Newton. The needs of
physical astronomy urged this work upon him.

Da Vinci had, in the latter half of the fifteenth century, summarized
as much of the statics of mechanical philosophy as had, up to his
time, been given shape; he also rewrote and added very much to what
was known on the subject of friction, and enunciated its laws. He had
evidently a good idea of the principle of "virtual velocities," that
simple case of equivalence of work, in a connected system, which has
done such excellent service since; and with his mechanical philosophy
this versatile engineer and artist curiously mingled much of physical
science. Then Stevinus, the "brave engineer of Bruges," a hundred
years later (1586), alternating office and field work, somewhat after
the manner of the engineer of to-day, wrote a treatise on mechanics,
which showed the value of practical experience and judgment in even
scientific work. And thus the path had been cleared for Newton.

Meantime, also, Kepler had hit upon the true relations of the
distances of the planets and their periodic times, after spending half
a generation in blindly groping for them, thus furnishing those great
landmarks of fact in the mechanics of astronomy; and Galileo had
enunciated the laws of motion. Thus the foundation of the science of
dynamics, as distinguished from statics, was laid, and the beginning
was made of that later science of energetics, of which the philosophy
of the steam-engine is so largely constituted.

Hooke, Huyghens, and others, had already seen some of the principal
consequences of these laws; but it remained for Newton to enunciate
them with the precision of a true mathematician, and to base upon them
a system of dynamical laws, which, complemented by his announcement of
the existence of the force of gravitation, and his statement of its
laws, gave a firm basis for all that the astronomer has since done in
those quantitative determinations of size, weight, and distance, and
of the movements of the heavenly bodies, which compel the wonder and
admiration of mankind.

The Arabians and Greeks had noticed that the direction taken by a body
falling under the action of gravitation was directly toward the centre
of the earth, wherever its fall might occur; Galileo had shown, by his
experiments at Pisa, that the velocity of fall, second after second,
varied as the numbers 1, 3, 5, 7, 9, etc., and that the distances
varied as the squares of the total periods of time during which the
body was falling, and that it was, in British feet, very nearly
sixteen times the square of that time in seconds. Kepler had proved
that the movements of the heavenly bodies were just such as would
occur under the action of central attractive forces and of centrifugal
force.

Putting all these things together, Newton was led to believe that
there existed a "force of gravity," due to the attraction, by the
great mass of the earth, of its own particles and of neighboring
bodies, like the moon, of which force the influence extended as far,
at least, as the latter. He calculated the motion of the earth's
satellite, on the assumption that his theory and the then accepted
measurements of the earth's dimensions were correct, and obtained a
roughly approximate result. Later, in 1679, he revised his
calculations, using Picard's more accurate determination of the
dimensions of the earth, and obtained a result which precisely tallied
with careful measurements, made by the astronomers, of the moon's
motion.

The science of mechanics had now, with the publication of Newton's
"Principia," become thoroughly consistent and logically complete, so
far as was possible without a knowledge of the principles of
energetics; and Newton's enunciations of the laws of motion, concise
and absolutely perfect as they still seem, were the basis of the whole
science of dynamics, as applied to bodies moving freely under the
action of applied forces, either constant or variable. They are as
perfect a basis for that science as are the primary principles of
geometry for the whole beautiful structure which is built up on them.

The three perfect qualitative expressions of dynamical law are:

1. Every free body continues in the state in which it may be, whether
of rest or of rectilinear uniform motion, until compelled to deviate
from that state by impressed forces.

2. Change of motion is proportional to the force impressed, and in the
direction of the right line in which that force acts.

3. Action is always opposed by reaction; action and reaction are
equal, and in directly contrary directions.

We may add to these principles a definition of a force, which is
equally and absolutely complete:

_Force_ is that which produces, or tends to produce, motion, or change
of motion, in bodies. It is measured statically by the weight that
will counterpoise it, or by the pressure which it will produce, and
dynamically by the velocity which it will produce, acting in the unit
of time on the unit of mass.

The quantitative determinations of dynamic effects of forces are
always readily made when it is remembered that the effect of a force
equal to its own weight, when the body is free to move, is to produce
in one second a velocity of 32.2 feet per second, which quantity is
the unit of dynamic measurement.

_Work_ is the product of the resistance met in any instance of the
exertion of a force, into the distance through which that force
overcomes the resistance.

_Energy_ is the work which a body is capable of doing, by its weight
or inertia, under given conditions. The energy of a falling body, or
of a flying shot, is about 1/64 its weight multiplied by the square of
its velocity, or, which is the same thing, the product of its weight
into the height of fall or height due its velocity. These principles
and definitions, with the long-settled definitions of the primary
ideas of space and time, were all that were needed to lead the way to
that grandest of all physical generalizations, the doctrine of the
persistence or conservation of all energy, and to its corollary
declaring the equivalence of all forms of energy, and also to the
experimental demonstration of the transformability of energy from one
mode of existence to another, and its universal existence in the
various modes of motion of bodies and of their molecules.

Experimental physical science had hardly become acknowledged as the
only and the proper method of acquiring knowledge of natural phenomena
at the time of Newton; but it soon became a generally accepted
principle. In physics, Gilbert had made valuable investigations before
Newton, and Galileo's experiments at Pisa had been examples of
similarly useful research. In chemistry, it was only when, a century
later, Lavoisier showed by his splendid example what could be done by
the skillful and intelligent use of quantitative measurements, and
made the balance the chemist's most important tool, that a science was
formed comprehending all the facts and laws of chemical change and
molecular combination. We have already seen how astronomy and
mathematics together led philosophers to the creation and the study of
what finally became the science of mechanics, when experiment and
observation were finally brought to their aid. We can now see how, in
all these physical sciences, four primitive ideas are comprehended:
matter, force, motion, and space--which latter two terms include all
relations of position.

Based on these notions, the science of mechanics comprehends four
sections, which are of general application in the study of all
physical phenomena. These are:

_Statics_, which treats of the action and effect of forces.

_Kinematics_, which treats of relations of motion simply.

_Dynamics_, or kinetics, which treats of simple motion as an effect of
the action of forces.

_Energetics_, which treats of modifications of energy under the action
of forces, and of its transformation from one mode of manifestation to
another, and from one body to another.

Under the latter of these four divisions of mechanical philosophy is
comprehended that latest of the minor sciences, of which the
heat-engines, and especially the steam-engine, illustrate the most
important applications--_Thermo-dynamics_. This science is simply a
wider generalization of principles which, as we have seen, have been
established one at a time, and by philosophers widely separated both
geographically and historically, by both space and time, and which
have been slowly aggregated to form one after another of the sciences,
and out of which, as we now are beginning to see, we are slowly
evolving wider generalizations, and thus tending toward a condition of
scientific knowledge which renders more and more probable the truth of
Cicero's declaration: "One eternal and immutable law embraces all
things and all times." At the basis of the whole science of energetics
lies a principle which was enunciated before Science had a birthplace
or a name:

_All that exists, whether matter or force, and in whatever form, is
indestructible, except by the Infinite Power which has created it._

That matter is indestructible by finite power became admitted as soon
as the chemists, led by their great teacher Lavoisier, began to apply
the balance, and were thus able to show that in all chemical change
there occurs only a modification of form or of combination of
elements, and no loss of matter ever takes place. The "persistence" of
energy was a later discovery, consequent largely upon the experimental
determination of the convertibility of heat-energy into other forms
and into mechanical work, for which we are indebted to Rumford and
Davy, and to the determination of the quantivalence anticipated by
Newton, shown and calculated approximately by Colding and Mayer, and
measured with great probable accuracy by Joule.

[Illustration: Benjamin Thompson, Count Rumford.]

The great fact of the conservation of energy was loosely stated by
Newton, who asserted that the work of friction and the _vis viva_ of
the system or body arrested by friction were equivalent. In 1798,
Benjamin Thompson, Count Rumford, an American who was then in the
Bavarian service, presented a paper[105] to the Royal Society of Great
Britain, in which he stated the results of an experiment which he had
recently made, proving the immateriality of heat and the
transformation of mechanical into heat energy. This paper is of very
great historical interest, as the now accepted doctrine of the
persistence of energy is a generalization which arose out of a series
of investigations, the most important of which are those which
resulted in the determination of the existence of a definite
quantivalent relation between these two forms of energy and a
measurement of its value, now known as the "mechanical equivalent of
heat." His experiment consisted in the determination of the quantity
of heat produced by the boring of a cannon at the arsenal at Munich.

  [105] "Philosophical Transactions," 1798.

Rumford, after showing that this heat could not have been derived from
any of the surrounding objects, or by compression of the materials
employed or acted upon, says: "It appears to me extremely difficult,
if not impossible, to form any distinct idea of anything capable of
being excited and communicated in the manner that heat was excited and
communicated in these experiments, except it be motion."[106] He then
goes on to urge a zealous and persistent investigation of the laws
which govern this motion. He estimates the heat produced by a power
which he states could easily be exerted by one horse, and makes it
equal to the "combustion of nine wax candles, each three-quarters of
an inch in diameter," and equivalent to the elevation of "25.68 pounds
of ice-cold water" to the boiling-point, or 4,784.4 heat-units.[107]
The time was stated at "150 minutes." Taking the actual power of
Rumford's Bavarian "one horse" as the most probable figure, 25,000
pounds raised one foot high per minute,[108] this gives the
"mechanical equivalent" of the foot-pound as 783.8 heat-units,
differing but 1.5 per cent. from the now accepted value.

  [106] This idea was not by any means original with Rumford. Bacon
  seems to have had the same idea; and Locke says, explicitly enough:
  "Heat is a very brisk agitation of the insensible parts of the
  object ... so that what in our sensation is heat, in the object is
  nothing but motion."

  [107] The British heat-unit is the quantity of heat required to heat
  one pound of water 1° Fahr. from the temperature of maximum density.

  [108] Rankine gives 25,920 foot-pounds per minute--or 432 per
  second--for the average draught-horse in Great Britain, which is
  probably too high for Bavaria. The engineer's "horse-power"--33,000
  foot-pounds per minute--is far in excess of the average power of
  even a good draught-horse, which latter is sometimes taken as
  two-thirds the former.

Had Rumford been able to eliminate all losses of heat by evaporation,
radiation, and conduction, to which losses he refers, and to measure
the power exerted with accuracy, the approximation would have been
still closer. Rumford thus made the experimental discovery of the real
nature of heat, proving it to be a form of energy, and, publishing
the fact a half-century before the now standard determinations were
made, gave us a very close approximation to the value of the
heat-equivalent. Rumford also observed that the heat generated was
"exactly proportional to the force with which the two surfaces are
pressed together, and to the rapidity of the friction," which is a
simple statement of equivalence between the quantity of work done, or
energy expended, and the quantity of heat produced. This was the first
great step toward the formation of a Science of Thermo-dynamics.
Rumford's work was the corner-stone of the science.

Sir Humphry Davy, a little later (1799), published the details of an
experiment which conclusively confirmed these deductions from
Rumford's work. He rubbed two pieces of ice together, and found that
they were melted by the friction so produced. He thereupon concluded:
"It is evident that ice by friction is converted into water....
Friction, consequently, does not diminish the capacity of bodies for
heat."

Bacon and Newton, and Hooke and Boyle, seem to have anticipated--long
before Rumford's time--all later philosophers, in admitting the
probable correctness of that modern dynamical, or vibratory, theory of
heat which considers it a mode of motion; but Davy, in 1812, for the
first time, stated plainly and precisely the real nature of heat,
saying: "The immediate cause of the phenomenon of heat, then, is
motion, and the laws of its communication are precisely the same as
the laws of the communication of motion." The basis of this opinion
was the same that had previously been noted by Rumford.

So much having been determined, it became at once evident that the
determination of the exact value of the mechanical equivalent of heat
was simply a matter of experiment; and during the succeeding
generation this determination was made, with greater or less
exactness, by several distinguished men. It was also equally evident
that the laws governing the new science of thermo-dynamics could be
mathematically expressed.

Fourier had, before the date last given, applied mathematical analysis
in the solution of problems relating to the transfer of heat without
transformation, and his "Théorie de la Chaleur" contained an
exceedingly beautiful treatment of the subject. Sadi Carnot, twelve
years later (1824), published his "Réflexions sur la Puissance Motrice
du Feu," in which he made a first attempt to express the principles
involved in the application of heat to the production of mechanical
effect. Starting with the axiom that a body which, having passed
through a series of conditions modifying its temperature, is returned
to "its primitive physical state as to density, temperature, and
molecular constitution," must contain the same quantity of heat which
it had contained originally, he shows that the efficiency of
heat-engines is to be determined by carrying the working fluid through
a complete cycle, beginning and ending with the same set of
conditions. Carnot had not then accepted the vibratory theory of heat,
and consequently was led into some errors; but, as will be seen
hereafter, the idea just expressed is one of the most important
details of a theory of the steam-engine.

Seguin, who has already been mentioned as one of the first to use the
fire-tubular boiler for locomotive engines, published in 1839 a work,
"Sur l'Influence des Chemins de Fer," in which he gave the requisite
data for a rough determination of the value of the mechanical
equivalent of heat, although he does not himself deduce that value.

Dr. Julius R. Mayer, three years later (1842), published the results
of a very ingenious and quite closely approximate calculation of the
heat-equivalent, basing his estimate upon the work necessary to
compress air, and on the specific heats of the gas, the idea being
that the work of compression is the equivalent of the heat generated.
Seguin had taken the converse operation, taking the loss of heat of
expanding steam as the equivalent of the work done by the steam while
expanding. The latter also was the first to point out the fact,
afterward experimentally proved by Hirn, that the fluid exhausted from
an engine should heat the water of condensation less than would the
same fluid when originally taken into the engine.

A Danish engineer, Colding, at about the same time (1843), published
the results of experiments made to determine the same quantity; but
the best and most extended work, and that which is now almost
universally accepted as standard, was done by a British investigator.

James Prescott Joule commenced the experimental investigations which
have made him famous at some time previous to 1843, at which date he
published, in the _Philosophical Magazine_, his earliest method. His
first determination gave 770 foot-pounds. During the succeeding five
or six years Joule repeated his work, adopting a considerable variety
of methods, and obtaining very variable results. One method was to
determine the heat produced by forcing air through tubes; another, and
his usual plan, was to turn a paddle-wheel by a definite power in a
known weight of water. He finally, in 1849, concluded these
researches.

[Illustration: James Prescott Joule.]

The method of calculating the mechanical equivalent of heat which was
adopted by Dr. Mayer, of Heilbronn, is as beautiful as it is
ingenious: Conceive two equal portions of atmospheric air to be
inclosed, at the same temperature--as at the freezing-point--in
vessels each capable of containing one cubic foot; communicate heat to
both, retaining the one portion at the original volume, and permitting
the other to expand under a constant pressure equal to that of the
atmosphere. In each vessel there will be inclosed 0.08073 pound, or
1.29 ounce, of air. When, at the same temperature, the one has doubled
its pressure and the other has doubled its volume, each will be at a
temperature of 525.2° Fahr., or 274° C, and each will have double the
original temperature, as measured on the absolute scale from the zero
of heat-motion. But the one will have absorbed but 6-3/4 British
thermal units, while the other will have absorbed 9-1/2. In the first
case, all of this heat will have been employed in simply increasing
the temperature of the air; in the second case, the temperature of the
air will have been equally increased, and, besides, a certain amount
of work--2,116.3 foot-pounds--must have been done in overcoming the
resistance of the air; it is to this latter action that we must debit
the additional heat which has disappeared. Now, 2,116.3/(2-3/4) = 770
foot-pounds per heat-unit--almost precisely the value derived from
Joule's experiments. Had Mayer's measurement been absolutely accurate,
the result of his calculation would have been an exact determination
of the heat-equivalent, provided no heat is, in this case, lost by
internal work.

Joule's most probably accurate measure was obtained by the use of a
paddle-wheel revolving in water or other fluid. A copper vessel
contained a carefully weighed portion of the fluid, and at the bottom
was a step, on which stood a vertical spindle carrying the
paddle-wheel. This wheel was turned by cords passing over
nicely-balanced grooved wheels, the axles of which were carried on
friction-rollers. Weights hung at the ends of these cords were the
moving forces. Falling to the ground, they exerted an easily and
accurately determinable amount of work, _W_ × _H_, which turned the
paddle-wheel a definite number of revolutions, warming the water by
the production of an amount of heat exactly equivalent to the amount
of work done. After the weight had been raised and this operation
repeated a sufficient number of times, the quantity of heat
communicated to the water was carefully determined and compared with
the amount of work expended in its development. Joule also used a pair
of disks of iron rubbing against each other in a vessel of mercury,
and measured the heat thus developed by friction, comparing it with
the work done. The average of forty experiments with water gave the
equivalent 772.692 foot-pounds; fifty with mercury gave 774.083;
twenty with cast-iron gave 774.987--the temperature of the apparatus
being from 55° to 60° Fahr.

Joule also determined, by experiment, the fact that the expansion of
air or other gas without doing work produces no change of temperature,
which fact is predicable from the now known principles of
thermo-dynamics. He stated the results of his researches relating to
the mechanical equivalent of heat as follows:

1. The heat produced by the friction of bodies, whether solid or
liquid, is always proportional to the quantity of work expended.

2. The quantity required to increase the temperature of a pound of
water (weighed _in vacuo_ at 55° to 60° Fahr.) by one degree requires
for its production the expenditure of a force measured by the fall of
772 pounds from a height of one foot. This quantity is now generally
called "Joule's equivalent."

During this series of experiments, Joule also deduced the position of
the "absolute zero," the point at which heat-motion ceases, and stated
it to be about 480° Fahr. below the freezing-point of water, which is
not very far from the probably true value,-493.2° Fahr. (-273° C.), as
deduced afterward from more precise data.

The result of these, and of the later experiments of Hirn and others,
has been the admission of the following principle:

Heat-energy and mechanical energy are mutually convertible and have a
definite equivalence, the British thermal unit being equivalent to 772
foot-pounds of work, and the metric _calorie_ to 423.55, or, as
usually taken, 424 kilogrammetres. The exact measure is not fully
determined, however.

It has now become generally admitted that all forms of energy due to
physical forces are mutually convertible with a definite
quantivalence; and it is not yet determined that even vital and mental
energy do not fall within the same great generalization. This
quantivalence is the sole basis of the science of Energetics.

The study of this science has been, up to the present time,
principally confined to that portion which comprehends the relations
of heat and mechanical energy. In the study of this department of the
science, thermo-dynamics, Rankine, Clausius, Thompson, Hirn, and
others have acquired great distinction. In the investigations which
have been made by these authorities, the methods of transfer of heat
and of modification of physical state in gases and vapors, when a
change occurs in the form of the energy considered, have been the
subjects of especial study.

According to the law of Boyle and Marriotte, the expansion of such
fluids follows a law expressed graphically by the hyperbola, and
algebraically by the expression PV^{_x_} = A, in which, with
unchanging temperature, _x_ is equal to 1. One of the first and most
evident deductions from the principles of the equivalence of the
several forms of energy is that the value of x must increase as the
energy expended in expansion increases. This change is very marked
with a vapor like steam--which, expanded without doing work, has an
exponent less than unity, and which, when doing work by expanding
behind a piston, partially condenses, the value of _x_ increases to,
in the case of steam, 1.111 according to Rankine, or, probably more
correctly, to 1.135 or more, according to Zeuner and Grashof. This
fact has an important bearing upon the theory of the steam-engine, and
we are indebted to Rankine for the first complete treatise on that
theory as thus modified.

Prof. Rankine began his investigations as early as 1849, at which time
he proposed his theory of the molecular constitution of matter, now
well known as the theory of molecular vortices. He supposes a system
of whirling rings or vortices of heat-motion, and bases his
philosophy upon that hypothesis, supposing sensible heat to be
employed in changing the velocity of the particles, latent heat to be
the work of altering the dimensions of the orbits, and considering the
effort of each vortex to enlarge its boundaries to be due to
centrifugal force. He distinguished between real and apparent specific
heat, and showed that the two methods of absorption of heat, in the
case of the heating of a fluid, that due to simple increase of
temperature and that due to increase of volume, should be
distinguished; he proposed, for the latter quantity, the term
heat-potential, and for the sum of the two, the name of thermo-dynamic
function.

[Illustration: Prof. W. J. M. Rankine.]

Carnot had stated, a quarter of a century earlier, that the efficiency
of a heat-engine is a function of the two limits of temperature
between which the machine is worked, and not of the nature of the
working substance--an assertion which is quite true where the material
does not change its physical state while working. Rankine now deduced
that "general equation of thermo-dynamics" which expresses
algebraically the relations between heat and mechanical energy, when
energy is changing from the one state to the other, in which equation
is given, for any assumed change of the fluids, the quantity of heat
transformed. He showed that steam in the engine must be partially
liquefied by the process of expanding against a resistance, and proved
that the total heat of a perfect gas must increase with rise of
temperature at a rate proportional to its specific heat under constant
pressure.

Rankine, in 1850, showed the inaccuracy of the then accepted value,
0.2669, of the specific heat of air under constant pressure, and
calculated its value as 0.24. Three years later, the experiments of
Regnault gave the value 0.2379, and Rankine, recalculating it, made it
0.2377. In 1851, Rankine continued his discussion of the subject, and,
by his own theory, corroborated Thompson's law giving the efficiency
of a perfect heat-engine as the quotient of the range of working
temperature to the temperature of the upper limit, measured from the
absolute zero.

During this period, Clausius, the German physicist, was working on the
same subject, taking quite a different method, studying the mechanical
effects of heat in gases, and deducing, almost simultaneously with
Rankine (1850), the general equation which lies at the beginning of
the theory of the equivalence of heat and mechanical energy. He found
that the probable zero of heat-motion is at such a point that the
Carnot function must be approximately the reciprocal of the "absolute"
temperature, as measured with the air thermometer, or, stated exactly,
that quantity as determined by a perfect gas thermometer. He confirmed
Rankine's conclusion relative to the liquefaction of saturated vapors
when expanding against resistance, and, in 1854, adapted Carnot's
principle to the new theory, and showed that his idea of the
reversible engine and of the performance of a cycle in testing the
changes produced still held good, notwithstanding Carnot's ignorance
of the true nature of heat. Clausius also gave us the extremely
important principle: It is impossible for a self-acting machine,
unaided, to transfer heat from one body at a low temperature to
another having a higher temperature.

Simultaneously with Rankine and Clausius, Prof. William Thomson was
engaged in researches in thermo-dynamics (1850). He was the first to
express the principle of Carnot as adapted to the modern theory by
Clausius in the now generally quoted propositions:[109]

  [109] _Vide_ Tait's admirable "Sketch of Thermodynamics," second
  edition, Edinburgh, 1877.

1. When equal mechanical effects are produced by purely thermal
action, equal quantities of heat are produced or disappear by
transformation of energy.

2. If, in any engine, a reversal effects complete inversion of all the
physical and mechanical details of its operation, it is a perfect
engine, and produces maximum effect with any given quantity of heat
and with any fixed limits of range of temperature.

William Thomson and James Thompson showed, among the earliest of their
deductions from these principles, the fact, afterward confirmed by
experiment, that the melting-point of ice should be lowered by
pressure 0.0135° Fahr, for each atmosphere, and that a body which
contracts while being heated will always have its temperature
decreased by sudden compression. Thomson applied the principles of
energetics in extended investigations in the department of
electricity, while Helmholtz carried some of the same methods into his
favorite study of acoustics.

The application of now well-settled principles to the physics of gases
led to many interesting and important deductions: Clausius explained
the relations between the volume, density, temperature, and pressure
of gases, and their modifications; Maxwell reëstablished the
experimentally determined law of Dalton and Charles, known also as
that of Gay-Lussac (1801), which asserts that all masses of equal
pressure, volume, and temperature, contain equal numbers of molecules.
On the Continent of Europe, also, Hirn, Zeuner, Grashof, Tresca,
Laboulaye, and others have, during the same period and since,
continued and greatly extended these theoretical researches.

During all this time, a vast amount of experimental work has also been
done, resulting in the determination of important data without which
all the preceding labor would have been fruitless. Of those who have
engaged in such work, Cagniard de la Tour, Andrews, Regnault, Hirn,
Fairbairn and Tate, Laboulaye, Tresca, and a few others have directed
their researches in this most important direction with the special
object of aiding in the advancement of the new-born sciences. By the
middle of the present century, the time which we are now studying,
this set of data was tolerably complete. Boyle had, two hundred years
before, discovered and published the law, which is now known by his
name[110] and by that of Marriotte,[111] that the pressure of a gas
varies inversely as its volume and directly as its density; Dr. Black
and James Watt discovered, a hundred years later (1760), the latent
heat of vapors, and Watt determined the method of expansion of steam;
Dalton, in England, and Gay-Lussac, in France, showed, at the
beginning of the nineteenth century, that all gaseous fluids are
expanded by equal fractions of their volume by equal increments of
temperature; Watt and Robison had given tables of the elastic force of
steam, and Gren had shown that, at the temperature of boiling water,
the pressure of steam was equal to that of the atmosphere; Dalton,
Ure, and others proved (1800-1818) that the law connecting
temperatures and pressures of steam was expressed by a geometrical
ratio; and Biot had already given an approximate formula, when
Southern introduced another, which is still in use.

  [110] "New Experiments, Physico-Mechanical, etc., touching the
  Spring of Air," 1662.

  [111] "De la Nature de l'Air," 1676.

The French Government established a commission in 1823 to experiment
with a view to the institution of legislation regulating the working
of steam-engines and boilers; and this commission, MM. de Prony,
Arago, Girard, and Dulong, determined quite accurately the
temperatures of steam under pressures running up to twenty-four
atmospheres, giving a formula for the calculation of the one quantity,
the other being known. Ten years later, the Government of the United
States instituted similar experiments under the direction of the
Franklin Institute.

The marked distinction between gases, like oxygen and hydrogen, and
condensible vapors, like steam and carbonic acid, had been, at this
time, shown by Cagniard de la Tour, who, in 1822, studied their
behavior at high temperatures and under very great pressures. He found
that, when a vapor was confined in a glass tube in presence of the
same substance in the liquid state, as where steam and water were
confined together, if the temperature was increased to a certain
definite point, the whole mass suddenly became of uniform character,
and the previously existing line of demarkation vanished, the whole
mass of fluid becoming, as he inferred, gaseous. It was at about this
time that Faraday made known his then novel experiments, in which
gases which had been before supposed permanent were liquefied, simply
by subjecting them to enormous pressures. He then also first stated
that, above certain temperatures, liquefaction of vapors was
impossible, however great the pressure.

Faraday's conclusion was justified by the researches of Dr. Andrews,
who has since most successfully extended the investigation commenced
by Cagniard de la Tour, and who has shown that, at a certain point,
which he calls the "critical point," the properties of the two states
of the fluid fade into each other, and that, at that point, the two
become continuous. With carbonic acid, this occurs at 75 atmospheres,
about 1,125 pounds per square inch, a pressure which would
counterbalance a column of mercury 60 yards, or nearly as many metres,
high. The temperature at this point is about 90° Fahr., or 31° Cent.
For ether, the temperature is 370° Fahr., and the pressure 38
atmospheres; for alcohol, they are 498° Fahr., and 120 atmospheres;
and for bisulphide of carbon, 505° Fahr., and 67 atmospheres. For
water, the pressure is too high to be determined; but the temperature
is about 775° Fahr., or 413° Cent.

Donny and Dufour have shown that these normal properties of vapors and
liquids are subject to modification by certain conditions, as
previously (1818) noted by Gay-Lussac, and have pointed out the
bearing of this fact upon the safety of steam-boilers. It was
discovered that the boiling-point of water could be elevated far above
its ordinary temperature of ebullition by expedients which deprive the
liquid of the air usually condensed within its mass, and which prevent
contact with rough or metallic surfaces. By suspension in a mixture of
oils which is of nearly the same density, Dufour raised drops of water
under atmospheric pressure to a temperature of 356° Fahr.--180°
Cent.--the temperature of steam of about 150 pounds per square inch.
Prof. James Thompson has, on theoretical grounds, indicated that a
somewhat similar action may enable vapor, under some conditions, to be
cooled below the normal temperature of condensation, without
liquefaction.

Fairbairn and Tate repeated the attempt to determine the volume and
temperature of water at pressures extending beyond those in use in the
steam-engine, and incomplete determinations have also been made by
others.

Regnault is the standard authority on these data. His experiments
(1847) were made at the expense of the French Government, and under
the direction of the French Academy. They were wonderfully accurate,
and extended through a very wide range of temperatures and pressures.
The results remain standard after the lapse of a quarter of a century,
and are regarded as models of precise physical work.[112]

  [112] _See_ Porter on the Steam-Engine Indicator for the best set of
  Regnault's tables generally accessible.

Regnault found that the total heat of steam is not constant, but that
the latent heat varies, and that the sum of the latent and sensible
heats, or the total heat, increases 0.305 of a degree for each degree
of increase in the sensible heat, making 0.305 the specific heat of
saturated steam. He found the specific heat of superheated steam to be
0.4805.

Regnault promptly detected the fact that steam was not subject to
Boyle's law, and showed that the difference is very marked. In
expressing his results, he not only tabulated them but also laid them
down graphically; he further determined exact constants for Biot's
algebraic expression,

  log. _p_ = _a_ - _b_A^{_x_} - _c_B^{_x_};

making _x_ = 20 + _t_° Cent.; _a_ = 6.264035; log. _b_ = 0.1397743;
log. _c_ = 0.6924351; log. A = [=1].9940493, and log. B = [=1].9983439;
_p_ is the pressure in atmospheres. Regnault, in the expression for the
total heat, H = A + _bt_, determined on the centigrade scale [theta] =
606.5 + 0.305 _t_ Cent. For the Fahrenheit scale, we have the
following equivalent expressions:

  H = 1,113.44° + 0.305 _t_° Fahr., if measured from 0° Fahr.
    = 1,091.9°  + 0.305 (_t_° - 32) Fahr.,;   } if measured from
    = 1,081.94° + 0.305 _t_° Fahr.,           } the freezing-point.

For latent heat, we have:

  L = 606.5° - 0.695 _t_° Cent.
    = 1,091.7°- 0.695 (_t_° - 32) Fahr.
    = 1,113.94°- 0.695 _t_° Fahr.

Since Regnault's time, nothing of importance has been done in this
direction. There still remains much work to be done in the extension
of the research to higher pressures, and under conditions which obtain
in the operation of the steam-engine. The volumes and densities of
steam require further study, and the behavior of steam in the engine
is still but little known, otherwise than theoretically. Even the true
value of Joule's equivalent is not undisputed.

Some of the most recent experimental work bearing directly upon the
philosophy of the steam-engine is that of Hirn, whose determination of
the value of the mechanical equivalent was less than two per cent.
below that of Joule. Hirn tested by experiment, in 1853, and
repeatedly up to 1876, the analytical work of Rankine, which led to
the conclusion that steam doing work by expansion must become
gradually liquefied. Constructing a glass steam-engine cylinder, he
was enabled to see plainly the clouds of mist which were produced by
the expansion of steam behind the piston, where Regnault's experiments
prove that the steam should become drier and superheated, were no heat
transformed into mechanical energy. As will be seen hereafter, this
great discovery of Rankine is more important in its bearing upon the
theory of the steam-engine than any made during the century. Hirn's
confirmation stands, in value, beside the original discovery. In 1858
Hirn confirmed the work of Mayer and Joule by determining the work
done and the carbonic acid produced, as well as the increased
temperature due to their presence, where men were set at work in a
treadmill; he found the elevation of temperature to be much greater in
proportion to gas produced when the men were resting than when they
were at work. He thus proved conclusively the conversion of
heat-energy into mechanical work. It was from these experiments that
Helmholtz deduced the "modulus of efficiency" of the human machine at
one-fifth, and concluded that the heart works with eight times the
efficiency of a locomotive-engine, thus confirming a statement of
Rumford, who asserted the higher efficiency of the animal.

Hirn's most important experiments in this department were made upon
steam-engines of considerable size, including simple and compound
engines, and using steam sometimes saturated and sometimes superheated
to temperatures as high, on some occasions, as 340° Cent. He
determined the work done, the quantity of heat entering, and the
amount rejected from, the steam-cylinder, and thus obtained a coarse
approximation to the value of the heat-equivalent. His figure varied
from 296 to 337 kilogrammetres. But, in all cases, the loss of heat
due to work done was marked, and, while these researches could not, in
the nature of the case, give accurate quantitative results, they are
of great value as qualitatively confirming Mayer and Joule, and
proving the transformation of energy.

Thus, as we have seen, experimental investigation and analytical
research have together created a new science, and the philosophy of
the steam-engine has at last been given a complete and well-defined
form, enabling the intelligent engineer to comprehend the operation of
the machine, to perceive the conditions of efficiency, and to look
forward in a well-settled direction for further advances in its
improvement and in the increase of its efficiency.

A very concise _résumé_ of the principal facts and laws bearing upon
the philosophy of the steam-engine will form a fitting conclusion to
this historical sketch.

The term "energy" was first used by Dr. Young as the equivalent of the
work of a moving body, in his hardly yet obsolete "Lectures on Natural
Philosophy."

Energy is the capacity of a moving body to overcome resistance offered
to its motion; it is measured either by the product of the mean
resistance into the space through which it is overcome, or by the
half-product of the mass of the body into the square of its velocity.
Kinetic energy is the actual energy of a moving body; potential energy
is the measure of the work which a body is capable of doing under
certain conditions which, without expending energy, may be made to
affect it, as by the breaking of a cord by which a weight is
suspended, or by firing a mass of explosive material. The British
measure of energy is the foot-pound; the metric measure is the
kilogrammetre.

Energy, whether kinetic or potential, may be observable and due to
mass-motion; or it may be invisible and due to molecular movements.
The energy of a heavenly body or of a cannon-shot, and that of heat or
of electrical action, are illustrations of the two classes. In Nature
we find utilizable potential energy in fuel, in food, in any available
head of water, and in available chemical affinities. We find kinetic
energy in the motion of the winds and the flow of running water, in
the heat-motion of the sun's rays, in heat-currents on the earth, and
in many intermittent movements of bodies acted on by applied forces,
natural or artificial. The potential energy of fuel and of food has
already been seen to have been derived, at an earlier period, from the
kinetic energy of the sun's rays, the fuel or the food being thus made
a storehouse or reservoir of energy. It is also seen that the animal
system is simply a "mechanism of transmission" for energy, and does
not create but simply diverts it to any desired direction of
application.

All the available forms of energy can be readily traced back to a
common origin in the potential energy of a universe of nebulous
substance (chaos), consisting of infinitely diffused matter of
immeasurably slight density, whose "energy of position" had been,
since the creation, gradually going through a process of
transformation into the several forms of kinetic and potential energy
above specified, through intermediate methods of action which are
usually still in operation, such as the potential energy of chemical
affinity, and the kinetic forms of energy seen in solar radiation, the
rotation of the earth, and the heat of its interior.

The _measure_ of any given quantity of energy, whatever may be its
form, is the product of the resistance which it is capable of
overcoming into the space through which it can move against that
resistance, i. e., by the product RS. Or it is measured by the
equivalent expressions (MV^{2})/2, or WV^{2}/2_g_, in which W is
the weight, M is the "mass" of matter in motion, V the velocity, and
_g_ the dynamic measure of the force of gravity, 32-1/6 feet, or 9.8
metres, per second.

There are three great laws of energetics:

1. The sum total of the energy of the universe is invariable.

2. The several forms of energy are interconvertible, and possess an
exact quantitative equivalence.

3. The tendency of all forms of kinetic energy is continually toward
reduction to forms of molecular motion, and to their final dissipation
uniformly throughout space.

The history of the first two of these laws has already been traced.
The latter was first enunciated by Prof. Sir William Thomson in 1853.
Undissipated energy is called "Entrophy."

The science of thermo-dynamics is, as has been stated, a branch of the
science of energetics, and is the only branch of that science in the
domain of the physicist which has been very much studied. This branch
of science, which is restricted to the consideration of the relations
of heat-energy to mechanical energy, is based upon the great fact
determined by Rumford and Joule, and considers the behavior of those
fluids which are used in heat-engines as the media through which
energy is transferred from the one form to the other. As now accepted,
it assumes the correctness of the hypothesis of the dynamic theory of
fluids, which supposes their expansive force to be due to the motion
of their molecules.

This idea is as old as Lucretius, and was distinctly expressed by
Bernouilli, Le Sage and Prévost, and Herapath. Joule recalled
attention to this idea, in 1848, as explaining the pressure of gases
by the impact of their molecules upon the sides of the containing
vessels. Helmholtz, ten years later, beautifully developed the
mathematics of media composed of moving, frictionless particles, and
Clausius has carried on the work still further.

The general conception of a gas, as held to-day, including the
vortex-atom theory of Thomson and Rankine, supposes all bodies to
consist of small particles called molecules, each of which is a
chemical aggregation of its ultimate parts or atoms. These molecules
are in a state of continual agitation, which is known as heat-motion.
The higher the temperature, the more violent this agitation; the total
quantity of motion is measured as _vis viva_ by the half-product of
the mass into the square of the velocity of molecular movement, or in
heat-units by the same product divided by Joule's equivalent. In
solids, the range of motion is circumscribed, and change of form
cannot take place. In fluids, the motion of the molecules has become
sufficiently violent to enable them to break out of this range, and
their motion is then no longer definitely restricted.

The laws of thermo-dynamics are, according to Rankine:

1. Heat-energy and mechanical energy are mutually convertible, one
British thermal unit being the equivalent in heat-energy of 772
foot-pounds of mechanical energy, and one metric _calorie_ equal to
423.55 kilogrammetres of work.

2. The energy due to the heat of each of the several equal parts into
which a uniformly hot substance may be divided is the same; and the
total heat-energy of the mass is equal to the sum of the energies of
its parts.[113]

  [113] This uniformity is not seen where a substance is changing its
  physical state while developing its heat-energy, as occurs with
  steam doing work while expanding.

It follows that the work performed by the transformation of the energy
of heat, during any indefinitely small variation of the state of a
substance as respects temperature, is measured by the product of the
absolute temperature into the variation of a "function," which
function is the rate of variation of the work so done with
temperature. This function is the quantity called by Rankine the
"heat-potential" of the substance for the given kind of work. A
similar function, which comprehends the total heat-variation,
including both heat transformed and heat needed to effect accompanying
physical changes, is called the "thermo-dynamic function." Rankine's
expression for the general equation of thermo-dynamics includes the
latter, and is given by him as follows:

  J_dh_ = _d_H = _kd_[tau] + [tau]_d_F = [tau]_d_[phi],

in which J is Joule's equivalent, _dh_ the variation of total heat in
the substance, _kd_[tau] the product of the "dynamic specific heat"
into the variation of temperature, or the total heat demanded to
produce other changes than a transformation of energy, and [tau]_d_F
is the work done by the transformation of heat-energy, or the product
of the absolute temperature, [tau], into the differential of the
heat-potential. [phi] is the thermo-dynamic function, and
[tau]_d_[phi] measures the whole heat needed to produce,
simultaneously, a certain amount of work or of mechanical energy, and,
at the same time, to change the temperature of the working substance.

Studying the behavior of gases and vapors, it is found that the work
done when they are used, like steam, in heat-engines, consists of
three parts:

(_a._) The change effected in the total actual heat-motion of the
fluid.

(_b._) That heat which is expended in the production of internal work.

(_c._) That heat which is expended in doing the external work of
expansion.

In any case in which the total heat expended exceeds that due the
production of work on external bodies, the excess so supplied is so
much added to the intrinsic energy of the substance absorbing it.

The application of these laws to the working of steam in the engine is
a comparatively recent step in the philosophy of the steam-engine, and
we are indebted to Rankine for the first, and as yet only, extended
and in any respect complete treatise embodying these now accepted
principles.

It was fifteen years after the publication of the first logical theory
of the steam-engine, by Pambour,[114] before Rankine, in 1859, issued
the most valuable of all his works, "The Steam-Engine and other Prime
Movers." The work is far too abstruse for the general reader, and is
even difficult reading for many accomplished engineers. It is
excellent beyond praise, however, as a treatise on the thermo-dynamics
of heat-engines. It will be for his successors the work of years to
extend the application of the laws which he has worked out, and to
place the results of his labors before students in a readily
comprehended form.

  [114] "Théorie de la Machine à Vapeur," par le Chevalier F. M. G. de
  Pambour, Paris, 1844.

William J. Macquorn Rankine, the Scotch engineer and philosopher, will
always be remembered as the author of the modern philosophy of the
steam-engine, and as the greatest among the founders of the science of
thermo-dynamics. His death, while still occupying the chair of
engineering at the University of Glasgow, December 24, 1872, at the
early age of fifty-two, was one of the greatest losses to science and
to the profession which have occurred during the century.




CHAPTER VIII.

_THE PHILOSOPHY OF THE STEAM-ENGINE._

ITS APPLICATION; ITS TEACHINGS RESPECTING THE CONSTRUCTION OF THE
ENGINE AND ITS IMPROVEMENT.

  "Oftentimes an Uncertaintie hindered our going on so merrily, but by
  persevering the Difficultie was mastered, and the new Triumph gave
  stronger Heart unto us."--RALEIGH.

  "If everything which we cannot comprehend is to be called an
  impossibility, how many are daily presented to our eyes! and in
  contemning as false that which we consider to be impossible, may we
  not be depreciating a giant's effort to give an importance to our
  own weakness?"--MONTAIGNE.

  "They who aim vigorously at perfection will come nearer to it than
  those whose laziness or despondency makes them give up its pursuit
  from the feeling of its being unattainable."--CHESTERFIELD.


As has been already stated, the steam-engine is a machine which is
especially designed to transform energy, originally dormant or
potential, into active and usefully available kinetic energy.

When, millions of years ago, in that early period which the geologists
call the carboniferous, the kinetic energy of the sun's rays, and of
the glowing interior of the earth, was expended in the decomposition
of the vast volumes of carbonic acid with which air was then charged,
and in the production of a life-sustaining atmosphere and of the
immense forests which then covered the earth with their almost
inconceivably luxuriant vegetation, there was stored up for the
benefit of the human race, then uncreated, an inconceivably great
treasure of potential energy, which we are now just beginning to
utilize. This potential energy becomes kinetic and available wherever
and whenever the powerful chemical affinity of oxygen for carbon is
permitted to come into play; and the fossil fuel stored in our
coal-beds or the wood of existing forests is, by the familiar process
of combustion, permitted to return to the state of combination with
oxygen in which it existed in the earliest geological periods.

The philosophy of the steam-engine, therefore, traces the changes
which occur from this first step, by which, in the furnace of the
steam-boiler, this potential energy which exists in the tendency of
carbon and oxygen to combine to form carbonic acid is taken advantage
of, and the utilizable kinetic energy of heat is produced in
equivalent amount, to the final application of resulting mechanical
energy to machinery of transmission, through which it is usefully
applied to the elevation of water, to the driving of mills and
machinery of all kinds, or to the hauling of "lightning" trains on our
railways, or to the propulsion of the Great Eastern.

The kinetic heat-energy developed in the furnace of the steam-boiler
is partly transmitted through the metallic walls which inclose the
steam and water within the boiler, there to evaporate water, and to
assume that form of energy which exists in steam confined under
pressure, and is partly carried away into the atmosphere in the
discharged gaseous products of combustion, serving, however, a useful
purpose, _en route_, by producing the draught needed to keep up
combustion.

The steam, with its store of heat-energy, passes through tortuous
pipes and passages to the steam-cylinder of the engine, losing more or
less heat on the way, and there expands, driving the piston before it,
and losing heat by the transformation of that form of energy while
doing mechanical work of equivalent amount. But this steam-cylinder is
made of metal, a material which is one of the best conductors of heat,
and therefore one of the very worst possible substances with which to
inclose anything as subtile and difficult of control as the heat
pervading a condensible vapor like steam. The process of internal
condensation and reëvaporation, which is the great enemy of economical
working, thus has full play, and is only partly checked by the heat
from the steam-jacket, which, penetrating the cylinder, assists by
keeping up the temperature of the internal surface and checking the
first step, condensation, which is an essential preliminary to the
final waste by reëvaporation. The piston, too, is of metal, and
affords a most excellent way of exit for the heat escaping to the
exhaust side.

Finally, all unutilized heat rejected from the steam-cylinder is
carried away from the machine, either by the water of condensation,
or, in the non-condensing engine, by the atmosphere into which it is
discharged.

Having traced the method of operation of the steam-engine, it is easy
to discover what principles are comprehended in its philosophy, to
learn what are known facts bearing upon its operation, and to
determine what are the directions in which improvement must take
place, what are the limits beyond which improvement cannot possibly be
carried, and, in some directions, to determine what is the proper
course to pursue in effecting improvements. The general direction of
change in the past, as well as at present, is easily seen, and it may
usually be assumed that there will be no immediate change of direction
in a course which has long been preserved, and which is well defined.
We may, therefore, form an idea of the probable direction in which to
look for improvement in the near future.

Reviewing the operations which go on in this machine during the
process of transformation of energy which has been outlined, and
studying it more in detail, we may deduce the principles which govern
its design and construction, guide us in its management, and determine
its efficiency.

In the furnace of the boiler, the quantity of heat developed in
available form is proportional to the amount of fuel burned. It is
available in proportion to the temperature attained by the products of
combustion; were this temperature no higher than that of the boiler,
the heat would all pass off unutilized. But the temperature produced
by a given quantity of heat, measured in heat-units, is greater as the
volume of gas heated is less. It follows that, at this point,
therefore, the fuel should be perfectly consumed with the least
possible air-supply, and the least possible abstraction of heat before
combustion is complete. High temperature of furnace, also, favors
complete combustion. We hence conclude that, in the steam-boiler
furnace, fuel should be burned completely in a chamber having
non-conducting walls, and with the smallest air-supply compatible with
thorough combustion; and, further, that the air should be free from
moisture, that greatest of all absorbents of heat, and that the
products of combustion should be removed from the furnace before
beginning to drain their heat into the boiler. A fire-brick furnace, a
large combustion-chamber with thorough intermixture of gases within
it, good fuel, and a restricted and carefully-distributed supply of
air, seem to be the conditions which meet these requisites best.

The heat generated by combustion traverses the walls which separate
the gases of the furnace from the steam and water confined within the
boiler, and is then taken up by those fluids, raising their
temperature from that of the entering "feed-water" to that due the
steam-pressure, and expanding the liquid into steam occupying a
greatly-increased volume, thus doing a certain amount of work, besides
increasing temperature. The extent to which heat may thus be usefully
withdrawn from the furnace-gases depends upon the conductivity of the
metallic wall, the rate at which the water will take heat from the
metal, and the difference of temperature on the two sides of the
metal. Extended "heating-surface," therefore, a metal of high
conducting power, and a maximum difference of temperature on the two
sides of the separating wall of metal, are the essential conditions of
economy here. The heating-surface is sometimes made of so great an
area that the temperature of the escaping gases is too low to give
good chimney-draught, and a "mechanical draught" is resorted to,
revolving "fan-blowers" being ordinarily used for its production. It
is most economical to adopt this method. The steam-boiler is generally
constructed of iron--sometimes, but rarely, of cast-iron, although
"steel," where not hard enough to harden or temper, is better in
consequence of its greater strength and homogeneousness of structure,
and its better conductivity. The maximum conductivity of flow of heat
for any given material is secured by so designing the boiler as to
secure rapid, steady, and complete circulation of the water within it.
The maximum rapidity of transfer throughout the whole area of
heating-surface is secured, usually, by taking the feed-water into the
boiler as nearly as possible at the point where the gases are
discharged into the chimney-flue, withdrawing the steam nearer the
point of maximum temperature of flues, and securing opposite
directions of flow for the gases on the one side and the water on the
other. Losses of heat from the boiler, by conduction and radiation to
surrounding bodies, are checked as far as possible by non-conducting
coverings.

The mechanical equivalent of the heat generated in the boiler is
easily calculated when the conditions of working are known. A pound of
pure carbon has been found to be capable of liberating by its perfect
combustion, resulting in the formation of carbonic acid, 14,500
British thermal units, equivalent to 14,500 × 772 = 11,194,000
foot-pounds of work, and, if burned in one hour, to 11194000/1980000 =
5.6 horse-power. In other words, with perfect utilization, but 10/56 =
0.177, or about one-sixth, of a pound of carbon would be needed per
hour for each horse-power of work done. But even good coal is not
nearly all carbon, and has but about nine-tenths this heat-producing
power, and it is usually rated as yielding about 10,000,000
foot-pounds of work per pound. The evaporative power of pure carbon
being rated at 15 pounds of water, that of good coal may be stated at
13-1/2. In metric measures, one gramme of good coal should evaporate
about 13-1/2 grammes of water from the boiling-point, producing the
equivalent of about 3,000,000 kilogrammetres of work from the 7,272
_calories_ of heat thus generated. A gramme of pure carbon generates
in its combustion 8,080 _calories_ of heat. Per hour and per
horse-power, 0.08, or less than one-twelfth, of a kilogram of carbon
burned per hour evolves heat-energy equal to one horse-power.

Of the coal burned in a steam-boiler, it rarely happens that more than
three-fourths is utilized in making steam; 7,500,000 foot-pounds
(1,036,898 kilogrammetres) is, therefore, as much energy as is usually
sent to the engine per pound of good coal burned in the steam-boiler.
The "efficiency" of a good steam-boiler is therefore usually not far
from 0.75 as a maximum. Rankine estimates this quantity for ordinary
boilers of good design and with chimney-draught at

          0.92
  E = ------------;
      1 + 0.5(F/S)

in which F/S is the ratio of weight of fuel burned per square foot of
grate to the ratio of heating to grate surface; this is a formula of
fairly close approximation for general practice.

The steam in the engine first drives the piston some distance before
the induction or steam valve is closed, and it then expands, doing
work, and condensing in proportion to work done as the expansion
proceeds, until it is finally released by the opening of the exhaust
or eduction valve. Saturated steam is modified in its action by a
process which has already been described, condensing at the beginning
and reëvaporating at the end of the stroke, thus carrying into the
condenser considerable quantities of heat which should have been
utilized in the development of power. Whether this operation takes
place in one cylinder or in several is only of importance in so far as
it modifies the losses due to conduction and radiation of heat, to
condensation and reëvaporation of steam, and to the friction of the
machine. It has already been seen how these losses are modified by the
substitution of the compound for the single-cylinder engine.

The laws of thermo-dynamics teach, as has been stated, that the
proportion of the heat-energy contained in the steam or other working
fluid which may be transformed into mechanical energy is a fraction
(H_{1} - H_{2})/H_{1}, of the total, in which H_{1} and H_{2} are the
quantities of heat contained in the steam at the beginning and at the
end of its operation, measuring from the absolute zero of heat-motion.
In perfect gases,

  H_{1} - H_{2}   [tau]_{1} - [tau]_{2}      T_{1} - T_{2}
  ------------- = --------------------- = --------------------
      H_{1}             [tau]_{1}         T_{1} + 461.2° Fahr.

but in imperfect gases, and especially in vapors which, like steam,
condense, or otherwise change their physical state, this equality may
still exist,

  (H_{1} - H_{2})/H_{1} = ([tau]_{1} - [tau]_{2})/[tau]_{1};

and the fluid is equally efficient with the
perfect gas as a working substance in a heat-engine. In any case it is
seen that the efficiency is greatest when the whole of the heat is
received at the maximum and rejected at the minimum attainable
temperatures.

Assuming this expression strictly accurate, a hot-air engine working
from 413.6° Fahr, or 874.8° absolute temperature, down to 122° Fahr,
or 583.2° absolute, should have an efficiency of 0.263, transforming
that proportion of available heat into mechanical work. The engines
of the steamer Ericsson closely approached this figure, and gave a
horse-power for each 1.87 pound of coal burned per hour.

Steam expands in the steam-cylinder quite differently under different
circumstances. If no heat is either communicated to it or abstracted
from it, however, it expands in an hyperbolic curve, losing its
tension much more rapidly than when expanded without doing work, in
consequence both of its change of volume and its condensation. The
algebraic expression for this method of expansion is, according to
Rankine, PV^{1.111} = C, a constant, or, according to other
authorities, from PV^{1.135} = C to PV^{1.140} = C. The greater the
value of the exponent of V, the greater the efficiency of the fluid
between any two temperatures. The maximum value has been found to be
given where the steam is saturated, but perfectly dry, at the
commencement of its expansion. The loss due to condensation on the
cooled interior surface of the cylinder at the commencement of the
stroke and the subsequent reëvaporation as expansion progresses is
least when the cylinder is kept hot by its steam-jacket and when least
time is given during the stroke for this transfer of heat between the
metal and the vapor.

It may be said that, all things considered, therefore, losses of heat
in the steam-cylinder are least when the steam enters dry, or
moderately superheated, where the interior surfaces are kept hottest
by the steam-jacket or by the hot-air jacket sometimes used, and where
piston-speed and velocity of rotation are highest.[115] The best of
compound engines, using steam of seventy-five pounds pressure and
condensing, usually require about two pounds of coal per
hour--20,000,000 foot-pounds of energy at the furnace--to develop a
horse-power, i. e., about ten times the heat-equivalent of the
mechanical work which they accomplish. Were the steam to expand like
the permanent gases, they would have a theoretical efficiency of about
one-quarter; actually, the efficiency is only one-tenth. The
steam-engine, therefore, utilizes about two-fifths the heat-energy
theoretically available with the best type of engine in general use.
By far the greater part, nearly all, in fact, of the nine-tenths
wasted is rejected in the exhaust steam, and can only be saved by some
such method as is hereafter to be suggested of retaining that heat and
returning it to the boiler.

  [115] In some cases, as in the Allen engine, the speed of piston has
  become very high, approaching 800((stroke)^{1/3}).

The mechanical power which has now been communicated to the mechanism
of the engine by the transfer of the kinetic energy of the hot steam
to the piston is finally usefully applied to whatever "mechanism of
transmission" forms the connection with the machinery driven by the
engine. In this transfer, there is some loss in the engine itself, by
friction. This is an extremely variable amount, and it can be made
very small by skillful design and good workmanship and management. It
may be taken at one-half pound per square inch of piston for good
engines of 100 horse-power and upward, but is often several pounds in
very small engines. It is least when the rubbing surfaces are of
different materials, but both of smooth, hard, close-grained metal,
well lubricated, and where advantage is taken of any arrangement of
parts which permits the equilibration of pressure, as on the
shaft-bearings of double and triple engines. The friction of a
steam-engine of large size and good design is usually between five and
seven per cent. of its total power. It increases rapidly as the size
of engine decreases.

Having now traced somewhat minutely the growth of the steam-engine
from the beginning of the Christian era to the present time, having
rapidly outlined the equally gradual, though intermittent, growth of
its philosophy, and having shown how the principles of science find
application in the operation of this wonderful machine, we are now
prepared to study the conditions which control the intelligent
designer, and to endeavor to learn what are the lessons taught us by
science and by experience in regard to the essential requisites of
efficient working of steam and economy in the consumption of fuel. We
may even venture to point out definitely the direction in which
improvement is now progressing as indicated by a study of these
requisites, and may be able to perceive the natural limits to such
progress, and possibly to conjecture what must be the character of
that change of type which only can take the engineer beyond the limit
set to his advance so long as he is confined to the construction of
the present type of engine.

First, we must consider the question: _What is the problem, stated
precisely and in its most general form, that engineers have been here
attempting to solve?_

After stating the problem, we will examine the record with a view to
determine what direction the path of improvement has taken hitherto,
to learn what are the conditions of efficiency which should govern the
construction of the modern steam-engine, and, so far as we may judge
the future by the past, by inference, to ascertain what appears to be
the proper course for the present and for the immediate future. Still
further, we will inquire, what are the conditions, physical and
intellectual, which best aid our progress in perfecting the
steam-engine.

This most important problem may be stated in its most general, yet
definite, form as follows:

_To construct a machine which shall, in the most perfect manner
possible, convert the kinetic energy of heat into mechanical power,
the heat being derived from the combustion of fuel, and steam being
the receiver and the conveyer of that heat._

The problem, as we have already seen, embodies two distinct and
equally important inquiries:

The first: What are the scientific principles involved in the problem
as stated?

The second: How shall a machine be constructed that shall most
efficiently embody, and accord with, not only those scientific
principles, but also all of those principles of engineering practice
that so vitally affect the economical value of every machine?

The one question is addressed to the man of science, the other to the
engineer. They can be satisfactorily answered, even so far as our
knowledge at present permits, after studying with care the scientific
principles involved in the theory of the steam-engine under the best
light that science can afford us, and by a careful study of the
various steps of improvement that have taken place and of accompanying
variations of structure, analyzing the effect of each change, and
tracing the reasons for them.

The theory of the steam-engine is too important and too extensive a
subject to be satisfactorily treated here in even the most concise
possible manner. I can only attempt a plain statement of the course
which seems to be pointed out by science as the proper one to pursue
in the endeavor to increase the economical efficiency of
steam-engines.

The teachings of science indicate that _success in economically
deriving mechanical power from the energy of heat-motion will, in all
cases, be the greater as we work between more widely separated limits
of temperature, and as we more perfectly provide against losses by
dissipation of heat in directions in which it is unavailable for the
production of power_.

Scientific research, as we have seen, has proved that, in all known
varieties of heat-engine, a large loss of effect is unavoidable from
the fact that we cannot, in the ordinary steam-engine, reduce the
lower limit of temperature, in working, below a point which is far
above the absolute zero of temperature--far above that point at which
bodies have no heat-motion. The point corresponding to the mean
temperature of the surface of the earth is above the ordinary lower
limit.

The higher the temperature of the steam when it enters the steam
cylinder, and the lower that which it reaches before the exhaust
occurs, the greater, science tells us, will be our success, provided
we at the same time avoid waste of heat and power.

Now, looking back over the history of the steam-engine, we may briefly
note the prominent improvements and the most striking changes of form,
and may thus endeavor to obtain some idea of the general direction in
which we are to look for further advance.

Beginning with the machine of Porta, at which point we may first take
up an unbroken thread, it will be remembered that we there found a
single vessel performing the functions of all the parts of a modern
pumping-engine; it was, at once, boiler, steam-cylinder, and
condenser, as well as both a lifting and a forcing pump.

The Marquis of Worcester divided the engine into two parts, using a
separate boiler.

Savery duplicated that part of the engine of Worcester which performed
the several parts of pump, steam-cylinder, and condenser, and added
the use of water to effect rapid condensation, perfecting, so far as
it was ever perfected, the steam-engine as a simple machine.

Newcomen and Calley next separated the pump from the steam-engine
proper, producing the modern steam-engine--the engine as a train of
mechanism; and in their engine, as in Savery's, we noticed the use of
surface condensation first, and subsequently that of the jet thrown
into the midst of the steam to be condensed.

Watt finally effected the crowning improvements, and completed the
movement o£ "differentiation" by separating the condenser from the
steam-cylinder. Here this process of change ceased, the several
important operations of the steam-engine now being conducted each in a
separate vessel. The boiler furnished the steam, the cylinder derived
from it mechanical power, and it was finally condensed in a separate
vessel, while the power which had been obtained from it in the
steam-cylinder was transmitted through still other parts, to the
pumps, or wherever work was to be done.

Watt, also, took the initiative in another direction. He continually
increased the efficiency of the machine by improving the proportions
of its parts and the character of its workmanship, thus making it
possible to render available many of those improvements in detail upon
which effectiveness is so greatly dependent and which are only useful
when made by a skillful workman.

Watt and his contemporaries also commenced that movement toward higher
pressures of steam and greater expansion which has been the most
striking feature noticed in the progress of steam-engineering since
his time. Newcomen used steam of barely more than atmospheric pressure
and raised 105,000 pounds of water one foot high with a pound of coal
consumed. Smeaton raised the pressure somewhat and increased the duty
considerably. Watt started with a duty double that of Newcomen and
raised it to 320,000 foot-pounds per pound of coal, with steam at 10
pounds pressure. To-day, Cornish engines of the same general plan as
those of Watt, but worked with 40 to 60 pounds of steam and expanding
three or four times, do a duty probably averaging, with the better
class of engines, 600,000 foot-pounds per pound of coal. The compound
pumping-engine runs the figure up to above 1,000,000.

The increase in steam-pressure and in expansion since Watt's time has
been accompanied by a very great improvement in workmanship--a
consequence, very largely, of the rapid increase in perfection, and in
the wide range of adaptation of machine-tools--by higher skill and
intelligence in designing engines and boilers, by increased
piston-speed, greater care in obtaining dry steam, and in keeping it
dry until thrown out of the cylinder, either by steam-jacketing or by
superheating, or both combined; it has further been accompanied by a
greater attention to the important matter of providing carefully
against losses by radiation and conduction of heat. We use, finally,
the compound or double-cylinder engine for the purpose of saving some
of the heat usually lost in internal condensation and reëvaporation,
and precipitation of condensed vapor from great expansion.

It is evident that, although there is a limit, tolerably well defined,
in the scale of temperature, below which we cannot expect to pass, a
degree gained in approaching this lower limit is more remunerative
than a degree gained in the range of temperature available by
increasing temperatures.[116]

  [116] The fact here referred to is easily seen if it is supposed
  that an engine is supplied with steam at a temperature of 400°
  above absolute zero and works it, without waste, down to a
  temperature of 200°. Suppose one inventor to adapt the engine to the
  use of steam of a range from 500° down to 200°, while another works
  his engine, with equally effective provision against losses, between
  the limits of 400° and 100°, an equal range with a lower mean. The
  first case gives an efficiency of one-half, the second three-fifths,
  and the third three-fourths, the last giving the highest effect.

Hence the attempt made by the French inventor, Du Trembly, about the
year 1850, and by other inventors since, to utilize a larger
proportion of heat by approaching more closely the lower limit, was in
accordance with known scientific principles.

We may summarize the result of our examination of the growth of the
steam-engine thus:

_First._ The process of improvement has been one, primarily, of
"differentiation;"[117] the number of parts has been continually
increased; while the work of each part has been simplified, a separate
organ being appropriated to each process in the cycle of operations.

  [117] This term, though perhaps not familiar to engineers, expresses
  the idea perfectly.

_Secondly._ A kind of secondary process of differentiation has, to
some extent, followed the completion of the primary one, in which
secondary process one operation is conducted partly in one and partly
in another portion of the machine. This is illustrated by the two
cylinders of the compound engine and by the duplication noticed in the
binary engine.

_Thirdly._ The direction of improvement has been marked by a continual
increase of steam-pressure, greater expansion, provision for obtaining
dry steam, high piston-speed, careful protection against loss of heat
by conduction or radiation, and, in marine engines, by surface
condensation.

The direction which improvement seems now to be taking, and the proper
direction, as indicated by an examination of the principles of
science, as well as by our review of the steps already taken, would
seem to be: working between the widest attainable limits of
temperature.

Steam must enter the machine at the highest possible temperature, must
be protected from waste, and must retain, at the moment before
exhaust, the least possible amount of heat. He whose inventive genius,
or mechanical skill, contributes to effect either the use of higher
steam with safety and without waste, or the reduction of the
temperature of discharge, confers a boon upon mankind.

In detail: In the engine, the tendency is, and may probably be
expected to continue, in the near future at least, toward higher
steam-pressure, greater expansion in more than one cylinder,
steam-jacketing, superheating, a careful use of non-conducting
protectors against waste, and the adoption of still higher
piston-speeds.

In the boiler: more complete combustion without excess of air passing
through the furnace, and more thorough absorption of heat from the
furnace-gases. The latter will probably be ultimately effected by the
use of a mechanically produced draught, in place of the far more
wasteful method of obtaining it by the expenditure of heat in the
chimney.

In construction we may anticipate the use of better materials, and
more careful workmanship, especially in the boiler, and much
improvement in forms and proportions of details.

In management, there is a wide field for improvement, which
improvement we may feel assured will rapidly take place, as it has now
become well understood that great care, skill, and intelligence are
important essentials to the economical management of the steam-engine,
and that they repay, liberally, all of the expense in time and money
that is requisite to secure them.

In attempting improvements in the directions indicated, it would be
the height of folly to assume that we have reached a limit in any one
of them, or even that we have approached a limit. If further progress
seems checked by inadequate returns for efforts made, in any case, to
advance beyond present practice, it becomes the duty of the engineer
to detect the cause of such hinderance, and, having found it, to
remove it.

A few years ago, the movement toward the expansive working of high
steam was checked by experiments seeming to prove positive
disadvantage to follow advance beyond a certain point. A careful
revision of results, however, showed that this was true only with
engines built, as was then common, in utter disregard of all the
principles involved in such a use of steam, and of the precautions
necessary to be taken to insure the gain which science taught us
should follow. The hinderances are mechanical, and it is for the
engineer to remove them.

The last remark is especially applicable to the work of the engineer
who is attempting to advance in the direction in which, as already
intimated, an unmistakable revolution is now progressing, the
modification of the modern steam-engine to adapt it safely and
successfully to run at the high piston-speed, and great velocity of
rotation which have been already attained and which must undoubtedly
be greatly exceeded in the future. As there is no known and definite
limit to the economical increase of speed, and as the limit set by
practical conditions is continually being set farther back as the
builder acquires greater skill and attains greater accuracy of
workmanship and the power to insure greater rigidity of parts and
durability of wearing surfaces, we must anticipate a continued and
indefinite progress in this direction--a progress which must evidently
be of advantage, whatever may be the direction that other changes may
take.

It is evident that this adaptation of the steam-engine to great speed
of piston is the work now to be done by the engineer. The requisites
to success are obvious, and may be concisely stated as follows:

1. Extreme accuracy in proportions.

2. Perfect accuracy in fitting parts to each other.

3. Absolute symmetry of journals.

4. Ample area and maximum durability of rubbing surfaces.

5. Perfect certainty of an ample and continuous lubrication.

6. A nicely calculated and adjusted balance of reciprocating parts.

7. Security against injury by shock, whether due to the presence of
water in the cylinder or to looseness of running parts.

8. A "positive-motion" cut-off gear.

9. A powerful but sensitive and accurately-working governor
determining the degree of expansion.[118]

  [118] The author is not absolutely confident on the latter point. It
  may be found more economical and satisfactory, ultimately, to
  determine the point of cut-off by an automatic apparatus adjusting
  the expansion-gear _by reference to the steam-pressure_, regulating
  the speed by attaching the governor elsewhere. The author has
  devised several forms of apparatus of the kind referred to.

10. Well-balanced valves and an easy-working valve-gear.

11. Small volume of "dead-space," or "clearance," and properly
adjusted "compression."

It would seem sufficiently evident that the engine with detachable
("drop") cut-off valve-gear must, sooner or later, become an obsolete
type, although the substitution of springs or of steam-pressure for
gravity in the closing of the detached valve may defer greatly this
apparently inevitable change. The "engine of the future" will not
probably be a "drop cut-off engine."

As regards the construction of the engine as a piece of mechanism, the
principles and practice of good engineering are precisely the same,
whether applied in the designing of the compound or of the ordinary
type of steam-engine. The proportioning of the two machines to each
other in such manner as to form an effective whole, by procuring
approximately equal amounts of work from both, is the only essential
peculiarity of compound-engine design which calls for especial care,
and the method of securing success in practice may be stated to be,
for both forms of engines, as follows:

1. A good design, by which is meant--

_a._ Correct proportions, both in general dimensions and in
arrangement of parts, and proper forms and sizes of details to
withstand safely the forces which may be expected to come upon them.

_b._ A general plan which embodies the recognized practice of good
engineering.

_c._ Adaptation to the specific work which it is intended to perform,
in size and in efficiency. It sometimes happens that good practice
dictates the use of a comparatively uneconomical design.

2. Good construction, by which is meant--

_a._ The use of good material.

_b._ Accurate workmanship.

_c._ Skillful fitting and a proper "assemblage" of parts.

3. Proper connection with its work, that it may do that work under the
conditions assumed in its design.

4. Skillful management by those in whose hands it is placed.

_In general_, it may be stated that, to secure maximum economical
efficiency, steam should be worked at as high a pressure as possible,
and the expansion should be fixed as nearly as possible at the point
of maximum economy for that pressure. In general, the number of times
which the volume of steam may be expanded in the standard
single-cylinder, high-pressure engine with maximum economy, is not far
from 1/2 sqrt(P), where P is the pressure in pounds per square inch;
it rarely exceeds 0.75 sqrt(P). This may be exceeded in
double-cylinder engines. It is even more disadvantageous to cut off
too short than to "'follow' too far." With considerable expansion,
steam-jacketing and moderate superheating should be adopted, to
prevent excessive losses by internal condensation and reëvaporation;
and expansion should take place in double cylinders, to avoid
excessive weight of parts, irregularity of motion, and great loss by
friction.

To secure this vitally important economy, it is advisable to seek some
practicable method of lining the cylinder with a non-conducting
material. This plan, as has been seen, was adopted by Smeaton, in
constructing Newcomen engines a century ago. Smeaton used wood on his
pistons, and Watt tried wood as a material for steam-cylinder linings.
That material is too perishable at temperatures now common, and no
metal has yet been substituted, or even discovered, which answers the
same purpose. The loss will also be reduced by increasing the speed of
rotation and velocity of piston. Where no effectual means can be found
of preventing contact of the steam with a good absorbent and conductor
of heat, it will be found best to sacrifice some of the efficiency due
to the change of state of the vapor, by superheating it and sending it
into the cylinder at a temperature considerably exceeding that of
saturation. With low steam and slowly-moving pistons, it is better to
pursue the latter course than to attempt to increase the efficiency of
the engine by greater expansion.

External surfaces should be carefully covered by non-conductors and
non-radiators, to prevent losses by conduction and radiation of heat.
It is especially necessary to reduce back-pressure and to obtain the
most perfect vacuum possible without overloading the air-pump, if it
is desired to obtain the maximum efficiency by expansion, and it then
becomes also very necessary to reduce losses by "dead-spaces" and by
badly-adjusted valves.

The piston-speed should be as great as can be sustained with safety.

Good engines should not require more than W = (200/sqrt(P)) where W =
the weight of steam per hour and per horse-power; the best practice
gives about W = (180/sqrt(P)) in large engines with dry steam, high
piston-speed, and good design, construction, and management.

The expansion-valve gear should be simple. The point of cut-off is
perhaps best determined by the governor. The valve should close
rapidly, but without shock, and should be balanced, or some other
device should be adopted to make it easy to move and free from
liability to cutting or rapid wear.

The governor should act promptly and powerfully, and should be free
from liability to oscillate, and to thus introduce irregularities
which are sometimes not less serious than those which the instrument
is intended to prevent.

Friction should be reduced as much as possible, and careful provision
should be made to economize lubricants as well as fuel.

The Principles of Steam-Boiler Construction are exceedingly simple;
and although attempts are almost daily made to obtain improved
results by varying the design and arrangement of heating-surface, the
best boilers of nearly all makers of acknowledged standing are
practically equal in merit, although of very diverse forms.

In making boilers, the effort of the engineer should evidently be:

1. To secure complete combustion of the fuel without permitting
dilution of the products of combustion by excess of air.

2. To secure as high temperature of furnace as possible.

3. To so arrange heating-surfaces that, without checking draught, the
available heat shall be most completely taken up and utilized.

4. To make the form of boiler such that it shall be constructed
without mechanical difficulty or excessive expense.

5. To give it such form that it shall be durable, under the action of
the hot gases and of the corroding elements of the atmosphere.

6. To make every part accessible for cleaning and repairs.

7. To make every part as nearly as possible uniform in strength, and
in liability to loss of strength by wear and tear, so that the boiler
when old shall not be rendered useless by local defects.

8. To adopt a reasonably high "factor of safety" in proportioning
parts.

9. To provide efficient safety-valves, steam-gauges, and other
appurtenances.

10. To secure intelligent and very careful management.

In securing complete combustion, the first of these desiderata, an
ample supply of air and its thorough intermixture with the combustible
elements of the fuel are essential; for the second--high temperature
of furnace--it is necessary that the air-supply shall not be in excess
of that absolutely needed to give complete combustion. The efficiency
of a furnace in making heat available is measured by

       T - T´
  E = -------;
      T - _t_

in which E represents the ratio of heat utilized to the whole
calorific value of the fuel, T is the furnace-temperature, T´ the
temperature of the chimney, and _t_ that of the external air. The
higher the furnace-temperature and the lower that of the chimney, the
greater the proportion of heat available. It is further evident that,
however perfect the combustion, no heat can be utilized if either the
temperature of the chimney approximates to that of the furnace, or if
the temperature of the furnace is reduced by dilution approximately to
that of the boiler. Concentration of heat in the furnace is secured,
in some cases, by special expedients, as by heating the entering air,
or as in the Siemens gas-furnace, heating both the combustible gases
and the supporter of combustion. Detached fire-brick furnaces have an
advantage over the "fire-boxes" of steam-boilers in their higher
temperature; surrounding the fire with non-conducting and highly
heated surfaces is an effective method of securing high
furnace-temperature.

In arranging heating-surface, the effort should be to impede the
draught as little as possible, and so to place them that the
circulation of water within the boiler should be free and rapid at
every part reached by the hot gases. The directions of circulation of
water on the one side and of gas on the other side of the sheet
should, whenever possible, be opposite. The cold water should enter
where the cooled gases leave, and the steam should be taken off
farthest from that point. The temperature of chimney-gases has thus
been reduced in practice to less than 300° Fahr., and an efficiency
equal to 0.75 to 0.80 the theoretical has been attained.

The extent of heating-surface simply, in all of the best forms of
boiler, determines the efficiency, and in them the disposition of that
surface seldom affects it to any great extent. The area of
heating-surface may also be varied within very wide limits without
very greatly modifying efficiency. A ratio of 25 to 1 in flue and 30
to 1 in tubular boilers represents the relative area of heating and
grate surfaces as chosen in the practice of the best-known builders.

The material of the boiler should be tough and ductile iron, or,
better, a soft steel containing only sufficient carbon to insure
melting in the crucible or on the hearth of the melting-furnace, and
so little that no danger may exist of hardening and cracking under the
action of sudden and great changes of temperature.

Where iron is used, it is necessary to select a somewhat hard, but
homogeneous and tough, quality for the fire-box sheets or any part
exposed to flames.

The factor of safety is invariably too low in this country, and is
never too high in Europe. Foreign builders are more careful in this
matter than our makers in the United States. The boiler should be
built strong enough to bear a pressure at least six times the proposed
working-pressure; as the boiler grows weak with age, it should be
occasionally tested to a pressure far above the working-pressure,
which latter should be reduced gradually to keep within the bounds of
safety. In the United States, the factor of safety is seldom more than
four in the new boilers, frequently much less, and even this is
reduced practically to one and a third by the operation of our
inspection-laws.

The principles just enunciated are those generally, perhaps
universally, accepted principles which are stated in all text-books of
science and of steam-engineering, and are accepted by both engineers
and men of science.

These principles are correct, and the deductions which have been here
formulated are rigidly exact, as applied to all types of heat-engine
in use; and they lead us to the determination, in all cases, of the
"modulus" of efficiency of the engine, i. e., to the calculation of
the ratio of its actual efficiency to that efficiency which it would
have, were it absolutely free from loss of heat by conduction or
radiation, or other method of loss of heat or waste of power, by
friction of parts or by shock.

The best modern marine compound engines sometimes, as we have seen,
consume as little as two pounds of coal per horse-power and per hour;
but this is but about one-tenth the power derivable from the fuel,
were all its heat thoroughly utilized. This loss may be divided thus:
70 per cent. rejected in exhausted steam; 20 per cent. lost by
conduction and radiation and by faults of mechanism and design; and
only the 10 per cent. remaining is utilized. Thirty per cent. of the
heat generated in the furnace is usually lost in the chimney, and of
the remainder, which enters the engine, 20 per cent. at most is all
which we can hope to save any portion of by improvements effected in
our best existing type of steam-engine. It has already been shown how
the engineer can best proceed in attempting this economy.

The direction in which further improvement must take place in the
standard type of engine is plainly that which shall most efficiently
check losses by internal condensation and reëvaporation by the
transfer of heat to and from the metal of the steam-cylinder. The
condensation of steam doing work is evidently not a disadvantage, but,
on the contrary, a decided advantage.

A new type of engine can, if at all, probably only supersede the
common form when engineers can employ steam of very high pressure, and
adopt much greater range of expansion than is now usual. Great
velocity of piston and high speed of rotation are also essential in
the attempt to make any revolution in steam-engine construction a
success.

When a new form of steam-engine is likely to be introduced, if at all,
can be scarcely even conjectured. It seems evident that its success is
to be secured, if a revolution is ever to occur, by the adoption of
high steam-pressures, of great piston speeds, by care and skill in
design, by the use of exceptionally excellent materials of
construction, by great perfection of workmanship, and by intelligence
in its management.

Experiment and experience will probably lead gradually to the general
and safe employment of much higher steam-pressures and very greatly
increased piston-speeds, and may ultimately reveal and remove all
those difficulties which must invariably be expected to be met here,
as in all other attempts to effect radical changes, however important
they may be.

[Illustration]


       *       *       *       *       *




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  which Sir John's mode of experiment differs from those of Huber,
  Forel, McCook, and others, is that he has carefully watched and
  marked particular insects, and has had their nests under observation
  for long periods--one of his ants' nests having been under constant
  inspection ever since 1874. His observations are made principally
  upon ants because they show more power and flexibility of mind; and
  the value of his studies is that they belong to the department of
  original research."

  "We have no hesitation in saying that the author has presented us
  with the most valuable series of observations on a special subject
  that has ever been produced, charmingly written, full of logical
  deductions, and, when we consider his multitudinous engagements, a
  remarkable illustration of economy of time. As a contribution to
  insect psychology, it will be long before this book finds a
  parallel."--_London Athenæum._


=DISEASES OF MEMORY=: An Essay in the Positive Psychology. By TH.
RIBOT, author of "Heredity," etc. Translated from the French by
William Huntington Smith. 12mo, cloth, $1.50.

  "M. Ribot reduces diseases of memory to law, and his treatise is of
  extraordinary interest."--_Philadelphia Press._

  "Not merely to scientific, but to all thinking men, this volume will
  prove intensely interesting."--_New York Observer._

  "M. Ribot has bestowed the most painstaking attention upon his
  theme, and numerous examples of the conditions considered greatly
  increase the value and interest of the volume."--_Philadelphia North
  American._

  "To the general reader the work is made entertaining by many
  illustrations connected with such names as Linnæus, Newton, Sir
  Walter Scott, Horace Vernet, Gustave Doré, and many
  others."--_Harrisburg Telegraph._

  "The whole subject is presented with a Frenchman's vivacity of
  style."--_Providence Journal._

  "It is not too much to say that in no single work have so many
  curious cases been brought together and interpreted in a scientific
  manner."--_Boston Evening Traveller._


=MYTH AND SCIENCE.= By TITO VIGNOLI. 12mo, cloth, price, $1.50.

  "His book is ingenious; ... his theory of how science gradually
  differentiated from and conquered myth is extremely well wrought
  out, and is probably in essentials correct."--_Saturday Review._

  "The book is a strong one, and far more interesting to the general
  reader than its title would indicate. The learning, the acuteness,
  the strong reasoning power, and the scientific spirit of the author,
  command admiration."--_New York Christian Advocate._

  "An attempt made, with much ability and no small measure of success,
  to trace the origin and development of the myth. The author has
  pursued his inquiry with much patience and ingenuity, and has
  produced a very readable and luminous treatise."--_Philadelphia
  North American._

  "It is a curious if not startling contribution both to psychology
  and to the early history of man's development."--_New York World._


=MAN BEFORE METALS.= By N. JOLY, Professor at the Science Faculty of
Toulouse; Correspondent of the Institute. With 148 Illustrations,
12mo. Cloth, $1.75.

  "The discussion of man's origin and early history, by Professor De
  Quatrefages, formed one of the most useful volumes in the
  'International Scientific Series,' and the same collection is now
  further enriched by a popular treatise on paleontology, by M. N.
  Joly, Professor in the University of Toulouse. The title of the
  book, 'Man before Metals,' indicates the limitations of the writer's
  theme. His object is to bring together the numerous proofs,
  collected by modern research, of the great age of the human race,
  and to show us what man was, in respect of customs, industries, and
  moral or religious ideas, before the use of metals was known to
  him."--_New York Sun._

  "An interesting, not to say fascinating volume."--_New York
  Churchman._


=ANIMAL INTELLIGENCE.= By GEORGE J. ROMANES, F. R. S., Zoölogical
Secretary of the Linnæan Society, etc. 12mo. Cloth, $1.75.

  "My object in the work as a whole is twofold: First, I have thought
  it desirable that there should be something resembling a text-book
  of the facts of Comparative Psychology, to which men of science, and
  also metaphysicians, may turn whenever they have occasion to
  acquaint themselves with the particular level of intelligence to
  which this or that species of animal attains. My second and much
  more important object is that of considering the facts of animal
  intelligence in their relation to the theory of descent."--_From the
  Preface._

  "Unless we are greatly mistaken, Mr. Romanes's work will take its
  place as one of the most attractive volumes of the 'International
  Scientific Series.' Some persons may, indeed, be disposed to say
  that it is too attractive, that it feeds the popular taste for the
  curious and marvelous without supplying any commensurate discipline
  in exact scientific reflection; but the author has, we think, fully
  justified himself in his modest preface. The result is the
  appearance of a collection of facts which will be a real boon to the
  student of Comparative Psychology for this is the first attempt to
  present systematically well-assured observations on the mental life
  of animals."--_Saturday Review._

  "The author believes himself, not without ample cause, to have
  completely bridged the supposed gap between instinct and reason by
  the authentic proofs here marshaled of remarkable intelligence in
  some of the higher animals. It is the seemingly conclusive evidence
  of reasoning; powers furnished by the adaptation of means to ends in
  cases which can not be explained on the theory of inherited aptitude
  or habit."--_New York Sun._


=THE SCIENCE OF POLITICS.= By SHELDON AMOS, M. A., author of "The
Science of Law," etc. 12mo. Cloth, $1.75.

  "To the political student and the practical statesman it ought to be
  of great value."--_New York Herald._

  "The author traces the subject from Plato and Aristotle in Greece,
  and Cicero in Rome, to the modern schools in the English field, not
  slighting the teachings of the American Revolution or the lessons of
  the French Revolution of 1793. Forms of government, political terms,
  the relation of law, written and unwritten, to the subject, a
  codification from Justinian to Napoleon in France and Field in
  America, are treated as parts of the subject in hand. Necessarily
  the subjects of executive and legislative authority, police, liquor,
  and land laws are considered, and the question ever growing in
  importance in all countries, the relations of corporations to the
  state."--_New York Observer._


=THE FUNDAMENTAL CONCEPTS OF MODERN PHILOSOPHIC THOUGHT, CRITICALLY
AND HISTORICALLY CONSIDERED.= By RUDOLPH EUCKEN, Ph. D., Professor in
Jena. With an Introduction by NOAH PORTER, President of Yale College.
One vol., 12mo, 304 pages. Cloth. Price, $1.75.

  President Porter declares of this work that "there are few books
  within his knowledge which are better fitted to aid the student who
  wishes to acquaint himself with the course of modern speculation and
  scientific thinking, and to form an intelligent estimate of most of
  the current theories."


=MIND IN THE LOWER ANIMALS IN HEALTH AND DISEASE.= By W. LAUDER
LINDSAY, M. D., F. R. S. E., etc. 2 vols., 8vo. Cloth, $4.00.

  "The author of this work, which, regarded merely as an accumulation
  of verified and classified facts, is a unique and precious
  contribution to the data of comparative psychology, claims that he
  entered on his inquiry without any theory to defend, support, or
  illustrate. We are bound to say that, while his general conclusions
  are boldly and continually avowed, his claim of fairness and caution
  is justified by his method of examining particular phenomena; that
  he seems willing at all times to renounce any impression or belief
  which is shown to be scientifically untenable."--_New York Sun._

  "In this work--two volumes of over 500 pages--Dr. Lindsay marshals a
  proportionately large number of facts against those philosophers who
  maintain that the intelligence of man differs in kind and not simply
  in degree from that of the lower animals. It is one purpose of his
  book to show that the main differences between man and the lower
  animals exist rather in their physical than in their mental
  structure. In this way of thinking, all animals possess not the
  semblance of, but the true substance of mind and will."--_New York
  World._

  "So far as we are aware there has been no treatise upon the subject
  of animal intelligence so broad in its foundations, so well
  considered, or so scientific in its methods of inquiry, as that
  which has been prepared by Dr. W. Lauder Lindsay in two large
  volumes, the first being devoted to a study of animal mind in
  health, and the second to animal mind in disease. We may safely say
  that his work is, in some respects, the most important essay of the
  kind that has yet been undertaken. His observations have been
  supplemented by a thorough mastery of the history and literature of
  the subject, and hence his conclusions rest upon the broadest
  possible foundation of safe induction. There is a good analytical
  index to the book, as there ought to be to every work of the
  kind."--_New York Evening Post._


=THE ELEMENTARY PRINCIPLES OF SCIENTIFIC AGRICULTURE.= By N. T.
LUPTON, LL. D., Professor of Chemistry in Vanderbilt University,
Nashville, Tenn. 18mo. Cloth. Price, 45 cents.


=A GLOSSARY OF BIOLOGICAL, ANATOMICAL, AND PHYSIOLOGICAL TERMS.= By
THOMAS DUNMAN. Small 8vo. Cloth. 161 pages. Price, $1.00.

  "It has been the author's task to furnish here a small and
  convenient but very complete glossary of those terms; and he has
  done this so well, both in his choice of terms for definition and in
  his clear exposition of their etymological and technical meaning, as
  to leave nothing to be desired in this direction."--_New York
  Evening Post._


   _For sale by all booksellers, or any work sent by mail, post-paid,
                         on receipt of price._

                      D. APPLETON & CO., Publishers,
                     1, 3, & 5 Bond Street, New York.




SCIENTIFIC LECTURES AND ESSAYS.


=Popular Lectures on Scientific Subjects.= By H. HELMHOLTZ, Professor
of Physics in the University of Berlin. First Series. Translated by E.
ATKINSON, Ph. D., F. C. S. With an Introduction by Professor TYNDALL.
With 51 Illustrations. 12mo. Cloth, $2.00.

  _CONTENTS._--On the Relation of Natural Science to Science in
  General.--On Goethe's Scientific Researches.--On the Physiological
  Causes of Harmony in Music--Ice and Glaciers.--Interaction of the
  Natural Forces.--The Recent Progress of the Theory of Vision.--The
  Conservation of Force.--Aim and Progress of Physical Science.


=Popular Lectures on Scientific Subjects.= By H. HELMHOLTZ. Second
Series. 12mo. Cloth, $1.50.

  _CONTENTS._--Gustav Magnus.--In Memoriam.--The Origin and
  Significance of Geometrical Axioms.--Relation of Optics to
  Painting.--Origin of the Planetary System.--On Thought in
  Medicine.--Academic Freedom in German Universities.

  "Professor Helmholtz's second series of 'Popular Lectures on
  Scientific Subjects' forms a volume of singular interest and value.
  He who anticipates a dry record of facts or a sequence of immature
  generalization will find himself happily mistaken. In style and
  method these discourses are models of excellence, and, since they
  come from a man whose learning and authority are beyond dispute,
  they may be accepted as presenting the conclusions of the best
  thought of the times in scientific fields."--_Boston Traveler._


=Science and Culture, and other Essays.= By Professor T. H. HUXLEY, F.
R. S. 12mo. Cloth, $1.50.

  "Of the essays that have been collected by Professor Huxley in this
  volume, the first four deal with some aspect of education. Most of
  the remainder are expositions of the results of biological research,
  and, at the same time, illustrations of the history of scientific
  ideas. Some of these are among the most interesting of Professor
  Huxley's contributions to the literature of science."--_London
  Academy._

  "It is refreshing to be brought into converse with one of the most
  vigorous and acute thinkers of our time, who has the power of
  putting his thoughts into language so clear and forcible."--_London
  Spectator._


=Scientific Culture, and other Essays.= By JOSIAH PARSONS COOKE,
Professor of Chemistry and Mineralogy in Harvard College. 12mo. Cloth,
$1.00.

  These essays are an outcome of a somewhat large experience in
  teaching physical science to college students. Cambridge,
  Massachusetts, early set the example of making the student's own
  observations in the laboratory or cabinet the basis of all teaching,
  either in experimental or natural history science; and this example
  has been generally followed. "But in most centers of education,"
  writes Professor Cooke, "the old traditions so far survive that the
  great end of scientific culture is lost in attempting to conform
  even laboratory instruction to the old academic methods of
  recitations and examinations. To point out this error, and to claim
  for science-teaching its appropriate methods, was one object of
  writing these essays."


       _For sale by all booksellers; or sent by mail, post-paid,
                       on receipt of price._

          New York: D. APPLETON & CO., 1, 3, & 5 Bond Street.