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SCIENTIFIC AMERICAN SUPPLEMENT NO. 711




NEW YORK, AUGUST 17, 1889

Scientific American Supplement. Vol. XXVIII., No. 711.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.


I.    AGRICULTURE.--How to Raise Turkeys.--A collection of hints
      and suggestions on the raising of the delicate fowls, so
      often the cause of trouble to farmers.                     11364

      Pear Duchesse D'Angouleme.--The history of the famous pear
      tree, with hints as to its culture and general treatment.  11362


II.   BIOLOGY.--Development of the Embryo.--A note of some
      interesting biological researches.--By Prof. PREYER,
      of Berlin.                                                 11365

      The "Hatchery" of the Sun Fish.--A curious incident in the
      life history of the common sunfish.--1 illustration.       11363

III.  CHEMISTRY.--On Allotropic Forms of Silver.--By M. CAREY
      LEA.--A continuation of this paper, containing one of the
      most important researches in the history of silver, with
      statement of interesting results attained.                 11361

      On the Occurrence of Paraffine in Crude Petroleum.--A
      valuable contribution to the history of paraffine, with
      reference to petroleum and ozokerite.                      11361

      Turpentine and its Products.--By EDWARD DAVIES.--A resume
      of the work done by chemists in the turpentine products.
      --The different compounds produced therefrom.              11361

IV.   ELECTRICITY.--Electric Lighting at the Paris Exhibition.
      --The Oerlikon works.--A very exhaustive exhibition of
      electric apparatus described and illustrated.--12
      illustrations.                                             11356

      Magnetism in its Relation to Induced Electromotive Force
      and Current.--By ELIHU THOMSON.--A most impressive paper,
      bringing the obscure laws of magnetic induction within the
      understanding of all without the application of
      mathematics.--12 illustrations.                            11354

      The Ader Flourish of Trumpets.--One of the curiosities in
      telephony from the Paris exhibition, by which sounds are
      transmitted to a large audience.--4 illustrations.         11358

      The Electric Motor Tests on the New York Elevated
      Railroad.--Abstracts of tests which were recently made of
      the Daft motor on the elevated railroad of this city.      11353

V.    ETHNOLOGY.--Ancient Lake Dwellings.--Interesting abstract
      of what is known about lake dwellings, the history of
      their construction, and the "finds" made on the sites by
      archæologists.                                             11363

VI.   FORESTRY.--Succession of Forest Growths.--A valuable paper
      on forestry, treating of the evils done by man and a plea
      for the necessity of intelligent treatment of our woods.   11362

VII.  HYGIENE AND MEDICINE.--Acetic Acid as a Disinfectant.--Use
      of acetic acid in septic medical cases as a substitute
      for carbolic acid and bichloride of mercury.               11365

      Counter-Irritation in Whooping Cough.--By G.F. INGLOTT,
      M.D.--Application of irritants to the skin for curing the
      paroxysms of whooping cough.                               11365

      On the Health Value to Man of the So-called Divinely
      Beneficent Gift, Tobacco.--By J.M.W. KITCHEN, M.D.--The
      evils to man and to the soil.--A formidable series of
      accusations well expressed.                                11365

      Water as a Therapeutical Agent.--By F.C. ROBINSON,
      M.D.--An interesting resume of different applications of
      water in therapeutics.--Suggestions of use for all
      households.                                                11364

VIII. MILITARY ENGINEERING.--Gibraltar.--A history of this
      important strategic position and of the different sieges
      the fortress has undergone.                                11352

      Gibraltar and Neighborhood.--A consular report on the
      statistics of the famous military station.                 11352

      The Defense of Gibraltar--Experimental Naval and Military
      Operations.--Interesting series of operations recently
      carried out under the shadow of the historic rock.--1
      illustration.                                              11352

IX.   NAVAL ENGINEERING.--Clark's Gyroscopic Torpedoes.--A
      recent torpedo, in which all the possible parts are made
      to rotate.--2 illustrations.                               11353

      The First Steamboat on the Seine.--The Marquis de
      Jouffroy's steamer of 1816.--1 illustration.               11353

      The Franz Josef I., New War Ship.--Details of the
      dimensions of the new Austrian ship.--Her armament,
      speed, armor, etc.                                         11353

X.    PHOTOGRAPHY.--Orthochromatic Photography.--By OSCAR O.
      LITZKOW.--The last developments in this interesting
      branch of photographic art, with formulæ.                  11360

      Platinotype Printing.--A description of the most advanced
      method of conducting the platinum print process.           11360

XI.   PHYSICS.--Iridescent Crystals.--By LORD RAYLEIGH.--An
      abstract of a lecture by the distinguished physicist,
      detailing some interesting experiments applicable to the
      colored reflection observed in crystals of chloride of
      potash.--1 illustration.                                   11366

       Transmission of Pressure in Fluids.--By ALBERT B.
      PORTER.--An apparatus for illustrating the laws of
      transmission of pressure in fluids, suitable for lecture
      purposes.--1 illustration.                                 11362

       XII. TECHNOLOGY.--Notes on Dyewood Extracts and Similar
      Preparations.--By LOUIS SIEBOLD.--The recent development
      in the preparation of dyewood extracts, with notes of
      their adulterations.                                       11359

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THE DEFENSE OF GIBRALTAR: EXPERIMENTAL NAVAL AND MILITARY
OPERATIONS.


[Illustration: THE DEFENSE OF GIBRALTAR--EXPERIMENTAL NAVAL AND
MILITARY OPERATIONS.]

A novel and interesting series of operations was carried out at
Gibraltar a few weeks ago, with a view to test the promptitude with
which the garrison of the famous Rock could turn out to resist a
sudden attack by a powerful iron-clad fleet. The supposed enemy was
represented by the Channel Squadron, under the command of Vice-Admiral
Baird, and consisting of H.M.S. Northumberland (flag ship), the
Agincourt, Monarch, Iron Duke, and Curlew. The "general idea" of the
operations was that a hostile fleet was known to be cruising in the
vicinity, and that an attack on the Rock might be made. The squadron
left Gibraltar and proceeded to the westward, returning to the
eastward through the Straits under cover of the night.

The Governor of Gibraltar, General the Hon. Sir Arthur Hardinge,
issued orders for the whole garrison to stand to their arms at dawn,
and subsequent days, until the attack should be made; but by his
express command no batteries were to be manned, or any troops moved
from their alarm posts, until the signal was given that an attack was
imminent. The alarm signal ordered was that of three guns fired in
rapid succession from the Upper Signal Station on the summit of the
Rock, to be followed, after a short pause, by two more shots. It was a
matter of complete uncertainty as to the direction from which the
attack would be made.

Every detail was carefully carried out, as if the impending attack was
a real affair. The telegraphic communication between the various parts
of the Rock was supplemented by signalers; arrangements were made for
the ready supply of reserve ammunition for all arms; and the medical
authorities established dressing stations, at numerous points of the
Rock, to render "first aid" to those who might chance to be numbered
among the "wounded." Day broke with a "Levanter," and the heavy clouds
hanging about rendered any distant view a matter of difficulty.
However, before it had become actually daylight the alarm guns gave
notice that the enemy had been sighted. The troops turned out with
great promptitude, being all at their assigned stations in less than a
quarter of an hour, and were shortly ordered to various points
commanding the east side of the Rock. As day broke, the hostile ships
were to be discerned steaming in single line ahead, from the northeast,
along the back of the Rock, and about 5,000 yards from it. The flag
ship, followed by the Monarch and the Agincourt, proceeded toward
Europa Point, while the Iron Duke and the Curlew stood close in to the
eastern beach, so as to engage the northern defenses of the fortress.
The first shot was fired by the flag ship, shortly before six o'clock
in the morning, at the southern defenses. It was replied to, in less
than three minutes, by the Europa batteries, and very shortly the
engagement became general. The plan of tactics employed by the
squadron was that of steaming rapidly up and down, and concentrating
their fire in turn on the various shore batteries. Later on, the whole
squadron assembled off Europa Point, and fired broadsides by
electricity as they steamed past at speed. The spectacle at this
moment was a very fine one, the roar of the heavy guns of the ships
being supplemented by the sharp, rapid report of the quick-firing
guns, which were supposed to be sending a storm of small shell among
the defenders of the Rock. The incessant rattle of the ships' machine
guns was also heard in the intervals between the thundering broadsides
of heavy ordnance. All the ships were, of course, cleared for action,
with topmasts and yards sent down, and it is needless to say they
looked exceedingly workmanlike and formidable.

The various batteries on the Rock replied with great vivacity, and the
general effect produced as gun after gun was brought to bear on the
ships, and the white smoke wreathed itself round the many crags and
precipices of the grim old Rock, was a sight long to be remembered.
The exercise afforded to both branches of the service was undoubtedly
most instructive. Our illustration is a sketch by Captain Willoughby
Verner from one of the batteries above the Europa Flats, at which
point the governor took up his position to watch the operations.
--_Illustrated London News._

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GIBRALTAR AND NEIGHBORHOOD.

REPORT BY CONSUL SPRAGUE.


Notwithstanding that the political situation of Europe seems to be
less threatening among its leading powers, still the uncertainty
prevalent among those who are generally considered the arbiters of
public affairs has had its influence in contracting the limits of
speculative adventure, thereby circumscribing the general course of
trade throughout the Mediterranean.

In renewing to the department my reports upon the navigation and
general commerce of Gibraltar, I beg to state that there has been a
tolerably fair current business prevailing in American produce during
the past quarter, consisting chiefly in flour, tobacco, and refined
petroleum in cases, imported direct from New York.

The steady demand for American petroleum confirms the fact that
Russian petroleum so far receives but little attention in this market
from the regular traders and consumers, so long as supplies from the
United States can be regularly imported at reasonable prices. It,
however, remains an open question, in the event of lower prices ruling
in the Russian petroleum regions, whether American supplies may not
later on experience some greater competitive foreign interference.

According to the statistical data, steam vessels of all nationalities
have continued to make Gibraltar their port of call, not only for
orders, but also for replenishing their stock of fuel and provisions,
and in larger numbers than ever before, the number in 1888 having
reached 5,712 steam vessels, measuring in all 5,969,563 tons, while in
1887 the number was only 5,187 steam vessels, with an aggregate
tonnage of 5,372,962. This increase cannot but result in considerable
benefit to the coal and maritime traffic, which now forms the most
important portion of the general commerce of Gibraltar, in spite of
the keen competition it experiences from other British and foreign
coaling ports.

Freights have also advanced in favor of steamship interests, which,
with higher prices in England for coal, have also caused an advance in
the price of coal at this port, to the benefit of the coal merchants
and others interested in this important trade. At present the ruling
price for steam coal is 24s. per ton, deliverable from alongside of
coal hulks moored in the bay. As near as I have been able to
ascertain, the quantity of coal sold in this market during the past
year for supplying merchant steam vessels has amounted to about
508,000 tons, which is an increase of about 20,000 tons over the year
1887.

Notwithstanding that plans have already been submitted to the British
government for the construction of a dry dock in Gibraltar, the matter
remains somewhat in suspense, since it meets with some opposition on
the part of the British government, which, in face of the European
fever for general arming, seems more inclined to utilize in another
form the expense which such a work would entail upon the imperial
government, by replacing the obsolete ordnance recently removed from
this fortress and substituting new defenses and guns of the most
approved patterns, a matter which has evidently been receiving, for
some time past, the special attention of the British military
authorities, not doubting that the recent visit to the fortress of the
Duke of Cambridge has had some connection with it. In fact, it is
reported that the duke has already expressed the opinion that this
fortress requires a larger number of artillerymen than are quartered
here at present to man its batteries, and it would seem that this
recommendation is likely to be carried out.

It is yet somewhat too early to venture an opinion regarding the
growing crops of cereals in this Spanish neighborhood, but the
agricultural and manufacturing interests in Spain have suffered so
much in the past years that the general feeling in Spain continues to
tend toward establishing increased restrictions against foreign
competition in her home markets. There is every probability that the
provinces of Malaga and Granada may shortly be granted the privilege
of cultivating the tobacco plant under government supervision, as an
essay. If properly managed, it may form an important and lucrative
business for those interested in land and agricultural pursuits.

After many consecutive years of heavy outlays, difficulties, and
constant disappointments, a new English company has recently succeeded
in commencing the construction of a railway from the neighboring
Spanish town of Algeciras to join, via Ronda, the railway station of
Bobadilla, on the railroad line toward Malaga. It is presumed that
when this railroad will be in running order it will greatly benefit
this community, especially if the Spanish government should decide to
establish custom houses at Algeciras and the Spanish lines outside the
gates of this fortress, similar to those existing on the frontiers of
France and Portugal.

That some idea may be formed of the constant important daily
intercourse which exists between this fortress and Spain, I may state
that late police statistics show that 1,887,617 passes were issued to
visitors entering this fortress on daily permits during the year 1888,
1,608,004 entering by the land route and 279,613 by sea. I must,
however, observe that the larger portion of these visitors consists of
laborers, coal heavers, market people, and others engaged in general
traffic.

A new industry in cork has lately sprung up, in which leading Spanish
and native commercial firms in Gibraltar are directly interested to a
considerable extent. Extensive warehouses for the storing of cork wood
and machinery for the manufacture of bottle corks have recently been
established at the Spanish lines, about a mile distant from this
fortress, in Spanish territory, where large quantities of cork have
already been stored. The cork is obtained and collected from the
valuable trees, which are owned by the representatives of some of the
oldest nobility of Spain, who have sold the products of their
extensive woods to private individuals for periods reaching as far on
as ten years, for which concession large cash advances have already
been made. The woods commence at a distance of about twelve miles from
Gibraltar, and are of considerable extent.

The railway now in course of construction passes through these woods,
which may ere long offer quite picturesque scenery for travelers,
especially when the cork trees are bearing acorns, which form the
principal food for the fattening of large herds of swine during
certain seasons of the year, in this way, also, contributing to the
value of this tree, which, like the other kinds of oak trees, is of
long and tardy growth. The tree from which the cork is obtained is
somewhat abundant in the mountainous districts of Andalusia. It grows
to a height of about 30 feet, and resembles the _Quercus ilex_, or
evergreen oak, and attains to a great age. After arriving at a certain
state of maturity it periodically sheds its bark, but this bark is
found to be of better quality when artificially removed from the tree,
which may be effected without injury to the tree itself. After the
tree has attained twenty-five years it may be barked, and the
operation is afterward repeated once in every seven years. The quality
of the cork seems to improve with the increasing age of the tree,
which is said to live over one hundred and fifty years. The bark is
taken off during July and August.

Cork dust is also obtained from this cork wood, and is much used in
the packing of grapes, which fruit is largely shipped from the eastern
coast of Spain, especially from Almeria, during the vintage seasons,
for the American and British markets.--_Reports of U.S. Consuls._

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GIBRALTAR.


The point or rock known as Gibraltar is a promontory two and one-half
miles long and from a quarter to three-quarters of a mile wide. It
rises abruptly from the sandy shore to a height at its highest point
of 1,408 ft. It is composed of gray limestone, honeycombed with caves
and subterranean passages, some of which contain most beautiful
stalactites in the form of massive pillars.

Gibraltar is emphatically a fortress, and in some respects its
fortifications are unique. On the eastern side the rock needs no
defense beyond its own precipitous cliffs, and in all other directions
it has been rendered practically impregnable. Besides a sea wall
extending at intervals round the western base of the rock, and
strengthened by curtains and bastions and three formidable forts,
there are batteries in all available positions from the sea wall up to
the summit, 1,350 feet above the sea, and a remarkable series of
galleries has been hewn out of the solid face of the rock toward the
north and northwest. These galleries have an aggregate length of
between two and three miles, and their breadth is sufficient to let a
carriage pass. Portholes are cut at intervals of twelve yards, so
contrived that the gunners are safe from the shot of any possible
assailants. At the end of one of the galleries hollowed out in a
prominent part of the cliff is St. George's Hall, 50 feet long by 85
feet wide, in which the governor was accustomed to give fetes.
Alterations, extensions, and improvements are continually taking place
in the defensive system, and new guns of the most formidable sort are
gradually displacing or supplementing the old fashioned ordnance.

The whole population of Gibraltar, whether civil or military, is
subjected to certain stringent rules. For even a day's sojourn the
alien must obtain a pass from the town major, and if he wish to remain
longer, a consul or householder must become security for his good
behavior. Licenses of residence are granted only for short
periods--ten, fifteen, or twenty days--but they can be renewed if
occasion require. Military officers may introduce a stranger for
thirty days. A special permit is necessary if the visitor wishes to
sketch.

Though the town of Gibraltar may be said to date from the fourteenth
century, it has preserved very little architectural evidence of its
antiquity. Rebuilt on an enlarged and improved plan after its almost
complete destruction during the great siege, it is still, on the
whole, a mean-looking town, with narrow streets and lanes and an
incongruous mixture of houses after the English and the Spanish types.
As a proprietor may at any moment be called upon to give up his house
and ground at the demand of the military authorities, he is naturally
deterred from spending his money on substantial or sumptuous
erections. The area of the town is about one hundred acres.

Gibraltar was known to the Greek and Roman geographers as Calpe or
Alybe, the two names being probably corruptions of the same local
(perhaps Phenician) word. The eminence on the African coast near
Ceuta, which bears the modern English name of Apes' Hill, was then
designated Abyla; and Calpe and Abyla, at least according to an
ancient and widely current interpretation, formed the renowned pillars
of Hercules (Herculis columnæ), which for centuries were the limits of
enterprise to the seafaring peoples of the Mediterranean world.

The strategic importance of the rock appears to have been first
discovered by the Moors, who, when they crossed over from Africa in
the eighth century, selected it as the site of a fortress. From their
leader, Tarik Ibn Zeyad, it was called Gebel Tarik or Tarik's Hill;
and, though the name had a competitor in Gebel af Futah, or Hill of
the Entrance, it gradually gained acceptance, and still remains
sufficiently recognizable in the corrupted form of the present day.
The first siege of the rock was in 1309, when it was taken by Alonzo
Perez de Guzman for Ferdinand IV. of Spain, who, in order to attract
inhabitants to the spot, offered an asylum to swindlers, thieves, and
murderers, and promised to levy no taxes on the import or export of
goods. The attack of Ismail Ben Ferez, in 1315 (second siege), was
frustrated; but in 1333 Vasco Paez de Meira, having allowed the
fortifications and garrison to decay, was obliged to capitulate to
Mahomet IV. (third siege). Alphonso's attempts to recover possession
(fourth siege) were futile, though pertinacious and heroic, and he was
obliged to content himself with a tribute for the rock from Abdul
Melek of Granada; but after his successful attack on Algeciras in 1344
he was encouraged to try his fortune again at Gibraltar. In 1349 he
invested the rock, but the siege (fifth siege) was brought to an
untimely close by his death from the plague in February, 1350. The
next or sixth siege resulted simply in the transference of the coveted
position from the hands of the King of Morocco to those of Yussef III.
of Granada; and the seventh, undertaken by the Spanish Count of
Niebla, Enrico de Guzman, proved fatal to the besieger and his forces.
In 1462, however, success attended the efforts of Alphonso de Arcos
(eighth siege), and in August the rock passed once more under
Christian sway. The Duke of Medina Sidonia, a powerful grandee who had
assisted in its capture, was anxious to get possession of the
fortress, and though Henry IV. at first managed to maintain the claims
of the crown, the duke ultimately made good his ambition by force of
arms (ninth siege), and in 1469 the king was constrained to declare
his son and his heirs perpetual governors of Gibraltar. In 1479
Ferdinand and Isabella made the second duke Marquis of Gibraltar, and
in 1492 the third duke, Don Juan, was reluctantly allowed to retain
the fortress. At length, in 1501, Garcilaso de la Vega was ordered to
take possession of the place in the king's name, and it was formally
incorporated with the domains of the crown. After Ferdinand and
Isabella were both dead the duke, Don Juan, tried in 1506 to recover
possession, and added a tenth to the list of sieges. Thirty-four years
afterward the garrison had to defend itself against a much more
formidable attack (eleventh siege)--the pirates of Algiers having
determined to recover the rock for Mahomet and themselves. The
conflict was severe, but resulted in the repulse of the besiegers.
After this the Spaniards made great efforts to strengthen the place,
and they succeeded so well that throughout Europe Gibraltar was
regarded as impregnable.

In the course of the war of the Spanish succession, however, it was
taken by a combined English and Dutch fleet under Sir George Rooke,
assisted by a body of troops under Prince George of Hesse-Darmstadt.
The captors had ostensibly fought in the interests of Charles Archduke
of Austria (afterward Charles III.), but, though his sovereignty over
the rock was proclaimed on July 24, 1704, Sir George Rooke on his own
responsibility caused the English flag to be hoisted, and took
possession in name of Queen Anne. It is hardly to the honor of England
that it was both unprincipled enough to sanction and ratify the
occupation and ungrateful enough to leave unrewarded the general to
whose unscrupulous patriotism the acquisition was due. The Spaniards
keenly felt the injustice done to them, and the inhabitants of the
town of Gibraltar in great numbers abandoned their homes rather than
recognize the authority of the invaders. In October, 1704, the rock
was invested by sea and land; but the Spanish ships were dispersed by
Sir John Leake, and the Marquis of Villadarias fared so ill with his
forces that he was replaced by Marshal Tesse, who was at length
compelled to raise the siege in April, 1705. During the next twenty
years there were endless negotiations for the peaceful surrender of
the fortress, and in 1726 the Spaniards again appealed to arms. But
the Conde de la Torres, who had the chief command, succeeded no better
than his predecessors, and the defense of the garrison under General
Clayton and the Earl of Portmore was so effectual that the armistice
of June 23 practically put a close to the siege, though two years
elapsed before the general pacification ensued. The most memorable
siege of Gibraltar, indeed one of the most memorable of all sieges,
was that which it sustained from the combined land and sea forces of
France and Spain during the years 1779-1783. The grand attack on the
place was made on the 13th September, 1782, and all the resources of
power and science were exhausted by the assailants in the fruitless
attempt. On the side of the sea they brought to bear against the
fortress forty-six sail of the line and a countless fleet of gun and
mortar boats. But their chief hope lay in the floating batteries
planned by D'Arcon, an eminent French engineer, and built at the cost
of half a million sterling. They were so constructed as to be
impenetrable by the red hot shot which it was foreseen the garrison
would employ; and such hopes were entertained of their efficiency that
they were styled invincible. The Count D'Artois (afterward Charles X.)
hastened from Paris to witness the capture of the place. He arrived in
time to see the total destruction of the floating batteries and a
considerable portion of the combined fleet by the English fire.
Despite this disaster, however, the siege continued till brought to a
close by the general pacification, February 2, 1783. The history of
the four eventful years' siege is fully detailed in the work of
Drinkwater, who himself took part in the defense, and in the life of
its gallant defender Sir George Augustus Eliott, afterward Lord
Heathfield, whose military skill and moral courage place him among the
best soldiers and noblest men whom Europe produced during the 18th
century.

Since 1783 the history of Gibraltar has been comparatively uneventful.
In the beginning of 1801 there were rumors of a Spanish and French
attack, but the Spanish ships were defeated off Algeciras in June by
Admiral Saumarez. Improvements in the fortifications, maintenance of
military discipline, and legislation in regard to trade and smuggling
are the principal matters of recent interest.

       *       *       *       *       *




THE FRANZ JOSEF I., NEW WAR SHIP.


Another addition was made to the Austrian navy by the launching on May
18 of the ram cruiser Franz Josef I. from the yards of S. Rocco in the
Stabilimento Tecnico Triestino. Her dimensions are: Length (over all),
103.7 meters; length (between perpendiculars), 97.9 meters; greatest
breadth (outside), 14.8 meters; draught (bow), 5.28 meters; draught
(stern), 6.05 meters; displacement on the construction water line,
4,000 tons. The armament consists of two 24-centimeter and six
15-centimeter Krupp breech loaders of 35 caliber length, two
7-centimeter Uchatius guns as an armament for the boats and for
landing purposes, eleven Hotchkiss quick-firing guns, and several
torpedo-launching ports; indicated horse power with natural draught
6,400, speed 17.5 knots; with forced draught 9,800, speed 19 knots.

The ship is built of steel, and constructed according to the "double
bottom" system along the engine, boiler, and ammunition rooms. The
vaulted armor deck, extending 1.25 meters below the water line and
protecting the most vital parts of the ship, is 0.057 meter thick.
There are more than 100 water tight compartments below and above the
deck. A protecting belt of "cellulose" is provided for the engines and
boilers, extending from the armor deck downward.

The two main guns, placed on Krupp's hydraulic carriages, occupy
positions in front and rear, and are protected by stands 0.09 meter
thick and 1.60 meters high. They fire _en barbette_ with a lateral
range each of 260 degrees at bow and stern--i.e., 130 degrees on
either of the broadsides. The weight of the barrel of the gun is 25
tons, that of the steel shell 215 kilogrammes (about 430 lb.), that of
the brown powder charge 100 kilogrammes; initial velocity of
projectile, 610 meters; penetration, 0.524 meter iron; longest range,
17 kilometers (about 10½ English miles); range at 15 deg. elevation,
10 kilometers. The six 15-centimeter guns are placed in a kind of
machicouli arrangement in two tiers on each of the broadsides, so that
always four guns can fire in the direction of the keel to the front
and rear. The weight of the barrel of the gun is each six tons, that
of the steel shells 51 kilogrammes, that of the charge 22 kilogrammes;
initial velocity, 610 meters.

The 11 quick-firing guns are partly placed along the broadsides,
partly in the masts, of which there are two. The triple expansion
engines, having each a bronze screw of 4.42 meters diameter, with
three blades and a rise of 6.3 meters, make with natural draught 105
revolutions, and with forced draught 120. The pumping apparatus are
able to lift in one hour 400 tons of water. The front boiler room
contains a special cylindrical boiler for the working of the
electrical apparatus, for hydraulic pumps of the artillery service,
for anchor windlasses, ventilators, fire engines, etc. The whole
engines weigh 890 tons. The bunkers have a capacity for 660 tons of
coal, which allows for a run of 4,500 sea miles.

       *       *       *       *       *




CLARK'S GYROSCOPIC TORPEDOES.


Figs. 1 and 2 represent, upon a scale of about 1/10, two types of
torpedoes, the greatest number possible of the parts of which are made
revolvable, so as to render the torpedoes as dirigible as the gyrating
motion permits of.

Fig. 1 represents an electric torpedo actuated by accumulators, A A,
keyed upon the shaft, and revolving along with the gearings. At the
beginning of the running, the accumulators are not all coupled, but
under the action of a clockwork movement which is set in motion at the
moment of starting, metallic brushes descend one after another upon
the collectors, B, and set in action new batteries for keeping
constant or, if need be, accelerating the speed at the end of the
travel.

[Illustration: Fig. 1.]

[Illustration: Fig. 2. CLARK'S GYROSCOPIC TORPEDOES.]

Fig. 2 represents an air torpedo proposed by the same inventor. The
air reservoir, C, revolves along with the gearings under the action
of the pneumatic machine, D. The central shaft is hollow, so as to
serve as a conduit. The admission of air into the slide valve of the
machine is regulated by a clockwork which actuates a slide in an
aperture whose form and dimensions are so calculated that the speed
remains as constant as possible toward the end of the travel.

The trajectory of the two torpedoes is regulated by a cylindrical
bellows, F, which gives entrance to the sea water. The springs shown
in the figure balance the hydraulic pressure. The tension of these
springs is regulated by the rod, H, according to the indications of
the scale of depths, I.

When the torpedo reaches too great a depth, the action of the springs
can no longer balance the increase of the hydraulic pressure, and the
accumulation of the charge in the rear causes the front to rise toward
the surface. When the torpedo reaches the surface, a contrary action
is produced.--_Revue Industrielle._

       *       *       *       *       *




THE FIRST STEAMBOAT ON THE SEINE.


[Illustration: FIRST STEAMBOAT BUILT ON THE SEINE.]

The accompanying engraving represents the remarkable steamboat that
the unfortunate Marquis de Jouffroy constructed at Paris in 1816,
after organizing a company for the carriage of passengers on the
Seine. De Jouffroy, as well known, made the first experiment in steam
navigation at Lyons in 1783, but the inventor's genius was not
recognized, and he met with nothing but deception and hostility. With
the obstinacy of men of conviction, he did not cease to prosecute his
task. He assuredly had an inkling of the future in store for the
invention that he was offering to humanity.

The paddle wheel boat that he constructed at Paris in 1816 did not
succeed any better than its predecessors; it was remarkable
nevertheless in appearance and structure.

The engine was forward, as shown in the engraving, which is copied
from a composition of Dubucourt's.

The company organized by the marquis was ruined, and, as well known,
the unfortunate inventor himself died in poverty in 1832, at the age
of eighty-one years.--_La Nature._

       *       *       *       *       *




THE ELECTRIC MOTOR TESTS ON THE NEW YORK ELEVATED RAILROAD.


The American Institute of Electrical Engineers at its last meeting of
the season, held June 25, again considered the subject of electrical
traction, the paper presented by Mr. Leo Daft being based upon some
recent electrical work on the elevated railroads and its bearing on
the rapid transit problem. The _Railroad Gazette_ gives the following
abstract:

    He introduced the subject with a tribute to the efficiency of
    the elevated railroad system as it is now operated by steam,
    with special reference to that section of it known as the Ninth
    Avenue line, upon which his experiments with the electric motor
    have been conducted, over which passengers are now conveyed a
    distance of five miles in 26 minutes for five cents, which he
    considered the best and cheapest municipal rapid transit in the
    world, and which is operated with a higher degree of safety than
    any other railroad in the world making an equal number of stops
    per 100 miles. On a recent holiday, April 30 last, 835,720
    passengers were carried upon the entire system without
    noticeable detention or accident. The rapidly increasing traffic
    makes the demand for better facilities a pressing one, and as
    the average half million now carried daily will soon become a
    million, it appears doubtful if any method can be devised of
    providing for the growth by the use of steam motors on the
    present structures, which are now taxed to their utmost. To the
    mind of the mechanical engineer, having in view the ordinary
    coefficients of tractive ability, there is no remedy for this.
    The speaker stated that these coefficients were not entirely
    trustworthy. He reiterated his previously expressed opinion,
    based on frequent experiments, that there is a decided increase
    in traction gained by the passage of the electric current from
    the wheels to the rails, giving the details of one test where a
    motor with a load making a total of 600 lb. climbed a gradient
    of 2,900 ft. per mile, starting from a state of rest. He stated
    that some of those people who had ridiculed his statements had
    finally admitted that they were true.

    The motor Ben Franklin, which had been used in making these
    tests on the elevated roads, weighed 10 tons, and performed
    service nearly equal to the steam motors weighing 18 tons. The
    object of these tests was the determination of coal economy.
    Tests with a Prony brake showed that the motor developed 128
    H.P. The piece of track on which the experiments were conducted
    embraced 2,200 ft. of level track and 1-8/10 miles of gradients,
    varying from 11-3/10 to 98-7/10 ft. per mile, while at Thirtieth
    street the station is at the foot of the steepest grade, thus
    testing to the utmost the tractive capacity of the motor. The
    experiments were begun in October, 1888, and carried on between
    the hours of 9 P.M. and 4 A.M., beginning with one or two cars,
    the load being increased nightly until it was finally made up of
    eight coaches of 12 tons each, which were hauled up the 98 ft.
    grade at a speed of 7½ miles per hour, the entire distance being
    covered at the rate of 14-6/10 miles per hour. The maximum speed
    obtained on level with that train was 16.36 miles per hour.
    Seventy trips were subsequently made with a 70 ton train
    operated between the steam trains under 3 minutes headway, but
    the work was considered too critical on account of the absence
    of suitable brakes. A number of experiments made about this time
    showed that the mean speed with a three-car train running
    express on the up-town track was about 24 miles per hour,
    although the ability of the motor on a level with a similar
    train was nearly 28 miles per hour. This, however, was not the
    maximum speed, as the level track was not long enough to permit
    of its attaining the highest rate. It was the opinion of the
    speaker, however, that the speed attained could not be exceeded
    with prudence on the elevated structure.

    The measurements of speed were made by dividing the track into
    19 sections of 500 ft., each section being provided with a
    circuit-closing plate connected with a chronograph which was
    carefully tested. The indicator cards were taken at the central
    station by Mr. Idell and his assistants, and the dynamometer
    used was of the liquid type made by Mr. Shaw, of Philadelphia.
    The diagrams prepared from the data obtained were then explained
    by the speaker, who stated that there was not a marked
    difference between the 10 ton motor and the 18 ton locomotive in
    the initial effort on the level, as will be seen by comparing a
    run observed by a railroad officer on March 9 with a steam motor
    and a load of about 57½ tons. The steam motor required 1 min.
    and 29 sec. to make the distance from 14th to 23d streets, while
    the electric motor with a train of 70 tons made the same trip in
    1 min. and 50 sec.; the absence of power brakes compelled the
    current to be taken off at 19th street, while it was probable
    that the throttle of the steam locomotive was not closed until
    it reached 23d street, this being the usual practice. The data
    obtained in these experiments shows that 29,940 h.p. is required
    to operate the Ninth avenue railroad for the 16 hours' service,
    or an average of 1,871 h.p. per hour, or 2,181 h.p., adding
    station friction. The varying requirements of the traffic during
    the day shows that the service could be advantageously divided
    up between four stationary engines of 800 h.p. each, there being
    but five hours of the day when all of them would be required.
    The fuel consumption per day, allowing 22 lb. of coal per h.p.
    per hour at $2.25 per ton, would make a total of $92.25 per diem
    for fuel, the coal being a mixture deliverable at the dock for
    about $1.80 per ton. The weight of coal used for the present
    locomotives is about the same, viz., 40 tons per day, but
    practice has shown it to be most economical to use coal of the
    best quality, costing $5 per ton, making the cost of fuel about
    double that required for the electric system. Without entering
    into other economies which the speaker claimed were in favor of
    electricity, and ignoring the plan suggested by Sir William
    Siemens of braking the train by converting the motor into a
    dynamo and thus utilizing the energy of momentum, he believed
    that the economy in fuel alone was sufficient to prove that the
    application of power by electricity was preferable to direct
    steam propulsion for the elevated railroad service.

       *       *       *       *       *




MAGNETISM IN ITS RELATION TO INDUCED ELECTROMOTIVE FORCE AND
CURRENT.[1]

   [Footnote 1: A paper read before the American Institute of
   Electrical Engineers, New York, May 22, 1889.]

By ELIHU THOMSON.


There is perhaps no subject which at the present time can have a
greater interest to the physicist, the electrician, and the electrical
engineer than the one which heads this paper. The advances which have
been made in the study from its purely theoretical or scientific side,
and the great technical progress in the utilization of the known facts
and principles concerning magnetic inductions, can but deepen and
strengthen that interest.

On the side of pure theory we find the eager collection of
experimental data to be submitted to the scrutiny of the ablest and
brightest minds, to be examined and reasoned upon with the hope of
finding some clew to satisfying explanations, and on the side of
practice we find the search for new facts and relations no less
diligent, though often stimulated by practical problems presented for
solution. Indeed, the urgency for results is often the greater on the
practical side, for theory can wait, practice cannot, at least in the
United States.

We must look for continued triumphs in both directions, and the most
welcome of all will be the framing of a theory or explanation which
will enable us to interpret magnetic and electric phenomena. The
recent beautiful experiments of Hertz on magnetic waves have opened a
fertile region for investigation.

It would seem that the study of magnetism and electricity will give us
the ability to investigate the ether of space, which medium has been
theorized upon at great length, with the result of leaving it very
much where it was before, a mysterious necessity.

Faraday says, speaking of magnetism:

    "Such an action may be a function of the ether, for it is not at
    all unlikely that if there be an ether it should have other uses
    than simply the conveyance of radiations." 3,075. Vol. III.,
    Exp. Res.

    "It may be a vibration of the hypothetical ether, or a state of
    tension of that ether equivalent to either a dynamic or a static
    condition," etc. 3,263. Vol. III., Exp. Res.

Faraday again says, speaking of the magnetic power of a vacuum:

    "What that surrounding magnetic medium deprived of all material
    substance may be I cannot tell, perhaps the ether." 3,277. Vol.
    III., Exp. Res.

Modern views would seem to point that through a study of magnetic
phenomena we may take a feeble hold upon the universal ether.
Magnetism is an action or condition of that medium, and it may be that
electrical actions are the expression of molecular disturbances
brought about by ether strains or interferences. The close relations
which are shown to exist between magnetism and light tend to
strengthen such views. Indeed, it would not be too much to expect that
if the mechanics of the ether are ever worked out, we should find the
relation between sensible heat and electric currents to be as close as
that of light to magnetism, perhaps find ultimately the forms of
matter, the elements and compounds to be the more complex
manifestations of the universal medium--aggregations in stable
equilibrium. It is a difficult conception, I confess, and a most
shadowy and imperfect one, yet facts and inferences which favor such
views are not wanting.

Our science of electricity seems almost to be in the same condition
that chemistry was before the work of Lavoisier had shed its light on
chemical theory. Our store of facts is daily increasing, and
apparently disconnected phenomena are being brought into harmonious
relation. Perhaps the edifice of complete theory will not be more than
begun in our time, perhaps the building process will be a very gradual
one, but I cannot refrain from the conviction that the intelligence of
man will, if it has time, continue its advance until such a structure
exists.

I have been led to make these general allusions to electrical theory
in order to emphasize the fact that in the present paper no unraveling
of the mystery is to be attempted, but rather the presentation of some
few considerations upon a subject of absorbing interest.

The conception of Faraday in regard to the existence of lines of
magnetic force representing directions of magnetic strain or tension
in a medium has not only lost nothing of its usefulness up to the
present time, but has continually been of great service in the
understanding of magnetic phenomena. We need spend no time in showing,
as Faraday and others have done, that these lines are always closed
circuits, polarized so that the direction of the lines cannot be
reversed without reversal of the actions. Nor need we take time to
show that in any medium the lines are mutually repellent laterally if
of the same direction of polarization. Opposing this tendency to
separation or lateral diffusion of magnetic force is the strong
apparent tendency of the lines to shorten themselves in any medium.
These actions are distributed by the presentation of a better medium,
as iron instead of space or air. Lines of force will move into the
better medium, having apparently the constant tendency to diminish the
resistance in their paths.

The peculiar and mysterious nature of media, such as iron, is to
permit an extraordinary crowding of lines on account of slight
resistance to their passage through it. We need not, in addition, do
more than refer to the other well-known facts of an electric current
developing magnetic lines encircling the conductor, as being the
general type, which includes all forms of magnetic field or
electro-magnets, sustained by currents, and the fact of a development
when magnetic lines or circuits and material masses are in relative
movement of electromotive forces transversely to the direction of the
lines of magnetism, and also transversely to the direction of relative
movement, as in the case of electric conductors traversing or cutting
through a field, or of a field traversing or being moved across a
conductor. We must not forget that even insulators, as well as
conductors, cutting lines of force, have the electromotive force
developed in them. The action simply develops potential difference,
and this generates the current where a circuit exists. While we are in
the habit of saying that a conductor moved across a field of lines, or
_vice versa_, generates electric current, I think the statement
incomplete. The movement only sets up a potential difference, and the
power expended in effecting the movement generates C × E. The current
is energy less the potential, or the energy expended gives the two
effects of potential or pressure and current or rate of movement.
Consequently an insulator, or an open-circuited conductor, traversing
a field, consumes no energy, potential difference only being produced.
Nevertheless, as will be shown, the magnetic circuits or lines
themselves may furnish the energy for their own movement across a
conductor, and so develop current as well as potential.

This occurs in the effort of lines to shorten their paths, to lessen
their density, to pass to better media. Indeed, a close examination
will show that wherever power is expended in developing current in a
circuit, cutting lines of force, the energy expended is first employed
in stretching the lines, which thus receive the energy required to
permit them, in shortening, to cut the conductor and set up currents
in the electric circuit in accordance with the potential difference
developed in that circuit and its resistance.

I think we may also say, though I do not remember to have seen the
statement so put, that whenever electric potential is set up
inductively, as in self-induction, mutual induction, induction from
one circuit to another, and induction from magnets or magnetic field,
it is set up by the movement of lines of force laterally across the
body, mass or conductor in which the potential is developed, and that
whenever current is set up in a wire or an existing current prolonged,
or an existing current checked by induction, self-induction, or
induction from magnets, the action is a transfer of energy,
represented by strained lines of force shortening or lessening their
resistance, or lengthening and increasing the resistance in their
paths. The magnetic field is like an elastic spring--it can in one
condition represent stored energy--it can be strained and will store
energy--it can be made to relieve its strain and impart energy.

[Illustration: Fig. 1.]

Let us examine some known phenomena in this light. Take the case of a
simple wire, conveying current, say, in a line away from observer,
Fig. 1. There exists a free field of circular magnetism (so called),
shading off away from the wire, and which is represented by concentric
circles of increased diameter. The superior intensity or strength of
the lines near the wire may also be represented by their thickness.
This is often shown also by crowding the lines near the wire, though I
am disposed to regard Fig. 1 as more nearly expressing the condition,
unless we are to regard the lines as simply indicating a sort of
atmosphere of magnetic effect whose density becomes less as we proceed
outward from the wire, in which case either form of symbol suffices.
The direction of polarization of the lines may be indicated by an
arrow head pointing in a direction of right-handed rotation in the
path of the lines. This is the typical figure or expression for all
forms of simple magnetic circuit--the form of the lines, their length,
position, density, will depend on the shape of the conductor or
conductors (when more than one) and the materials surrounding or in
proximity to the wire or wires.

If the current traversing the conductor is constant, the magnetic
field around it is stable and static, unless other influences come in
to modify it. The cutting off of the current is followed by
instability of the field whereby it can and must produce dynamic
effects. I say _must_ because the field represents stored energy, and
in disappearing _must_ give out that energy. To throw light on this
part of the subject is one of the objects of the present paper.
Cutting off the current supply in the case assumed leaves the
developed magnetic lines or strains unsupported. They at once shorten
their paths or circuits, collapsing upon the conductor as it were, and
continuing this action, cut the section of the conductor, and
apparently disappear in magnetic closed circuits of infinitesimal
diameter but of great strength of polarization. It appears to me that
we must either be prepared to give up the idea of lines of force or
take the position that the magnetic circuits precipitate themselves in
shortening their circuits and disappearing upon and cut the conductor.
It was Hughes who put forward the idea that an iron bar in losing its
apparent magnetism really short-circuits the lines in itself as
innumerable strongly magnetized closed circuits among the molecules.
In becoming magnetic once more these short circuits are opened or
extended into the air by some source of energy applied to strain the
lines, such as a current in a conductor around the bar.

May not this idea be extended, then, to include the magnetic medium,
the ether itself? Does it contain intensely polarized closed circuits
of magnetism which are ready to be stretched or extended under certain
conditions by the application of energy, which energy is returned by
the collapse of the extended circuits? This is doubtless but a crude
expression of the real condition of things, for the lines are only
symbols for a condition of strain in a medium which cannot be
represented in thought, as we know nothing of its real nature. There
is one point in this connection which I must emphasize. The strained
lines, Fig. 1, are indications of stored energy in the ether, and the
lines _cannot_ disappear without giving out that energy. Ordinarily,
it makes its appearance as the extra current, and adds itself so as to
prolong the current which extended the lines when an attempt is made
to cut off such current. Were it conceivable that the current could be
cut off and the wire put on open circuit while the lines still
remained open or strained, the energy must still escape when the field
disappears. It would then produce such a high potential as to be able
to discharge from the ends of the conductor, and if the conductor were
of some section, part of the energy would be expended in setting up
local currents in it. The field could not disappear without an outlet
for the energy it represents. But we cannot cut off a current in a
wire so as to leave the wire on open circuit with the lines of the
magnetic circuit remaining around it without iron or steel or the like
in the magnetic circuit. We can approach that condition, however, by
breaking the circuit very quickly with a condenser of limited capacity
around the break. This is done in the Ruhmkorff coil primary; the
condenser forms a sort of blind alley for the extra current on its
beginning to flow out of the primary coil. But the condenser charges
and backs up and stops the discharge from the primary, even giving a
reverse current. The lines of magnetic force collapse, however, and
have their effect in the enormous potential set up in the secondary
coil.

Take away the secondary coil so as to stop that outlet, the energy
expends itself on the iron core and the primary coil. Take away the
iron core, and the energy of magnetization of the air or ether core
expends itself on the wire of the primary and, possibly, also on the
dielectric of the condenser to some extent. The extra current becomes
in this instance an oscillatory discharge of very high period back and
forth through the primary coil from the condenser, until the energy is
lost in the heat of C2 × R. This conversion is doubtless rendered
all the more rapid by uneven distribution of current and eddy current
set up in the wire of the coil.

The considerations just given concern the loss of field or the
shortening and apparent disappearance of the magnetic lines or
circuits, as giving rise to the self-induction or increased potential
on breaking. Where the energizing current is slowly cut off or
diminished the energy is gradually transferred to the wire in
producing elevation of potential during the decrease; and the collapse
and cutting of the wire by the collapsing circuits or lines is then
only more gradual.

Let the current be returned to the wire after disappearance of
magnetism, and the lines again seem to emanate from the wire and at
the same time cut it and produce a counter potential in it, which is
the index of the abstraction of energy from the circuit, and its
storing up in the form of elastically strained lines of magnetism
around the conductor. The effect is that of self-induction on making
or upon increase of current, the measure of the amount being the
energy stored in the magnetic circuits which have been extended or
opened up by the current. The greater the current and the shorter the
path for the lines developed around the axis of the conductor, the
greater the energy stored up. Hence, a circular section conductor has
the highest self-induction, a tube of same section less as its
diameter increases, a flat strip has less as its width increases and
thickness diminishes, a divided conductor much less than a single
conductor of same shape and section. Separating the strands of a
divided conductor increases the length of magnetic paths around it,
and so diminishes the self-induction. A striking instance of this
latter fact was developed in conveying very heavy alternating currents
of a very low potential a distance of about three feet by copper
conductors, the current being used in electric welding operations.

The conductors were built up of flat thin strips of copper for
flexibility. When the strips were allowed to lie closely together, the
short conductor showed an enormous self-induction, which cut down the
effective potential at its ends near the work. By spreading apart the
strips so as to lengthen a line around the conductor, the
self-induction could be easily made less than 35 per cent. of what it
had been before. The interweaving of the outgoing and return conductor
strands as one compound conductor gets rid almost entirely of the
self-inductive effects, because neither conductor has any free space
in which to develop strong magnetic forces, but is opposed in effect
everywhere by the opposite current in its neighbor.

Where a number of conductors are parallel, and have the same direction
of current, as in a coil or in a strand, it is evident that statically
the conductor may be considered as replaceable by a single conductor
with the same external dimensions and same total current in the area
occupied, the magnetic forces or lines surrounding them being of same
intensity. But with changing current strength the distribution of
current in the conductor has also a powerful effect on the energy
absorbed or given out in accordance with the magnetism produced. Hence
the self-induction of a strand, coil or conductor of the same section
varies with the rapidity of current changes, owing to the conduction
being uneven.

The uneven distribution of current, or its tendency to flow on the
outer parts of a conductor when the rate of variation or alternation
is made great, is in itself a consequence of the fact that less energy
is transferred into magnetism in this case than when the current flows
uniformly over the section, or is concentrated at the center. In other
words, when a uniform current traverses a conductor of the same
section, the circular magnetism, or surrounding magnetic lines, are to
be found not only outside the conductor, but also beneath its
exterior. Since in forming these lines on passage of current the
middle of section would be surrounded by more lines than any other
part of the conductor, the current tends to keep out of that part and
move nearer the exterior in greater amount. Hence, in rapidly
alternating currents the conductor section is practically lessened,
being restricted largely to the outer metal of the conductor. If the
round conductor, Fig. 2, were made of iron, the magnetism interior to
it and set up by a current in it would be very much greater, the
section of the conductor being filled with magnetic circuits or lines
around the center. The total magnetism, external and internal, would
be much greater in this case for a given current flow, and the energy
absorbed and given out in formation and loss of field or the
self-induction would be much increased. This could, however, be
greatly diminished by slitting the conductor radially or making it of
a number of separate wires out of lateral magnetic contact one with
the other, Fig. 3. In these cases the resistance of the interior
magnetic circuits would be increased, as there would be several breaks
in the continuity around the center of the conductor. The total
magnetism which could be set up by a current would be lessened, and
the self-induction, therefore, lessened.

[Illustration: Fig. 2.]

[Illustration: Fig. 3.]

The moment we begin the bringing of iron into proximity with an
electric conductor conveying current, we provide a better medium for
the flow or development of magnetic lines or circuits. In other words,
the lines may then be longer, yet equally intense, or more lines may
be crowded into a section of this metal than in air or space. Figs.
4a, 4b, 4c show the effect brought about by bringing iron of
different forms near to the conductor.

[Illustration: Fig. 4a.]

[Illustration: Fig. 4b.]

[Illustration: Fig. 4c.]

It shows, in other words, the development of the ordinary
electro-magnet of the horseshoe form, and the concentration of the
lines in the better medium. The lines also tend to shorten and
diminish the resistance to their passage, so that attraction of the
iron to the conductor takes place, and if there is more than one piece
of iron, they tend to string themselves around the conductor in
magnetic contact with one another.

When copper bars of 1 inch diameter are traversed by currents of
40,000 to 60,000 amperes, as in welding them, the magnetic forces just
referred to become so enormous that very heavy masses of iron brought
up to the bar are firmly held, even though the current be of an
alternating character, changing direction many times a second.

[Illustration: Fig. 5]

[Illustration: Fig. 6]

When a conductor is surrounded by a cast iron ring, as in Fig. 5, the
current in such conductor has an excellent magnetic medium surrounding
it. A large amount of energy is then abstracted on the first impulse
of current, which goes to develop strong and dense magnetic lines
through the iron ring and across the gap in it. On taking off the
current the energy is returned as extra current, and its force is many
times what would be found with air alone surrounding the conductor. We
have then greatly increased the self-induction, the storing of energy
and opposition to current flow at the beginning, the giving back of
energy and assistance to the current flow on attempting to remove or
stop the current. Let us now complete the ring, by making it of iron,
endless, Fig. 6, with the conductor in the middle.

We now find that on passing current through the conductor it meets
with a very strong opposing effect or counter potential. The evolution
of magnetic lines, or the opening out of magnetic circuits, goes on at
a very rapid rate. Each line or magnetic circuit evolved, and cutting
the conductor, flies at once outward, and locates itself in the iron
ring. This ring can carry innumerable lines, and they do not crowd one
another. It permits the lines even to lengthen in reaching it, and
yet, on account of its low resistance to their passage, the
lengthening is equivalent to their having shortened in other media. We
will suppose the current not sufficient to exhaust this peculiar
capacity for lines which the iron has. Equilibrium is reached, the
conductor has opened up innumerable closed circuits, and caused them
to exist in the ring still closed; but in iron, not space or ether
merely. The current passing has continued its action and storage of
energy until to emit another line in view of the resistance now found
in the crowded iron ring is impossible.

Now let us cut off the current. We are surprised to find a very weak
extra current, a practical absence of self-induction on breaking, or,
at least, a giving out of energy in nowise comparable to that on
making. Let us put on the current as it was before. Another curious
result. But little self-induction now on making energy not absorbed.

Now cut off the current again. Same effect as before. Now let us put
on the current reversed in direction. At once we find a very strong
counter potential or opposing self-induction developed.

The ring had been polarized, or retained its magnetic energy, and we
are now taking out one set of lines and putting in reversely polarized
lines of force. This done, we break the reversed current without much
effect of self-induction. The ring remains polarized and inert until
an opposite flow of current be sent through. Iron is then a different
medium from the ether.

The ring once magnetized must, in losing its magnetism, permit a
closure of the lines by shortening. This involves their passage from
the iron across the space in the center of the ring, notwithstanding
its great resistance to the lines of force. As passage from iron to
air is equivalent to lengthening of the lines, it is readily seen that
such lengthening may oppose more effect than a slight shortening due
to leaving iron, for air or space may give in provoking a closure and
disappearance of the lines. Looked at from another standpoint, the
lines on the iron may actually require a small amount of initial
energy to dislodge them therefrom, so that after being dislodged they
may collapse and yield whatever energy they represent.

I must reserve for the future further consideration of the iron ring,
but in thinking upon this matter I am led to think that the production
of a magnetic line in an iron ring around a conductor may represent a
sort of wave of energy, an absorption of energy on the evolution of
the line from the conductor, and a slight giving out of energy on the
line reaching that position of proximity to the iron ring, that its
passage thereto may be said to be a shortening process or a lessening
of its resistance.

The magnetism in air, gases, and non-magnetic bodies, being assumed to
be that of the ether, this medium shows no such effects as those we
get with the ring. It does not become permanently polarized, as does
even soft iron under the condition of a closed ring. The iron
possesses coercive force, or magnetic rigidity, and a steel ring would
show more of it. The molecules of the iron or steel take a set. If we
were to cut the soft iron ring, or separate it in any way, this
introduction of resistance of air for ether in the magnetic circuit
would cause the lines to collapse and set up a current in the
conductor. The energy of the ring would have been restored to the
latter. The curious thing is that physically the polarized ring does
not present any different appearance or ordinary properties different
from those of a plain ring, and will not deflect a compass needle. Its
condition is discoverable, however, by the test of self-induction to
currents of different direction. As a practical consideration, we may
mention in this connection that a self-inductive coil for currents of
one direction must be constructed differently from one to be used with
alternating currents. The former must have in its magnetic circuit a
section of air or the like, or be an imperfectly closed circuit, as it
were. The latter should have as perfectly closed a magnetic circuit as
can be made. We see here also the futility of constructing a Ruhmkorff
core coil on the closed iron magnetic circuit plan, because the
currents in the primary are interrupted, not reversed.

The considerations just put forward in relation to the closed iron
ring, and its passive character under the condition of becoming
polarized, are more important than at first appears. It has been found
that the secondary current wave of a closed iron circuit induction
coil or transformer, whose primary circuit receives alternating
current, is lagged from its theoretical position of 90 degrees behind
the primary wave an additional 90 degrees, so that the phases of the
two currents are directly opposed; or the secondary current working
lamps only in its circuit is one half a wave length behind a primary,
instead of a quarter wave length, as might have been expected.

But when it is understood that the iron core polarized in one
direction by the primary impulse does not begin to lose its magnetism
when that impulse simply weakens, but waits until an actual reversal
of current has taken place, it will be seen that the secondary
current, which can only be produced when magnetic lines are leaving
the core and cutting the secondary coil, or when the lines are being
evolved and passing into the core from the primary coil, will have a
beginning at the moment the primary reverses, will continue during the
flow of that impulse, and will end at substantially the same time with
the primary impulse, provided the work of the secondary current is not
expended in overcoming self-induction, which would introduce a further
lag. Moreover, the direction of the secondary current will be opposite
to that of the primary, because the magnetic circuits which are opened
up by the primary current in magnetizing the core, or which are closed
or collapsed by it in demagnetizing the core, will always cut the
secondary coil in the direction proper for this result. Transformers
of the straight core type with very soft iron in the cores and not too
high rates of alternation should approximate more nearly the
theoretical relation of primary and secondary waves, because the
magnetic changes in the core are capable of taking place almost
simultaneously with the changes of strength of the primary current.
This fact also has other important practical and theoretical bearings.

Let us assume a plain iron core, Fig. 7, magnetized as indicated, so
that its poles, N, S, complete their magnetic circuits by what is
called free field or lines in space around it. Let a coil of wire be
wound thereon as indicated. Now assume that the magnetism is to be
lost or cease, either suddenly or slowly. An electric potential will
be set up in the coil, and if it has a circuit, work or energy will be
produced or given out in that circuit, and in any other inductively
related to it. Hence the magnetic field represents work or potential
energy. But to develop potential in the wire the lines must cut the
wire. This they can do by collapsing or closing on themselves. The bar
seems, therefore, to lose its magnetism by gaining it all, and in
doing so all the external lines of force moving inward cut the wire.
The magnetic circuits shorten and short-circuit themselves in the bar,
perhaps as innumerable molecular magnetic circuits interior to the
iron medium. To remagnetize the bar we may pass an electric current
through the coil. The small closed circuits are again distended, the
free field appears, and the lines moving outward cut across the wire
coil opposite to the former direction and produce a counter potential
in the wire, and consequent absorption of the energy represented in
the free field produced. As before studied, the magnetism cannot
disappear without giving out the energy it represents, even though the
wire coil be on open circuit, and therefore unable to discharge that
energy. The coil open-circuited is static, not dynamic. In such
assumed case the lines in closing cut the core and heat it. Let us,
however, laminate the core or subdivide it as far as possible, and we
appear to have cut off this escape for the energy. This is not really
so, however. We have simply increased the possible rate of speed of
closure, or movement of the lines, and so have increased for the
divided core the intensity of the actions of magnetic friction and
local currents in the core, the latter still receiving the energy of
the magnetic circuit. This reasoning is based on the possibility in
this case of cutting off the current in the magnetizing coil and
retaining the magnetic field. This is of itself probably impossible
with soft iron. That the core receives the energy when the coil cannot
is shown in the well known fact that in some dynamos with armatures of
bobbins on iron cores, the running of the armature coils on open
circuit gives rise to dangerous heating of the cores, and that under
normal work the heating is less. In the former case the core
accumulates the energy represented in the magnetic changes. In the
latter the external circuit of the machine and its wire coils take the
larger part of the energy which is expended in doing the work in the
circuit. In this case, also, the current in the coils causes a
retardation of the speed of change and extent of change of magnetism
in the iron cores, which keeps down the intensity of the magnetic
reaction. In fact, this retardation or lag and reduction of range of
magnetic change may in some machines be made so great by closing the
circuit of the armature coils themselves or short-circuiting them that
the total heat developed in the cores is much less than under normal
load.

[Illustration: Fig. 7.]

I wish now, in closing, to refer briefly to phenomena of moving lines
of force, and to the effects of speed of movement. In order to
generate a given potential in a length of conductor we have choice of
certain conditions. We can vary the strength of field and we can vary
the velocity. We can use a strong field and slow movement of
conductor, or we can use a weak field and rapid movement of the
conductor. But we find also that where the conductor has large section
it is liable to heat from eddy currents caused by one part of its
section being in a stronger field than another at the same time. One
part cuts the lines where they are dense and the other where they are
not dense, with the result of difference of potential and local
currents which waste energy in heat. We cannot make the conductor move
in a field of uniform density, because it must pass into and out of
the field. The conditions just stated are present in dynamos for heavy
current work, where the speed of cutting of lines is low and the
armature conductor large in section.

But we find that in a transformer secondary we can use very large
section of conductor, even (as in welding machines) 12 to 15 square
inches solid copper, without meeting appreciable difficulty from eddy
currents in it. The magnetic lines certainly cut the heavy conductor
and generate the heavy current and potential needed. What difference,
if any, exists? In the transformer the currents are generated by
magnetic field of very low density, in which the lines are moving
across the conductor with extreme rapidity. The velocity of emanation
of lines around the primary coil is probably near that of light, and
each line passes across the section secondary conductor in a
practically inappreciable time. There is no cause then for differences
of potential at different parts of the section heavy secondary. Then
to avoid eddy currents in large conductors and generate useful
currents in them, we may cause the conductor to be either moved into
and out of a low density field with very great speed, or better, we
must cause the lines of a very low or diffused field to traverse or
cut across the conductor with very high velocity.

It is a known fact that, in dynamos with large section armature
conductors, there are less eddy currents produced in the conductors
when they are provided with iron cores or wound upon iron cores than
when the conductors are made into flat bobbins moved in front of field
poles. Projections existing on the armature between which the
conductors are placed have a like effect, and enable us to employ
heavy bars or bundles of wire without much difficulty from local
currents. The reason is simple. In the armatures with coils without
iron in them, or without projections extending between the turns, the
conductor moves into and out of a very dense field at comparatively
low velocity, so that any differences of potential developed in the
parts of the section of conductor have full effect and abundant time
to act in setting up harmful local currents. In the cases in which
iron projects through the coil or conductor, the real action is that
the lines of the magnetic circuits move at high speeds across the
conductor, and the conductor is at all times in a field of very low
density. Figs. 8 and 9 will make this plain. In Fig. 8 we have shown a
smooth armature surface, having a heavy conductor laid thereon, and
which is at a just entering a dense field at the edge of the pole,
N, and at b leaving such field. It will be seen that when in such
position the conductor, if wide, is subjected to varying field
strength, and moves at a low speed for the generation of the working
potential as it passes through the field, thus giving rise to eddy
currents in the conductor.

[Illustration: Fig. 8.]

In Fig. 9 the conductors are set down between projections, in which
case both armature and field poles are laminated or subdivided. As
each projection leaves the edge of field pole, N, the lines which it
had concentrated on and through it snap backward at an enormous speed,
and cross the gap to the next succeeding projection on the armature,
cutting the whole section of the heavy armature conductor at
practically the same instant. This brisk transfer of lines goes on
from each projection to the succeeding one in front of the field pole,
leaving a very low density of field at any time between the
projections. The best results would be obtained when the armature
conductor does not project beyond or quite fill the depth of groove
between the projections. Of course there are other remedies for the
eddy current difficulty, notably the stranding and twisting of the
conductor on the armatures so as to average the position of the parts
of the compound conductor.

[Illustration: Fig. 9.]

Perhaps the most extreme case of what may be called dilution of field
by projections and by closed magnetic circuits in transformers would
be that of a block of iron, B, Fig. 10, moved between poles, N and S,
and having a hole through it, into and through which a conductor is
carried. The path through the iron is so good that we can scarcely
consider that any lines cross the hole from N to S; yet as B moves
forward there is a continual snapping transfer of lines from the right
forward side of the hole to the left or backward side, cutting the
conductor as they fly across, and developing an electromotive force in
it. I have described this action more in detail because we have in it
whatever distinction in the manner of cutting the lines of the field
is to be found between wire on smooth armatures and on projection
armatures and modifications thereof; and also between flat, open coils
passing through a field and bobbins with cores of iron. The
considerations advanced also bring out the relation which exists
between closed iron circuit transformers and closed iron circuit
(projection) dynamos, as we may call them.

[Illustration: Fig. 10.]

I had intended at the outset of this paper to deal to some extent with
the propagation of lines of magnetism undergoing retardation in
reference to alternating current motor devices, transformers with
limited secondary current, or constant average current, an alternating
motor working with what I may term a translation lag, etc.; but it was
soon found that these matters must remain over for a continuation of
this paper at some future time. My endeavor has been in the present
paper to deal with the lines of force theory as though it were a
symbol of the reality, but I confess that it is done with many
misgivings that I may have carried it too far. Yet, if we are to use
the idea at all it has seemed but right to apply it wherever it may
throw any light on the subject or assist in our understanding of
phenomena.

       *       *       *       *       *




ELECTRIC LIGHTING AT THE PARIS EXHIBITION--THE OERLIKON
WORKS.


Immediately on entering the Machinery Hall by the _galerie_ leading
from the central dome, and occupying a prominent position at the
commencement of the Swiss section, is a very important plant of
dynamos, motors, and steam engines, put down by the Oerlikon Works, of
Zurich. During the time the machinery is kept running in the hall,
power is supplied electrically to drive the whole of the main shafting
in the Swiss section and part of that in the Belgian section,
amounting in all to some 200 ft., a large number of machines of
various industries deriving their power from these lines of shafting,
while during the evening a portion of the upper and lower galleries
adjoining this section is lit by some twenty-five arc lamps run from
this exhibit. Steam is supplied from the Roser boilers in the motive
power court. The whole of the generating plant is illustrated in one
view, and a separate view is given of the motor employed to drive the
main shafting, this latter view showing the details of connection to
the same. On the extreme right hand side of the first view is a direct
coupled engine and dynamo of 20 horse power, a separate cut of which
is given in Fig. 3. The engine is of the vertical single cylinder
type, standing 5 ft. high, and fitted, as are the other two engines
exhibited, with centrifugal governor gear on the fly wheel, acting
directly on the throw of the cutoff valve eccentric. The two
standards, supporting the cylinder and forming the guide bars,
together with the entire field magnets and pole pieces of the dynamo,
and the bed plate common to both, are cast in one piece.

[Illustration: FIG. 3 ENGINE AND DYNAMO FOR STEAMSHIPS.]

The machine is specially designed for ship lighting, and with the view
of preventing any magnetic effect upon the ship's compass, the field
is arranged so that the armature, pole pieces, and coils are entirely
inclosed by iron. Any tendency to leakage of magnetic lines will
therefore be within the machine, the iron acting as a shield. This
build of field--shown in Fig. 3A--is also advantageous as a mechanical
shield to the parts of the machine most likely to suffer from rough
handling in transport, and it will be seen that the field coils are
easily slipped on before the armature is mounted in its bearings.

[Illustration: FIG. 3A]

The winding is compound, and in such a direction that the two opposite
horizontal poles have the same polarity; it follows from this that
there will be two consequent poles in the iron, these being opposite
in name to the horizontal poles and at right angles to them, viz.,
above and below the armature. Opposite sections of the commutator are
connected together internally as in most four-pole machines, so that
only two brushes are necessary, at 90 deg. apart.

The section of iron in the field is 60 square inches and rectangular
in form, and the whole machine measures 4 ft. 3 in. in length, and 2
ft. in height, without including the height of the bed plate. The
armature is 17 in. in length and the same in diameter, measured over
the winding, and develops at the machine terminals 70 volts and 200
amperes at 480 revolutions. The moving parts of the engine are well
balanced, and run remarkably well and without noise at this high rate
of speed.

This dynamo serves to develop power to run a motor in an adjoining
inclosure, containing some fine specimens of lathes and machine tools
constructed by the Oerlikon Works. These are driven by the motor
through the medium of a countershaft, and the power and speed are
controlled from the switch board seen at the left of the exhibit, and
in Fig. 11. The resistance, R1, serves to vary the intensity of the
shunt field of the dynamo, the volts being indicated by the voltmeter
V1, and a resistance separate from the switch board is inserted in
the main circuit of the two machines. The ammeter, A2, is directly
connected to the dynamo, and therefore indicates the current, whatever
circuit this machine is running.

[Illustration: Figs. 5-9, 11 plus THE PARIS EXHIBITION--STAND OF THE
OERLIKON WORKS.]

A larger combined engine and dynamo, seen in the center of the stand,
serves to run the lighting of the galleries. The engine is a 60 horse
power compound, running at 350 revolutions, and fitted with a governor
on the fly wheel, like that described above.

The dynamo is a two-pole machine, the upper pole and yoke being cast
in one, and the lower pole, yoke, and combined bed plate forming a
separate casting. The two vertical cores, over which the field bobbins
are slipped, are of wrought iron, and are turned with a shoulder at
either end, the yokes being recessed to fit them exactly. The cores
are then bolted to the yokes vertically from the top and horizontally
below. The field of this machine is shunt-wound, and in order to
maintain the potential constant a hand-regulated resistance--R2 on
the switch board--is added in circuit with the shunt field. The
voltmeter, V2, immediately above this resistance, serves to
indicate the difference of potential at the machine terminals. Both
voltmeters are fitted with keys, so that they are only put in circuit
when the readings are taken.

The main terminals of this machine are fitted on substantial
insulating bases, fixed one at each end of the top yoke. These connect
to the external circuit by a heavy cable--the machine being capable of
developing 500 amperes--and to the shunt circuit, and regulating
resistance by small wires; while the two connections to the brushes
are by four covered wires in parallel on each side. This mode of
connection is more flexible than a short length of heavy cable, and
looks well, the wires being held neatly together by vulcanized fiber
bridges. The dynamo is a low tension machine, the field being
regulated to give 65 volts when running the lamp circuits.

[Illustration: Fig. 10.]

The illustration, Fig. 10, represents the automatic
re-regulator--C.E.L. Brown's patent. Motion is imparted to the cores
of two electro-magnets at the ends by the pulleys, W W1. The cores
have a projection opposite to the spindle, ab, which latter is
screw-threaded. By a relay one or other electro-magnet is put in
action, and the rotating core, which is magnetized, causes rotation of
the spindle by attraction, resulting in the movement of the contact
along the resistance stops. The relay is acted upon directly by the
potential of the dynamo, and the variable resistance is included in
the shunt field of the machine, so that changes in the potential,
resulting from changes in load or speed, are compensated for.

The arrangements of the lamp circuits and the lamp itself may now be
described. The lamps are all run in parallel circuit, but are divided
into groups of five, each group being controlled by a separate switch
on the board--Figs. 11 and 11A. These switches are not in
direct communication with the dynamo, but make that connection through
a large central switch, S2, which therefore carries the whole
current. The returns from each group are brought to the connections
seen between the two resistances, where the circuits may be
disconnected if desired, and the main current then passes through the
ammeter, A3, to the other terminal of the machine. One of the smaller
switches at the top, Fig. 11A, is directly connected with one terminal
of the 20 horse power dynamo before mentioned, and the other side of
the switch to the motor in the machine tool exhibit. Also one of the
switches in connection with the central switch, S2, is connected to
the same motor, and therefore the latter may be run by either machine,
or, in fact, any combination of machines, lamps, and motor be made as
required.

The form of switch made by the Oerlikon Works is illustrated in Fig.
7. Two thick semicircular bands of copper are screwed at one end to
opposite sides of a square block which is turned round by the switch
handle. The block has a projection at each corner, and two strong,
flat, stationary springs are attached to the framework of the switch
and press on opposite sides of the block. The ends of the springs
engage in the projections and prevent the switch being turned round
the wrong way, while the pressure of the springs on opposite sides
forces the copper bands to take up a position exactly in line with the
terminal contacts when the switch is closed, or at right angles to
them when it is opened.

[Illustration: FIG. 4A]

[Illustration: FIGS. 4, 4B and 4C]

Further, each lamp has its own separate adjustable resistance, fuse,
and switch. These are of special construction, combined in one, and
are illustrated in Figs. 4 and 4A; the other figures, 4B and 4C,
showing some of the details of the same. The wires, W W, lead from and
to one lamp. The current enters at one wire, passes through the fuse,
f--Figs. 4C and 4A--down the center of the cylinder to a divided
contact, into which a switch arm can be shot. When this is so, a
connection is made to the upright brass rod, T, which serves to grip
the band, R, passing round the body of the cylinder. The current then
passes through all the turns of wire above the band, and out at the
other terminal. The resistance can be varied by raising or lowering
the band. Fig. 4B shows the manner of tightening the band against the
wires on the cylinder. The upright rod, T, is seen in section, and is
fixed in one position to the frame of the apparatus. Abutting against
this, and working in the block to which the two ends of the band are
screwed, is a thumb screw, S, by turning which the band may be
loosened for adjusting, and tightened when the right position is
found. The cylinder is covered with asbestos sheet, and the wire,
which is of nickel, and measures altogether from 3 to 4 ohms, is wound
helically round this. The switch arm, to which the handle is attached
below, does not itself make and break the circuit, but carries a
spring, as shown, which, when the arm is at the end of its movement,
pulls over the contact lever with a rapid action, shooting the same
between the divided contact piece, and making a perfect contact. The
switchboard forms one side of a closed wooden case or cupboard, with
sufficient room for a man to enter and adjust the resistances or
switches for each lamp. These are screwed to the inside of the case in
rows, to the number of twenty-five. The greatest care has been taken
in the fixing of the connections to the inside of this case, and no
leading wires of different potential are allowed to cross each other.

[Illustration: FIG. 11A]

The Oerlikon lamp, which is designed to work with constant potential,
is shown partly in section in Fig. 8. There is only one solenoid, A,
through which all the current passes, and whose action is to strike
the arc and maintain the current constant. The soft iron core, C, is
suspended from the inside of the tube, T, in which it has an up and
down movement checked by an air piston in the tube. An end elevation
of the brake wheels and solenoid is given in Fig. 9, where it will be
seen that the spindle carrying these wheels also carries between them
a pinion engaging with the rack rod, R. The top carbon attached to the
rack rod falls by its own weight, and is therefore in contact with the
lower carbon before the lamp is switched in circuit. When this is done
the core is instantly magnetized, and attracted to the soft iron brake
wheels, which it holds firmly. The air cushion in the tube prevents
the core being drawn up until it has fairly gripped the sides of the
wheels. The subsequent raising of the core therefore turns the wheels,
raises the rack rod, and strikes the arc. The feed is operated by the
weakening of the magnetic field of the coil, which causes the core to
lose its grip of the wheels, and allows the top carbon to descend. The
catch, L, Fig. 8, has a lateral play, and serves to engage in the
teeth of the rack rod, so as to prevent its falling when being
trimmed. Each carbon when in position is held against two rectangular
guide bars by the pressure of a wire spring--see figure. In this way
the carbon is pressed against two parallel knife edges, and is
therefore always in true alignment. The action of the lamp is very
simple, the working parts are few and solidly constructed, and the
regulation, as exhibited by the lamps running in the galleries, is
exceptionally steady.

The transmission of power plant consists of two 250 horse power
dynamos--C.E.L. Brown's patent--the generator being driven by a
vertical compound condensing engine of the same power, running at 180
revolutions. The dynamo generator is a four-pole 600 volt direct
current machine, series wound, and may be distinguished in the
engraving next to the switch board; while the motor receiver
connected to it, and erected in another portion of the Swiss section,
is of exactly the same size and type. The field, which is hexagonal in
shape, is cast in two pieces, bolted together horizontally, the
cross-sectional area of iron being 170 square inches. The armature is
cylindrical, and built up of flat rings stamped out of soft sheet
iron, eight notches in the same being provided to fit over the arms of
the spider keyed to the shaft. The spider is in halves, which are
bolted together longitudinally after the rings are in position. It is
Gramme wound, and measures over the winding 7 in. radial depth, 37 in.
outside diameter, and 22 in. in length. The current is collected by
four brushes. The fitting and mechanical build of the dynamos leaves
nothing to be desired. All the working parts of the dynamos and
engines are turned up to gauge and template, so as to be
interchangeable. As an instance of this, the armature of the generator
was built in the works, while the field magnets were being erected in
the exhibition, and, on arrival, fitted in position perfectly, and ran
at once without trouble.

The energy taken off on the motor shaft is close on 200 horse power,
but varies according to the machines at work; the speed of the motor
does not, however, vary more than 3 per cent., and the brushes need no
adjustment. About 6 ft. of shafting is coupled on in line with the
motor shaft, and an extra plummer block fixed at the end. This
shafting carries at its extremity an additional 2 ft. pulley, the
power being delivered by belting from these pulleys to two large
pulleys on the main shaft.

The machines run by this transmission consist of the looms of Rieter &
Co., of Winterthur; the large flour mill and lift of A. Millot & Co.;
the flour milling machinery of Frederick Wegmann & Co., of Zurich; the
brick and tile making machines of the Rorschach foundries; and the
looms of Messrs. Houget & Teston, of Verviers, in the Belgian section.
A 15 horse power two-pole Oerlikon dynamo is also run by a belt from
the main shaft, and generates power to drive a motor of similar type
in the Swiss section of the upper gallery. This runs a length of
countershafting supplying power to three silk-weaving machines
constructed by Benninger Frères; six weaving machines from the Ruti
works, near Zurich; and one knitting machine exhibited by Edward
Dubied & Co., of Couvet.

The dynamo and motor are connected to the main cable by switches of
the type shown in Fig. 5. These are specially designed to destroy the
extra current on breaking circuit by the formation of an arc which
gradually increases the resistance till the break occurs, rendering it
less sudden. One wire passes through the handle and makes contact with
the springs, and the other is attached to the clamp in which the
carbon rod is held. The current is made to enter at the carbon rod, so
that the arcs formed cause consumption of the carbon. A magnetic
cut-out--Fig. 6--is also provided to each machine; this consists of an
electro-magnet, through which the main current passes, provided with
side pole pieces. A flat soft iron plate armature is hinged so as to
come up against the pole pieces when attracted. When the current is
not sufficiently strong to cause the plate to be attracted, a hole in
the center of the latter engages over a small projection in the top of
a weighted arm hinged in the center of the board, and keeps it
upright. If now the current exceeds the limits of safety to the
machine, due to a too heavy load being thrown on, the armature is
attracted and releases the vertical arm, which falls over and enters
with considerable force between the two spring contacts below. These
contacts are connected to the field terminals, which are, therefore,
short-circuited, and prevent the dynamo generating any current. A
retractile spring can be adjusted to cause cut-off at any required
current. These details are indicated in our illustrations mounted on
their respective switch boards.

Since the erection of plant by these works at Solothurn for
transmitting 50 horse power five miles distant, which attracted so
much interest some time ago, several important works have been carried
out. Among these we may mention a 280 horse power transmission at 1½
kilom. distance to a cotton mill at Derendingen in Switzerland, a 250
horse power transmission at ½ kilom. distance, carried out for Gaetano
Rossi at Piovene in Italy, and a 300 horse transmission at 6 kilom.
distance installed for Giovanni Rossi, in which the power is given off
at two different stations.--_The Engineer._

       *       *       *       *       *




THE ADER FLOURISH OF TRUMPETS.


Although telephonic novelties are not numerous at the Universal
Exposition, telephony--that quite young branch of electric science--is
daily the object of curious and interesting experiments which we must
make known to our readers, a large number of whom were not yet born to
scientific life when the experiments were made for the first time at
Paris in 1881; and it is proper to congratulate the Société Générale
des Téléphones on having repeated them in 1889 to the great
satisfaction of the rising generation.

We allude to the Ader system of telephonic transmissions of sounds in
such a way that they can be heard by an audience.

The essential parts of this mode of transmission consist of two
distinct systems--transmitters and receivers.

[Illustration: FIG. 1.--THE ADER FLOURISH OF TRUMPETS]

The transmitters are four in number, and are actuated by the same
number of musicians, each humming into them his part of the quartet
(Fig. 1). This transmitter, represented apart in elevation and section
in Fig. 2, is identical with the one used in the curious experiment
with the singing condenser. At A is a mouthpiece before which the
musician hums his part as upon a reed pipe. He causes the plate, B, to
vibrate in unison with the sound that he emits, and this produces
periodical interruptions of varying rapidity between the disk, B, and
the point, C. The button, D, serves to regulate the distance in such a
way that the breakings of the circuit shall be very complete and
produce sounds in the receivers as pure as allowed by this special
mode of transmission, in which all the harmonics are systematically
suppressed in order to re-enforce the fundamental.

[Illustration: FIG. 2.--DETAILS OF THE TRANSMITTER.]

This transmitter interrupter is interposed in the circuit of a battery
of accumulators, with the five receivers that it actuates, in such a
way that the four transmitters and five receivers form in reality four
groups of distinct autonomous transmission, the accordance of which is
absolutely dependent upon that of the artists who make them vibrate.

The five receivers are arranged over the front door of the telephone
pavilion, near the Eiffel tower (Fig. 3). Each consists of a horseshoe
magnet provided, between its branches, with two small iron cores
having a space of a few millimeters between them (Fig. 4). Each of
these soft iron cores carries a copper wire bobbin, N, the number of
spirals of which is properly calculated for the effect to be produced.
Opposite the vacant space left by the two cores, there is a small
piece, t, of rectangular form, and also of soft iron, fixed to a
vibrating strip of firwood, L, of about 4 inches section. The
periodical breaking of the circuit produced by the transmitter causes
a variation in the magnetization of the iron cores of the five
receivers and makes the firwood strips vibrate energetically. These
vibrations are received and poured forth as it were in front of the
telephone pavilion, by large brass trumpets arranged in front of each
receiver, as shown in Fig. 3.

[Illustration: FIG. 3.--THE ADER FLOURISH OF TRUMPETS]

It would be difficult for us to pass any judgment whatever upon the
musical and artistic value of these transmissions of trumpet music to
a distance; we prefer to confess our incompetency in the matter. But
it is none the less certain that these experiments are having the same
success that they had at their inception in 1881 at the Universal
Exposition of Electricity, and they allow us to foresee that there is
a time coming in which it will be possible to transmit speech to a
distance with the same intensity that the present trumpet flourishes
have. Although all the tentatives hitherto made in this direction have
not given very brilliant results, we must not despair of attaining the
end some day or other. Less than fifteen years ago the telephone did
not exist; now it covers the world with its lines.--_La Nature._

[Illustration: Fig. 4.--DETAILS OF THE RECEIVER.]

       *       *       *       *       *




NOTES ON DYEWOOD EXTRACTS AND SIMILAR PREPARATIONS.

By LOUIS SIEBOLD, F.I.C., F.C.S.


During the last ten years there has been an enormous increase in the
production of these preparations, and the time will come when their
application in dyeing and calico printing will become so general as to
completely supersede the employment of the raw materials. The
manufacture of these extracts, to be thoroughly successful, requires
to be so conducted as to secure the perfect exhaustion of the dyewoods
without the slightest destruction or deterioration of the coloring
matters contained in them; and though nothing like perfection has been
reached in the attainment of these objects, it is certain that the
processes of extraction and evaporation now employed by the best
makers are a very great improvement on the older methods. Indeed,
there is no difficulty nowadays in procuring dyewood extracts of high
excellence if the consumer is willing to pay a price for them
corresponding to their quality, and knows how to avail himself of the
aid of chemical skill to control his purchases. Unfortunately,
however, there is so much hankering after cheap articles, and so
little care is taken to ascertain their real quality, that every scope
is afforded to the malpractices of the adulterer. There are many dye
and print works in which large quantities of these extracts are used
without being subjected to trustworthy tests. Moreover, much of the
testing is done by fallacious methods and often by biased hands. So
fallacious, indeed, are some of these tests, that grossly adulterated
extracts are often declared superior to the purer ones, the cause of
this being the application of an insufficient proportion of mordant in
the dyeing or printing trials, and the consequent waste of the excess
of coloring matter in the case of the purer preparation.

Professional analytical chemists have hitherto given but little
attention to these preparations, and the employment of experienced
chemists in works is as yet far from general. The testing of dyewood
extracts in such a manner as to throw full light on their purity, the
quality of raw material from which they are prepared, their exact
commercial value their suitability for special purposes, and the
proportion and nature of any adulterants they may contain, is of
course a difficult and tedious task, and must be left to the expert
who is in possession of authentic specimens prepared by himself of all
the different extracts made from every variety and quality of raw
materials, and who combines a thorough knowledge of experimental
dyeing and printing with a large experience in the chemical
investigation of these preparations. But when the object of the
testing is merely careful comparison of the sample in question with an
original sample or previous deliveries, the case is much simplified,
and comes within the scope of the general chemist or the laboratory
attached to works. A few years ago I recommended carefully conducted
dyeing trials on woolen cloth mordanted with bichromate of potash as
the best and simplest mode adapted to such cases, and my subsequent
experience enables me to confirm that observation to the fullest
extent. Most of these extracts contain the coloring matter in two
states, the developed and the undeveloped, and an oxidizing mordant
such as bichromate of potash causes the latter as well as the former
to enter completely into combination with a metallic base; whereas
many of the other mordants, such as alumina or tin compounds, merely
take up the developed portion of the coloring matter together with
such small and variable proportions of the undeveloped as might
undergo oxidation during the process of dyeing. I would therefore
suggest dyeing trials with alumina, tin, iron, etc., only as
subsidiary tests indicating the suitability of an extract for certain
special purposes, while recommending the trial with bichromate of
potash as the one giving the best information respecting the actual
strength of the extract in relation to the raw material from which it
was obtained, and as giving a fair idea of the money value of the
sample. Cotton dyeing does not, as a general rule, afford a good means
of assaying extracts, as it is generally done under conditions which
do not admit of complete exhaustion of the dye bath, but it might
often with advantage be resorted to as an additional trial throwing
further light on the degree of oxidation or development of the
coloring matter. Printing trials are apt to give fallacious results
unless the proportion of mordant is carefully adjusted to the amount
of coloring matter present, and several trials with different
proportions would be necessary to prevent erroneous conclusions. For
the trials with bichromate of potash on wool I would recommend pieces
of cloth weighing about 150 grains, and the most suitable proportion
of bichromate of potash is 3 per cent. of the weight of the cloth. The
requisite number of pieces (equal to the number of samples to be
tested) should be thoroughly scoured and then heated in the bichromate
solution at or near the boiling point for not less than 1½ hours,
after which they should be well washed and then dyed separately in the
solutions of equal weights of the extracts at the same temperature and
for the same length of time; 15 grains of extract is a suitable
quantity for a first trial under these conditions. These trials can
then be repeated with different relative proportions of extract in
order to ascertain what weight of a sample would give the same depth
of color as 15 grains of the standard example. Many precautions are
required both in the mordanting and dyeing processes in order to
obtain trustworthy results; and though the trials with bichromate of
potash give the most reliable information of any single test, they
should be supplemented by the subsidiary tests already alluded to, and
also by a chemical examination, in order to obtain a knowledge, not
merely of the wood strength, but also of the general nature of the
extract. An adulteration with molasses or glucose can be best
determined by fermentation in comparison with a pure sample. Mineral
adulterants may, of course, be detected by an estimation and analysis
of the ash, after making due allowances for variations due to
differences in different kinds of the same dyewoods. The estimation of
the individual coloring matters in these extracts by means of a
chemical analysis is under all circumstances a task requiring much
experience, especially as the coloring principles are associated in
different qualities of each class of dyewood with different
proportions of other constituents which often give much trouble to the
unpracticed experimenter. Extracts made from logwood roots are now
largely manufactured and often substituted or mixed with the extracts
of real logwood, and have in some instances been palmed of as logwood
extracts of high quality. The correct determination of such
admixtures, like the fixing of anything like the exact commercial
value of dyewood extracts, requires nothing less than a complete
chemical investigation coupled with numerous dyeing trials in
comparison with standard preparations, and should be left to an
expert.

The presence in dyewood extracts of coloring matters in various stages
of development has hitherto militated against their use in place of
the raw materials by many dyers and printers who are still employing
inherited and antiquated processes in which the whole of the coloring
matter is not rendered available. It is often asserted by these that
even the best of extracts fail to give anything like the results
attained by the use of well-prepared woods, and that, indeed, their
application proves a complete failure. Such failure, however, is
simply due to the want of chemical knowledge on the part of the dyers,
for there is no real difficulty in making any good and pure extract
serve all the purposes for which the woods were used. It is to be
hoped that in this branch of industry, as well as in many others, the
employment of chemists will become more general than at present, and
not be restricted, as is often the case, to young men without
experience and without the trained intellect so essential to success
in chemical investigations. High class chemical skill is of course
available to the manufacturer, but the man of science who brings
matured knowledge and valuable brain work into the business required
social as well as pecuniary recognition, and the sooner and more
fuller this fact is appreciated the better it will be for the
maintenance and progress of our industries.

With regard to the astringent extracts, such as sumac, myrabolam,
divi, valonia, quebracho, oak, etc., it is the aim of the
manufacturer, whenever such extracts are intended for the purposes of
dyeing and printing, to obtain the tannin in a form in which it is
best calculated to fix itself upon the fiber. The case is somewhat
different when the same extracts are required for tanning. For this
purpose it is necessary that the extract shall have considerable
permeating power, and that the tannin contained in it shall readily
yield leather of the desired texture, color, and permanency. Extracts
specially suited for this purpose are by no means always the most
suitable for the dyer, and _vice versa_.

A brief description of the processes by which the astringent extracts
may be tested with particular reference to their fitness for definite
purposes concluded the paper.

With regard to the question as to whether experimental dyeing with
bichromate of potash should be employed as a test even in works where
all the dyeing was done with other mordants, he was decidedly of
opinion that it should always be resorted to as one of the tests,
inasmuch as it was the only simple and expeditious method giving a
fair idea of the actual wood strength and money value of the extract.
The test should, in such cases, be supplemented by dyeing trials with
the mordants used at the works, and, if necessary, also by a chemical
analysis. Printing trials were not necessarily bad tests, since
oxidizing was usually added in these where it was necessary, and any
undeveloped coloring matter would thus be oxidized during the steaming
process: but, as he had stated before, it was essentially necessary in
such cases to have a fair idea of the amount of actual coloring matter
in the extract and to adjust the proportion of mordant accordingly.
Such trials should therefore be preceded by carefully conducted dyeing
trials with bichromate of potash. Mr. Thomson had raised the question
whether it would not be well for the manufacturer to prepare these
extracts in such a manner that they would contain all the coloring
matter in one condition only, in order to insure greater uniformity in
their quality and mode of application. This would, no doubt, be a
desirable step to take if the owners of dye and print works were more
in the habit of availing themselves of the service of competent
chemists experienced in this branch, for then they would be able to
make any extract do its full work irrespective of the state of
development of the coloring matter. Such, however, was not the case,
and it was a very common thing for the consumer of dyewood extracts to
require the manufacturer to prepare them specially for him so as to
suit his own dyeing recipes, or in other words to give exactly the
same shades, weight for weight, by his own method of dyeing as the
article he was in the habit of using. The manufacturer was thus often
compelled to make many different qualities of the same extract to suit
different customers. For the same reason adulterated articles were
often preferred to the pure ones. There was, perhaps, no branch of
industry in which chemical skill of a high order could be applied with
greater advantage than in dyeing, and nowhere was this fact less
recognized. Some of the processes of dyeing were exceedingly wasteful
and stood in much need of improvement. He (Mr. Siebold) knew a large
works in which a ton of logwood extract was used daily for black
dyeing only, and he might safely assert that of this enormous quantity
only a very small proportion would be fixed on the fiber, while by far
the greater proportion was utterly wasted. Such a waste could only be
prevented by a searching investigation of its causes by trained skill.
Mr. Thomson had further alluded to the color obtained with logwood or
logwood extract and wool mordanted with bichromate of potash, and
seemed to be under the impression that the color thus obtained was not
black, but blue. This was undoubtedly the case in dyeing trials
performed as tests, as these were conducted purposely with a very
small proportion of coloring matter in order to admit of a better
comparison of the resulting depth of shades. But with larger
proportions of logwood the color obtained was a fine bluish-black, and
with the addition of a small proportion of fustic or quercitron bark
to the logwood a jet black was readily produced. With regard to Mr.
Watson Smith's observation as to fractional dyeing, he (Mr. Siebold)
did not regard this method as a suitable trial for ascertaining the
strength of an extract, but he admitted it was occasionally very
valuable for detecting an admixture of extracts of other dyewoods,
such as quercitron bark extract in logwood extract. It was also a good
method of ascertaining the speed of dyeing and hence the relative
proportion of fully developed coloring matter of an extract.--_Jour.
Soc. Chem. Industry._

       *       *       *       *       *




ORTHOCHROMATIC PHOTOGRAPHY.[1]

   [Footnote 1: Read before the Photographic Association of
   Brooklyn.]

By OSCAR O. LITZKOW.


What I want to show is the manner in which the process has been
tested. My employer, Mr. Bierstadt, has given me permission to show
you some samples, and also his chart containing the spectrum colors:
violet, indigo blue, green, yellow, orange, red, and black. This chart
has been photographed in the orthochromatic and also in the ordinary
way.

There are many ways of producing an orthochromatic effect; one is the
use of a glass tank placed behind or in front of the lens, in which a
coloring matter from either a vegetable or mineral product is placed;
this tank or cell is, however, only for use in the studio, as for
outdoor photography we have a colored glass screen, so as not to be
bothered with carrying colored solution.

The tank is constructed as follows: Procure two pieces of best white
plate glass, about 6 inches square; between these place a piece of
rubber of the same size square, and about 3/8 of an inch thick. In the
center of this rubber cut out a circle about 4 inches diameter, and
from one of the corners to the center of the circle cut out a narrow
strip ¼ inch wide; this serves as the mouth of the tank. The two
pieces of glass and the rubber are cemented together with rubber
cement; then, to hold it firmly together, two brass flanges are used
as a clamp, with four screws at an equal distance apart; a thin sheet
of rubber is on the glass side of the flanges to prevent direct
contact with the glass, the center remaining clear for the rays of
light to pass through solution and glass.

One of the best orthochromatic effects made through this tank is with
a three-grains-to-the-ounce solution of bichromatic of ammonia or
bichromate of potassium. In this method there is no preparation used
on the plate. A common rapid dry plate is exposed through this
solution; the exposure, however, is about twenty times longer than it
would be if you removed the tank with the yellow solution, or, in
other words, if a dry-plate is exposed one minute without the yellow
solution it would have to be exposed twenty minutes through a
three-grain solution of bichromate of potassium or ammonia. It
produces wonderful results on an oil painting or any highly colored
object.

Another method, and the one best adapted for landscapes, is to bathe
the plate in erythrosine and then expose it through a yellow glass
screen.

As an illustration, suppose we have before us a beautiful landscape.
In the foreground beautiful foliage, in the center a lake, in the
distance hills, with a bluish haze appearing pleasing to the eye, also
a nice sky with light clouds. Now make a plain negative, and see what
has become of your clouds, hills, and the distance--not visible! Some
photographers have been led to think that by underexposing they retain
the distance, but they sacrifice the foreground; besides, it does not
produce an orthochromatic effect.

But it is a good idea to expose longer on the foreground than you do
on the distance. This can be done by raising the cap of the lens
skyward and gradually shut off, giving the foreground more exposure.

Plates are prepared for orthochromatic work as follows: Take any
ordinary rapid dry plate, place it in a bath containing

  Distilled water                    200 c.c.
  Strong liquid ammonia                2 c.c.

Rock it for two minutes, work as dark as you possibly can. Now take it
out, and place it in the second bath for one and one-fourth minutes
and keep it rocking. Have on hand for use a stock solution of

  Distilled water                       1,000 parts.
  Erythrosine "Y" brand                     1 part.

Prepare second bath as follows:

  Erythrosine stock solution               25 c.c.
  Distilled water                         175 c.c.
  Strong water ammonia                      4 c.c.

After removing the plate, dip it again face down to rinse off any
particles of scum, etc., that may get in the bath accidentally. This
bath may be used for one dozen 8 by 10, when it should be thrown away
and fresh bath used.

After the plates come out of the last bath, they should be stood on
clean blotting paper to absorb the excess of solution. I would also
advise to use clean fingers. Pyro. or hypo. on the fingers is a
drawback to success.

After plates have been drained, place them in a cleaned rack in an
absolutely light-tight closet, with air holes so constructed as to
admit air but no light; the plates will dry in from eight to twelve
hours. They are best prepared in the evening, and, if the closet is
good, will be dry in the morning.

After the plates are dry they may be packed face to face with nothing
between them, in a double-cover paper box, and put in a dark closet
free from sulphureted hydrogen gas, until ready for use. I have kept
plates for three months in this way, and they were in good condition.
Great care should be used in developing these plates, as they are
sensitive to the red; get used to developing in a dark part of the
dark room; occasionally you may look at the process of development in
a little stronger light.

The exposure through the yellow screen with an erythrosine plate is
about the same as if you had no orthochromatic plate--a plain plate
instead--provided you are not using too dark a yellow on your screen.
This can only be determined by experience. I will give to a common
plate about four seconds, an orthochromatic plate under the same
conditions five seconds.

The yellow glass screen is prepared as follows: Take a piece of best
plate glass--common cannot be used--clean it nicely; take another
large plate glass, or anything that is level and true, level it with a
small spirit-level. Now take the cleaned piece of glass and coat it
with

AURENTIA COLLODION.

  Ether                                  5 oz.
  Alcohol                                5 oz.
  Cotton                                60 grs.

The aurentia to be added to suit your judgment; it takes a very small
quantity to make an intense yellowish-red collodion. Pour it on the
center of the glass, flow it to the edges, and before it sets place it
on the level glass and allow it to set; when set put it in a rack to
dry.

Should it dry in ridges, the collodion may be too thick, and it must
be thinned down with equal parts of alcohol and ether. A single piece
of plate glass, about one-eighth inch thick, coated with aurentia
collodion, is all that is required with an erythrosine plate. Or,
after a piece has been successfully coated, another piece of the same
plate glass, and the same size, may be cemented together with balsam,
having the coated aurentia side between the two glasses; the edges may
then be bound with paper.

In using different colored solutions, collodion, etc., I have found
that one will change the focus and the other not. With some screens
you must focus with them in their positions; take away the screen, and
the picture appears out of focus. I cannot fully explain why it is,
and for this reason will not make the attempt; experience alone can
teach it.

Another thing that has been tried lately is to do away with the yellow
screen by substituting a yellow coating direct on the plate. No doubt
the focus on an object that requires absolute sharpness is somewhat
affected by the use of a glass. We have been successful, on a small
scale, to coat the plate with the following yellow solution:

Place in a tray enough of a saturated solution of tropæolin in wood
alcohol to cover the plate; allow it to remain ten seconds. It is
necessary that the plate should be bathed previously in erythrosine
and dried. Before applying the tropæolin, which, being in alcohol,
dries in a few minutes, have some blotting paper on hand, as the
solution gathers in a pool and leaves bad marks on the end of the
plate.

The plate can be developed in the usual way. Try it and see the
results.--_Reported in the Beacon._

       *       *       *       *       *




PLATINOTYPE PRINTING.[1]

   [Footnote 1: A communication to the North London Photographic
   Society.]


Platinotype, which may be considered to be the most artistic of
photographic printing processes, may be separated into its three
modifications--the hot bath and cold bath, in which a faintly visible
image is developed, and the Pizzighelli printing-out paper. The hot
bath process, again, may be divided into the black and white and sepia
papers. I intend to give you a rough outline of the preparation of the
paper and working of these modifications, concluding by demonstrating
the hot bath method, and handing around prints by it.

Platinotype may almost be styled an iron printing process, for, while
no trace of iron or its salts is found in the finished print, certain
salts of iron are mixed with the platinum salt, which is platinum
combined with two atoms of chlorine (PtCl2), as a means for readily
reducing it; this, however, cannot be effected without the presence of
neutral oxalate of potash, hence the use of the oxalate bath. There is
no platinum in the paper for the cold bath process, it being coated
with ferric oxalate mixed with a very small quantity of chloride of
mercury--somewhere about one grain to an ounce of ferric oxalate
solution. When dry it is ready for exposure, which is about three
times less than with silver printing.

It is absolutely necessary to store all papers for platinum printing
in an air-tight tin containing chloride of calcium, which must be
dried by heating from time to time. For the cold bath, however, it is
important to have moisture present during printing, or it may be after
printing and before development. If the paper is left in a dampish
room for fifteen minutes, it should be sufficient. Prints made by
exposing damp paper, or damping dry paper just before development,
must be developed within one hour if the maximum of vigor is desired;
by delaying the development some hours, the prints in the meantime
being stored in a drawer so that they may retain their moisture, an
increase of half tone and warmth of color will be obtained. If it
should be necessary to delay development for a day or two, the prints
must be dried before a fire soon after being removed from the frames,
and then stored in a calcium tube until wanted for development.

While printing, the lemon color of the paper receives a grayish
colored image, which, although faint, can, with practice, be judged as
easily as silver printing.

The developer consists of oxalate of potash and potassic
chloro-platinite--about thirty grains of the platinum salt to half an
ounce of oxalate forming about six ounces of solution; a great many
variations, however, may be made in the proportions of platinum salt
and oxalate, and different effects secured. Development is effected by
sliding the print face downward on to the developer, which must be
rocked after the development of each print to avoid scum marks. To
clear the prints they are washed in three or four baths of a weak
solution of hydrochloric acid after leaving the developer, to remove
all traces of the iron salts, and finally washed for a quarter of an
hour in three changes of water; they are then finished, and may be
dried between clean blotting paper.

Pizzighelli's process differs from the above in being one that prints
fully out in the frame without development; the paper contains the
platinum and iron salts as well as the developer, and so prints and
develops at the same time. Although excellent prints can be produced
with it, for general work the results of the paper, as at present
made, will not compare with the hot and cold bath processes. It is,
however, excellent for printing from very dense negatives, and
occasional negatives that seem extremely suitable for it. The paper
should be breathed on before printing, as if it is quite dry the
printing will be very slow and irregular. The best conditions for the
preparation of the paper have scarcely been decided upon yet, and it
is not quite fair to judge the process. The prints are cleared in the
acid baths and washed for about a quarter of an hour.

The sepia and black hot bath processes are much alike in the general
treatment. There are, however, some special precautions to be observed
with the sepia paper, the chief being to protect it from any but the
faintest rays of light; the prints, unlike the black ones, may be
affected by light when in the acid bath. A special solution must be
added to the developer to keep the lights pure. Over-exposure cannot
be corrected by using a cooler bath, as is the case with the black
prints, and the paper does not remain good so long.

The paper for the black prints by the hot bath process is washed with
a mixture of potassic platinous chloride and ferric oxalate, the
proportion being about sixty grains of the platinum salt to one ounce
of the iron solution. It will not keep good longer than twenty minutes
or so, and must be applied to the paper directly after mixing. The
ferric oxalate in the paper is reduced by the action of light to
ferrous oxalate, which forms the faint visible image; this, when the
paper is floated on the oxalate of potash bath, is capable of reducing
the platinum salt in contact with it into metallic platinum; but the
ferric salt, which remains unaltered, has no action on the platinum
salt, leaving these parts, which represent the high lights of the
print, untouched. The ferric oxalate is removed by the acid baths
which follow the development. A good temperature for development is
150° Fahr., and when using this so much detail should not be apparent
as when printing for the cold bath process, in which all the detail
desired should be very faintly visible. There are, however, many
methods of exposing the paper and developing it, and no fixed rule can
be made, but the development must in every case be suited to the
exposure or the result will be a failure. For instance, the paper may
be printed until all detail is visible, but a very much cooler
development must be used, say 80° or 90°; on the other hand, a
slightly short exposure may be given, and a temperature of 180° to
200° used. 150° should be taken as the normal temperature, and kept to
until some experience has been gained, as employing all temperatures
will lead to confusion, and nothing will be learned. Some negatives
require a special treatment, and both printing and development must be
altered, while for a very dense negative the paper may be left out in
a dampish room for some time. It will then print with less contrast
and more half tone. A thin negative is better printed by the cold bath
process, but negatives should be good and brilliant for platinotype
printing. Any one taking up platinotype and getting only weak prints
would do well to look to his negatives instead of blaming the paper,
as the high lights should be fairly dense, and the deep shadows nearly
clear glass.

Time for complete development should always be allowed; with a hot
bath fifteen seconds will be sufficient, but if a cooler development
is used, or the prints are solarized in the shadows, more time should
be allowed. When the deep shadows are solarized, or appear lighter
than surrounding parts, a hot and prolonged development is required to
obtain sufficient blackness, as they have a tendency to look like
brown paper. I have found breathing on solarized shadows useful, as in
the presence of slight moisture they begin to print out and become
dark before development, getting black almost directly the print is
floated on the oxalate. Three or four acid baths of about ten minutes
each are used, and the prints are washed as before. The process
throughout takes much less time than silver printing, and can be kept
on all the winter, when it is nearly impossible to print in silver.
Prints can be developed in weak daylight or gaslight, and prolonged
washing is dispensed with.--_N.P. Fox, reported in Br. Jour. of
Photo._

       *       *       *       *       *

[Continued from Supplement, No. 706, page 11283.]




ON ALLOTROPIC FORMS OF SILVER.

By M. CAREY LEA.


In the first part of this paper were described certain forms of
silver; among them a lilac blue substance, very soluble in water, with
a deep red color. After undergoing purification, it was shown to be
nearly pure silver. During the purification by washing it seemed to
change somewhat, and, consequently, some uncertainty existed as to
whether or not the purified substance was essentially the same as the
first product; it seemed possible that the extreme solubility of the
product in its first condition might be due to a combination in some
way with citric acid, the acid separating during the washing. Many
attempts were made to get a decisive indication, and two series of
analyses, one a long one, to determine the ratio between the silver
and the citric acid present, without obtaining a wholly satisfactory
result, inasmuch as even these determinations of mere ratio involved a
certain degree of previous purification which might have caused a
separation.

This question has since been settled in an extremely simple way, and
the fact established that the soluble blue substance contains not a
trace of combined citric acid.

The precipitated lilac blue substance (obtained by reducing silver
citrate by ferrous citrate) was thrown on a filter and cleared of
mother water as far as possible with a filter pump. Pure water was
then poured on in successive portions until more than half the
substance was dissolved. The residue, evidently quite unchanged, was,
of course, tolerably free from mother water. It was found that by
evaporating it to dryness over a water bath, most of the silver
separated out as bright white normal silver; by adding water and
evaporating a second time, the separation was complete, and water
added dissolved no silver. _The solution thus obtained was neutral._
It must have been acid had any citric acid been combined originally
with the silver. This experiment, repeated with every precaution,
seems conclusive. The ferrous solution, used for reducing the silver
citrate, had been brought to exact neutrality with sodium hydroxide.
After the reduction had been effected, the mother water over the lilac
blue precipitate was neutral or faintly acid.

A corroborating indication is the following: The portions of the lilac
blue substance which were dissolved on the filter (see above) were
received into a dilute solution of magnesium sulphate, which throws
down insoluble allotropic silver of the form I have called B (see
previous paper). This form has already been shown to be nearly pure
silver. The magnesia solution, neutral before use, was also neutral
after it had effected the precipitation, indicating that no citric
acid had been set free in the precipitation of the silver.

It seems, therefore, clear that the lilac blue substance contains no
combined citric acid. Had the solubility of the silver been due to
combination with either acid or alkali, the liquid from which it was
separated by digestion at or below 100° C. must have been acid or
alkaline; it could not have been neutral.

We have, therefore, this alternative: In the lilac blue substance we
have either pure silver in a soluble form or else a compound of
silver, with a perfectly neutral substance generated from citric acid
in the reaction which leads to the formation of the lilac blue
substance. If this last should prove the true explanation, then we
have to do with a combination of silver of a quite different nature
from any silver compounds hitherto known. A neutral substance
generated from citric acid must have one or more atoms of hydrogen
replaced by silver. This possibility recalls the recent observations
of Ballo, who, by acting with a ferrous salt on tartaric acid,
obtained a neutral colloid substance having the constitution of
arabin, C6 H10 O6.

To appreciate the difficulty of arriving at a correct conclusion, it
must be remembered that the silver precipitate is obtained saturated
with strong solutions of ferric and ferrous citrate, sodium citrate,
sulphate, etc. These cannot be removed by washing with pure water, in
which the substance itself is very soluble, but must be got rid of by
washing with saline solutions, under the influence of which the
substance itself slowly but continually changes. Next, the saline
solution used for washing must be removed by alcohol. During this
treatment, the substance, at first very soluble, gradually loses its
solubility, and, when ready for analysis, has become wholly insoluble.
It is impossible at present to say whether it may not have undergone
other change; this is a matter as to which I hope to speak more
positively later. It is to be remarked, however, that these allotropic
forms of silver acquire and lose solubility from very slight causes,
as an instance of which may be mentioned the ease with which the
insoluble form B recovers its solubility under the influence of sodium
sulphate and borate, and other salts, as described in the previous
part of this paper.

The two insoluble forms of allotropic silver which I have described as
B and C--B, bluish green; C, rich golden color--show the following
curious reaction. A film of B, spread on glass and heated in a water
stove to 100° C. for a few minutes becomes superficially bright
yellow. A similar film of the gold colored substance, C, treated in
the same way, acquires a blue bloom. In both cases it is the surface
only that changes.

_Sensitiveness to Light._--All these forms of silver are acted upon by
light. A and B acquire a brownish tinge by some hours' exposure to
sunlight. With C the case is quite different, the color changes from
that of red gold to that of pure yellow gold. The experiment is an
interesting one. The exposed portion retains its full metallic
brilliancy, giving an additional proof that the color depends upon
molecular arrangement, and this with the allotropic forms of silver is
subject to change from almost any influence.

_Stability._--These substances vary greatly in stability under
influences difficult to appreciate. I have two specimens of the gold
yellow substance, C, both made in December, 1886, with the same
proportions, under the same conditions. One has passed to dazzling
white, normal silver, without falling to powder, or undergoing
disaggregation of any sort; the fragments have retained their shape,
simply changing to a pure frosted white, remaining apparently as solid
as before; the other is unchanged, and still shows its deep yellow
color and golden luster. Another specimen made within a few months and
supposed to be permanent has changed to brown. Complete exclusion of
air and light is certainly favorable to permanence.

_Physical Condition._--The brittleness of the substances B and C, the
facility with which they can be reduced to the finest powder, makes a
striking point of difference between allotropic and normal silver. It
is probable that normal silver, precipitated in fine powder and set
aside moist to dry gradually, may cohere into brittle lumps, but these
would be mere aggregations of discontinuous material. With allotropic
silver the case is very different, the particles dry in optical
contact with each other, the surfaces are brilliant, and the material
evidently continuous. That this should be brittle indicates a totally
different state of molecular constitution from that of normal silver.

_Specific Gravities._--The allotropic forms of silver show a lower
specific gravity than that of normal silver.

In determining the specific gravities it was found essential to keep
the sp. gr. bottle after placing the material in it for some hours
under the bell of an air pump. Films of air attach themselves
obstinately to the surfaces, and escape but slowly even in vacuo.

Taken with this precaution, the blue substance, B, gave specific
gravity 9.58, and the yellow substance, C, specific gravity 8.51. The
specific gravity of normal silver, after melting, was found by G. Rose
to be 10.5. That of finely divided silver obtained by precipitation is
stated to be 10.62.[1]

   [Footnote 1: Watts' Dict., orig. ed., v. 277.]

I believe these determinations to be exact for the specimens employed.
But the condition of aggregation may not improbably vary somewhat in
different specimens. It seems, however, clear that these forms of
silver have a lower specific gravity than the normal, and this is what
would be expected.

Chestnut Hill, Philadelphia, May, 1889.

--_Amer. Jour. of Science._

       *       *       *       *       *




TURPENTINE AND ITS PRODUCTS.[1]

   [Footnote 1: Read at a meeting of the Liverpool Chemists'
   Association.]

By EDWARD DAVIES, F.C.S., F.I.C.


In treating this subject it is necessary to limit it within
comparatively narrow bounds, for bodies of the turpentine class are
exceedingly numerous and not well understood. In this definite class
turpentine means the exudation from various trees of the natural order
Coniferæ, consisting of a hydrocarbon, C10 H16, and a resin. The
constitution of the hydrocarbons in turpentine from different sources,
though identical chemically, varies physically, the boiling point
ranging from 156° C. to 163° C., the density from 0.855 to 0.880, and
the action on polarized light from -40.3 to +21.5. They are very
unstable bodies in their molecular constitution, heat, sulphuric acid,
and other reagents modifying their properties. The resins are also
very variable bodies formed probably by oxidation of the hydrocarbons,
and as this oxidation is more or less complete, mixtures are formed
very difficult to separate and study.

Turpentine as met with in commerce is mainly derived from _Pinus
maritima_, yielding French turpentine, and _Pinus australis_,
furnishing most of the American turpentine. The latter is obtained
from North and South Carolina, Georgia and Alabama. In Hanbury and
Fluckiger's Pharmacographia there is a full description of the manner
in which the trees are wounded to obtain the turpentine. Besides these
there are Venice turpentine from the larch, _Pinus Larix_, Strassburg
turpentine from _Abies pectinata_, and Canada balsam from _Pinus
balsamea_.

The crude American turpentine is a viscid liquid of about the
consistence of honey, but varying to a soft solid, known as gum, thus,
according to the amount of exposure which it has undergone, it
contains about 10 to 25 per cent. of "spirits," to which the name of
turpentine is commonly given, the rest being resin, or as it is
usually called, rosin.

In Liverpool almost all the spirits of turpentine comes from America,
so that it is almost impossible to get a sample of French.

The terpene from American turpentine is called austraterebenthene. It
possesses dextro-rotatory polarization of +21.5. Its density is 0.864.
Boiling point 156° C.

In taking the boiling point of a commercial sample of spirits it is
necessary to wait until the thermometer becomes steady. Not more than
5 per cent. should pass over before this takes place, and then there
is not more than two or three degrees of rise until almost all is
distilled over.

The liquids of lower boiling point do not appear to have been much
studied. In French spirits they seem to be of the same composition as
the main product, but with more action on polarized light.

French spirits of turpentine is mainly composed of terebenthene. The
boiling point and sp. gr. are the same as those of the austraterebenthene,
but the polarization is left handed and amounts to -40.5.

Isomeric modifications. Heated to 300° C. in a sealed tube for two
hours, it becomes an isomeric compound, boiling at 175° C., while the
density is lowered, being only 0.8586 at 0° C. The rotatory power is
only -9°. It oxidizes much more rapidly. It is called isoterebenthene
and has a smell of essential oil of lemons.

By the action of a small quantity of sulphuric acid, among other
products terebene is formed. It has the same boiling point and sp. gr.
as terebenthene, but is without action on polarized light.
Austraterebenthene forms similar if not identical bodies.

Polymers. One part of boron fluoride BF3 instantly converts 160
parts of terebenthene into polymers boiling above 300° C., and
optically inactive. H2 SO4 does the same on heating and forms
diterebene C20 H32.

Terchloride of antimony does the same, and also produces tetraterebene
C40H64, a solid brittle compound formed by the union of four
molecules of C10 H16. It does not boil below 350° C. and
decomposes on heating.

Compound with H2O. Terpin C10 H18 2HO is formed when 1 volume
of spirits of turpentine is mixed with 6 of nitric acid and 1 of
alcohol, and exposed to air for some weeks. Crystals are formed which
are pressed, decolorized by animal charcoal, and recrystallized from
boiling water.

Compounds with HCl. When a slow current of HCl is passed through
cooled spirits of turpentine, two isomeric compounds are formed, one
solid, and one liquid. The lower the temperature is kept, the more of
the solid body is produced. To obtain the solid body pure it is
pressed and recrystallized from ether or alcohol. It is volatile and
has the odor of camphor. It is called artificial camphor, and has the
composition C10 H16 HCl. There is also a compound with 2HCl.

Oxidation products. By passing air into spirits of turpentine oxygen
is absorbed. It was thought at one time that ozone was produced, but
Kingzett's view is that camphoric peroxide is formed C10 H14 O4,
and that in presence of water it decomposes into camphoric acid and
H2 O2. This liquid constitutes the disinfectant known as
"sanitas," which possesses the advantages of a pleasant smell and
non-poisonous properties. C10 H18 O2 may be obtained by
exposing spirits of turpentine in a flask full of oxygen with a little
water.

Camphor C16 H16 O has been made in small quantity by oxidizing spirits
of turpentine. Terebenthene belongs to the benzene or aromatic series,
which can be shown from its connection with cymene. Cymene is
methylpropyl-benzene, and can be made from terpenes by removing two
atoms of H. It has not yet been converted again into terpene, but the
connection is sufficiently proved. The presence of CH3 in terpenes is
shown by their yielding chloroform when distilled with bleaching
powder and water. The resin is imperfectly known. It was supposed to
consist of picric and sylvic acids. It is also stated to contain
abietic anhydride C44 H62 O4, but it is difficult to understand how a
compound containing C44 can be produced from C10 H16. The most
probable view is that it is the anhydride of sylvic acid, which is
probably C20 H30 O2.

The dark colored resin which is obtained when the turpentine is
distilled without water can be converted into a transparent slightly
yellow body by distillation with superheated steam. A small portion is
decomposed, but the greater part distills unchanged. It is used in
making soap which will lather with sea water.

When distilled alone, various hydrocarbons, resin oil and resin pitch,
are obtained.

I find that commercial spirits of turpentine varies in sp. gr. from
0.865 to 0.869 at 15° C. The higher sp. gr. appears to be connected
with the presence of resinous bodies, the result of oxidation. The
boiling point is very uniform, ranging from 155° C. to 157° C. at 760
mm. Taking these two points together, it is hardly possible to
adulterate spirits of turpentine without detection. I give the figures
for a few imitations or adulterations:

                              Sp. gr.   B.P.
  No. 1                        0.821  137° C.
  No. 2                        0.884  165° C.
  No. 3                        0.815  150° C.
  No. 4                        0.895  156° C.

There is a considerable difference in the flashing point, no doubt due
to the longer or shorter exposure of the crude turpentine, by which
more or less of the volatile portion escapes.

       *       *       *       *       *




ON THE OCCURRENCE OF PARAFFINE IN CRUDE PETROLEUM.[1]

   [Footnote 1: An abstract of thesis by E.A. Partridge, class of
   '89, Univ. of Pa. Read before the Chemical Section of the
   Franklin Institute by Prof. S.P. Sadtler.]


It is well known that the paraffine obtained by the distillation of
petroleum residues is crystalline, while that obtained directly (as in
the filtration of residuum) is amorphous. Ozokerite or ceresine
differs but slightly from paraffine, the principal distinction being
want of crystalline structure in it as found. Other characteristics,
such as the melting point, specific gravity, etc., vary in both, and
so are not of importance in a comparison. Hence it has been asked, Is
the paraffine occurring in petroleum and ozokerite identical with that
which is produced by their distillation? As crystalline paraffine
could be obtained from ozokerite by distillation alone, many persons
have supposed that it was engendered in the process. Recently,
however, crystalline paraffine has been obtained from ozokerite by
dissolving the latter in warm amyl alcohol; on cooling the greater
part separates out in crystals having the luster of mother-of-pearl.
By repetition of this process, a substance is obtained that is
scarcely to be distinguished from the paraffine obtained by
distillation. Apparently there exists then in ozokerite, together with
paraffine, other substances not capable of crystallization which keep
the paraffine from crystallizing. These colloids appear to be
separated by amyl alcohol in virtue of their greater solubility in
that menstruum. It is also reasonable to suppose that they undergo
change or decomposition by distillation.

So as petroleum residues are amorphous, and the crystalline paraffine
is first produced by distillation, it has been argued that the
paraffine present in crude petroleum is approximately the same thing
as ozokerite.

This, however, is not sufficient to establish the pyrogenic origin of
all crystallized paraffine, as crystals can be obtained from the
amorphous residues by distillation at normal or reduced pressure or in
a current of steam. To explain these facts two assumptions are
possible. Either the chemical and physical properties of all or some
of the solid constituents are changed by the distillation, and the
paraffine is changed from the amorphous into the crystalline variety,
or the change produced by the distillation takes place in the medium
(i.e., the mother liquid) in which the paraffine exists. The change
effected in ozokerite and in petroleum residues when crystalline
paraffine is obtained by distillation is to be regarded as a
purification, and can be effected partially by treatment with amyl
alcohol. In the same way, by repeated treatment of petroleum residuum
with amyl alcohol, a substance of melting point 59° C. can be
obtained, which cannot be distinguished from ordinary paraffine.

The treatment with amyl alcohol has therefore accomplished the same
results as was obtained by distillation, and the action is probably
the same, i.e., a partial separation of colloid substance. These
facts point to the conclusion that crystallizable paraffine exists
ready formed in both petroleum and in ozokerite, but in both cases
other colloidal substances prevent its crystallization. By
distillation, these colloids appear to be destroyed or changed so as
to allow the paraffine to crystallize.

It is a generally known fact that liquids always appear among the
products of the distillation of paraffine, no matter in what way the
distillation be conducted. This shows that some paraffine is
decomposed in the operation.

The name _proto-paraffine_ has been given to ozokerite and to the
paraffine of petroleum in contradistinction to _pyro-paraffine_, the
name that has been applied to the paraffine obtained by distillation
from any source.

According to Reichenbach, paraffine may crystallize in three forms:
needles, angular grains, and leaflets having the luster of
mother-of-pearl. Hofstadter, in an article on the identity of
paraffine from different sources, confirmed this statement, and added
further that at first needles, then the angular forms, and then the
leaflets are formed. Fritsche found, by means of the microscope, in
the ethereal solution of ozokerite, very fine and thin crystal
leaflets concentrically grouped, and in the alcoholic solution fine
irregular leaflets. Zaloziecki has recently developed these
microscopic investigations to a much greater extent. According to this
observer, the principal part of paraffine, as seen under the
microscope, consists of shining stratified leaflets with a darker
edge. The most characteristic and well developed crystals are formed
by dissolving paraffine in a mixture of ethyl and amyl alcohols and
chilling. The crystals are rhombic or hexagonal tablets or leaves, and
are quite regularly formed. They are unequally developed in different
varieties of paraffine. The best developed are those obtained from
ceresine. Their relative size and appearance give an indication as to
the purity of the paraffine, and, as they are always present, they are
to be counted among the characteristic tests for paraffine.
Reichenbach observed that mere traces of empyreumatic oil prevented
their formation.

The old method of determining the amount of paraffine in petroleum was
to carry out the refining process on a small scale; that is, to
distill the residue from the kerosene oils to coking, chill out the
paraffine, press it thoroughly between filter paper, and weigh the
residue. The sources of error in this procedure are manifold; the
principal one is the solubility of paraffine in oils, which depends
upon the character of both the paraffine and the oil, and also upon
the temperature. The next greatest source of error is variation in the
process of distillation and the difference between working on the
small scale and on the large scale.

In most cases, where a paraffine determination is to be carried out,
one has to deal with a mixture of paraffine with liquid oils. Now,
paraffine is not a substance defined by characteristic physical
properties which distinguish it from the liquid portions of petroleum.
It consists of a mixture of homologous hydrocarbons, which form a
solid under ordinary conditions. The hydrocarbons of this mixture show
a gradation in their properties, and gradually approximate to those
which are liquid at ordinary temperatures. It is a well known fact
that a separation of these homologues is entirely impossible by
distillation. It has also been ascertained that the liquid
constituents of petroleum do not always possess boiling points that
are lower than those of the solid constituents. This shows that we
have to deal not merely with hydrocarbons of one, but of several
series.

When determinations of the amount of paraffine are to be made, then it
becomes necessary to specify with exactness what is to be called
paraffine. The most definite property that can be made use of for this
purpose is the melting point. For several reasons it is convenient to
include under this name hydrocarbons of melting point as low as
35°-40° C.

The method proposed by Zaloziecki for the determination of paraffine
is the following: The most volatile portions of the petroleum are
separated by distillation, until the thermometer shows 200° C. These
portions are separated, as they exert great solvent action upon
paraffine. At the same time he finds that no pyro-paraffine is formed
under this temperature. A weighed portion of the residue is taken and
mixed with ten parts by weight of amyl alcohol and ten parts of
seventy-five per cent. ethyl alcohol: the mixture is then chilled for
twelve hours to 0° C. It is then filtered cold, washed first with a
mixture of amyl and ethyl alcohols, and then with ethyl alcohol alone.
The paraffine is transferred to a small porcelain evaporating dish and
dried at 110° C. It is then heated with concentrated sulphuric acid to
150°-160° C. for fifteen to thirty minutes with constant stirring. The
acid is then neutralized and the paraffine extracted by petroleum
ether. On evaporation of the solvent, the paraffine is dried at 100°
C. and weighed. Zaloziecki found, according to this method, in three
samples of Galician petroleums, 4.6, 5.8 and 6.5 per cent.,
respectively, of proto-paraffine. The method was carried out as above
with four samples of American petroleums, Colorado oil from Florence,
Col.; Warren County oil from Wing Well, Warren, Pa.; Washington oil
from Washington County, Pa.; Middle District oil from Butler County,
Pa., all furnished by Professor Sadtler.

They were very different in physical properties and in appearance, the
Colorado oil being a much heavier oil than the others and the
Washington oil being an amber oil, while the other two were of the
ordinary dark green color and consistence. The losses on distillation
to 200° C. were very different, being about one-tenth in the case of
the Colorado oil and nearly one-half in the case of the others. The
percentages of partially refined proto-paraffine in the four reduced
oils (all below 200° C. off) were as follows: for the Colorado oil,
23.9 per cent.; for the Warren oil, 26.5 per cent.; for the Washington
oil, 26.6 per cent.; and for the Middle District oil, 28.2 per cent.

The question now arises, What value has this determination of the
proto-paraffine which may exist in an oil? As before said, a portion
of the paraffine is always decomposed in distillation at temperatures
sufficiently high to drive over the paraffine oils, so the yield of
pyro-paraffine is always less than the proto-paraffine shown to be
present originally. Zaloziecki found this in the case of the several
Galician oils he examined. Corresponding to the 4.6, 5.8 and 6.5 per
cent. of proto-paraffine in the several oils he obtained 2.18, 2.65
and 2.35 per cent., respectively, of pyro-paraffine.

For the present, however, the extraction of proto-paraffine on a large
scale by means of such solvents as amyl and ethyl alcohols is out of
the question on account of their cost. A distillation, under reduced
pressure and with superheated steam, would, however, prevent much of
the decomposition of the original proto-paraffine and increase the
yield of pyro-paraffine.

This study of Zaloziecki's method and the examination of American oils
was suggested by Professor Sadtler and carried out in his laboratory.

       *       *       *       *       *




TRANSMISSION OF PRESSURE IN FLUIDS.

By ALBERT B. PORTER.


The young student of physics occasionally has difficulty in grasping
the laws of pressure in fluids. His every day experience has taught
him that a push against a solid body causes it to push in the same
direction, and he often receives with some doubt the statement that
pressure applied to a fluid is transmitted equally in every direction.
The experiments ordinarily shown in illustration of this principle
prove that pressure is transmitted in all directions, but do not prove
the equality of transmission, and in spite of all the text books may
tell him, the student is apt to cling to the idea that a downward
pressure applied to a liquid is more apt to burst the bottom than the
side of the containing vessel.

[Illustration: Figs. 1. and 2.]

The little piece of apparatus shown in Fig. 1 was designed to furnish
a clear demonstration of the principle under consideration. It is
essentially an arrangement by which a downward pressure is applied to
a confined mass of air or water, and the resultant pressures measured
in the three directions, down, up, and sideways. By means of a broken
rat tail file kept wet with turpentine three holes are bored through a
bottle, one through the bottom, one through the side, and one through
the shoulder, as near the neck as may be convenient. The operation is
quick and easy, the only precaution to be observed being to work very
slowly and use but a slight pressure when the glass is nearly
perforated. The holes may be enlarged to any size required by careful
filing with the wet file. From each of the holes a rubber tube leads
to one of the glass manometer tubes at the right in the figure, the
joints being made air tight by slipping into each rubber tube a piece
of glass tubing about half an inch long in order to swell it to the
size of the hole it is to fit. The ends of these glass tubes must be
well rounded by partial fusion in a gas flame, that there may be no
sharp edges to cut the rubber. The bottle rests in a depression in the
turned wood base, the lower rubber tube passing out through a hole in
the wood. Fig. 2 shows the shape of the manometer tubes. They are made
of quarter inch glass tubing bent to shape in a flame and left open at
both ends. They are mounted on a scale board which has several
equidistant horizontal lines running across it. The two bent wires
which support the scale board fit loosely in holes in it and in the
base. This method of mounting is very handy, since it permits the
scale board to be swung to right or left as may be convenient, or
turned round so as to show the fittings on its back, without moving
the bottle. The three manometers are filled to the same level with
mercury, the quantity being adjusted by means of a pipette. A
perforated rubber stopper, fitted with a glass tube on which is
slipped a rubber syringe bulb, completes the apparatus.

When the bulb is pinched between the fingers, the mercury is forced up
to the same height in each of the manometers, thus proving that the
pressure is exerted equally in the three directions, up, down, and
sideways. With the bottle filled with water the same effect follows,
the law being the same for liquids and gases. When using water in the
apparatus it is essential that the rubber tubes, as well as the
bottle, be filled, and when used in the class room it is better to
show the experiment with water first, it being easier and quicker to
empty the bottle and tubes than to fill them.

       *       *       *       *       *




PEAR DUCHESSE D'ANGOULEME.


Although well known to fruit growers and generally represented in all
parts of Britain, this noble French pear has not become a universal
favorite. If the quality of the fruit, independently of its fine,
handsome appearance, was bad, or even indifferent, it might be
exterminated from our lists, but this we know is not the case, as any
one who has tasted good samples grown in France, the Channel Islands,
and upon favorable soils in this country will bear out the statement
that the flavor is superb. Some fruits, we know, are quite incapable
of being good, as they have no quality in them; but here we have one
of the hardiest of trees, capable of giving us quantity as well as
quality, provided we cultivate properly. Pears, no doubt, are
capricious, like our seasons, but given a good average year, soils and
stocks which suit them, a light, warm, airy aspect, and good culture,
a great number of varieties formerly only good enough for stewing are
now elevated, and most deservedly so, to the dessert table. But,
assuming that some sorts known to be good do not reach their highest
standard of excellence every year, they are infinitely superior to
many of the old stewers, as they carry their own sugar, a quality
which fits them for consumption by the most delicate invalids. Indeed,
so prominently have choice dessert pears, and apples too for that
matter, come to the front for cooking purposes, that a new demand is
now established, and although Duchesse d'Angoulême, always juicy and
sweet, from bad situations does not always come up to the fine quality
met within Covent Garden in November, it is worthy of our skill, as we
know it has all the good points of a first rate pear when properly
ripened.

The original tree of this pear was observed by M. Anne Pierre
Andusson, a nurseryman at Angers, growing in a farm garden near
Champigne, in Anjou, and having procured grafts of it, he sold the
trees, in 1812, under the name of Poire des Eparannais. In 1820, he
sent a basket of the fruit to the Duchesse d'Angoulême, with a request
to be permitted to name the pear in honor of her. The request was
granted, and the pear has since borne its present name.

That such a fine pear, which does so well in France, would soon find
its way to England there exists little doubt, as we find that within a
few years it became established and well known throughout the United
Kingdom. All the earliest trees would be worked upon the pear or free
stock, and as root pruning until recently was but little practiced, we
may reasonably suppose that the majority of them are deeply anchored
in clay, marl, and other subsoils calculated to force a crude, gross
growth from which high flavored fruit could not be expected. These
defects under modern culture upon the quince and double grafting are
giving way, as we find, on reference to the report of the committee of
the pear conference, held at Chiswick in 1885, that twenty counties in
England, also Scotland, Ireland, and Wales, contributed no less than
121 dishes to the tables, and thirty-eight growers voted in favor of
the Duchesse being recognized as one of our standard dessert
varieties. This step looks like progress, as it is a record of facts
which cannot be gainsaid, and it now remains to be seen whether the
English grower, whose indomitable will has brought him to the front in
the subjugation of other fruits, will be successful with the fine
Duchesse d'Angoulême. Although this remarkable pear cannot easily be
mistaken, for the benefit of those who do not know it, the following
description may not be out of place. Fruit large, often very large, 3½
inches wide and 3 inches to 4 inches high, roundish obovate, uneven,
and bossed in its outline. Skin greenish yellow, changing to pale dull
yellow, covered with veins and freckles of pale brown russet, and when
grown against a south wall it acquires a brown cheek. Eye open, with
erect dry segments, set in a deep irregular basin. Stalk 1 inch long,
inserted in a deep irregular cavity. Flesh white, buttery, and
melting, with a rich flavor when well ripened; otherwise rather coarse
grained and gritty.

As to culture, experienced fruitists say the tree grows vigorously and
well. It bears abundantly, and succeeds either on the pear or quince
stock, forming handsome pyramids, but is better on the quince. Here,
then, we have the key to the secret of success: The cordon on the
quince; roots near the surface; loam, sound, sandy, and good; and good
feeding. Aspect, a good wall facing south or west--the latter,
perhaps, the best. Those who have not already done so, should try
trees on the quince as pyramids and bushes, as this, like some other
capricious pears, although the fruit be smaller, may put in better
flavor than is met with in fruit from hot walls.--_The Garden._

       *       *       *       *       *




SUCCESSION OF FOREST GROWTHS.


The following is from an address delivered by Mr. Robert Douglas
before the Association of American Nurserymen at the meeting in
Chicago recently.

It is the prevailing and almost universal belief that when native
forests are destroyed they will be replaced by other kinds, for the
simple reason that the soil has been impoverished of the constituents
required for the growth of that particular tree or trees. This I
believe to be one of the fallacies handed down from past ages, taken
for granted, and never questioned. Nowhere does the English oak grow
better than where it grew when William the Conqueror found it at the
time he invaded Britain. Where do you find white pines growing better
than in parts of New England where this tree has grown from time
immemorial? Where can you find young redwoods growing more thriftily
than among their giant ancestors, nearly or quite as old as the
Christian era?

The question why the original growth is not reproduced can best be
answered by some illustrations. When a pine forest is burned over,
both trees and seeds are destroyed, and as the burned trees cannot
sprout from the stump like oaks and many other trees, the land is left
in a condition well suited for the germination of tree seeds, but
there are no seeds to germinate. It is an open field for pioneers to
enter, and the seeds which arrive there first have the right of
possession. The aspen poplar (_Populus tremuloides_) has the advantage
over all other trees. It is a native of all our northern forests, from
the Atlantic to the Pacific. Even fires cannot eradicate it, as it
grows in moist as well as dry places, and sprouts from any part of the
root. It is a short-lived tree, consequently it seeds when quite young
and seeds abundantly; the seeds are light, almost infinitesimal, and
are carried on wings of down. Its seeds ripen in spring, and are
carried to great distances at the very time when the ground is in the
best condition for them. Even on the dry mountain sides in Colorado,
the snows are just melting and the ground is moist where they fall.

To grow this tree from seed would require the greatest skill of the
nurseryman, but the burnt land is its paradise. Wherever you see it on
high, dry land you may rest assured that a fire has been there. On
land slides you will not find its seeds germinating, although they
have been deposited there as abundantly as on the burned land.

Next to the aspen and poplars comes the canoe birch, and further north
the yellow birch, and such other trees as have provision for
scattering their seeds. I have seen acorns and nuts germinating in
clusters on burned lands in a few instances. They had evidently been
buried there by animals and had escaped the fires. I have seen the red
cherry (_Prunus Pennsylvanica_) coming up in great quantities where
they might never have germinated had not the fires destroyed the
debris which covered the seed too deeply.

A careful examination around the margin of a burned forest will show
the trees of surrounding kinds working in again. Thus by the time the
short-lived aspens (and they are very short-lived on high land) have
made a covering on the burned land, the surrounding kinds will be
found re-established in the new forest, the seeds of the conifers,
carried in by the winds, the berries by the birds, the nuts and acorns
by the squirrels, the mixture varying more or less from the kinds
which grew there before the fire.

It is wonderful how far the seeds of berries are carried by birds. The
waxwings and cedar birds carry seeds of our tartarean honeysuckles,
purple barberries and many other kinds four miles distant, where we
see them spring up on the lake shore, where these birds fly in flocks
to feed on the juniper berries. It seems to be the same everywhere. I
found European mountain ash trees last summer in a forest in New
Hampshire; the seed must have been carried over two miles as the crow
flies.

While this alternation is going on in the East, and may have been
going on for thousands of years, the Rocky Mountain district is not so
fortunate. When a forest is burned down in that dry region, it is
doubtful if coniferous trees will ever grow again, except in some
localities specially favored. I have seen localities where short-lived
trees were dying out and no others taking their places. Such spots
will hereafter take their places above the timber line, which seems to
me to be a line governed by circumstances more than by altitude or
quality of soil.

There are a few exceptions where pines will succeed pines in a
burned-down forest. _Pinus Murrayana_ grows up near the timber line in
the Rocky Mountains. This tree has persistent cones which adhere to
the trees for many years. I have counted the cones of sixteen years on
one of these trees, and examined burned forests of this species, where
many of the cones had apparently been bedded in the earth as the trees
fell. The heat had opened the cones and the seedlings were growing up
in myriads; but not a conifer of any other kind could be seen as far
as the fire had reached.

In the Michigan Peninsula, northern Wisconsin and Minnesota, _P.
Banksiana_, a comparatively worthless tree, is replacing the valuable
red pine (_P. resinosa_), and in the Sierras _P. Murrayana_ and _P.
tuberculata_ are replacing the more valuable species by the same
process.

In this case, also, the worthless trees are the shortest lived. So we
see that nature is doing all that she can to remedy the evil. Man only
is reckless, and especially the American man. The Mexican will cut
large limbs off his trees for fuel, but will spare the tree. Even the
poor Indian, when at the starvation point, stripping the bark from the
yellow pine (_P. ponderosa_), for the mucilaginous matter being formed
into sap wood, will never take a strip wider than one third the
circumference of the tree, so that its growth may not be injured.

We often read that oaks are springing up in destroyed forests where
oaks had never grown before. The writers are no doubt sincere, but
they are careless. The only pine forests where oaks are not intermixed
are either in land so sandy that oaks cannot be made to grow on them
at all, or so far north that they are beyond their northern limit. In
the Green Mountains and in the New England forests, in the pine
forests in Pennsylvania, in the Adirondacks, in Wisconsin and
Michigan--except in sand--I have found oaks mixed with the pines and
spruces. In northwestern Minnesota and in northern Dakota the oaks are
near their northern limit, but even there the burr oak drags on a bare
existence among the pines and spruces. In the Black Hills, in Dakota,
poor, forlorn, scrubby burr oaks are scattered through the hills among
the yellow pines. In Colorado we find them as shrubs among the pines
and Douglas spruces. In New Mexico we find them scattered among the
piñons. In Arizona they grow like hazel bushes among the yellow pines.
On the Sierra Nevada the oak region crosses the pine region, and
scattering oaks reach far up into the mountains. Yet oaks will not
flourish between the one hundredth meridian and the eastern base of
the Sierras, owing to the aridity of the climate. I recently found
oaks scattered among the redwoods on both sides of the Coast Range
Mountains.

Darwin has truly said, "The oaks are driving the pines to the sands."
Wherever the oak is established--and we have seen that it is already
established whereever it can endure the soil and climate--there it
will remain and keep on advancing. The oak produces comparatively few
seeds. Where it produces a hundred, the ash and maple will yield a
thousand, the elm ten thousand, and many other trees a hundred
thousand. The acorn has no provision for protection and transportation
like many tree seeds. Many kinds are furnished with wings to float
them on the water and carry them in the air. Nearly every tree seed,
except the acorn, has a case to protect it while growing, either
opening and casting the seeds off to a distance when ripe or falling
with them to protect them till they begin to germinate. Even the
equally large seeds of other kinds are protected in some way. The
hickory nut has a hard shell, which shell itself is protected by a
strong covering until ripe. The black walnut has both a hard shell and
a fleshy covering. The acorn is the only seed I can think of which is
left by nature to take care of itself. It matures without protection,
falls heavily and helplessly to the ground, to be eaten and trodden on
by animals, yet the few which escape and those which are trodden under
are well able to compete in the race for life. While the elm and maple
seeds are drying up on the surface, the hickories and the walnuts
waiting to be cracked, the acorn is at work with its coat off. It
drives its tap root into the earth in spite of grass, and brush, and
litter. No matter if it is shaded by forest trees so that the sun
cannot penetrate, it will manage to make a short stem and a few leaves
the first season, enough to keep life in the root, which will drill in
deeper and deeper. When age or accident removes the tree which has
overshadowed it, then it will assert itself. Fires may run over the
land, destroying almost everything else, the oak will be killed to the
ground, but it will throw up a new shoot the next spring, the root
will keep enlarging, and when the opportunity arrives it will make a
vigorous growth, in proportion to the strength of the root, and throw
out strong side roots, and after that care no more for its tap root,
which has been its only support, than the frog cares for the tail of
the tadpole after it has got on its own legs.

There is no mystery about the succession of forest growths, nothing in
nature is more plain and simple. We cannot but admire her wisdom,
economy, and justness, compensating in another direction for any
disadvantage a species may have to labor under. Every kind of tree has
an interesting history in itself. Seeds with a hard shell, or with a
pulpy or resinous covering which retards their germination, are often
saved from becoming extinct by these means.

The red cedar (_Juniperus Virginiana_) reaches from Florida to and
beyond Cape Cod; it is among the hills of Tennessee, through the
Middle States and New England. It is scattered through the Western
States and Territories, at long distances apart, creeping up the
Platte River, in Nebraska. (I found only three in the Black Hills, in
Dakota, in an extended search for the different trees which grow
there. Found only one in a long ramble in the hills at Las Vegas, New
Mexico.) Yet this tree has crept across the continent, and is found
here and there in a northwesterly direction between the Platte and the
Pacific Coast. It is owing to the resinous coating which protects its
seeds that this tree is found to-day scattered over that immense
region.

       *       *       *       *       *

[NATURE.]




THE "HATCHERY" OF THE SUN-FISH.


I have thought that an example of the intelligence (instinct?) of a
class of fish which has come under my observation during my excursions
into the Adirondack region of New York State might possibly be of
interest to your readers, especially as I am not aware that any one
except myself has noticed it, or, at least, has given it publicity.

The female sun-fish (called, I believe, in England, the roach or
bream) makes a "hatchery" for her eggs in this wise. Selecting a spot
near the banks of the numerous lakes in which this region abounds, and
where the water is about 4 inches deep, and still, she builds, with
her tail and snout, a circular embankment 3 inches in height and 2
thick. The circle, which is as perfect a one as could be formed with
mathematical instruments, is usually a foot and a half in diameter;
and at one side of this circular wall an opening is left by the fish
of just sufficient width to admit her body, thus:

[Illustration]

The mother sun-fish, having now built or provided her "hatchery,"
deposits her spawn within the circular inclosure, and mounts guard at
the entrance until the fry are hatched out and are sufficiently large
to take charge of themselves. As the embankment, moreover, is built up
to the surface of the water, no enemy can very easily obtain an
entrance within the inclosure from the top; while there being only one
entrance, the fish is able, with comparative ease, to keep out all
intruders.

I have, as I say, noticed this beautiful instinct of the sun-fish for
the perpetuity of her species more particularly in the lakes of this
region; but doubtless the same habit is common to these fish in other
waters.

William L. Stone.

Jersey City Heights, N.J.

       *       *       *       *       *




ANCIENT LAKE DWELLINGS.


Among the many traces which man has left of his existence in long past
ages on the face of the earth, says a correspondent of the _Scotsman_,
none are more interesting and instructive than the lake dwellings of
Switzerland and other countries, which have been discovered within the
last fifty years or so. Although these relics of the past are far more
modern than those which we referred to in a late article on "Primeval
Man," and are probably included within the range of Egyptian and
other chronologies, yet they stretch far beyond the historic period,
so far as Europe is concerned, and throw a flood of light on the
habits of our ancestors, or at any rate predecessors, in these
regions. We are tolerably well acquainted with the history of the Jews
when David worked his way up from the shepherd's staff to the royal
scepter, or when Joshua drove out the Canaanites and took possession
of their land, but of what was going on in Europe in these times we
have hitherto had no knowledge whatever. These lake dwellings,
however, were in all probability inhabited by human beings somewhere
about the time when the events we have referred to took place, and may
have been inhabited before the earlier of them.

The first hint we had of the existence of these remarkable dwellings
was obtained in 1829, when an excavation was being made on the shore
of a Swiss lake. Some wooden piles, apparently very old, and other
antiquities were found by the workmen. Not much attention, however,
was paid to this discovery till 1854, when a Mr. Aeppli drew attention
to some remains of human handiwork found near his house, in part of
the bed of a lake which had been left dry during a season of great
drought. The workmen employed in recovering some land from the lake
found the heads of a great many wooden piles protruding through the
mud, and also a number of stags' horns, and implements of various
descriptions. Stimulated by this discovery, search was made in various
lakes, and the result was truly astonishing. In every direction
remains of the habitations of prehistoric man were discovered, and
relics were found in such abundance that the history of this unknown
past could be traced through long ages, and the habits of the people
ascertained with a very considerable amount of probability. The
details are so numerous that it would be impossible in the space at
our disposal to go into them all.

Of course, during the long time that has elapsed since these
structures were erected, their remains have been reduced to mere
ruins, and it is only by comparing one with another that we are able
to picture to ourselves what they were originally like and what sort
of life was led by the men who inhabited them. The oldest of these
dwellings belong to the stone age, when man had not acquired any
knowledge of the use of metal; when all his instruments were merely
sharpened stones, fixed in wooden handles, or pieces of bone, horn, or
other natural material. They are therefore somewhat roughly finished,
but at the same time exhibit considerable ingenuity and skill. The
method of construction seems to have been somewhat as follows: A
suitable situation, not far from the shore, where the water was not
very deep, having been fixed upon, these prehistoric builders drove
into the muddy bottom of the lake a number of piles or long stakes,
arranged generally pretty close together, and in some sort of regular
order. These piles were formed generally from stems of trees, with the
bark on, but occasionally from split wood. The ends were sharpened to
a point by the aid of fire or by cutting with stone axes. On a
sufficient number being driven in, and their upper ends brought to a
level above the surface of the water, platform beams were laid across,
fastened by wooden pegs, or in some cases fixed into notches cut in
the heads of the vertical piles. The platform was generally very
roughly made, just a series of unbarked stems placed side by side and
covered with layers of earth or clay, with numerous openings through
which refuse of all kinds fell into the water beneath. In many cases
connection with the shore was made by means of a narrow bridge or
gangway, constructed in the same manner. On this rude platform huts
were erected by driving small piles or stakes which projected above
the floor, and to these were fastened boards standing edgeways like
the skirting of our ordinary rooms, and marking out the size of each
building. The walls of the huts were formed of small branches of twigs
interwoven and plastered over with clay. The roof was made of straw or
reeds like a thatched cottage. In size these huts were probably
eighteen to twenty feet long, eight or ten feet broad, and about six
feet high. They may have been divided into rooms, but there is no
evidence of this. Each was provided with a hearth formed of three or
four slabs of stone. The number of huts in each settlement must have
been considerable, in fact, they must have formed villages of no mean
extent, for as many as forty, fifty, or even a hundred thousand piles
have been found spread over a large extent of ground, forming the
foundation of one such settlement. It is probable, however, that these
were not so numerous when first erected, but were gradually added to
as the population increased. This fact, along with many others, shows
that these dwellings were inhabited for long periods of time, during
which the population pursued their ordinary life in comparative peace
and quietness in their island homes.

Such is, in brief, a general account of these remarkable structures.
Of course there were several variations in the methods of fixing these
piles, one of which may be mentioned as showing the ingenuity of the
builders. Where the piles did not get a firm hold of the lake bottom,
they carried out in boats or rafts loads of stones, which they threw
down between the piles, thus firmly fixing them, just as modern
engineers sometimes do for a similar purpose. As to the habits of the
people who dwelt in these lake dwellings, we get a considerable amount
of information from the various implements, refuse, etc., which fell
through the imperfectly closed platforms into the lake, and which have
been preserved in the mud at the bottom. They were fishers, hunters,
shepherds, and agriculturists. Skeletons of fish are found in large
abundance, and in some settlements even the fishing nets, and hooks
made of boar's tusks, have been discovered. Then again there is an
abundance of remains of the hunter's feast; bones of the stag, wild
boar, bear, wolf, otter, squirrel, and many other wild animals are
found in rich profusion, and often these are split and the marrow
extracted. These ancient men, however, did not entirely rely on such
precarious provision for their wants, but were so far advanced in
civilization that they kept cattle and domestic animals of various
kinds. They possessed dogs in great numbers, as well as cows, sheep,
goats, and pigs, and in winter time had these housed on their
settlements, as among the remains found are litters of straw, etc.,
which had evidently served as bedding for these animals. This, of
course, necessitated the gathering of grass or other material for
their food. They also cultivated wheat, barley, flax, and a number of
other vegetable products. Their methods of cultivation were no doubt
very rude, consisting of a mere scratching of the ground with crooked
branches of trees or with simple instruments made of stags' horn; but,
nevertheless, they succeeded in getting very good results. Among the
relics which they have left are found stones for crushing corn, the
grain which they used, and even the very cakes or bread which they
made. There are also fruits, such as the apple, pear, nut, etc.; so
that the bill of fare of prehistoric man was by no means contemptible.
He had fish, game, beef, mutton, pork, bread, and fruit, besides a
plentiful supply of water from the lake at his door. He was acquainted
with the potter's art, and manufactured earthen vessels of various
kinds. He seems to have produced two kinds--a coarser and a finer; the
former made from clay mixed with a quantity of grains of stone, and
the latter of washed loam. These he ornamented in an elementary
fashion with certain lines and marks. Some of the vessels he used have
been found with a burnt crust of the porridge which he had been making
adhering. As to his clothes, these were probably formed in great part
from the skins of wild or domestic animals, but he also used fabrics
made from flax, which he had learned to weave, as remains of cloth,
twine, rope, etc., are not infrequently found in his dwellings.

One prominent feature in the history of these lake dwellers is their
gradual advance in the arts of civilization. While the main features
of their settlements remain very much the same during the whole period
of their residence, there is a gradual improvement in the details; the
settlements become larger, and the implements, etc., better finished.
And this is especially observable in the change of material which the
dweller uses. In the earlier stages of his existence stone is the
predominant feature, all his knives, saws, chisels, axes, etc., are
made from this substance; but as time rolls on, one or two implements
are found made of bronze, which is a mixture of tin and copper, and
requires for its production a certain amount of knowledge and
mechanical skill. Gradually the number of bronze implements increases
until eventually stone is superseded altogether, and improved forms of
weapons of war make their appearance, and his work has a more finished
look, arising from his improved implements. Whether the manufacture of
bronze was an original discovery of his own, or whether it was an
importation from some more advanced race, is not certainly known; but
as he undoubtedly had intercourse with the East, it is probable that
the first bronze was imported, and that afterward he discovered the
way to manufacture it himself. However this may be, it seems evident
that the introduction of this material greatly aided his development.
As stone gave place to bronze, so in the course of time this latter
gave place to iron, probably introduced in the same manner some
considerable time before the dawn of history; and this metal held its
place until these habitations were finally abandoned.

With regard to the religion of these lake dwellers, if they had any,
nothing is known. From some curious objects formed somewhat like the
crescent of the moon, which are found in considerable numbers, it has
been supposed that they worshiped that body; but there seems to be
really no evidence for this supposition, and these objects may only
have been ornaments, or perhaps charms, fixed above the doors of their
huts something after the manner of the horse shoe nailed over the door
in modern times to keep away evil spirits. So far as can be inferred
from the remains that have been examined, the same race seems to have
inhabited these dwellings from their commencement to their end. There
is no appearance of invasion from without; all seems continuous.
Probably his race came in early time from the East, and were a
pastoral people, with flocks, herds, and domestic animals, and built
their peculiar habitations to protect themselves from human enemies.
Certainly the arrangements were well fitted for the purpose in those
days, when the club and the spear were almost the only weapons of
offense. Dr. Keller, who has investigated this subject with great
care, is of the opinion that these lake dwellers were a branch of the
great Celtic race.

       *       *       *       *       *

[New England Farmer.]




HOW TO RAISE TURKEYS.


The best feed for young turkeys and ducks is yelks of hard-boiled
eggs, and after they are several days old the white may be added.
Continue this for two or three weeks, occasionally chopping onions
fine and sometimes sprinkling the boiled eggs with black pepper; then
give rice, a teacupful with enough milk to just cover it, and boil
slowly until the milk is evaporated. Put in enough more to cover the
rice again, so that when boiled down the second time it will be soft
if pressed between the fingers. Milk must not be used too freely, as
it will get too soft and the grains will adhere together. Stir
frequently when boiling. Do not use water with the rice, as it forms a
paste and the chicks cannot swallow it. In cold, damp weather, a half
teaspoonful of Cayenne pepper in a pint of flour, with lard enough to
make it stick together, will protect them from diarrhea. This amount
of food is sufficient for two meals for seventy-five chicks. Give all
food in shallow tin pans. Water and boiled milk, with a little lime
water in each occasionally, is the best drink until the chicks are two
or three months old, when loppered and buttermilk may take the place
of the boiled milk. Turkeys like best to roost on trees, and in their
place artificial roots may be made by planting long forked locust
poles and laying others across the forks.--_American Agriculturist._


HOW TO RAISE TURKEYS.

Keep the turkey hens tame by feeding them close to the house. Have two
or three barrels in sheltered corners containing plenty of straw or
leaves for them to lay in. Gather the eggs every evening, as turkey
eggs are very easily chilled. Keep the eggs in a woolen cloth on end
and turn them every three days. Set the first seven eggs under a
chicken hen, as they get too old before the turkey hen will go to
sitting. Make a board pen ten or twelve feet square and twelve or
fourteen inches high. Put a coop in it and put your hen and turkeys in
it. Feed the hen with corn and the turkeys soaked wheat bread (corn
meal will kill them), until they are a week old (I feed five or six
times a day). Then feed wheat until they are big enough to eat corn.
Give plenty of fresh water in a shallow vessel. Keep the mother in
the pen until they are large enough to fly over the top of the boards.
Let them out awhile about the middle of the day. Shut them in at
night. A turkey hen does not like to be shut up, but have a good big
coop for her and she will go in. Don't let the little turkeys get
their backs wet until they are feathered. The turkey hen will sit down
when night comes just where she happens to be, but if you drive her
home a few times she will come herself after that. Always feed them
when they come home, no matter if they are full of "hoppers." Have
your No. 2 pen in the orchard under an apple tree where it is shady.
Have the turkey hen's pen close to the chicken hen's pen, so that when
the chicken hen weans her turkeys, they will soon learn to go with the
turkey hen. Give them a dose of black pepper in their feed every cold
rain. And never, no never, get excited and in a hurry while working
with turkeys if you don't want them to get wild and fly all over the
plantation. Three or four weeks before selling, feed all the corn they
will eat.


FOOD HINTS.

Restrain your desire to count your young turkeys, and let them alone
for twenty-four hours after they get into this world. Remove them to a
clean, airy, roomy coop, and give them boiled eggs, stale wheat bread
crumbs just moistened with milk or water, "Dutch" cheese, or a mixture
of all these.

For the first two weeks feed entirely with the eggs, bread, curds,
cooked rice and cooked oatmeal. About the third week commence feeding
cooked cornmeal; and from that on they may have any cooked food that
would be suitable for chickens of the same age. Season all food
slightly with salt and pepper, and twice a week add a level
tablespoonful of bone meal to a pint of feed. Never feed any sour food
or sloppy food of any kind, except sour milk, and never feed any
uncooked food of any kind until after they have thrown out the red on
their heads. Feed often, five or six times a day, until after they are
three months old; then, if insects are numerous, you may gradually
reduce the number of meals per day to three or even two.

After they are three months old they may be given wheat, cracked corn,
etc., but not whole corn until they are five months old. Keep the
coops dry and clean, and the turkeys out of the dew and rain until
they are fully feathered, and have thrown out the red. Dampness and
filth will kill young turkeys as surely as a dose of poison. For the
first few days confine the poults to the limits of the coop and safety
run; then, if all appear strong and well, give the mother hen and her
brood liberty on pleasant days after the dew is off.

If they get caught out in a shower, get them to shelter as soon as
possible; and if they are chilled take them to the house and
thoroughly dry and warm them. See that the little turkeys come home
every night. The turkey mother must, for the first few nights, be
hunted up and driven home. After they are three months old, turkeys
are quite hardy, and may be allowed range at all times. If turkeys
that are well cared for, and have always seemed all right, show signs
of drooping when about six weeks or two months old, give Douglas
mixture in the drink or food, and add a little cooked meat to the food
once a day.--_The Practical Farmer._


ABOUT SITTING.

For an ordinary place, select from a good breed (I prefer the bronze)
a large gobbler and two or three hens. As soon as the warm weather
comes, place about the barn in sheltered places two or three barrels
on their sides, and in them make nice nests. In these the hens will
lay. Gather the eggs every day, keeping them in a cool place. When a
box contains 23 eggs mark it No. 1 and begin to fill a second box, and
when it contains 23 eggs mark it No. 2 and so continue. It is well to
leave turkey hens on the nest two or three days, for they often lay
one or two eggs after they begin to show signs of sitting.

When you have decided to sit a hen, give her a good nest and 15 eggs
and at the same time give a common hen eight eggs. These, when
hatched, are all to be given to the turkey hen. Never try to raise
turkeys with a domestic fowl. If you have no place free of grass, you
can start turkeys with difficulty. Feeding is of the greatest
importance. For the first week I have found wheat bread moistened in
water the most satisfactory. If you can feed them by sunrise for the
first three or four weeks, you need lose hardly a bird. Each evening
try and call them nearer and nearer home, so that you will not be
troubled with their wandering to the neighbors'. As early as possible
train them to roost high, so as to be out of danger at night. Bird
dogs are often very destructive to turkeys, at times destroying a
whole flock in a single night. Fatten with corn. The turkey crop ought
to be one of the most profitable on our farms.

Dr. G.G. GROFF.
Pennsylvania.


GRAHAM.

Turkeys want care, especially for the first two or three weeks. I feed
graham and wheat bread, made by scalding the flour, making a very
stiff dough, and baking in a hot oven; soak over night in cold water.
I also give them plenty of young onions, cutting them up with
scissors. Be careful not to let young turkeys out in the morning while
the grass is wet. After the birds are two weeks old I feed wheat, but
no corn until they are about a month old. I like hen mothers best, for
turkey mothers are rangers, and do not take kindly to being kept in a
coop. The bread will keep a week if made right, but do not soak more
than will be wanted in a day, as it soon sours. I feed scraps from the
table, such as potatoes and bits of meat cut very fine, but not much
of the latter to young birds. I rarely lose a bird.--_Mrs. E. Reith,
in Homestead._


CARE AND GENERAL MANAGEMENT.

In turkey raising the one who is the most careful and attentive to the
small things is the most successful. The first laying of eggs should
be set under a chicken hen. The turkey hen will, after a few days'
confinement, lay another batch of eggs. A good-sized hen will cover
and care for ten eggs; a turkey hen, seventeen. Make a large, roomy
nest of soft, fine hay--straw is too brittle and slippery. If there is
danger of lice in the nest-box, sprinkle with water in which carbolic
acid has been mixed in the proportion of eight drops to a half gallon
of water. Don't wet the eggs with this. After the eggs have been sat
on one week, sprinkle with warm water every other day, until the last
week; then every day, until they hatch. Have the water clear, and use
a flower or fine rose sprinkler. Let the water be of the same
temperature as the eggs, which can be ascertained by slipping a
thermometer under the hen for a few minutes. This softens the shells,
and as a little turkey is very weak, it is helped out easily, and is
stronger than if working long to get out.

Let the little turkeys get well dried and strong enough to climb
around the edges of their nest before taking them off. Have a pen, say
six feet square, built for them, and made tight at the sides clear
down to the ground, to keep them from getting out and being chilled.
Put sand and fine gravel over the ground, and cover enough of it to
afford shelter at night and when it rains. They may be kept in this
pen the first four or five days, then let out after dew is off, and
shut up before night.

For the first few days' feed, nothing is better than clabber cheese or
curd made by scalding clabbered milk until the curd separates and is
cooked, then skimmed out and fed. Mix a little black pepper with this
every other day. Meal must not be fed raw for several weeks, and then
should be mixed with sour milk instead of water. Bake the meal into
bread by mixing it, unsifted, with sour milk, and adding a little soda
and pepper. Spinach, lettuce, onion tops and any other tender greens,
chopped fine, are excellent food. From the time a turkey is hatched
until it is ready for market it should have plenty of milk. Give them
clear water to drink, for milk is a food. See that the very young ones
have milk and water in quite shallow dishes, for they are in danger of
getting wet if the dish is deep.


GATHER THE LITTLE TURKEYS IN

at the first signs of rain, and they will soon learn to run and fly to
their coop at the first drops. Always shut them up at night, for they
are early risers and will be out long before the dew is dried off.
Don't pen them too near the house. Feed them at or near the same place
all the time and they will learn to go there when hungry. Give them a
good feed at night and they will remember to come home for it. If the
morning is dry, feed lightly and let them hunt the rest in the orchard
and fields. Keep the grass and weeds mowed around their pen and
feeding places. Mix slaked lime in the dust for them to take their
dust bath in, and sprinkle the carbolic acid and water over and around
their roosting pen. Keep pails and kettles covered, for they will get
drowned if they have half a chance, as they begin to fly so young. Of
course a turkey hen will take her young off, and care for them after a
fashion, but the safest way to make them tame is to raise them where
they may be cared for. Even if the turkey hen hatches her last batch
of eggs, it is a good plan to have a hen ready to take the little
turkeys and slip them away at night. If she still stays on her nest
give her 20 or 25 hen's eggs, and if she hatches them let her run with
the chickens. They are not so tender or so easily led astray as
turkeys are, nor as valuable.--_Mrs. Jas. R. Hinds, in Orange Judd
Farmer._

       *       *       *       *       *




WATER AS A THERAPEUTICAL AGENT.

By F.C. ROBINSON, M.D.


My experience in the use of water in almost every disease occurring in
this climate has long since satisfied me that it is less objectionable
and produces quicker and better results than any other treatment, and
can be used when all other medication is contra-indicated. Drinking
water should be pure, uncontaminated by animal or vegetable
impurities, and given _ad libitum_, unless, in rare instances, it
should cause vomiting or interfere with the capability of digesting
food. If children are comatose or delirious, as they frequently are in
typhoid fever, give water to them regularly, or force it upon them, if
they refuse to take it, as I was obliged to do with a child of six
years just recovering from that fever.

It is my custom to allow cold drinks of water in all cases of measles
whenever patients desire it, and I am satisfied that it aids the early
appearance of the rash, and certainly is cooling and grateful to the
patient. Hot drinks or vile and nauseous teas are unnecessary in this
disease, and should be discarded as useless, odious, and disgusting.
If congestion of the lungs or any intercurrent inflammation occurs, or
the rash is much delayed, a hot water bath or the old reliable corn
sweat will break up the complication with amazing rapidity, and if the
head is kept cool, will not generally be unacceptable to the patient.

Hot baths reduce temperature by causing free perspiration afterward,
and cold packs reduce it by cooling the surface sufficiently long to
reduce the heat of the blood, and, if used judiciously, seldom fail of
success. I have reduced the temperature four degrees in two hours by
wrapping around a child a sheet wet with tepid water, and no other
covering. Cold packs are sometimes objectionable, because of their
depressing effects, and should only be used to reduce high temperature
and when there is no congestion or inflammation of any of the vital
organs of the body.

Cold water poured in a small stream from a pitcher upon the head for
five or ten minutes will often relieve headache, and is a benefit in
all inflammatory brain diseases, if, at the same time, you can put the
feet into hot water containing mustard or pepper.

Large enemas of warm water will care for spasmodic colic, and I have,
in one instance, relieved strangulated hernia by the same method, and
at another time the same result was accomplished by a large injection
of warm linseed oil. I have often applied a cloth wet with cold water
upon the throats of children suffering with spasmodic croup, with
satisfactory results.

I have seen infants suffering with diarrhea or summer complaint,
sleepless, worrying, fretting, or crying from thirst, begging for
water, and the mother or nurse afraid to give it more than a
teaspoonful or two at a time, saying that it vomited everything it
drank as soon as taken. I have often, when visiting such cases, called
for a glass of cold water, and, to the surprise of the mother, would
allow it to take all it could drink, which usually would be retained,
and the child would soon be wrapped in a refreshing sleep. Without
medicine, a proper regulation of the child's diet would soon restore
it to health again.

The spasms of children, from whatever causes, or the eclampsia from
uræmic poisoning, are often readily controlled when immersed in hot
water or given a hot vapor bath or corn sweat. If the convulsions of
children are accompanied by a high temperature, put them into water of
100° and then gradually cool it down to 68° or 70°, and then keep them
in a room of the same temperature, with little covering. If the
temperature rises, repeat the treatment as frequently as necessary,
and I think you will not be disappointed in the results.

Scarlet fever and diphtheria, two of the most dreaded and formidable
diseases of children, are largely shorn of their terrors when, in
addition to an early and thorough medicinal treatment, the little
patients are bathed in as warm water as the surface will allow
frequently, or for thirty minutes wrapped in a warm, wet blanket,
followed by warm, dry coverings, to maintain the perspiration that
such treatment usually produces. It has proved to me a valuable aid in
eliminating from the blood the specific poison which causes these
diseases, and I can safely recommend it to your notice and trial.

There is no disease more favorably influenced by this treatment than
pneumonia, and in mild cases one daily warm bath or sweat, without
medicine, will be sufficient to arrest this disease, and it is among
the first things I usually order. If I find a child or infant with a
temperature of 103° to 105°, short, dry, and painful cough,
dyspnoea, rapid pulse, great thirst, or vomiting, with dry
crepitation in any part of the lung tissue, I order it rolled up in a
blanket or sheet coming out of hot water, and in thirty minutes change
it to warm, dry blankets, and soon the little fretful, worrying
sufferer would rest in a quiet, peaceful sleep.--_Peoria Med. Mo._

       *       *       *       *       *




ON THE HEALTH VALUE TO MAN OF THE SO-CALLED DIVINELY BENEFICENT
GIFT, TOBACCO.

By J.M.W. KITCHEN, M.D., New York.


With perhaps the exception of heredity, the question of stimulants and
narcotics in their relation to the physical welfare of the race is
second to none in importance. With trifling exceptions, the whole
world is addicted to their use. The universality of such use has led
many to consider them a necessity to man, and that they are God's
gifts to him, and, if rightly used, are of physical benefit. It may
not be a perversion of judgment to consider that their widespread
popular use is greatly due to the efforts of the race to gain
anæsthesia for, and distraction from, those pains and punishments that
are the inevitable sequence of departure from hygienic and social law
on the part of the individual, his ancestry, and society in general.

The taste for these things is acquired, not natural, though the
acquisition may be through hereditary influence. An idea is held by a
majority of even fairly intelligent individuals that there is a
justifiable, harmless, and even beneficial use of these substances by
the general public, though acknowledging that beyond a certain
indefinite line this use becomes an abuse.

I believe that there may occasionally be cases in which the physical
benefits derived from their use outweigh the injury they inflict, but
I think this use is very much less than is generally supposed, and if
we can judge from the preponderance of evil effected by such use,
these substances ought to be considered as the materialized curses of
God rather than as beneficent gifts. The prevalent idea as to the
beneficent nature of these substances I consider to be a delusion that
can only be explained upon the hypothesis that there is a widespread
lack of appreciation of the fact that, though they may have an
immediate pleasant and agreeable effect upon the body, their injurious
effects are cumulative, and are usually ultimate, and so distant as to
be difficult of direct connection with their cause to ordinary
observation. The more moderate the use of these substances, the more
remotely is the effect removed from the cause and more difficult of
detection. That the ordinary habitual, so-called moderate use of
stimulants and narcotics, such as tea, coffee, tobacco, and alcohol,
is, in the vast majority of cases, really an abuse, is a proposition
that I think should be admitted by all who have given the subject an
unbiased study.

The idea that the user of tobacco and other injurious substances will
be cognizant of the injury inflicted by habitual use in moderate or
even excessive amounts is an undoubted fallacy. The daily, weekly, or
monthly injurious effect may be entirely unobservable to even trained
physicians, and yet the ultimate cumulative effect may be fatal. I can
instance numerous cases of physicians directly fatally injured by the
use of alcohol, who have never had the slightest cognizance of the
fact; and I can also instance cases of grave disease from the use of
tobacco where the patients never have believed that tobacco has been
the cause of their troubles, even after a unanimous opinion to that
effect has been expressed by a number of competent medical advisers.
The habitual consumption of opium, in doses of any amount, is
generally admitted by most people to be physically injurious outside
of its strict medicinal application. Moderate indulgence in alcohol as
a beverage is beginning to acquire a very widespread evil reputation.
But how about tobacco? Tea and coffee we can confidently leave to the
consideration of a somewhat remote posterity of a considerably
advanced intelligence and elevated hygienic ideals.

The relation of tobacco to the physical welfare of man can only be
fairly estimated by viewing the subject in its broadest aspect; by
considering its effects upon the race as a whole rather than in
individual cases; by taking into consideration economical and other
social conditions that at first sight might be considered as having
little relevancy to the medical side of the subject. But there can be
no just consideration of the matter otherwise. The direct deleterious
effects of the immoderate use of tobacco are readily observable; but
the great bulk of the evil physical effects due to the moderate use of
this plant are of an intermediate nature and not directly noticeable;
nevertheless, they are real, and worthy of medical attention. The
plainly marked results following the use of tobacco in relatively
large amounts seem to be due to quick and extreme interference with
nutrition, and a diminution of function of all kinds, which may be
represented by anything from a slight decrease of appetite and
digestive ability up to a complete loss of function of almost any
important organ. Tobacco has stimulating as well narcotic properties,
but as ordinarily used its stimulating effect appears to be slight as
compared with its narcotic influence. In this respect it differs from
alcohol, the use of which, owing to the usual method of introduction
in large amounts through the stomach, produces directly, by
stimulation, readily noticeable structural changes. But with tobacco
the direct evil results are mostly of a functional character, and are
more generally diffused, owing to the usual slow manner of
introduction into the body. These two properties have an effect upon
the body in moderate use as well as in immoderate use, the effect
being simply in proportion to the quantity used, though the effects of
moderate use may not be measurable by ordinary means. It is easy to
see the effects of large amounts of tobacco in the stunted growth of
adolescents; in functional cardiac disorders; in intellectual
sluggishness, loss of memory, and color blindness; in loss of
appetite, and other neuroses of motion, and marked blunting of various
functions of sensation, and in degeneracy of descendants; but that
lesser evils are produced must be proved mostly by inference,
circumstantial collateral evidence, and analogy.

The greater evils that are the outcome of a moderate use of tobacco
are probably due to prolonged slight interference with nutrition, and
consequent general decrease of vitality, which renders the individual
more susceptible through indirect influence to the invasion of
disease, and which lessens the capacity for productive effort.

It is of course difficult, and perhaps even impossible, to accurately
estimate the value of tobacco to the race; but let us glance at the
pros and cons, and then each one can roughly estimate for himself.
Tobacco may be used medicinally, but it is a dangerous and uncertain
remedy, and it probably has not one medicinal use that cannot be more
suitably met by other remedies. One can readily imagine easier
digestion as the result of the sedative influence of the after-dinner
cigar upon a disquieted nervous system, especially if the coincident
irritation of alcohol and coffee have need of correction; but it can
also be imagined that in most of such cases the remedy has been the
cause of and will further increase the disordered condition, and that
nutrition of deficiently nourished nerve tissue is rationally
indicated rather than partial narcotization. There then remains, so
far as I can see, the solace of moderate anæsthesia and, occasionally,
of occupation for idlers, as the only items that can be placed to the
credit of tobacco. There certainly are individual cases where such
usage may be more provocative of physical benefit than evil, but,
before judging for the race as a whole, compute the other side of the
question.

Tobacco injures the general health of the public through the economic
loss caused by its consumption. The people of our country spend
annually over seven hundred millions of dollars for tobacco--twenty
per cent. more than is spent for bread. This sum represents only a
minor part of the cost of the tobacco habit to the country. The crop
is immensely exhaustive to the soil. Its culture has blighted whole
sections of fertile territory. In the time consumed by the producer
and the trader in its production, manufacture, and sale, and by the
consumer in its use, and by the general interference with vital
activity and consequent decreased productive capacity, there is
represented an almost unimaginable sum of money. Certainly the people
at large are not so well fed both as to quantity and quality, or so
thoroughly clothed, or so hygienically housed that they can afford
this gigantic economic waste.

There can be little doubt that if the people had sufficient
intelligence and moral strength to taboo tobacco, this comparatively
senseless outgo would be largely devoted to supplying these and other
necessities of an exalted health status.

Tobacco injures health through its moral effects. The tobacco habit is
certainly a dirty and frequently a disgusting habit, and encourages
other dirty practices. Its use tends to make men cowardly, irritable
in temper, and low in spirits. It blunts ideas of purity and courtesy,
leading to invasion of the rights of others. It is presumed that few
medical men would visit a delicate, sensitive patient after saturation
with the "fragrant" effluvia of onions, but thousands whose systems
are saturated with nicotine and who reek with nauseating odor do not
hesitate to inflict their presence on sick or well. The time will come
when the tobacco user will not be allowed to poison the atmosphere
that is the common property of the public--will not be allowed to
force the inhalation of nicotine upon the general public, to say
nothing of being allowed to poison the infants and women in his own
family. What would be said of a man who introduced poison in any
degree into the food or drink of his child? Is the poisoning of the
household atmosphere by the ignorant, thoughtless, or selfish smoker
morally more defensible? Tobacco injures health through hereditary
influence. The tobacco user begets, more certainly than the non-user,
puny children with disordered nervous conditions. Luckily for our
race, the women, who have the most important prenatal influence in
guarding its physical well-being, are practically non-users of the
plant. The general health status of the race is improving, not because
the use of tobacco or the indulgence in other questionable practices
is harmless, but because, among other things, of the great advance in
general intelligence and knowledge of hygienic law.

A person, or the public in general, may practice an injurious habit,
and yet more than counteract its influence by opposing beneficial
practices.

Horace Greeley said, "Show me a drunkard who does not use tobacco, and
I will show you a white blackbird." In this country, where dietetic
drinking habits are not common in the family, the weakening of moral
fiber by indulgence in tobacco is usually the introduction into the
round of vicious indulgences, and thus directly or indirectly affects
health. Smoking induces dryness of the mucous membrane of the mouth
and consequent thirst. The partially paralyzed nerve terminals want
something more stimulating than water to afford relief. Furthermore,
blunted appetite induces deficient nutrition, and consequently there
is a call for some "pick-me-up;" hence we find that the use of tobacco
tends to the habitual use of alcoholic beverages, and there are very
few habitual users of alcohol who escape without structural injuries
to the body as well as perversion of its functions. Decrease of vital
activity in all the tissues of the body marks the use of tobacco. The
tendency is toward functional paralysis, though occasional signs of
stimulative irritation are to be noticed, especially in the
respiratory passages. The interference with intellectual activity is
marked. It is said that during a period of fifty years no tobacco user
stood at the head of his class in Harvard. The accumulated testimony
of investigating observers is conclusive that, other things being
equal, users of tobacco, in schools of all grades, never do so well in
their studies as non-users.

One head of a public school said he could always tell when a boy
commenced to use tobacco by the record of his recitations. Professor
Oliver, of the Annapolis Academy, said he could indicate the boy who
used tobacco by his absolute inability to draw a clean, straight line.
The deleterious effects of tobacco have become so clearly apparent
that we find its sale to minors is prohibited in France, Germany, and
various sections of this country. It is somewhat a question if, at the
present time, the race is not doing itself more injury by its use of
tobacco than it is with alcohol, because of its more universal use,
particularly by youth, and because of the respectability of the habit,
which comes of its use by a certain intelligent part of the race,
including teachers of morals and physics, and even temperance
reformers. There is a widespread sentiment in existence that it is not
a respectable thing to be even partly paralyzed by alcohol, but how
few there are who consider narcosis as in any way connected with the
use of tobacco. Its effect is more diffused and masked, and is not so
acutely serious in individual cases, but through its interference with
vital activity, tobacco is probably more generally injurious to the
race than alcohol.

The editorial fiat of "too long" prevents a full exposition of the
subject, but, in closing, let me say I hear millions of tobacco users
ask, "Why, then, was this plant given to man, if its general effects
are so decidedly evil?" The question presupposes design in creation.
Without subscribing to this theory, or pretending to have solved the
mystery of the presence of evil in the world, the answer may be
suggested that the overcoming of many seductive evils becomes to man a
means of his progressive higher development. Of one thing I am
convinced, that the physical development and welfare of man is
interfered with in strict sequence to his consumption of substances
that are unnecessary for his nutrition--stimulants and narcotics
inclusive.--_Medical Record._

       *       *       *       *       *




ACETIC ACID AS A DISINFECTANT.


Dr. F. Engelmann, in _Cent. f. Gyn._, claims that acetic acid
possesses equally as good antiseptic properties as carbolic acid; in
fact, that it is to be preferred, as it is completely harmless, even
if used in concentrated solutions, and that it is a valuable
hæmostatic, an advantageous addition particularly in obstetrics.
Another important property is its ease of transition into the tissues,
which, according to Engelmann's experiments, is by far greater than
that of all the other antiseptics. Of bichloride it is well known that
it forms an insoluble combination with albumen, and can therefore act
only on the surface, while acetic acid extends into the deeper tissues
with ease.

Acetic acid also affects the metal of the instruments, but not as
severely as the bichloride; the forceps, for instance, may be placed
for a quarter of an hour in an irrigator filled with a three per cent.
solution of acetic acid without being injured.

A pleasant effect of acetic acid is that it softens and lubricates the
skin. The author generally used a three per cent. solution; at times
he has made use of a five per cent. solution, which would easily cause
a painful burning at sore places, so that he only used the latter
strength in septic cases, as the three per cent. solution proved to be
a satisfactory antiseptic for general purposes.

       *       *       *       *       *




COUNTER-IRRITATION IN WHOOPING COUGH.

By G.F. INGLOTT, M.D.


To combat this often distressing disease I have tried the
administration of several medicines, namely, bromide of potassium,
asafoetida, valerian, morphine, belladonna, etc., and I have very
closely watched their effects, but none of them proved of much use.
Having observed, however, that during the late cholera epidemic some
of the patients admitted into the hospital under my medical charge
slept well, had their anxiety improved, and some of them ultimately
recovered, after the application of a strong counter-irritation of the
pneumogastric nerves in the neck, namely, between the mastoid process
and the angle of the lower jaw, I tried the same treatment on whooping
patients, and I have no hesitation in stating that the result was very
satisfactory. I may quote one single case of the many I have had under
treatment.

A boy, aged twelve years, of weak constitution, was suffering from
frequent and intense attacks of whooping cough. At a time the fits
were so vehement that blood came out of his eyes and mouth. The case
was a severe one, and I thought it would very likely end fatally. I
prescribed several medicines, and even subcutaneous injections of
morphine, but without any avail. I then tried for the first time the
counter-irritation on both sides of the neck, and this means acted
like magic. In four or five days the patient recovered, and was able
to go to school. Since that time I have been applying the same
treatment, either on the right side only or on both, with the greatest
benefit.--_Br. Med. Jour._

       *       *       *       *       *




DEVELOPMENT OF THE EMBRYO.


At a recent meeting of the Physical Society, Berlin, Prof. Preyer
spoke on reflexes in the embryo. His researches extended over many
classes of animals. As representing mammals, guinea pigs were chiefly
used; and for reptiles, snakes; while in addition the embryos of
fishes, frogs, mollusks, and other lower animals were also employed.
But of all animals birds are most suitable for embryological
observations, inasmuch as with due precautions the development of one
and the same individual can be followed for a considerable time.
Birds' eggs can be incubated in a warm chamber, and by removing a
portion of the shell and replacing it by an unbroken piece from
another egg, it becomes possible to follow the daily development of
the chick and to experiment upon it. As early as the ninetieth hour of
incubation, spontaneous "impulsive" movements may be observed, taking
place apparently without any external stimulus as a cause, and at a
time when no muscles or nerves have as yet been developed. After the
occurrence of these spontaneous movements, and at the earliest on the
fifth day of incubation, movements are observed to result from the
application of mechanical, chemical, and electrical stimuli. In order
to observe these the eggs must be allowed to cool down until all
spontaneous movements have ceased. From the tenth to the thirteenth
day more complicated and reflex actions occur on the application of
stimuli, as, for instance, movements of the eyelids, beak, and limbs;
and if the stimuli are strong, reflex respiratory movements. These
reflexes make their appearance before any ganglia have become
differentiated. Prof. Preyer considered himself justified in
concluding from this that ganglia are not essential for the liberation
of reflex actions. He intends, on some future occasion, to give a more
detailed account of these experiments, and of the conclusions which
may be drawn from them. In the discussion which ensued the conclusions
of the speaker were contested from many sides.

       *       *       *       *       *




IRIDESCENT CRYSTALS.[1]

   [Footnote 1: Abstract of the Friday evening lecture delivered by
   Lord Rayleigh, F.R.S., at the Royal Institution, on April 12,
   1889.]

By LORD RAYLEIGH.


The principal subject of the lecture is the peculiar colored
reflection observed in certain specimens of chlorate of potash.
Reflection implies a high degree of discontinuity. In some cases, as
in decomposed glass, and probably in opals, the discontinuity is due
to the interposition of layers of air; but, as was proved by Stokes,
in the case of chlorate crystals the discontinuity is that known as
twinning. The seat of the color is a very thin layer in the interior
of the crystal and parallel to its faces.

The following laws were discovered by Stokes:

    (1) If one of the crystalline plates be turned round in its own
    plane, without alteration of the angle of incidence, the
    peculiar reflection vanishes twice in a revolution, viz., when
    the plane of incidence coincides with the plane of symmetry of
    the crystal. [Shown.]

    (2) As the angle of incidence is increased, the reflected light
    becomes brighter and rises in refrangibility. [Shown.]

    (3) The colors are not due to absorption, the transmitted light
    being strictly complementary to the reflected.

    (4) The colored light is not polarized. It is produced
    indifferently, whether the incident light be common light or
    light polarized in any plane, and is seen whether the reflected
    light be viewed directly or through a Nicol's prism turned in
    any way. [Shown.]

    (5) The spectrum of the reflected light is frequently found to
    consist almost entirely of a comparatively narrow band. When the
    angle of incidence is increased, the band moves in the direction
    of increasing refrangibility, and at the same time increases
    rapidly in width. In many cases the reflection appears to be
    almost total.

[Illustration: FIG. 1 GENERAL SCHEME
               FIG. 2 DETAIL OF LAZY-TONGS]

In order to project these phenomena a crystal is prepared by cementing
a smooth face to a strip of glass whose sides are not quite parallel.
The white reflection from the anterior face of the glass can then be
separated from the real subject of the experiment.

A very remarkable feature in the reflected light remains to be
noticed. If the angle of incidence be small, and if the incident light
be polarized in or perpendicularly to the plane of incidence, the
reflected light is polarized in the _opposite_ manner. [Shown.]

Similar phenomena, except that the reflection is white, are exhibited
by crystals prepared in a manner described by Madan. If the crystal be
heated beyond a certain point the peculiar reflection disappears, but
returns upon cooling. [Shown.]

In all these cases there can be little doubt that the reflection takes
place at twin surfaces, the theory of such reflection (_Phil. Mag._,
Sept., 1888) reproducing with remarkable exactness most of the
features above described. In order to explain the vigor and purity of
the color reflected in certain crystals, it is necessary to suppose
that there are a considerable number of twin surfaces disposed at
approximate equal intervals. At each angle of incidence there would be
a particular wave length for which the phases of the several
reflections are in agreement. The selection of light of a particular
wave length would thus take place upon the same principle as in
diffraction spectra, and might reach a high degree of perfection.

In illustration of this explanation an acoustical analogue is
exhibited. The successive twin planes are imitated by parallel and
equidistant disks of muslin (Figs. 1 and 2) stretched upon brass rings
and mounted (with the aid of three lazy-tongs arrangements) so that
there is but one degree of freedom to move, and that of such a
character as to vary the interval between the disks without disturbing
their equidistance and parallelism.

The source of sound is a bird call, giving a pure tone of high pitch
(inaudible), and the percipient is a high-pressure flame issuing from
a burner so oriented that the direct waves are without influence upon
the flame (see _Nature_, xxxviii., 208; Proc. Roy. Inst., January,
1888). But the waves reflected from the muslin arrive in the effective
direction, and if of sufficient intensity induce flaring. The
experiment consists in showing that the action depends upon the
distance between the disks. If the distance be such that the waves
reflected from the several disks co-operate,[2] the flame flares, but
for intermediate adjustments recovers its equilibrium. For full
success it is necessary that the reflective power of a single disk be
neither too great nor too small. A somewhat open fabric appears
suitable.

   [Footnote 2: If the reflection were perpendicular, the interval
   between successive disks would be equal to the half wave-length,
   or to some multiple of this.]

It was shown by Brewster that certain natural specimens of Iceland
spar are traversed by thin twin strata. A convergent beam, reflected
at a nearly grazing incidence from the twin planes, depicts upon the
screen an arc of light, which is interrupted by a dark spot
corresponding to the plane of symmetry. [Shown.] A similar experiment
may be made with small rhombs in which twin layers have been developed
by mechanical force after the manner of Reusch.

The light reflected from fiery opals has been shown by Crookes to
possess in many cases a high degree of purity, rivaling in this
respect the reflection from chlorate of potash.

The explanation is to be sought in a periodic stratified structure.
But the other features differ widely in the two cases. There is here
no semicircular evanescence, as the specimen is rotated in azimuth. On
the contrary, the colored light transmitted perpendicularly through a
thin plate of opal undergoes no change when the gem is turned round in
its own plane. This appears to prove that the alternate states are not
related to one another as twin crystals. More probably the alternate
strata are of air, as in decomposed glass. The brilliancy of opals is
said to be readily affected by atmospheric conditions.

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