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SCIENTIFIC AMERICAN SUPPLEMENT NO. 447




NEW YORK, JULY 26, 1884

Scientific American Supplement. Vol. XVIII, No. 447.

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.    CHEMISTRY.--The Bitter Substance of Hops.--By Dr. H. BUNGENER.
      --What gives hops their bitter taste?--Processes for obtaining
      hop-bitter acid.--Analysis of the same.

II.   ENGINEERING AND MECHANICS.--Improvements in the Harbor
      of Antwerp.--With engraving of caisson for deepening the
      river.

      Progress of Antwerp.--Recent works in the harbor.

      Bicycles and Tricycles.--By C.V. BOYS.---Advantages of the
      different machines.--Manner of finding the steepness of a hill
      and representing same on a map.--Experiments on ball bearings.--
      The Otto bicycle.

      The Canal Iron Works, London.

      Marinoni's Rotary Printing Press.--With 2 engravings.

      Chenot's Economic Filter Press.--With engraving.

      Steel Chains without Welding.--Method and machines for making
      same.--Several figures.

III.  TECHNOLOGY.--Some Economic Processes connected with the
      Cloth Making Industry.--By Dr. WM. RAMSAY.--How to save and
      utilize soap used in wool scouring.--To recover the indigo from
      the refuse.--Extraction of potash from _suint_.--Use of
      bisulphide of carbon.

IV.   PHYSICS. ELECTRICITY, ETC.--Thury's Dynamo Electric Machine.
      --5 figures.

      Breguet's Telephone.

      Munro's Telephonic Experiments.--9 figures.

      Apparatus for Maneuvering Bichromate of Potassa Piles from a
      Distance.--2 figures.

      Magnetic Rotations.--By E.L. VOICE.--1 figure.

      Lighton's Immersion Illuminator.--1 figure.

      Foucault's Pendulum Experiments.--By RICHARD A. PROCTOR.
      --4 figures.

V.    ARCHITECTURE, ART, ETC.--St. Paul's Vicarage, Forest Hill,
      Kent.--2 engravings.

      Designs for Iron Gates.--An engraving.

VI.   ASTRONOMY.--A New Lunarian.--By Prof. C.W. MACCORD.
      --With 3 figures.

VII.  GEOLOGY.--Coal and its Uses.--By JAMES PYKE.--Formation
      of carboniferous rocks and the coal in the same.--Processes of
      nature.--Greatness of this country due to coal.--Manufacture of
      gas.--Products of the same.

VIII. NATURAL HISTORY, BOTANY. ETC.--The Wine Fly.--The
      egg.--Larva.--Pupa and fly.

      The "Potetometer." an Instrument for Measuring the Transpiration
      of Water by Plants.--1 figure.

      Bolivian Cinchona Forests.

      Ferns.--Nephrolepis Davillioides Furcans and Nephrolepis Duffi.
      --2 engravings.

IX.   PHYSIOLOGY, HYGIENE, ETC.--The Upright Attitude of Mankind.
      --Review of a lecture by Dr. S.V. CLEVENGER, in which he
      tries to prove that man must have originated from a four footed
      being.

      Our Enemies, the Microbes.--Affections caused by the same.--
      Experiments of Davaine, Pasteur, and others.--How to prevent
      bacterides from entering the body.--5 figures.

X.    BIOGRAPHY.--Gaston Plante, the Scientist.--With portrait

      Warren Colburn, the American Mathematician.

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IMPROVEMENTS IN THE HARBOR OF ANTWERP.


The harbor of Antwerp, which, excepting those of London and Liverpool,
is the largest in Europe, has been improved wonderfully during the last
decade. Before 1870 it was inferior to the harbor at Havre, but now it
far surpasses the same. The river Scheldt, which is about 1,500 ft.
wide, was badgered out up to the vertical walls of the basin, so that
the largest ships can land at the docks. The river was deepened by the
use of caissons, in the lower parts of which the workmen operated in
compressed air. The annexed cut shows that part of one of the caissons
which projects above the surface of the water. The depth of the river at
low tide is about 26 ft., and at high tide about 39 ft. Some of the old
sluices, channels, basins, etc., which were rendered useless by the
improvements made in the river Scheldt have been filled up, and
thereby the city has been enriched by several handsome and elegant
squares.--_Illustrirte Zeitung_.

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PROGRESS OF ANTWERP.


Antwerp is now the chief port on the Continent. Since 1873 the progress
has continued, and made very rapid advances. In 1883 the tonnage of the
port reached 3,734,428 registered tons. This marvelous development is
partly due to the position of Antwerp as the embarking point from the
Continent of Europe to America, and partly also to the recent additions
and changes which have been carried out there, and which, now nearly
completed, have made this cosmopolitan port one of the best organized in
the world. This is so well known that vessels bound for Switzerland with
a cargo of corn from Russia pass Marseilles and go two thousand miles
out of their way for the purpose of unloading at Antwerp. No other port,
in fact, offers the same facilities. There is not another place in the
world where fifty vessels of 3,000 tons can come alongside as easily as
the penny boats on the Thames run into the landing.

[Illustration: CAISSONS FOR DEEPENING THE RIVER AT ANTWERP.]

Since the opening of the St. Gothard Tunnel nearly all the alimentary
provisions that Italy sends to the British Isles pass through Antwerp.
In 1882 82,000,000 eggs and 30,000 pounds of fruit were shipped there
for England. The greater part of these came from Italy. Antwerp has
become also an important port for emigrants; 35,125 embarked in 1882,
out of which number 3,055 were bound for New York. The city was always
destined, from its topographical position, to be at the head of a very
considerable traffic; political reasons alone for many years prevented
this being the case. These have happily now disappeared, and, since
1863, when the "Scheldt was liberated," the progress of commerce has
been more rapid than even the most ardent Antwerp patriot dared hope. At
that date the toll of 1s. 11d. on all vessels going up the river, and of
7½d. on vessels going down, was abolished, and reforms were introduced
among the taxes on the general navigation; the tax on tonnage in the
port itself was abolished, and the pilot tax was lowered. The results of
these measures became immediately apparent. Traffic increased with
such rapidity that in 1876 the crowding on the quays was such that the
relation of the tonnage to the length of the quay was about 270 tons per
yard, which is four times as great as at Liverpool.

A few words now, briefly, as to the nature of the important works[1]
completed at Antwerp. They were commenced in 1877, and have opened for
the port an era of prosperity such as was never experienced even during
the sixteenth century, the zenith of her splendor. These works have
cost £4,000,000, and have necessitated the employment of 12,000 tons
of wrought iron, of 490,000 cubic yards of brickwork and concrete, of
32,000 cubic yards of masonry, and of more than 3,300,000 cubic yards
of earthwork in filling and dredging, etc. The quay walls run the whole
length of the town, a distance of rather more than two miles. It rests
on a foundation laid without timber footings, and giving a depth of
twenty-six feet at low water, sufficient drawing for the largest ships
afloat. Beyond this wall are the real quays, which consists of first a
line of rails reserved for hydraulic cranes serving to unload vessels
and deposit their cargo railway trucks; secondly, a second line of rails
parallel with the first, on which these trucks are stationed; thirdly,
sheds extending toward the town for a width of one hundred and fifty
feet, and covered with galvanized iron sheetings. A third line of rails
parallel with the two others runs from end to end of these sheds, and a
number of lines placed transversely with this one connect it by means of
spring bridges with, fourthly, four more lines also parallel with the
quays, whence the goods start for the different stations, and thence to
their destinations. The total width of these immense constructions is
about three hundred and twenty feet. Such is their magnitude that about
six hundred houses had to be pulled down to make place for them. A
railing running along their entire length cuts them off from the town.

[Transcribers note 1: changed from 'words']

During the course of last year 4,379 vessels entered the port of
Antwerp, gauging a total of 3,734,428 tons, which places Antwerp, as I
have already stated, at the head of European ports. In 1882 the tonnage
of Havre was only 2,200,000, that of Genoa 2,250,000, and of Bilboa
315,000, owing to its iron ore exports. Among the English ports a few
only exceed Antwerp. London is still the first port in the world, with
a tonnage of 10,421,000 tons, and Liverpool the second, with 7,351,000
tons; Newcastle follows with 6,000,000 tons, also in excess of Antwerp,
but both Hull and Glasgow are below, with respectively 1,875,000 and
2,110,000 tons.--_Pall Mall Gazette_.

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BICYCLES AND TRICYCLES.

[Footnote: A recent lecture before the Society of Arts, London.]

By C.V. BOYS.


The subject of this paper is one of such wide interest, and of such
great importance, that it is quite unnecessary for me to make any
apology for bringing it to your notice. Exactly two months ago, I had
the honor of dealing with the same subject at the Royal Institution. On
that occasion I considered main principles only, and avoided anything in
which none but riders were likely to take an interest, or which was in
any way a matter of dispute. As it may be assumed that the audience here
consists largely of riders, and of those who are following those matters
of detail, the elaboration, simplification, and perfection of which
have brought the art of constructing cycles to its present state of
perfection, I purpose treating the subject from a totally different
point of view. I do not intend, in general, to describe anything,
assuming that the audience is familiar with the construction of the
leading types of machines, but rather to consider the pros and cons
of the various methods by which manufacturers have striven to attain
perfection. As a discussion on the subject of this paper will doubtless
follow--and I hope makers or riders of every class of machine will
freely express their opinion, for by so doing they will lend an interest
which I alone could not hope to awaken--I shall not consider it
necessary to assume an absolutely neutral position, which might be
expected of me if there were no discussion, but shall explain my own
views without reserve.

The great variety of cycles may be grouped under the following heads:

  1. The Bicycle unmodified.
  2. The Safety bicycle, a modification of 1.
  3. The Center-cycle.
  4. The Tricycle, which includes five general types:
  (a.) Rear steerer of any sort.
  (b.) Coventry rotary.
  (c.) Front steerer of any sort (except e).
  (d.) Humber pattern.
  (e.) The Oarsman.
  5. Double machines: sociables and tandems.
  6. The Otto.

It is perfectly obvious that not one machine is superior to all others
in every respect, for if that were the case, the rest would rapidly
become extinct. Not one shows any signs of becoming extinct, and,
therefore, it may be assumed that each one possesses some points in
which it is superior to others, the value of which is considered by
its riders to far outweigh any points in which it may be inferior. The
widely varying conditions under which, and purposes for which, machines
are used and the very different degrees of importance which differently
constituted minds attach to the peculiarities of various machines, will,
probably, prevent any from becoming extinct. Nevertheless, the very
great advantages which some of these possess over others will, no doubt,
in time become evident by the preponderance of the better class of
machines.

The bicycle, which surpasses all other machines in simplicity,
lightness, and speed, will probably, for these reasons, always remain a
favorite with a large class. The fact that it requires only one track
places it at a great advantage with respect to other machines, for it is
common for a road which is unpleasant from mud or stones to have a hard,
smooth edge, a kind of path, where the bicyclist can travel in peace,
but which is of little advantage to other machines. Again, the bicycle
can be wheeled through narrow gates or door ways, and so kept in places
which are inaccessible to tricycles. One peculiarity of the bicycle,
and to a certain extent of the center-cycle, is that the plane of the
machine always lies in the direction of the resultant force, that the
machine leans over to an amount depending on the velocity and the
sharpness of the curve described. For this reason all lateral strain on
the parts is abolished, and if we except the slipping away of the wheel
from under the rider, which can hardly occur on a country road, an upset
from taking a curve too quickly is impossible. This leaning to either
side by the machine and rider gives rise to that delightful gliding
which none but the bicyclist or the skater can experience. In this
respect the bicycle has an enormous advantage over any machine, tricycle
or Otto, which must at all times remain upright, and which must,
therefore, at a high speed, be taken round a curve with discretion.

The perfect and instantaneous steering of the bicycle, combined with
its narrowness, counteract, to a great extent, the advantage which the
tricyclist has of being able to stop so much more quickly, for
the bicyclist can "dodge" past a thing for which the rider of the
three-wheeler must pull up. In one other respect the bicyclist has an
advantage which, though of no real importance, has great weight with
many people. The bicycle well ridden presents a picture of such perfect
elegance that no one on anything else need expect to appear to advantage
in comparison.

The chief disadvantage of the bicycle is the fact that a rider cannot
stop for any purpose, or go back a little, without dismounting. For town
riding, where a stoppage is frequently necessitated by the traffic, this
perpetual mounting and dismounting is not only tiresome, but wearying,
so much so that few bicyclists care to ride daily in town.

The position of the rider on a bicycle, with respect to the treadles,
is by no means good, for if he is placed sufficiently far forward to be
able to employ his weight to advantage without bending himself double,
he will be in so critical a position that a mere touch will send him
over the handles. He has, therefore, to balance stability and safety
against comfort and power; the more forward he is, the more furiously he
can drive his machine, and the less does he suffer from friction and the
shaking of the little wheel; the more backward he is, the less is he
likely to come to grief riding down hill, or over unseen stones. The
bicyclist is no better off than the rider of any other machine with a
little wheel, the vibration from which may weary him nearly as much as
the work he does. The little wheel as a mud-throwing machine engine is
still more effective on the bicycle than it is on any tricycle, for in
general it is run at a higher speed.

I now come to the usual complaint about the bicycle. There is a fashion
just now to call it dangerous and the tricycle safe. But the difference
in safety has been much exaggerated. The bicyclist is more likely to
suffer from striking a stone than his friend on three wheels, but then
he should not strike one where the tricyclist would strike a dozen.
Properly ridden, neither class of machine can be considered dangerous;
an accident should never happen except it be due to the action of
others. People, carts, cattle, and dogs on the road are liable to such
unexpected movements, that the real danger of the cyclist comes from the
outside; to danger from absolute collapse, due to a hidden flaw in
the materials employed, every one is liable, but, the bicyclist more
remotely than the tricyclist, owing to the greater simplicity of his
machine. The bicyclist, though he has further to fall in case of an
accident from any of these causes, is in a better position than the
tricyclist, for he is outside instead of inside his machine; he can in
an instant get clear.

It would appear that many tricyclists consider accidents of the kind
next to impossible, for in several machines the rider is so involved
that an instantaneous dismount without a moment's notice, at any speed,
is absolutely impossible. There remains one objection, which, however,
should be of next to no importance--the difficulty of learning the
bicycle prevents many from taking to the light and fast machine, because
they are afraid of a little preliminary trouble.

The chief objections to the bicycle, then, are the liability of the
rider to go over the handles, the impossibility of stopping very
quickly, and the inability to remain at rest or go backward, and the
difficulty of learning.

The first two of these are, to a large extent, overcome in the safety
bicycles, but not without the introduction of what is in comparison a
certain degree of complication, or without the loss of the whole of the
grace or elegance of the bicycle. On almost all of these safety bicycles
the rider is better placed than on the unmodified bicycle, but though
safer, I do not think bicyclists find them complete in speed, though, no
doubt, they are superior in that respect to the tricycle. Though they do
not allow the rider to stop without dismounting, the fatigue resulting
from this cause is less than it is with a bicycle, owing to the fact
that with the small machines the rider has so small a distance to climb.
Of these machines, the Extraordinary leaves the rider high up in the air
on a full-sized wheel, but places him further back and more over the
pedals. The motion of these is peculiar, being not circular, but oval, a
form which has certain advantages.

In the Sun and Planet and Kangaroo bicycles a small wheel is "geared
up," that is, is made to turn faster than the pedals, so as to avoid the
very rapid pedaling which is necessary to obtain an ordinary amount
of speed out of a small wheel. In each of these the pedals move in a
circular path, and their appearance is in consequence less peculiar than
that of the Facile, which, in this respect, does not compare favorably
with any good machine. The pedal motion on the Facile is merely
reciprocating. Riders of machines where circular motion is employed,
among them myself, do not believe that this reciprocating motion can
be so good as circular, but I understand that this view is not held by
those who are used to it. Of course, the harmonic motion of the Facile
pedal is superior to the equable reciprocating motion employed in some
machines where speed is an object, especially with small wheels.

If I have overlooked anything typical in the modified bicycle class,
I hope some one will afterward supply the omission, and point out any
peculiarities or advantages.

That very peculiar machine, the center-cycle, seems to combine many of
the advantages of the bicycle and tricycle. On it the rider can remain
at rest, or can move backward; he can travel at any speed round curves
without an upset being possible; he can ride over brickbats, or
obstructions, not only without being upset, but, if going slowly,
without even touching them. As this machine is very little known, a few
words of explanation may be interesting.

In the first place, the rider is placed over the main wheel, as in the
bicycle, but much further forward. There are around him, on or near the
ground, four little wheels, two before and two behind, supported in a
manner the ingenuity of which calls for the utmost admiration. Turning
the steering handle not only causes the front and rear pairs to turn
opposite ways, but owing to their swiveling about an inward pointing
axis, the machine is compelled to lean over toward the inside of the
curve; not only is this the case, but each pair rises and falls with
every inequality of the road, if the rider chooses that they run on the
ground; but he can, if he pleases, arrange that in general they ride in
the air, any one touching at such times as are necessary to keep him on
the top of the one wheel, on which alone he is practically riding. He
can, if he likes, at any time lift the main wheel off the ground and run
along on the others only. The very few machines of the kind which I have
seen have been provided with foot straps, to enable the rider to pull as
well as push, which is a great advantage when climbing a hill, but this
is on every machine except the Otto, of which I shall speak later,
considered a dangerous practice.

Some of the objections to the bicycle to which I have referred were
sufficient to prevent many, especially elderly men, from dreaming of
becoming cyclists. So long as the tricycle was a crude and clumsy
machine, there was no chance of cycling becoming a part, as it almost is
and certainly soon will be, of our national life. The tricycle has been
brought to such a state of perfection that it is difficult to imagine
where further progress can be made.

Perhaps it will be well to mention what is necessary in order that a
three-wheeled machine may be made to roll freely in a straight line, and
also round curves. At all times each wheel must be able to travel in
its own plane in spite of the united action of the other two. To run
straight, the axes of all the wheels must obviously be parallel. To run
round a curve, the axis of each must, if continued, pass through the
center of curvature of the curve. If two wheels have a common axis, the
intersection of the two lines forming the axes can only meet in one
point. To steer such a combination, therefore, the plane of the third
wheel only need be turned. If the axis of no two are common, then the
planes of two of the wheels must be turned in order that the three axes
may meet in a point.

Not only does free rolling depend on the suitable direction of the
planes of the wheels, each wheel must be able to run at a speed
proportional to its distance from the point of intersection of the three
axes, i.e., from the ever-shifting center of curvature.

The most obvious way, then, of contriving a three wheeler is to drive
one wheel, steer with another, and leave the third, which must be
opposite the driver, idle. The next in simplicity is to drive with one
wheel, and steer with the other two, having one in front and the other
behind. So far then, the single driving rear-steerer and the Coventry
rotary pattern are easily understood. The evils of single driving,
minimized, it is true, to a large extent, in the Coventry rotary, have
led to the contrivance of means by which a wheel on each side may be
driven without interfering with their differential motion in turning a
corner.

Three methods are commonly used, but as only two are employed on
tricycles, I shall leave the third till I come to the special machine
for which it is necessary. The most easy to understand is the clutch,
a model of which I have on the table. If each main wheel is driven by
means of one of these, though compelled to go forward by the crankshaft,
it is yet free to go faster without restraint. By this means "double
driving" is effected in several forms of tricycle.

Differential gear, which is well understood, and of which there are
several mechanically equivalent forms, divides the applied driving
power, whether forward or backward, between the main wheels, equally if
the gear is perfect, unequally if imperfect. To understand the effect
of the two systems of driving, and of single driving, let us place on
grooves a block which offers resistance to a moving force. If we wish
to move it, and apply our force at the end of one side, it will tend to
turn round as well as move forward, and much friction will be spent on
the guides by their keeping it straight.

This is the single driver. If, instead of applying force at one side, we
push the block bodily forward by a beam moving parallel to itself, then
so long as the guides are straight no strain will be put upon them,
even though one side of the block is resisted more than the other; if,
however, the guides compelled the block to travel round a curve, then
the power, instead of being divided between the two sides in such
proportion as is necessary to relieve the guides of all strain, is
suddenly applied only to the inside, and the effect is that of a single
driver only. This is the clutch. Lastly, if the last-mentioned beam,
instead of being pushed along parallel to itself, were pivoted in the
middle, and that pivot only pushed, the same power would be applied to
each side of the block, and no strain would be thrown on the guides,
whether straight or curved, so long as the resistance opposed to the
block on the two sides were equal; if, however, one side met with more
resistance than the other, then the guides would have to keep the block
straight. This is the differential gear.

I have assumed that in the last case the force was applied to the middle
of the beam; this corresponds to every evenly-balanced gear. In the gear
employed by Singer, which is not evenly balanced, but which derives its
good qualities from its simplicity, the same effect is produced as
if the beam were pivoted on one side of the center instead of on the
center. Thus, though both sides are driven, one is driven more than the
other. On the whole, there is no doubt that the balanced gear gives a
superior action to the clutch, for except when the two sides of the
machine meet with very different resistance, and then only when running
straight, the clutch will not compare with the other. The clutch also
gives rise to what is considered by most riders a grave defect, the
inability to back treadle, while the free pedal, which is an immediate
consequence, is considered by others a luxury.

On the other hand, this same free pedal can be obtained on
differentially driven machines to which speed and power gear have been
applied.

Of the relative merits of different forms of differential gear there is
little to be said. Perhaps it will not be thought I am unduly thrusting
myself forward, if I refer to a scheme of my own, in which no toothed
wheels are employed, but in which two conical surfaces are driven by a
series of balls lying in the groove between them, and jambed against
them by a recessed ring.

I have here a large wooden diagrammatic model, and a small working
model in steel, which shows that the new principle employed is correct,
namely, that a ball while jambed is free to turn, or if turning is able
to jamb. All Humbers, and most front steerers, employ differential
gearing; in some front steerers the clutch of necessity is used.

Neglecting for the present the different modes of transmitting power
from the pedals to the main wheels, it is possible now to consider the
four typical builds of tricycle. The only advantage that a rider can
find in a rear-steerer is the open front, so that in case of accident
he can more easily clear himself of his machine; as I have already
remarked, this power of instantly escaping seems to be considered by
many as of no importance.

In a rear-steerer which has not an open front, whether driven by a
clutch or by differential gear, I fail to discover any good quality.
The steering of a rear-steerer is so very uncertain, that such machines
cannot safely be driven at anything like a high speed, because any wheel
meeting with an obstruction will, by checking the machine, diminish the
weight on the steering wheel just at the time when a greater weight than
usual should be applied. It is for the corresponding reason that the
steering of a front-steerer is so excellent; the more the machine is
checked by obstruction, by back treading, or by the brake, the greater
is the weight on the front wheel.

For shooting hills, or for pulling up suddenly, no machine of any kind
will compare with a good front-steerer. In all respects it is superior
to the rear-steerer if we except the open front, but against this may
be set the fact that on many the rider can mount from behind, or can
dismount in the same manner while the machine is in motion. Experience
shows that the front-steerer is for general excellence, safety, easy
management, and light-running, the best all-round tricycle that is to be
had.

The Humber build, which departs less from the ordinary bicycle than any
othar, is far superior to all others for speed; it is, however, somewhat
difficult to manage, for the steering is not only delicate, but
critical, requiring constant care lest a stone or other obstruction
should take the rider unawares, and steer the machine for him.

The control which a skillful rider of the Humber has over his machine is
wonderful; the elegance of the machine among tricycles is unequaled.
So great a favorite is this form, especially among the better class of
riders, that almost every firm have brought out their own Humber, each
with a distinguishing name.

The only improvement or change, whichever it may be, that has been made
by others with which I am acquainted, is the triple steering, in which
the hind wheel moves the opposite way to the others. The corresponding
change in the bicycle was soon discarded; I do not know what advantage
can result from the increased delicacy of steering here. I should have
thought it delicate enough already.

One noticeable change in the front-steering tricycle, which has been
largely made, lately, is the substitution of central for side gearing,
in consequence of which bicycle cranks can be employed, instead of
the cranked axle, with its fixed throw. This gives an appearance of
lightness which the older types of machine do not possess.

I now come to that very difficult and all-important subject, the method
of transmitting power from the body of the rider to the main axle. Next
to the structural arrangement, this is most important in distinguishing
one type of machine from another.

The first to which I shall refer is the direct action employed on the
National and the Monarch tricycles. It is obvious that by having no
separate crank shaft, much greater simplicity and cheapness and less
friction are attained than can be possible when the extra bearings and
gear generally used are employed. In this respect the direct action
machines undoubtedly have an advantage, but an advantage of any kind may
be too dearly bought, as it certainly is here.

In the first place, the direct action can only be applied to a
rear-steering, clutch-driven machine, or single driver, for if the
wheels were not free to run ahead, it would be impossible to go round a
curve. In the second place, the rider must be placed at such a height
for his feet to work on the axle that the machine, of necessity, is very
unstable, and is likely to upset if ridden without great caution round
a curve. Thirdly, to diminish as far as possible this last objection,
miserable little wheels must be employed, which cannot be geared up,
that is, made to travel faster than the treadles, and so be equivalent
to larger wheels. Therefore, though it is likely that at such low speeds
only as it is safe to run such a machine it may move more easily than a
machine of a recognized type, and though direct action would undoubtedly
be advantageous if it did not entail defects of a most serious order of
magnitude, we may dismiss this at once from our consideration. It is
true that in the Monarch a few inches of height are gained by the
hanging pedals, but I question very much whether one machine is much
better than the other.

The chain which is used on almost every make of machine cannot be
considered perfect; it is, on the whole, a dirty and noisy contrivance,
giving rise to friction where the links take and leave the teeth of
the pulleys; stretching, or rather lengthening, by wear, and, finally,
allowing back lash, which is most unpleasant. In spite of all this, it
affords a convenient and reliable means of transmitting power, which is
applicable to every type of tricycle, except one.

Instead of a chain, an intermediate or idle wheel has been tried, but
this has not been found advantageous. The intermediate wheel has been
removed, and the crank and wheel pulley allowed to gear directly
together, making reverse motion of the feet necessary, and possibly
reducing friction.

The crank and connecting rod are employed in some machines. If there are
two only, they must not be placed in opposite positions, but be fixed at
an angle, so that there are times when each rod is under compression,
a strain which delicate rods cannot stand. In the three-throw crank,
employed in the Matchless tricycle, this objection is obviated, for one,
at least, is at all times in such a position as to be in tension. The
objection to the crank is the fact that it weakens the shaft, and that
it can only be used with a clutch, not with a differential gear.

The most silent, neatest, and cleanest driver, the one of which the
working friction is least, is the endless steel band, so well known in
connection with the Otto bicycle. This is not, as far as I am aware,
employed on any tricycle, makers probably fearing lest it should slip.
The Otto shows that it can safely be employed.

I have devised a scheme, of which I now show a model, which seems to me
to be free from the objections which may be urged against other methods;
but I, of course, cannot be considered in this respect a judge.
Eccentrics are well known as equivalent to cranks, but if used in the
same way, with a connecting rod, either fatal friction or enormous
ball-bearings would be necessary. Instead of these, I connect two pair
of equal eccentrics by an endless band embracing each, so that the band
acts like a connecting rod without friction, and, at the same time,
acts by its turning power as on the Otto, thus making two eccentrics
sufficient instead of three, and carrying them over the dead points.

There is one more system of transmitting power employed on a few
machines. In these, a band or line passes over the circumference of a
sector or wheel, and the power is directly applied to it. The motion of
the feet in the omnicycle, and of the hands and body in the Oarsman, is
therefore uniform. There would be no harm in this if it were not for the
starting and the stopping, which cannot be gradual and at the same time
effective in machines of this type. For this reason, a high speed cannot
be obtained; nevertheless, these machines are better able to climb hills
than are tricycles with the usual rotary motion, for, at all parts of
the stroke--which may be of any length that the rider chooses--his
driving power on the wheels is equal. The ingenious expanding drums on
the omnicycle make this machine exceptionally good in this respect, for
increased leverage is effected without increased friction, which is the
result of "putting on the power" in some of the two-speed contrivances.

Having spoken of the Oarsman tricycle, I must express regret that I have
not been able to find an opportunity to ride on or with the machine, so
that I cannot from observation form an opinion of its going qualities.
There can be no doubt that the enormous amount of work that can be got
from the body in each stroke on a sliding seat in a boat must, applied
in the same manner on the Oarsman tricycle, make it shoot away in a
surprising manner; whether such motion, when continued for hours, is
more tiring than the ordinary leg motion only, I cannot say for certain,
but I should imagine that it would be. The method by which the steering
is effected by the feet, and can with one foot be locked to a rigidly
straight course, is especially to be admired.

There is much difference of opinion with respect to the most suitable
size for the wheels of machines. Except with certain machines, this has
nothing to do with the speed at which the machine will travel at a given
rate of pedaling, for the wheels may be geared up or down to any extent,
that is made to turn more quickly or slowly than the cranks. Thus the
most suitable speeding is a separate question, and must be treated by
itself.

Large wheels are far superior to small wheels in allowing comfortable,
easy motion, a matter of considerable importance in a long journey. They
are also far better than small for running over loose or muddy ground,
for with a given weight upon them they sink in less, from the longer
bearing they present, and this, combined with their less curvature,
makes the everlasting ascent which the mud presents to them far less
than with a smaller wheel. On the other hand, the large wheel is
heavier, and suffers more from air resistance than the small wheel. For
racing purposes a little wheel, geared up of course, is certainly better
than a high wheel; for comfortable traveling, and in general, the high
wheel is preferable. Though this is certainly the case, it does not
follow that large wheels are worth having on a machine when there is
already one little wheel. If the rider is to be worried with the evils
of a little wheel at all, it is possible that any advantage which large
wheels would give him would be swamped by the vibration and mud-sticking
properties of the small steering wheel. One firm, in their endeavors
to minimize these evils, have designed machines without any very small
wheels; all three wheels are large, and a steadier and more comfortable
motion no doubt results.

High and low gearing are the natural sequel to high and low wheels. Of
course the lower the gearing the greater is the mechanical advantage in
favor of the rider when meeting with much resistance, whether from wind,
mud, or steepness of slope. In spite of this, for some reason which I
cannot divine, the machines with excessively low gear do not seem to
obtain so great an advantage in climbing hills as might be expected. To
make such a machine travel at a moderate speed only, excessively rapid
pedaling is necessary, and the rider is made tired more by the motion of
his legs than by any work he is doing. The slow, steady stroke by which
a rider propels a high-geared machine is far more graceful and less
wearying than the furious motion which is necessary on a low-geared
machine. The height up to which the driving-wheels are usually geared
may be taken as an indication of the ease with which any class of
machines runs. A rider on a low-geared machine can start his machine
much more quickly than an equal man on one that has high gearing, and
therefore in a race he has an advantage at first, which he speedily
loses as his rapid pedaling begins to tell. For ordinary riding the
slight loss of time at starting is a matter of no importance whatever.

There are several devices which enable us to obtain the advantages of
high and low gearing on the same machine, which at the same time give
the rider the benefit of a free pedal whenever he wishes. On some single
driving rear-steering tricycles the connection on one side is for speed,
and that on the other for power, either being in action at the wish of
the rider, or both speed and power combinations are applied on the same
side. To drive with a power gear a single wheel only seems to me to be
the height of folly; in my opinion no arrangement of this type is worthy
of serious attention. Among the better class of machines there are three
methods by which this change is effected--first, that employed on the
omnicycle, to which I have already referred; secondly, an epicyclic
combination of wheelwork which moves as one piece when set for speed,
thus adding nothing to the working friction except by its weight, but
which works internally when set for power, thus reducing to a small
extent, by the additional friction, the gain of power which the rider
desires; thirdly, a double set of chains and pulleys, each set always in
movement, so that, whether set for speed or power, there is rather more
friction than there would be if there were no additional chains, but
these are free from that increased friction due to toothed wheel
gearing, from which the epicyclic contrivances suffer only when set
for power. There is much difference of opinion whether any of these
arrangements are worth carrying, for perhaps nine miles, for the sake of
any advantage that may be obtained in the tenth. It is on this account
that the drums on the omnicycle are so excellent; whether expanded or
not, there is, on their account, no loss of work whatever, for there is
no additional friction. The subject of these two speed gears will, I
hope, be discussed; it is one which, though not new, is coming more to
the front, and about which much may be said.

Having now dealt with the means by which tricycles are made to climb
hills more easily, I wish to leave the subject of bicycles and tricycles
altogether for a few minutes, to say a few words which may specially
interest those who are fond of trying their power in riding up our best
known hills. The difficulty of getting up depends to a large extent on
the surface and on the wind, but chiefly on the steepness. The vague
manner in which one hill is compared with another, and the wild ideas
that many hold who have not made any measurements, induces me to
describe a method which I have found specially applicable for the
measurement of steepness of any hill on which a cyclist may find
himself, and also a scheme for the complete representation of the
steepness and elevation of every part of a hill on a map so as to be
taken in at a glance. The force required to move the thing up a slope is
directly proportional not to the angle, but to the trigonometrical sine
of that angle. To measure this, place the tricycle, or Otto--a
bicycle will not stand square to the road, and therefore cannot be
used--pointing in direction at right angles to the slope of the hill, so
that it will not tend to move. Clip on the top of the wheel a level, and
mark that part of the road which is in the line of sight. Take a string
made up of pieces alternately black and white, each exactly as long as
the wheel is high, and stretch it between the mark and the top of the
wheel. If there are n pieces of string included, the slope is 1 in n,
for by similar triangles the diameter of the wheel is to the length of
the string as the vertical rise is to the distance on the road. This
gives the average steepness of a piece sufficiently long to be worth
testing, because an incline only a few feet in length, of almost any
steepness, can be mounted by the aid of momentum.

There is only one process, with which I am acquainted, which supplies a
method of representing on a map the steepness of a road at every part.
Contours, of course, show how far one has to go to rise 50 or 100 feet,
but as to whether the ascent is made uniformly or in an irregular
manner, with steep and level places, they tell us nothing. Let the
course of a road be indicated by a single line where it is level, and by
a pair of lines where inclined. Let the distance between the lines be
everywhere proportional to the steepness, then the greatest width will
show the steepest part, and an intermediate width will show places
of intermediate steepness; the crossing of the lines, which must be
distinguishable from one another, will show where the direction of the
slope changes. Further, the size of the figure bounded by the two lines
will show the total rise; a great height being reached only by great
steepness or by great length, a large figure being formed only by great
width or by great length. Those who are mathematically inclined will
recognize here that I have differentiated the curve representing the
slope of the bill, and laid the differential curve down in plan.

Having wandered off my subject, I must return to more mechanical things,
and give the results of some experiments which I have made on the balls
of ball bearings. There is no necessity to argue the case of ball vs.
plain bearings, the balls have so clearly won their case, that it would
be waste of time to show why. Of the wear of the twelve balls forming
one set belonging to the bearings of the wheels of my Otto, I have on a
previous occasion spoken; I may, however, repeat that in running 1,000
miles, the twelve balls lost in weight only 1/20.8 grain, or each ball
lost only 1/250 grain. The wear of the surface amounted to only 1/158000
inch; at the same rate of wear, the loss in traveling from here to the
moon would amount to only 1/34.3 of their weight. I examined each ball
every 200 miles, and was surprised to find that on the whole the wear of
each, during each journey, varied very little. The balls experimented on
were a new set obtained from Mr. Bown. I also had from him one ball of
each of each of the following sizes 3, 4, 5, 6, and 7 16ths of an inch
in diameter, as I was curious to know what weight they would suppport
without crushing. As as preliminary experiment, I placed a spare 5/16
ball between the crushing faces of the new testing machine at South
Kensington, and applied a gradually increasing force up to 7 tons 9½
cwt., at which it showed no signs of distress. On removing it I found
that it had buried itself over an angle of about 60° in the hard steel
faces, faces so hard that a file would not touch them. Those marks will
be a permanent record of the stuff of which the ball was made. The ball
itself is sealed in a tube, so that any one who is curious to see it can
do so. Finding that the crushing faces were not sufficiently hard, I
made two anvils of the best tool steel, and very carefully hardened
them. These, though they were impressed slightly, were sufficiently good
for the purpose. In the following table are the results of the crushing
experiments:

3/16 ball at 2 tons 13 cwt. did not break, but crushed on removing part
of the weight.

¼ ball at 3 tons 15 cwt. did not break, but crushed on removing part of
the weight.

5/16 ball at 4 tons 9 cwt. broke.

3/8 ball at 8 tons 6 cwt. did not break, crushed under another 120 lb.

7/16 ball crushed before 3 tons, with which I was starting, had been
applied. Examination showed that the steel bar of which it was made had
been laminated.

These experiments do not tell much of importance; they are curious,
and perhaps of sufficient interest to bring before your notice. The
fragments are all preserved in tubes, and labeled, so that any one who
likes to see them can do so.

Of the advantage which a machine which will collapse or fold up when
desired, but retain its form on the road, offers in convenience, it is
unnecessary for me to speak.

Of double machines, the Rucker tandem bicycle seems to me to be in every
respect the best, but I should add that I speak only from imagination
and not from experience. The independent steering, the impossibility of
capsizing forward or sideways, the position of the rider over his work,
the absence of any little wheel with its mud throwing and vibrating
tendencies, combine to make a machine which ought to be superior in
almost every desirable quality to any other; what it may be in practice
I hope to hear in the discussion.

Of double tricycles, the Sociable has been tried by many, and is
practically a failure in so far as traveling quickly and easily
is concerned. The Tandem, though it presents so objectionable an
appearance, seems likely to become a favorite, for it surpasses any
single tricycle, and rivals the bicycle in speed. How it may compare in
comfort or in safety with the single machine, perhaps those few who are
well acquainted with them will say; at any rate, in the case of the
Humber, greater stability is given to the steering, owing to the weight
of the front rider.

Time will not allow me to say more of these machines, or to attack the
subject of steam, electric, or magic tricycles, which I had hoped to do.
With steam and electricity we are well acquainted; by magic tricycles, I
mean those driven by a motor which, without any expense, will drive one
twenty miles an hour, up or down hill, with perfect safety. Highway
regulations, and certain reasons not well understood, have at present
prevented these contrivances from making a revolution.

There remains one machine which must be considered separately, for it
cannot be classed with any other. This is the Otto bicycle. My opinion
of this machine is so pronounced that I do not care to state it fully. I
shall merely give the reasons why I prefer it to anything else, and in
so doing I shall be taking the first step in the discussion, in which it
will be interesting to hear from riders of other machines the reasons
for their preference.

In the first place, the evils of a third or little wheel, the cause of
trouble in all tricycles, are avoided. There is none of the vibration
which makes all other machines almost unbearable to Ottoists, vibration
which tricyclists have learnt to consider a necessary accompaniment of
cycling, but which has, no doubt, been diminished by the use of the
spring support of the front steering Humber. It would be presumptuous
in me to make any remarks on the effect of this vibration on the human
system; we shall all be anxious to hear what our Chairman has to say on
this point. By having only two wheels, we have only two tracks, so that
we can travel at a fair speed along those places in the country called
roads, which consist of alternate lines of ruts and stones, where a
three-track machine could not be driven, and where, from the quantity
of loose limestone in the ruts, a little wheel of a two-track tricycle
would be likely to suffer. By having no little wheel, we can ride in
dirty weather without having the rest of our machine pelted with mud, so
that cleaning takes less time than it does with anything else. As I have
already remarked, the small wheel is the culprit which makes the bicycle
and tricycle drive so heavily on a soft road. The ease with which the
Otto can therefore be run through the mud astonishes every one. Having
no little wheel, we can obtain the full advantage of the high 56
inch wheel, which almost every one prefers. As I have ridden all
combinations, from a 50 inch geared up to 60 inch, to a 60 inch geared
level, I can speak from experience of the increased comfort to be
derived from these large wheels, though for speed only they do not
compare with the smaller and lighter wheels geared up. A further point
gained by the use of two wheels only is the fact that the whole weight
of machine and rider is on the driving-wheel, as it is also on the
steering-wheel, so that by no possibility can the wheels be made to slip
in the driving, or to fail in steering from want of pressure upon them.

The most important consequence, however, is the absence of any fixed
frame. In all machines, bicycles and tricycles, with the usual fixed
frame, a position is found for the saddle which is, on the whole, most
suitable. For some particular gradient it will be perfect; on a steeper
gradient the treadles will be further in advance, but with a steeper
gradient the rider should be more over the front of the treadles. To get
his weight further to the front, he has to double up in the middle, and
assume a position in which he cannot possibly work to advantage. The
swinging frame of the Otto carries the treadles, of necessity, further
back, so that the Ottoist, when working at his hardest, is still
upright, with his hands in the line between his shoulders, and his feet
and his arms straight, so that he can hold himself down, and employ his
strength in a perfectly natural position. On going down a slope, the
fixed frame of a bicycle or tricycle leans forward, and places the rider
in such a position that extra weight is thrown on his arms and his
shoulders, whereas the swing frame of the Otto goes back, and the rider
of necessity assumes that position in which his arms are relieved of all
strain. In so far as the general position taken by the automatic Otto
frame is concerned, nearly the same effect can be obtained by using the
swing frame of the Devon tricycle, which can be shifted and locked in
any position which the rider wishes, or by the sliding saddle, which can
be slid backward or forward and locked so as to place the rider in one
of three positions. Though the rider can by these devices assume nearly
that position with respect to the treadles which is most advantageous,
he cannot obtain that curious fore and aft oscillation made use of by
the Ottoist in climbing hills, which, as the model on the table shows,
enables him to get past the dead points without even moving, and which,
therefore, makes the Otto by far the best hill-climbing machine there
is, if account is taken of the high speeding with which all Ottoists
ride. This is a proposition which none who knows the machine will
question for one moment.

The freedom of motion resulting from the swing of the frame of the Otto
gives a pleasurable sensation, which those who have only experienced the
constrained motion of a three-wheeler cannot even understand.

The very peculiar method of driving and steering, which seems so
puzzling to the novice, especially if he is a good rider of other
machines--for in that case he is far worse off than one who has never
ridden anything--give the rider, when he is familiar with them, a
control over the machine which is still surprising to me. In the first
place, the machine will run along straight, backward or forward, so
long as the handles are let alone. This automatic straight running is a
luxury, for until a deviation has to be made, the steering handles need
not be touched, and the rider may, if sufficiently confident, travel
with his arms folded or his hands in his pockets. The rigid connection
between the cranks and the wheels does away with all the backlash,
which is so unpleasant with chain or toothed wheel gearing. There is no
differential gear or clutch, but the machine possesses the advantage
of the clutch over the differential gear when meeting with unequal
resistance on a straight course, for each wheel must travel at the same
speed; but, in turning a corner, instead of driving the inner wheel
only, which is done by the clutch or both wheels equally, which is the
case with differential gear, each wheel is driven, but the outer one
more than the inner. At high speeds, the steering of the Otto has this
advantage, that whereas, with a given action on a tricyle, the same
deviation will be effected in the same _space_ at high as at low speeds,
the same action on the Otto will, at high speeds, produce the same
deviation in the same _time_ as it does at low speeds; and so instead of
becoming more sensitive at high speeds, as is the case with the tricyle,
the steering of the Otto remains the same. This is because the steering
of the tricycle depends on a kinematical, that of the Otto on a
dynamical principle.

In another respect, no machine can approach the Otto; at almost any
speed the rider can, if there is reason, instantly dismount, by which
action he puts on the brakes, and the machine will save him from
falling, stopping with him almost instantly. As is well known, we can
move backward and forward, we can twist around and around in our own
width, or can ride over bricks with impunity.

One objection to the machine is the difficulty of learning, which is
considerable, but which presents no danger. This difficulty has been
much exaggerated, for before the present powerful brake was applied it
did require considerable skill to ride it down a steep hill. The way
to do this must still be learnt, but it is now comparatively easy. For
going down steep hills, the front steering tricycle is without a rival;
I do not know what other machine will do this better than the Otto.
Lastly, the foot straps, which would be a great advantage on any
machine, if only they were safe, are not--though none but riders will
believe it--in any way a source of danger on the Otto. Having ridden
this machine for close upon 10,000 miles, I can speak with more
authority on this point than can those who are not able to sit upon it
for a moment.

The only disadvantage which the machine presents is the fact that it is
impossible to remove the feet from the pedals while running, without
dismounting; but though they must at all times follow the pedals, the
Ottoist is not, as is generally thought, working when descending a hill.

The enthusiastic terms in which every one who has mastered the
peculiarities of the Otto speaks of it would be considered as evidence
in its favor, if we were not all considered by other cyclists to be in
various stages of lunacy.

       *       *       *       *       *




THE CANAL IRON WORKS, LONDON.


Some interest is awakened in engineering circles in London, just now, by
the approaching close of the old engineering works so well known as the
"Canal Ironworks," at the entrance to the Isle of Dogs, London, E. This
notable establishment stands second in priority in London--that of
Messrs. Maudslay, Sons & Field being the oldest--for the manufacture of
marine engines. It was founded by the late Messrs. Seawards, above sixty
years ago. Here was originated Seaward's hoisting "sheers" with the
traveling back leg, a modern example of which, 100 feet high, in iron,
stands on the wharf. An interesting tool, also, is the large vertical
boring machine for largest size cylinders; Seaward spent £5,000 upon
this, and it is certainly an admirable tool. There is also the large
vertical slotting machine, with a stroke up to 5 feet 2 inches, a
wonderfully powerful and compact machine. The extensive collection of
screwing tackle is, perhaps, unsurpassed, and extends up to 8 inches
diameter. There is a peculiar erecting shop roof, which will still repay
examination.

       *       *       *       *       *




MARINONI'S ROTARY PRINTING PRESS.


The greatest progress that has been made in recent years in the art
of printing is in the invention of the high speed press provided with
continuous paper.

Three French constructors, Messrs. Marinoni, Alauzet, and Derriey, have
brought this kind of apparatus to such a degree of perfection that
the majority of foreign journals having a large circulation buy their
presses in France. We reproduce in Fig. 1 a perspective view of the
Marinoni press, and in Fig. 2 a diagram showing the parts of the same.
In order to give a complete description of it, we cannot do better than
to reproduce the very interesting study that has been made of it by Mr.
Monet, a civil engineer.

[Illustration: FIG. 1.--MARINONI'S ROTARY PRINTING PRESS.]

The roller, J (Fig. 2), is placed in the machine in the state in which
it is received from the paper manufactory. The paper unwinds, runs over
the rollers, e and e', which serve only for tautening it, and then
passes between the two cylinders, A and B. The cylinder, A, carries the
form, and B carries the blanket, and the paper thus receives its first
impression. It afterward passes between the cylinders, A' and B', and
receives an impression on the other side, the cylinder, A', carrying the
form, and B' the blanket. Being now printed on both sides, it passes
between the cylinders, KK', which cut it off and allow the sheet to
slide between the cords of the rollers. These latter lead the sheets
over the rollers, g h, on which they wind, one over the other, when the
rollers, a a', are in the position shown by unbroken lines in the cut.

The part of the machine that holds the rollers, g h, and the different
cords that wind over them, is the _accumulator_, and it is in this part
of the press that the sheets accumulate, one over the other, to any
number desired.

The size of the rollers, g h, and their distance apart are so regulated
that when the sheet reaches the accumulator, it falls exactly on those
that have preceded it. When the proper number of sheets is in the
accumulator (4 or 5 being the number most employed for afterward
facilitating the separation into packets on the receiving table), the
two small rollers, a a', advance over the rack, N, and the sheets,
instead of continuing to roll over into the accumulator, fall on the
rack and are deposited by it upon the receiving table, O.

[Illustration: FIG. 2.--MARINONI'S PRESS.]

The rack having fallen twenty times, and deposited five sheets each
time, or one hundred in all, the table moves in such a way as to prevent
the sheets subsequently deposited from getting mixed with them. When the
rack has fallen twenty times, the table returns to its initial position.

The distributing rollers, D, come in contact with the inking rollers, I,
once during each revolution of the printing cylinders, and are mounted
on racking levers provided with regulating screws that permit of easily
regulating the amount of ink taken up. The supports of the inking
rollers are movable and can be made to approach or recede from the
distributing rollers, so as to still further vary the amount of ink
taken up by them.

The distributing rollers supply the ink to a roller, E, of large
diameter, which, having a backward and forward motion, begins to
distribute the ink and to transmit it to a second roller, F, of the same
diameter. This latter then spreads it over a metallic cylinder, G, which
is of the same diameter as the printing cylinders, and against which
revolve three distributing rollers, H, that have a backward and forward
motion.

Between the cylindrical inking table, G, and the type cylinder, there
are situated inking cylinders, T, of large diameter, that constantly
take up ink from the inking table and distribute it over the types.

The machine here described, when designed for printing large sized
journals, has cylinders whose circumference corresponds to the size of
paper for two widths of pages, and whose length is sufficient to allow
it to receive two forms. Each cylinder, then, carries four forms, or
eight in all, and prints two complete copies at each revolution.

The large sheet cut off by the cylinders, K K', contains, then, two
copies; and this sheet, on passing under the roller, f is again cut in
two by a disk which separates it in a direction perpendicular to the
cylinders.

To this press there may be added a mechanical folder of Mr. Marinoni's
invention, capable of folding a journal five times.--_Annales
Industrielles_.

       *       *       *       *       *




CHENOT'S ECONOMIC FILTER PRESS.


Mr. E. Chenot, who is occupied in the manufacture of wine from dry
grapes, has been led to devise a new style of filter, which by reason of
its mode of action and its construction, he calls the "Economic Filter
Press."

The apparatus, which is shown in the accompanying cut, consists of flat
bags whose mouth may be at the top, as usual, or at the side. Through
this orifice there is introduced a flat piece of wood or metal, which,
like the bag, has an aperture through the center. The whole is suspended
from a distributing pipe that is fixed at one end to the frame and is
free at the other. This pipe is slotted beneath, and the pieces of wood
or metal contain, opposite the slot, a number of small apertures that
put the distributer in communication with the interior of the bags.
Between these latter there are placed wire cloth frames which hold them
in position and facilitate the flow of the filtered liquid. The cut
shows the filter provided with a portion of its bags and frames. When
all the frames are in place they are locked by causing the movable plate
to move forward by means of two screws connected with an endless chain
and actuated by a hand wheel. The pressure of this plate closes up the
bags hermetically. Then, the feed cock being opened, the liquid flows
into all the bags, deposits therein what it holds in suspension, and the
clarified product flows to the inclined bottom of the filter and from
thence to the exterior.

[Illustration: CHENOT'S ECONOMIC FILTER PRESS.]

The apparatus may be supplied either through an upper reservoir, a juice
elevator, or a pump. The discharge is proportional to the square root
of the pressure. When the bags are full of residuum, the feed cock is
closed, the filter is unscrewed, and the bags and frames are taken out.
With fresh bags and the same frames, it is possible to at once set the
apparatus in operation again.

Before the filter is taken apart, the residuum may be exhausted by
washing it either with water or steam, or by pressure. To effect the
operation by pressure, the pieces of wood or metal are removed, the
mouths are closed by making a fold in the top of the bags, and the
latter are then put back into the apparatus or into an ordinary press
and submitted to another squeezing.

To render the maneuvering of it easier, the apparatus has been given a
horizontal position.--_Revue Industrielle_.

       *       *       *       *       *

[American Engineer]




STEEL CHAINS WITHOUT WELDING.


We take the following description, together with the illustrations, of
a method and machine for making steel chain without welding, from our
valued contemporary, _Le Genie Civil_, of Paris:

When we regard an ordinary oval-linked chain endwise, it presents itself
in the form of a metal cross, and it was this that gave the cue to M.
Oury, of the Government Arsenals, to construct chain without welding. By
a series of matrices and punches, etc., he contrives, with small loss of
metal, to model a chain out of cross-shaped steel bar.

Steel is the better material for such usage, from its homogeneity, both
as to composition and strength.

Referring to the plate below, Figs. 1 to 10 explain the successive steps
from the bar to the finished chain.

Fig. 1 shows in plan and section the steel bar, whose length may be some
40 feet, and which would make a chain say 50 feet long. The shape of the
bar presents no difficulties in the way of rolling.

Figs. 2 and 3 give, in side elevations of the two faces and sections,
the first rough form of the links. These first begin to take the
exterior shape with the rounding of the angles.

The operations following, represented by Figs. 4 and 5, is the piercing
of the center of the links, which can later be furnished with a stay for
such chains as require special strength. The point now is to detach the
links, which is accomplished by oblique piercings, as shown in Fig. 6.
In the operation represented by Fig. 7, the oval shape is imparted to
the link, and the operation finishes as shown in Fig. 8.

Actually, the links are circular and separate. This separation is
retarded as much as possible, for it is plain that it is easier
to operate a rigid bar than a chain, above all when the operation
necessitates its being pushed forward.

By means of a good system of heating, analogous to that employed on the
large parts entering into ship construction, it is hoped to perform a
major part of the operations, of which we have given but an idea, at a
single heat.

[Illustration: MACHINE FOR MAKING CHAIN WITHOUT WELDING.]

These operations require work on both faces alternately--this presents
no difficulties; but what appears to us most difficult to realize is
_continuous work_, the bar passing through several machines which
successively impress upon it the steps of progress toward the finished
chain. If the machines are end on to each other in a direct line, there
will necessarily be a fixed place for each tool; the rough cut chain
must accurately reach the point where another tool is ready to continue
the modeling. This appears to us practically impossible, the more so as
the elongation which the bar takes at each stamp varies with its initial
diameter.

What is more admissible is that with one heat and in the same machine an
operation could be performed on the two faces perpendicularly. The bar
could then be taken from one furnace and put in another immediately,
to pass at once to another machine to again undergo the operations
following. The work could then be done rapidly, submitting the bar to
several heats.

A few words on the tools as they exist.

The most important principle to note, and on which the different
machines employed are designed, is this: The punches or matrices acting
on the chain at its different points of progress are put in motion by
spiral springs worked by means of tappets or cams distributed over the
circumference of a cylinder, having a rotary movement imparted to it by
pulleys and belts.

The figures on our plate show with sufficient clearness the working of
one of these machines. It will be seen that the bar traverses through
and through the machine for stamping, and that it can be disengaged for
a reheating before passing to subsequent operations.

       *       *       *       *       *

The bog peat of Mexico is now being used on a considerable scale as fuel
for locomotives, stationary engines, smelting purposes, smiths' fires,
and househould use. The peat is mixed with a proper proportion of
bitumen, and is said not only to burn freely, and without smoke in much
quantity, but to give a higher dynamic equivalent of heat than the same
amount of wood.

       *       *       *       *       *




THE BITTER SUBSTANCE OF HOPS.

[Footnote: _The Brewers' Guardian_, from the _Zeit. f. d. gesammte
Brauwesen_.]

By DR. H. BUNGENER.


Little that is definite is known of the substance or substances to
which the hop owes its bitterness. Lermer has succeeded, it is true, in
separating from hops a crystallized colorless substance, insoluble in
water, an alkaline solution of which has a marked bitter flavor, and
which easily changes on exposure to the air, assuming a resinous form.
According to Lermer, the formula of this substance is C_{32}H_{50}O_{7};
it possesses the properties of a weak acid and forms a characteristic
copper salt, which is soluble in ether. This hop bitter is, however,
produced from the hop by a very roundabout process, by treatment of the
extract with alkalies; it is not therefore regarded by many as present
in this form in the hop, and they hold that it is only produced by
the action of the alkalies. On the other hand, however, Etti, by a
complicated extracting process, but without using an alkali, succeeded
in producing a bitter substance from hops, which is, however, soluble in
water.

Several experiments convinced me that there really existed in hops a
crystallizable substance, insoluble in water, the alcoholic and alkaline
solution of which had a bitter flavor, in short, which possessed all
the properties of Lermer's hop bitter acid. Petroleum ether is the best
practical solvent in use for its isolation, as it does not dissolve
the majority of the remaining constituents of the hop, especially the
hop-resin, which they contain in considerable quantity. Still, the
extraction of hop-bitter acid from hops is a troublesome and thankless
job, the petroleum ether taking up certain substances which add greatly
to the difficulty of purifying the crystals. On the other hand, we can
readily and quickly attain our object, if we employ for our original
material fresh lupuline from unsulphured hops.

The following process has furnished me the best results:

The lupuline is first freed from gross impurities (hop-seed leaves,
etc.), and then covered with petroleum ether boiling at a low
temperature (40° to 70°) in stoppered flasks. The mixture is shaken up
from time to time. After twenty-four hours, by means of a Zullowsky
filter immersed in the mass, and with the aid of a suction-pump, the
dark brown solution is drawn off; then fresh ether is poured on to the
lupuline, and it is allowed to stand for another twenty-four hours.
After this process has been three times repeated, nearly everything the
petroleum will dissolve has probably been extracted. The solutions are
put together, and the petroleum ether distilled off _in vacuo_ at a low
temperature, until there remains in the flask a dark brown sirup, which
on cooling solidifies into a crystalline mass. This is pulverized and
turned on to a filter composed of a large funnel, in which a smaller
funnel covered with muslin is inserted. With the aid of a suction-pump,
the greater portion of the thick, crude solution can be filtered
through. There remains on the filter a highly colored crystalline
"cake," which should be pulverized with a small quantity of petroleum
ether and again filtered. After this operation has been repeated three
or four times, we obtain an almost colorless mass, consisting of
hop-bitter acid, contaminated by small quantities of a fatty substance,
and a substance which I could not isolate, and which I had at first
great trouble in separating from the hop-bitter acid.

If we do not wish to utilize this crude substance at once, it will be
necessary to melt it in the water bath and pour it into a bottle under
close seal, where it will at once crystallize and solidify. If it
remains exposed to the atmosphere, it will soon become sticky and
turn partly into resin. Six kilos of lupuline, which included a large
proportion of sand, furnished 400 grammes of crude hop-bitter acid. The
first experiments in crystallization with petroleum ether gave poor
results; it is difficult to produce the acid pure in large quantities
by this process, as a small quantity of the above substance obstinately
clings to it, and it readily assumes a non-crystallizable form. Our
object is more readily attained if we crystallize it once from alcohol,
for which purpose we dissolve it in a little lukewarm alcohol, then
quickly cool the solution; flakes of a fatty substance will be
separated, which are removed by filtration with the aid of a
suction-pump. Then we throw a few small crystals of the acid into the
solution, and after a short time crystallization commences. As soon as
it appears to be ended, the mother solution is removed with the aid of a
platinum cone, and the crystals washed with a little cold alcohol. The
alcoholic mother solution, which still contains the chief part of the
bitter acid, must be quickly evaporated, and the residue consigned to
a flask. The acid crystallized from the alcohol is then recrystallized
several times from petroleum-ether. In order to quickly dissolve the
bitter substance, it should be carefully melted in a flask, and double
its volume of ether gradually added; on its cooling, we obtain beautiful
prismatic crystals, which attain a length of 1 cm., and become perfectly
pure after four or five crystallizations. The mother solutions must be
speedily evaporated if we still wish to obtain crystals; after a time
they will only furnish a resinous residue.

The hop-bitter acid melts at 92° to 93°. It is easily soluble in
alcohol, ether, benzol, chloroform, sulphide of carbon, and vinegar; to
a lesser extent in cold petroleum ether, and not at all in water.

In the analysis I obtained figures which correspond best with those
calculated from the formula C_{25}H_{35}O_{4}.

                                     Obtained.
  Calculated.  ------------------------^-----------------------
  -----^-----  2. Crystal. 3. Crystal.  5. Crystal. 6. Crystal.
        p.c.   p.c.    p.c.     p.c.   p.c.    p.c.    p.c.
    C  75.19   74.79   74.83    74.9   75.04   75.05   75.07
    H   8.77    8.97    8.90     8.85   8.87    8.83    8.80
    O  16.04

If we shake up the ether solution of bitter substance with an aqueous
solution of acetate of copper, the ether will assume a green color, and
gradually deposits a green crystalline powder, a cupreous combination
of the bitter acid. It is difficult to obtain in a pure state, as the
solutions are readily subject to slight decomposition, accompanied by a
small deposit of copper oxide. This combination is readily soluble in
alcohol, to a lesser extent in ether, and is insoluble in water.

In the course of analysis, I obtained the following figures:

   C    69.4 per cent.        69.3  per cent.
   H     7.95     "            7.98     "
   Cu    7.20     "            7.18     "

If we suppose that the copper combines with two molecules of hop-bitter
acid, by the decomposition of one of its atoms, H, we obtain the formula
C_{50}H_{68}O_{8}Cu. This combination will contain 69.87 per cent. C,
7.91 per cent. H, and 7.33 per cent. Cu. The figures obtained do not
perfectly coincide with those calculated; it is nevertheless probable
that the formula is correct, and the combined substance analyzed was not
perfectly true.

I have already referred to the fact that solutions of hop-bitter acid,
if left standing too long, assume a yellow color, and on evaporation
leave only a yellow resinous residue. This, as its reaction shows,
evinces a complete analogy with the crystallized acid. The dark-colored
mother solution, from which the crystalline cakes of bitter acid are
obtained, contains a large proportion of this resinous compound, which
can be isolated by treatment with a weak soda-lye; this substance, like
the crystallized acid, is soluble in alkalies, and can be precipitated
from an alkaline solution by an acid. Old hops furnish far less
crystallizable acid than new hops; from some samples I have been able to
obtain only a few crystals; the remainder had been transformed into the
resinous modification.

If pure hop-bitter acid be pulverized and exposed to the atmosphere, it
soon turns yellow and the surface assumes a resinous consistency. At
the same time, a more pronounced odor of fatty acids and aldehydes is
apparent. Still more rapidly will this oxidation occur if a thin layer
of an alcoholic solution of the acid is allowed to evaporate in the air.
On the other hand, we can allow hop-oil to stand for days without its
odor being perceptibly changed; it appears to me more than probable that
the peculiar smell of old hops is due far more to the oxidation of the
bitter substance than to the oxidation of oil.

Hop-bitter acid appears to possess the character of an aldehyde and of
a weak acid; for the present I am not in a position to state its
constitution more clearly. Most of the oxidizing processes have an
energetic effect on it, forming also considerable quantities of
valerianic acid.

The question as to whether the hop owes chiefly to this acid and its
resinous modifications the property of imparting a pronounced bitter
flavor to a solution, I must for the present leave unanswered. The acid
and its isomer are both insoluble in water; they are, on the other hand,
very readily dissolved in hop oil; they also furnish a tolerably bitter
solution, if boiled for a long time in water, probably on their account
of their gradual decomposition. I will not for the present go further
into the subject, as I hope soon to be in a position to give more
definite information.

       *       *       *       *       *




ST. PAUL'S VICARAGE, FOREST HILL, KENT.


This vicarage, for the Rev. Frank Jones, has recently been completed
from the designs of Mr. E.W. Mountford, A.R.I.B.A.; of 22 Buckingham
Street, Strand, W. C., and Mr. H. D. Appleton, A.R.I.B.A., of the Wool
Exchange, Coleman Street, E. C., who were the joint architects. The
builder was Mr. William Robinson, of Lower Tooting, S. W. The walls are
of yellow stock bricks, with red brick arches, quoins, etc., the gables
being hung with Kentish tiles and the roofs covered with Broseley tiles.
The internal joinery is of pitch pine.

[Illustration: ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM ROAD.]

[Illustration: ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM GARDEN.]

The illustrations are from drawings by Mr. J. Stonier.--_The Architect_.

       *       *       *       *       *




SOME ECONOMICAL PROCESSES CONNECTED WITH THE CLOTHWORKING INDUSTRY.

[Footnote: Read before the Society of Arts, London, May, 1884.]

By Dr. WILLIAM RAMSAY, Professor of Chemistry at University College,
Bristol.


In this present age of scientific and technical activity, there is
one branch which has, I think, been the subject of an article in the
_Quarterly Journal of Science_. It is one which deserves attention. It
was there termed "The Investigation of Residual Phenomena," and I can
conceive no better title to express the idea. The investigator who
first explores an unknown region is content if he can in some measure
delineate its grand features--its rivers, its mountain chains, its
plains; if he be a geologist, he attempts no more than broadly to
observe its most important rock formations; if a botanist, its more
striking forms of vegetation. So with the scientific investigator. The
chemist or physicist who discovers a new law seldom succeeds in doing
more than testing its general accuracy by experiments; it is reserved
for his successors to note the divergence between his broad and sweeping
generalization and particular instances which do not quite accord with
it. So it was with Boyle's law that the volume of a gas varies in
inverse ratio to the pressure to which it is exposed; so it is with the
Darwinian theory, inasmuch as deterioration and degeneration play a part
which was, perhaps, at first overlooked; and similar instances may be
found in almost all pure sciences.

I conceive that the parallel from the technical point of view is a
double one. For just as every technical process cannot be considered
to be beyond improvement, there is always scope for technical
investigation; but the true residual phenomena of which I would speak
to-night are waste products. There is, I imagine, no manufacture in
which every substance produced meets with a market. Some products are
always allowed to run to waste, yet it is evident that every effort
consistent with economy should be made to prevent such waste; and it has
been frequently found that an attempt in this direction, though at first
unsuccessful, has finally been worked into such a form as to remunerate
the manufacturer.

It is my purpose to-night to bring under your notice methods by which
saving can be effected in the cloth industry. I am aware that these
methods have not much claim to novelty; but I also know that there are,
unfortunately, few works where they are practiced.

The first of these relates to the saving and utilization of the soap
used in wool scouring and milling. It is, perhaps, hardly necessary to
explain that woolen goods are scoured by being run between rollers,
after passing through a bath of soap, and this is continued for several
hours, the cloth being repeatedly moistened with the lye, and repeatedly
wrung out by the rollers. The process is analogous to ordinary washing;
the soap dissolves the greasy film adhering to the fibers, and the
"dirt" mechanically retained is thus loosened, and washed away. Now, in
order to dissolve this greasy matter, a considerable amount of soap must
be employed; and in the course of purification of the fabric, not merely
what may be characterized as "dirt" is removed, but also short fibers,
and various dye-stuffs with which the fabric has been dyed, many of
which are partially soluble in alkaline water; moreover, it invariably
happens that some dye does not combine with the fiber and mordant, thus
becoming fixed, but merely incrusts the fiber; hence this portion is
washed off when the retaining film of grease is removed from the fiber.
The suds, therefore, after fulfilling this purpose, are no longer a pure
solution of soap, but contain many foreign matters; and the problem is
so to treat these suds as to recover the fat in some condition available
for re-conversion into soap.

For this purpose wooden runnels are placed beneath the rollers, through
which the cloth passes in the scouring machine, so as to collect the
suds after they have been spent. These runnels lead to a wooden pipe or
runnel, which receives the spent suds from all the scouring machines,
and the whole of the waste, instead of being let off into the stream,
polluting it, delivers into a tank or trough, which may also be
constructed of wood, but, as it has to withstand the action of acid, is
better lined with lead. This tank is necessarily proportioned in size
to the number of scouring machines and the quantity of spent suds to
be treated. When a sufficient quantity has collected, oil of vitriol,
diluted with twice its bulk of water, is added, one workman pouring it
in gradually while another stirs the contents of the tank vigorously. At
short intervals, the liquid is tested by means of litmus paper, and
when it shows a faint acid reaction, by turning the blue paper red, the
addition of acid is stopped. The acid has then combined with the alkali
of the soap, while the fatty acids formerly in combination with the
alkali are liberated, and float to the surface of the liquid, carrying
with them the impurities in the shape of short fibers and dye stuffs;
the sand and heavier impurity, should any be present, sinks to the
bottom.

After standing for some hours, the separation is complete. In order to
separate the two layers, the tank is provided with an exit in the side,
near the bottom, closed by a sluice or valve. This valve is opened, and
the watery portion is allowed to escape into a sand filter bed.

The filter serves to retain any solid impurities which may still remain
suspended in the water; but it will be found that the escaping water is
nearly pure.

The dark brown fatty acid is mixed with a large amount of impurity, such
as short wool fibers, burrs, sand, and dye stuffs washed from the wool.
To remove water more completely, the semi-fluid mass is pumped from the
tank, and delivered into hair-cloth filters; the liquid which drains
from these bags finds its ways to the sand filters joining the drainage
which formerly passed out from the tank through the sluice. After being
turned over in the filter several times, the residue is transferred to
canvas sacks. These sacks are placed in a filter press, where they are
exposed to pressure while heated to a temperature sufficient to melt
the fat. The solid impurities remain in the bags, while the fatty acids
escape, and are received in a barrel or tank for the purpose. The fatty
acids, when cold, are of a deep brown color, and of the consistency
of butter. The residue is kept, and the method of treating it for the
recovery of indigo will afterward be described.

The fatty acids are now ready for conversion into soap. It may here be
remarked that, on distillation, they yield a nearly white fatty mass,
which, when treated with soda-lye, is capable of yielding a perfectly
white soap. But, for the clothworker's purpose, this purification is
unnecessary.

The conversion into soap is a very simple matter. As the fats are
acids--a mixture of palmitic, oleic, and stearic acids--and not the
glycerine salts of these acids, like ordinary fats, soap is made by
causing them directly to unite with caustic soda. The fats are melted
in a copper, by means of a steam-jacket, or coil of steam-pipe in the
copper, and the soda-lye is run in until complete union has taken place.
The exact point of neutralization can easily be found by taking out
a small sample after stirring, and dissolving it in some methylated
spirits. A few drops of alcoholic tincture of phenol-phthalein are then
added, and as soon as a faint red color appears, addition of soda is
stopped. This shows that the fatty acids have been over-saturated.
Addition of a little more fat renders them perfectly neutral, and the
soap is then ladled out into wooden moulds, lined with loose sheets of
zinc.

The resulting soap is of a brown color, but is perfectly adapted for the
purpose of wool-scouring. It should here be mentioned that, in practice,
the soap is always made somewhat alkaline; in point of fact, it contains
about 2 per cent. of free alkali. This is found to assist in scouring; I
presume that the free alkali forms a soap with the oil added to the wool
during spinning, and if no free alkali be present, this oil would not be
so thoroughly removed.

It will be noticed that in this simple method of soap-making, there is
no salting out to separate the true soap from the watery solution of
glycerine, for no glycerine is present. The apparatus may be of the
simplest nature, and on any required scale, proportionate to the size of
the mill. It is a process which requires no specially skilled labor; in
any works some hand may be told off to conduct the process as occasion
requires; and as a very large proportion of the fatty matter is
recovered, the soap-bill is reduced to a very small fraction of the
amount which would be paid were recovery not practiced. And lastly, the
streams are not polluted; the only waste is a little sulphate of soda,
which can hardly be regarded as a nuisance, inasmuch as it is a not
unfrequent constituent of many natural waters.

Let us now return to the solid matter from which the fatty acids have
been removed by pressure. This brown, earthly-looking cake consists of
vegetable impurity washed off from the cloth, of short fibers, and of
various dye stuffs. It is divided into two lots: That which contains
indigo, and that which contains none, or which contains too small a
quantity for profitable extraction. And it may here be remarked, that it
is advisable to collect the suds from cloth dyed with indigo separate
from that to dye which no indigo has been employed. The residue from
indigo-dyed cloth has always a more or less blue shade, and if much
indigo is present, the well-known copper-color is evident. Of course,
the amount of indigo must greatly vary, but it may rise to 8 or 10 per
cent. of the total weight of the refuse.

To recover the indigo from this refuse, the somewhat hard cakes are
broken up, placed in a tank, and allowed to steep in water. When quite
disintegrated, they are transferred to another tank--a barrel may be
used for small quantities--and thus this refuse is exposed to the
reducing action of copperas and lime. The indigo is converted into
indigo-white, and is rendered soluble, and it oxidizes on the surface,
forming a layer of blue froth on the top of the liquid, while the
remainder of the impurities sinks. This process of reduction may last
for twenty-four hours, and is helped by frequent stirring.

The indigo scum is preserved, and placed in filter cloths, where it is
thoroughly washed with water two or three times. The residue which has
sunk to the bottom is removed, dried, and forms a valuable manure,
owing to the amount of the nitrogen which it contains. Its value may be
increased by addition of weak vitriol, which exercises a decomposing
action on the nitrogenous matter, forming with it sulphate of ammonia.
The original residue from the filter-press, if it does not contain
indigo, may be at once put to similar use.

In large works, which dye their own goods, it is well known that the
"fermentation vat" is in general use for indigo-dyeing. But this vat
requires constant superintendence, and must be kept in continual action;
besides, it is successful only on a comparatively large scale. And,
moreover, it requires skilled labor. Small works, or works in which
dyeing is only occasionally practiced, find it more convenient to use
Schützenberger and Lalande's process. Although this process is well
known, a short description of it may not here be out of place.

The process depends on the reduction of indigo to indigo-white, or
soluble indigo, by means of hyposulphite, or, as it is generally termed
to avoid confusion with antichlore, rightly named thiosulphate of soda,
hydrosulphite of soda. The formula of this substance is NaHSO_{2}, as
distinguished from what is commonly known as hyposulphite of soda,
Na_{2}S_{2}O_{3}. It is produced by the action of zinc-dust on the acid
sulphite of soda. The zinc may be supposed to remove oxygen from the
acid sulphite, NaHSO_{3}, giving hyposulphite, NaHS0_{2}. The reduction
of the acid sulphite is best performed in a cask, which can be closed at
the top, so as to avoid entrance of air. The acid sulphite of soda, at a
strength of 50 or 60 Twaddell (specific gravity 1.26 to 1.3), is placed
in the cask, and zinc-dust is added, with frequent stirring. The liquid
is then mixed with milk of lime, and after again thoroughly stirring,
the liquid is allowed to settle, and the clear is decanted into the
dyeing-copper. The indigo, in the frothy state in which it is skimmed
from the purifying barrels or tanks, is then added, with sufficient lime
to dissolve it when it has been reduced. It is heated gently by a steam
coil, to about 90° Fahr., and the goods are dyed in it. The colors
obtained by means of this indigo are light in shade, and the goods must
be dipped several times if dark shades are required. But it is found
better in practice not to attempt to dye dark shades by this process;
the ordinary indigo-vat is better adapted for such work. The object of
not wasting indigo is sufficiently attained by employing it for the
purpose to which it is best adapted. Of course the recovered indigo may
be used in the ordinary manner. I merely mention the most convenient way
of disposing of it in works where only a small quantity is recovered,
and which do not practice dyeing on an extensive scale.

I have now to ask you to turn to a different subject, namely, the
scouring of wool, not by the usual agent, water, but by a liquid,
bisulphide of carbon, made by the action of sulphur vapor on red hot
coke or charcoal.

This, again, is not wholly a new process, for various attempts have
been made to dissolve out the yolk, or _suint_, or greasy matter from
unwashed wool, as it comes from the back of the sheep. Fusel oil
has been patented for this purpose. Carbon disulphide has also been
patented, but, as will afterward be shown, the old method of removing it
from the wool injured the color and quality of the fiber, so as to make
the application of this scouring agent a failure.

Wool in its unwashed state contains a considerable proportion of what is
termed _suint_. This consists of the fatty matter exuded as perspiration
from the sheep, along with, or in some form of combination with, potash
derived from the grass on which the sheep feed. _Suint_ was first
investigated by Vauquelin. He obtained it by evaporating, after
filtration, the water in which raw fleeces had been washed. The residue
is of a brown color, and has a saline, bitter taste. On addition of an
acid to its solution in water, it coagulates, and a fatty matter rises
to the surface. It is, in fact, a potash soap, to a great extent
containing carbonate and acetate of potash, along with chloride of
potassium and lime, probably in combination also with fatty acids. It is
usually mixed with sand and carbonate of lime.

In 1828, M. Chevreul, who is still alive in Paris, although nearly a
century old, published an analysis of merino wool. It consisted of:

                                 Per cent.
  Pure wool                        31.23
  Soluble _suint_                  32.74
  Insoluble                         8.57
  Earthy matter                    27.46
                                  ------
                                  100.00

It is easily seen that _suint_ forms a very important constituent of raw
wool. Its proportion varies, of course, according to the nature of the
pasture on which the sheep are fed, the climate, etc. Wool from Buenos
Ayres, for example, contains much less than that analyzed by M.
Chevreul; its amount is only 12 per cent. of the weight of the raw wool.

This _suint_ contains always about 52 per cent. of residue when ignited.
The composition of this residue is:

                                 Per cent.
  Carbonate of potash              86.78
  Chloride of potassium             6.18
  Sulphate of potash                2.83
  Silica, alumina, etc.             4.21
                                  ------
                                  100.00

In 1859, MM. Maumene and Rogelet patented the use of the water in
which wool has been washed as a source of potash, and at present the
extraction of potash from _suint_ is practiced in France on a large
scale. The wool is washed in a systematic manner, in casks, with cold
water, which runs out of the last cask with specific gravity 1.1. These
washings are evaporated to dryness, and the residue is calcined in iron
retorts, the gas evolved being used for illuminating purposes. The
remaining cinder, consisting of a mixture of charcoal and carbonate of
potash, is treated with water, whereby the latter is dissolved out.
The residue left on evaporation of this water consists largely--almost
entirely--of white carbonate of potash. At present there are works at
Rheims, Elboeuf, Fourmier, and Vervier, which yield about 1,000 tons of
carbonate of potash annually. Now, only 15,000 tons are made per annum
by Leblanc's process. In 1868, 62,000 tons of wool were imported into
Britain from Australia alone, and from this 7,000 to 8,000 tons of
carbonate of potash might have been recovered, the value of which is
£260,000. Yet it was all wasted! And this estimate does not include the
fats of the _suint_, which are worth an even greater sum.

Now, it is evident that there is here a profitable source of economy. So
far as I am aware, no work in this country saves its washings. The water
all goes to pollute the nearest river.

The use of carbon disulphide has again been introduced, and it is to be
hoped with better success, for methods have been devised whereby the
wool is not injured by it, but is even rendered better than when scoured
by the old process of washing with carbonate of soda and water, or by
soap. The process is due to Mr. Thomas J. Mullings. Briefly described,
it consists in exposing the wool, placed in a hydro-extractor, to the
action of bisulphide of carbon; the machine is then made to revolve, and
the excess of solvent is expelled, carrying with it the fatty matters;
the solvent finds its way into a tank, from which it flows into a still,
heated with steam; the carbon disulphide, which boils at a very low
temperature, distills over, and is again ready for use, while the
residue in the still consists of _suint_ washed from the wool. To
remove the last trace of carbon disulphide from the wool in the
hydro-extractor, cold water is admitted, and when the wool is soaked,
the machine again revolves. On expulsion of the water, the wool is ready
for washing in the ordinary machines, but with cold water only instead
of hot soapsuds.

The distinguishing features of Mr. Mullings' process are, method by
which loss of carbon disulphide is avoided, and the extraction of
that solvent by means of cold water. The apparatus consists of a
hydro-extractor or centrifugal machine of special construction, fitted
with a bell-shaped cover, which can be lifted into and out of position
by means of a weighted lever. The rim of this cover fits into an annular
cup filled with water, which surrounds the top of the machine, forming
an effective seal or joint. Upon the spindle of this machine is
suspended, as in ordinary forms of the hydro-extractor, a perforated
basket, and in this basket is placed the wool to be treated. The cover
being closed, the carbon disulphide is admitted, and passing through the
wool, the greasy matter is dissolved, and along with the solvent enters
a reservoir. The machine is now set in motion, and the bulk of the
solvent is drawn off. Cold water is then admitted, and the machine being
again caused to rotate, the whole of the bisulphide is expelled. It is
a curious fact that, although wool soaks remarkably easily with carbon
disulphide, and at once becomes wet, cold water expels and replaces
almost all that liquid. This operation takes about twenty minutes, and
at one operation about 1½ cwt. of raw wool may be treated. The wool is
then washed in suitable washing machines of the ordinary type, but with
cold water, no soap or alkali being employed. The bisulphide of carbon,
mixed with water, flows into a reservoir, provided with diaphragms to
prevent splashing, and consequent loss by evaporation. From its gravity
it sinks, forming a layer below the water; it is then separated and
recovered by distillation, and may be used in subsequent operations.

The point in which this process differs from the old and unsuccessful
ones formerly tried, is in the expulsion of the carbon disulphide. It
was imagined that it was necessary to expel it by means of heat or
steam. Now, when wool moist with bisulphide is heated, it invariably
turns yellow. No heat must, therefore, be employed. As already remarked,
the solvent is expelled with cold water.

The residue, after distillation of the carbon disulphide, is a grayish
colored, very viscous oily matter, still retaining a little bisulphide,
as may be perceived from the smell. It has not the composition of
ordinary _suint_, inasmuch as it contains no carbonate of potash, and
indeed little mineral matter of any kind. A sample which I analyzed
lost in drying 36.2 per cent., the loss consisting of water and carbon
disulphide. It gave a residue on ignition amounting only to 1.6 per
cent. of the original fatty matter, or 2.5 per cent. of the dried fat.
The oil appears, from some experiments which I made, to be a mixture of
a glycerine salt and a cholesterine salt of fatty acids. It distills
without much decomposition, giving a brown-yellow oil, which fluoresces
strongly, and has a somewhat pungent smell. The molecular weight was
determined by saponification with alcoholic potash, and subsequent
titration of the excess of potash employed. This was found to equal
546.3. This would correspond to a mixture of 18.7 parts of stearate,
palmitate, and oleate of glycerine, with 81.3 parts of the same acids
combined with cholesteryl. But this is largely conjecture. The
boiling point of the oil is high, much above the range of a mercurial
thermometer, so that it is difficult to gain an insight into its
composition.

An objection which has been raised to this process is that the use of
such an easily inflammable substance as bisulphide of carbon is attended
by great risk of fire. Were the bisulphide to be exposed to free air,
there might be force in this objection; but there is no reason why it
should ever be removed from under a layer of water. The apparatus, to
make all safe, should not be under the same roof as the mill; and no
open fire need be used in the building set apart for it. It is easy to
rotate the centrifugal machine by a belt from the mill, but better by a
small engine attached, the power for which can be conducted by a small
steam-pipe, and the distillation of the bisulphide can also be conducted
without danger by the use of steam, as its boiling point is a very low
one. The question may be naturally asked, "How do the wool and fabric
made from the wool scoured by this process, compare with that scoured in
the usual way?" To answer this question I may refer to a test made by
Messrs. Isaac Holden & Co., at their works at Roubaix. A sample of wool
was divided into two portions, one of which was scoured by the usual
method, and the other by the turbine or Mullings' process. Skilled
workers then span each sample to as fine a thread as possible. Now
the thinness to which a wool can be spun is evidence of its power of
cohesion--in other words, its strength. The weight of 1,000 meters of
the wool cleaned by the new process bore to that scoured by the old
process the proportion of 1,015 to 1,085, showing that a considerably
finer thread had been produced. And in total quantity, 67.53 kilos.
of the former corresponded to 71.77 kilos. of the latter, showing
a proportionately less waste. Such fine yarn had never before been
obtained from similar wool. The yarn of the soap-washed wool could not
be spun, for it could not withstand the strain; whereas, that scoured by
the new process gave an admirable thread.

Another test to which it was subjected may be cited. It is the custom in
France, before the wool is scoured, to put it through a sorting process,
by which all the short lengths are weeded out. On a quantity exceeding
11,000 kilogrammes, half of which was scoured by the turbine process,
and half by the ordinary process, the former in scouring lost in weight
2 per cent. less than the latter, although the short length extracted
from the moiety thus treated weighed only 10 kilogrammes, while that
taken from the other weighed over 150 kilogrammes. This saving, even
with the unequal treatment, amounted in value to from 30 to 40 centimes
per kilogramme.

In order that the importance of this application may be realized, I
shall conclude with some figures:

The raw wool imported into England, in the year 1882, amounted to
1,487,169 bales, its total value being about £22,000,000. The cost of
washing this wool by the old process, with carbonate of soda, amounts to
about ½d. per lb. of the raw material. The cost for the total quantity
of wool imported is at least £1,214,000. But it is customary to wash
wool with soap, especially for the combing trade, and the cost is then
about 1d. per lb. The cost of scouring by the new process is about £1
5s. per ton, or 0.13d. per lb. Taking the least favorable comparison,
were all the imported wool (home-grown wool is here left out of the
calculation, for want of sufficient returns) cleansed by the turbine
process, the actual saving would be £1,214,500 _minus_ £315,700, or
nearly £900,000 per annum.

It is thus seen that there is room for a very important economy in
the treatment of wool. I have endeavored to show how economy may be
practiced in scouring by the old process with soap, and how one dye
stuff may be profitably recovered. It is to be hoped that means of
extracting other dyes from the residue may soon follow. Unless the
process were too costly to repay the trouble of extraction, it would
be well worth practicing; for it would not merely be a solution of the
problem of how to avoid waste, but would at the same time prevent the
pollution of our streams, now, unfortunately, only too rarely pellucid;
and were the last process to have as successful a future as I hope it
may have, a very important saving of expense would result, and a large
quantity of valuable fatty matter would no longer be thrown away.

       *       *       *       *       *


[Illustration: SUGGESTIONS IN DECORATIVE ART.--DESIGNS FOR IRON GATES.]

       *       *       *       *       *




COAL AND ITS USES.

[Footnote: From a paper lately read before the Association of Foremen
Engineers.]

By JAMES PYKE.


The records from which geologists draw their information can scarcely be
compared to written or printed histories. There are, however, nations
of whom no written account exists, who perhaps never had any written
history, but about whom we are still able to gather from other sources
a vast amount of information. Their houses, their monuments, their
weapons, and their tools have survived, and these tell us the kind of
life, the state of civilization, and the skill of the men to whom they
belonged; from the contents of their tombs we learn what manner of men
they were physically; sometimes a sudden change in the appointments and
belongings of the folk indicates that tribes which had for a long time
inhabited a district were driven out and replaced by a new race. Thus,
then, from waifs and strays we can piece together a fairly connected
account of the events of a period long antecedent to any written
history.

The investigations of Dr. Schliemann on the supposed site of the city of
Troy furnish a good example of this method of research. He found lying,
one on the top of another, traces of the existence of five successive
communities of men, differing in customs and social development, and was
able to establish the fact that some of the cities had been destroyed by
fire, and that later on other towns had grown up over the buried remains
of the earlier settlements. The lowest layers were, of course, the
oldest, and the position of each layer in the pile gives its date, not
in years, but with regard to the layers above and below it.

Now, from time immemorial nature has been at work building up monuments
and providing tombs which tell us what were the events going on,
and what kind of inhabitants the earth had long before man made his
appearance on its surface. The monuments are the rocks which compose the
ground under our feet, and these, like many ancient monuments of human
construction, are the tombs of the creatures that lived while they were
being built.

Many facts testify that the earth's crust did not come into existence
exactly as we find it now, but that its rocks have been built up by the
slow action of natural agencies. These rocks constantly inclose the
remains of plants and animals, and as it is evident that neither plant
nor animal could have lived in the heart of a solid rock, this fact
shows that the rock must in some way have gathered round the remains
that are now found in it. Again, many of these remains, or fossils,
belonged to animals that lived in water, the larger part, indeed, to
marine creatures. This indicates that the rock was formed beneath the
sea, and when we examine the way in which the constituents of the rock
are arranged, we frequently find it to correspond exactly with the
manner in which the sand and mud that rivers sweep down into the sea or
lakes are spread out over the bottom of the water. In a pile of rocks
formed in this way it is clear that the lowest is the oldest of all, and
that any one stratum lying above is younger than the one beneath it.
Further, the occurrence of rocks inland containing marine fossils far
above the sea level shows that the sea and land have changed places.
When, again, we find that the fossils of one group of rocks differ
entirely from those of a group lying above them, we learn that one race
of creatures died out and was supplanted by a new assemblage of animal
forms.

These general remarks will, I trust, give some notion of the evidence
which is available for reconstructing the history of those remote
periods with which geology deals, and of the kind of reasoning which the
geologist employs for interpreting the records that are submitted to
him.

We will now briefly examine, by aid of these methods, the group of rocks
in which coal occurs in Great Britain, and see how far we can read the
story they have to tell.

The group with which we have to deal is called the carboniferous or
coal bearing system, and it includes four classes of rocks, viz.: 1,
sandstone; 2, shale or bind; 3, limestone; 4, coal and underclay.

We will take the sandstones and shales first. They are grains of sand
known to mineralogists as quartz, and consisting of a substance called
silica by chemists. The grains of sand are bound together by a cement
which in some few cases is identical in composition with themselves, and
consists of pure silica, but usually is a mixture of sandy, clayey, and
other substances. The shales are made up very largely of clay, mixed,
however, usually with sand and other substances, forming a conglomerate.
Both sandstones and shales are divided into layers or beds, and are said
to be stratified. It is this stratified or bedded structure that gives
us the first clew to the way in which these rocks were formed. Rivers
are constantly carrying down sand and mud into the sea or lakes, and
when their flow is slackened on entering the still water the materials
they bring down with them sink and are spread out in layers over the
bottom. The structure of the sandstones and shales shows that they were
formed in this way; they often inclose the remains of plants that have
been carried down from land, and occasionally of animals that lived in
the water where they were deposited.

The next we have to consider is limestone, which is mainly made up of a
substance known to chemists as calcium carbonate, or carbonate of lime.

In some districts, especially in volcanic countries, springs occur very
highly charged with carbonate of lime. The warm springs of Matlock are
a case in point; they are probably the last vestige of volcanic action
which was in operation in that neighborhood during carboniferous times.
Limestone is chiefly formed by the agency of small marine creatures of
low organization. By the aid of these animals the carbonate of lime is
brought back to a solid form; at their death their hard parts fall to
the bottom and accumulate in a mass of pure limestone, which afterward
becomes solidified into limestone rock.

The information that limestone gives us is this:

When we find, as is often the case, a mass of limestone hundreds of feet
thick, and composed of little else but carbonate of lime, we know that
the spot where it occurs was, at the time it was formed, far out at sea,
covered by the clear water of mid ocean; and when we find that this
limestone grows in certain directions earthy and impure, and that layers
of shale and sandstone, thin at first, but gradually thickening out in
a wedge-shape form, come in between its beds, we know that in those
directions we are traveling toward the shore lines of that sea whence
the water was receiving from time to time supplies of muddy and sandy
sediment.

The next class of rocks are the clays that are found beneath every
bed of coal, and which are known as _underclays_, or _warrant_, or
_spavins_. They vary very much in mineral composition. Sometimes they
are soft clay; sometimes clay mixed with a certain portion of sand; and
sometimes they contain such a large proportion of silicious matters that
they become hard, flinty rock, which many of you know under the name
of _gannister_. But all underclays agree in two points: they are all
unstratified. They differ totally from the shales and sandstones in this
respect, and instead of splitting up readily into thin flakes, they
break up into irregular lumpy masses. And they all contain a very
peculiar vegetable fossil called _Stigmaria_.

This strange fossil was for a long time a sore puzzle to fossil
botanists, and after much discussion the question was fairly solved by
Mr. Binney by the discovery of a tree embedded in the coal measures,
and standing erect just as it grew, with its roots spread out into the
stratum on which it stood. These roots were Stigmaria, and the stuff
into which they penetrated was an underclay. Sir Charles Lyell mentions
an individual sigillaria 72 feet in length found at Newcastle, and a
specimen taken from the Jarrow coal mine was more than 40 feet in length
and 13 feet in diameter near the base. It is not often these trees are
found erect, because the action of water, combined with natural decay,
has generally thrown them down. They are, however, found in very large
numbers in the roof of the coal, evidently having been tossed over, and
lying there flat and squeezed thin by the pressure of the measures that
lie above them.

Lastly, we come to coal itself--a rock which constitutes a small portion
of the whole bulk of the carboniferous deposits, but which may be fairly
looked upon as the most important member of that group, both on account
of its intrinsic value and also from the interest that attaches to its
history. That coal is little else but mineralized vegetable matter is a
point on which there has for a long time been but small doubt. The
more minute investigations of recent years have not only placed this
completely beyond question, but have also enabled us to say what the
plants were which contributed to the formation of coal, and in some
cases even to decide what portions of those plants enter into its
composition. It is a thing so universally admitted on all hands, that I
shall take it for granted you are all perfectly convinced that coal has
been nothing in the world but a great mass of vegetable matter. The only
question is: How were these great masses of vegetable matter brought
together? And you must realize that they were very large masses indeed.
Just to take one instance. The Yorkshire and Derbyshire coal field is
somewhere about 700 to 800 square miles in area, and Lancashire about
200. Well, in both these coal fields you have a great number of beds of
coal that spread over the whole of them with tolerable regularity and
thickness, and very often with scarcely any break whatever. And this is
only a very small portion of what must have been the original sheet of
coal, so that you see we have to account for a mass of vegetable matter
perfectly free from any admixture of sand, mud, or dirt, and laid down
with tolerably uniform thickness over many hundreds of square miles.

At one time it was supposed that coal was formed out of dead trees and
plants which were swept down by rivers into the sea, just in the same
way as shales and sandstones were formed out of mud and sand so swept
down. The fatal objection to this theory, however, is that rivers would
not bring down dead wood alone, but they would bring down sand and mud,
and other matters, and that in the bottom of the sea the dead wood would
be mixed with these matters, and instead of getting a perfectly unmixed
mass of vegetable matter, we should get a mixture of dead plants, sand,
mud, and other things, which would give rise to something like coal, but
something very different, as any one who tries to burn such coal will
soon find out, from really good, pure house coal. So that this theory,
which is generally known as the "drift" theory, was totally inadequate
to account for the facts as we know them.

The other theory was that coal was formed out of plants and trees that
grew on the spot where we now find coal itself. On this supposition it
is easy to account for the absence of foreign admixtures of sand, mud,
and clay in the coal; and we can also understand very much better than
by the aid of the drift theory how the coal had accumulated with such
wonderful uniformity of thickness over such very large areas. This
theory was for some time but poorly received; but after the discovery
of Sir William Logan, that every bed of coal had a bed of underclay
beneath, and the discovery of Mr. Binney, that these underclays were
true soils on which plants had undoubtedly grown, there was no doubt
whatever that this was the real and true explanation of the matter.

I dare say many of you have had occasion to walk across peat bogs.
The peat bog is a great mass of vegetable matter, which is every year
growing thicker and thicker; and underneath it there is almost always a
bed of thin clay, in look very much like the underclays, and this thin
clay is penetrated by the rootlets of the moss forming the peat, exactly
the same way as the underclays of the coal measures are penetrated by
the stigmaria and its rootlets. But you must not suppose that the plants
out of which coal was formed were exactly the same low type of moss
which forms our present peat bogs. However, it is pretty certain that
they were for the most part of a loose, succulent texture, and that they
grew very rapidly indeed.

You will have noticed that there is one step more wanted to make good
this theory of the growth of coal on the spot where we now find it.
The coal is found, as already described, interbedded with shales and
sandstones. These shales and sandstones, as shown, were formed beneath
the water of the sea, and as long as they remained there of course no
plants could grow upon them. The question is, How was the land surface
formed for the growth of plants? It must have been formed in some way or
other by the sea bottom having been raised above the level of the water.
Now, we have distinct proof in many cases that elevation of the sea
bottom and depression of the land is now going on in many parts of the
earth's surface. And, therefore, we shall be assuming nothing beyond the
range of experience if we say that such elevations and depressions went
on during coal measure times. The coal measure times must have been
times during which the same spot was now below the sea, and now dry
land, over and over again. There was a land surface on which plants grew
fast and multiplied rapidly, and as they died fell and accumulated in
a great heap of dead vegetable matter. After a time this layer of
vegetable matter was slowly and gently let down beneath the waters of
the sea--so slowly that the water flowing over it did not, as a rule,
disturb the loose, pasty mass; and then, by the method I have described
to you, shales and sandstones were deposited on the top of this mass
of dead vegetable matter. By their weight they compressed it, and
by certain chemical changes (which we have not time to go into this
evening) this dense mass of vegetable matter became converted into coal.
After a time the shales and sandstones which had been piled above this
stuff, which was to form coal for the future, were again elevated to
form a land surface; upon this another forest sprang up, and by its
decay produced another mass of vegetable matter fit to form coal. This
again was let down below the water, more shales and sandstones were
deposited on the top, and this process went on over and over again till
the whole mass of our present coal measures was formed. You will now see
how it is that trees are so seldom found in an upright position in the
coal beds. As the land went down, they would in very many cases be
toppled over by the water as it flowed against them, or their base would
be rotted, and they would then either fall or be blown over; that is the
reason why in most cases they are found lying flat on the roof of the
coal bed. But in a few cases, when the depression was very gentle and
gradual, the trees were not overthrown, and the shales and sandstones
accumulated round them and preserved them in the position in which they
grew.

I do not know that I can point out to you anything nowadays that exactly
resembles the state of things that must have gone on during the times
these coal measures were being formed; but there are a great many cases
strikingly analogous to them. I shall not attempt to describe them to
you, but may just mention the mangrove swamps that very often fringe the
coasts in the tropics, and the cypress swamps of the Mississippi, which
are so well described by Sir Charles Lyell in his recent works; also
the great Dismal Swamp of Virginia, which appears to me to furnish the
nearest analogue to the state of things that existed during coal measure
times.

Having explained the way in which coal measures have been formed, we
will now take a brief sketch of its uses and products. The year 1259 is
memorable in the annals of coal mining. Hitherto the mineral had not
been raised by authority, but in that year Henry III. granted a charter
to the freemen of Newcastle-on-Tyne for liberty to dig coal, and a
considerable export trade was established with London, and it speedily
became an article among the various manufacturers of the metropolis. But
its popularity was but short lived. An impression became general
that the smoke arising therefrom contaminated the atmosphere and was
injurious to public health. Years of experience have proved the fallacy
of the imputation; but in 1306 the outcry became so general that a
proclamation was issued by Edward I forbidding the use of the offending
fuel, and authorizing the destruction of all furnaces, etc., of those
persons who should persist in using it. Prejudice gradually gave way as
the value of the fossil fuel became better known, and from that time
downward its use has become more and more extended down to the enormous
extent of our present trade. The annual increase in the production of
coal in the British Isles since the year 1854 is over 2½ million tons.
In that year the coal produce was about 65 million tons, and it has
grown up to the year 1880 to the grand total of 135 million tons.

We will now deal with some of the uses that this valuable black diamond
is now being put to. It is, in the first place, the center of all our
enterprise and prosperity, and upon it depends our chief success as a
manufacturing nation for the future. When it is exhausted we shall have
to look forward to the condition of things which now obtains in those
regions where there is no coal--that is to say, instead of our being a
nation full of manufacturing and mercantile enterprise, a great nation
to which all the people of the earth resort, we shall be merely a people
who live for ourselves by the cultivation of the ground. The duration of
our coal fields has been ascertained within certain limits. Mr. Hall, an
accomplished geologist, tells us that in England at the present time we
have a stock of coal sufficient for our consumption for no less than
1,000 years. On the other hand, Professor Jevons, whose opinion is
worthy of the very greatest weight on such questions, calculates that
100 years is about the tenure of our coal fields, according to the
present rate of increase in the consumption. Whichever view we take,
sooner or later the end must ultimately come when the coal will be
exhausted; when the great mainspring of our commercial enterprise will
be gone, and we shall revert to that condition in which we were before
the coal fields were worked. In this point of view, therefore, coal has
an especial interest to us as engineers. If coal is important in this
direction, it is no less important in a purely scientific point of view,
apart from any mercantile end.

The chemist or physicist will tell you the wondrous story that the black
substance which you burn is simply so much light and heat and motion
borrowed from the sun and invested in the tissues of plants. He will
tell you that when you sit round your firesides the flame which enlivens
you, and the gas which enables you to read, and which civilizes you, is
nothing in the world but so much sunlight and so much sunheat bottled up
in the tissues of vegetables, and simply reproduced in your grates and
gas burners. Very few persons, I am afraid, realize this, which is one
of the many stories which science in its higher teachings shows us--one
of those fairy tales which are the result of the most careful scientific
investigation. Of the hundred and odd million tons of coal which we in
this country burn in the course of a year, about 20,000,000 tons are
thrown on our house fires; 30,000,000 tons find their way into our blast
furnaces, or are otherwise used in the smelting and manufacture of
metals; about 48,000,000 are burnt under steam boilers; 6,000,000 are
used in gas-making; while the remainder is consumed in potteries, glass
works, brick and lime kilns, chemical works, and other sundries which I
need not speak of.

To go into the chemistry of coal is quite sufficient to take up more
time than I have at my disposal this evening, therefore I will briefly
touch on a few of the main points. Coal gas is made, as you are all
aware, by heating coal or cannel, which is the special form of coal
most valued for the purpose, on account of the high quality of gas it
produces in cylindrical fireclay retorts.

The by-products obtained in the manufacture of coal gas, the tar and the
ammonia water, are nowadays scarcely less important than the coal gas
itself. The ammonia water furnishes large quantities of salts to be
used, among other applications, as food for plants. We thus restore
to-day to our vegetation the nitrogen which existed in plants of
primeval times. The tar, black and noisome though it be, is a marvelous
product, by the reason of scores of beautiful substances which are
concealed within it.

Coal tar when distilled yields three main products: naphtha, dead oil,
and pitch or asphalt. The naphtha on redistillation yields benzine, from
which are prepared some of our most beautiful dyes; the dead oil, as
the less volatile portion is termed, furnishes carbolic acid, used as a
disinfectant and antiseptic, together with anthracene and naphthaline;
all three substances the starting points of new series of coloring
matters.

This discovery of these coloring matters marks an era in the history
of chemical science; it exercised an extraordinary influence on the
development of organic chemistry. Theoretical and applied chemistry were
knit together in closer union than ever, and dye followed dye in quick
succession; after mauve came magenta, and in close attendance followed a
brilliant train of reds, yellows, oranges, greens, blues, and violets;
in fact, all the simple and beautiful colors of the rainbow.

But there is still another story of coal tar to be told. Among the
many curious substances that wonderful fluid contains is the beautiful
wax-like body called paraffine, the development of which chiefly owes
its origin to the genius and energy of Mr. James Young. As early as
1848, Mr. Young had worked a small petroleum spring in a coal mine in
Derbyshire, and had produced oils suitable for burning and lubricating
purposes, but the spring gave out, and then Mr. Young sought to obtain
these oils by distilling coal. After many trials, in conjunction with
other gentlemen connected therewith, he proved successful, and the
present magnitude of this industry is without parallel in the history of
British manufactures.

In Scotland alone there are about sixty paraffine oil works, one alone
occupying a site of nearly forty acres. Here about 120,000 gallons of
crude oil are produced weekly, and among the various works in Scotland
about 800,000 tons of shale are distilled per annum, producing nearly
30,000,000 gallons of crude oil, from which about 12,000,000 gallons of
refined burning oil are obtained in addition to the large quantities
of naphtha, solid paraffine, ammonia, and other chemical products.
Twenty-five years ago scarcely a dozen persons had seen this paraffine,
and now it is turned out by the ton, fashioned into candles delicately
tinted with colors obtained from coal tar.

I might dwell on this subject until it becomes wearisome to you,
therefore I will not trespass too much on your time. But from every
point we look we reach this fact, that our coal trade is one which
develops itself according to laws that we are perfectly powerless to
control; if it seems to promise a less rapid increase here, it is only
that it may spread abroad with accelerated vigor elsewhere; if it is our
slave in some aspects, it seems as if it were our master in others.

Finally, we have to ask, What of our export coals? Rapid as has been the
growth of our total production during the last twenty-three years, the
growth of our export of coals has been greater still. Beginning at
4,300,000 tons in '54, we find it reaching 16,250,000 tons in '76, and
an increase at a corresponding ratio up to the present date as far as
statistics will carry us. At such a rate of increase it would seem as
if our whole annual production would be ultimately swallowed up in our
exports, and it is not, perhaps, impossible that after we have ceased to
be to any great extent a manufacturing people, a certain export trade
in coal may still continue. Just the same as the export trade in coal
preceded by centuries our own uses for it other than domestic, so may
it also survive these by a period as prolonged. If our descent from
our present favored position be a gradual one, much may be done in the
interval to adapt ourselves to the future outcome, but it is certain
that nothing will be done except under the stern persuasion of
necessity.

When our coal fields become exhausted, be it soon or late, he would be
a wise or, perhaps, a rash speculator who fixed himself to a year or a
generation. Being inevitable, the best philosophy is to make our decline
more gradual and less bitter. Sentimental regrets that these hills and
valleys will no longer resound with the din of labor, or be blackened by
the smoke of the factory, would surely be out of place. What we might
regret is that Britain, which we know and are proud of, the Britain
of great achievements in politics and literature, of free thought and
self-respecting obedience, of a thousand years of high endeavor and
constant progress, was indeed to perish when these factories and
furnaces whirled and blazed their last. But, it is not so. This
country's fortunes are gradually being merged into those of a Greater
Britain, which largely, through the aid of coal, whose prospective
loss we are lamenting, has grown beyond the limits of these islands to
overspread the vastest and richest regions of the earth; and we have no
reason to fear that the great inheritance that America and Australia
and New Zealand have accepted from us will in their hands be dealt
unworthily with in the future.

       *       *       *       *       *




GASTON PLANTE.


This eminent scientist was born in Orthez (Department of
Basses-Pyrénées) on the 22d of April, 1834; at present in his fiftieth
year. He began his scientific career as assistant to Edmund Becquerel at
the Conservatoire des Arts et Métiers at Paris. In the year 1859, after
resigning his position at the above named institution, he entered upon
his researches in electricity, and has continued them ever since.
His work entitled "Recherches sur l'Electricité" is a model of clear
language and elegant demonstration, and contains all the papers
presented by Planté to the Paris Academy of Sciences since 1859.

[Illustration: GASTON PLANTE.]

At the Paris Electrical Exhibition in 1881, Planté received a Diploma
of Honor, the highest distinction conferred, while in the same year the
Academy of Sciences voted him the "Lacaze" prize, and the Society for
the Encouragement of National Industry presented him with the "Ampère"
medal, its highest award.

Planté deserves not only the honors conferred upon him by his own
country, but those of the world on account of his cosmopolitan
character--a rarity among his countrymen. He sends his apparatus to all
exhibitions of any consequence; they appeared at Munich and Vienna,
where their interpretation by the attendant added considerably to the
renown of their author.--_Zeitch f. Elektrotechnik_.

       *       *       *       *       *




WARREN COLBURN.


Warren Colburn, the eminent American mathematician, was born in Dedham,
Mass., March 1, 1793.

He was the eldest son of a large family of children. His parents were
poor, and "Warren" was, during his childhood, frequently employed in
different manufacturing establishments to aid the family by his small
earnings.

In early boyhood he manifested an unusual taste for mathematics, and
in the common district school was regarded as remarkable in this
department. He learned the trade of a machinist, studying winters, until
he was over twenty-two years of age, when he began to fit for Harvard
College, which he entered in 1817 and graduated with high honors in
1820. He taught school in the winter months, while in college, in
Boston, Leominster, and in Canton, Mass. From 1820 to 1823 he taught a
select school in Boston.

While in college he was regarded as by far the best mathematician in his
class, and during this period thought there was the necessity for such a
book as his "First Lessons in Intellectual Arithmetic." This conviction
had been forced upon his mind by his experience in teaching. In the
autumn of 1821 he published his "first edition." His plan was well
digested, although he was accustomed to say that "the pupils who were
under his tuition made his arithmetic for him;" that the questions they
asked and the necessary answers and explanations which he gave in reply
were embodied in the book, which has had a sale unprecedented for
any book on elementary arithmetic in the world, having reached over
2,000,000 copies in this country, and the sale still continues, both in
this country and in Great Britain. It has been translated into most of
the European languages and by missionaries into many Asiatic languages.

After teaching in Boston about two and one-half years, he was chosen
superintendent of the Boston Manufacturing Company's works at Waltham,
Mass., and accepted the position; and in August, 1824, owing to the
mechanical genius he displayed in applying power to machinery, combined
with his great administrative ability, he was appointed superintendent
of the Lowell Merrimac Manufacturing Co., at Lowell, Mass. Here he
projected a system of lectures of an instructive character, presenting
commerce and useful subjects in such a way as to gain attention and
enlighten the people.

For several years he delivered gratuitous lectures on the Natural
History of Animals, Light, Electricity, the Seasons, Hydraulics,
Eclipses, etc. His knowledge of machinery enabled him admirably to
illustrate these lectures by models of his own construction; and his
successful experiments and simple teaching added much to the practical
knowledge of his operatives.

He proposed to occupy the space between the common schools and the
college halls by carrying, so far as might be practicable, the design of
the Rumford Lectures of Harvard into the community of the actual workers
of common life.

In the mean time he discharged his official duties efficiently, and the
superintendence of the schools of Lowell was also added to his labors.
He never relinquished, during these busy years, the design formed in his
college days of furnishing to the children of the country a series of
text-books on the _inductive plan_ in mathematics.

His "Algebra upon the Inductive Method of Instruction," appeared in
1825, and his "Sequel to Intellectual Arithmetic" in 1836. He regarded
the "Sequel" as a book of more merit and importance than the "First
Lessons."

He also published a series of selections from Miss Edgeworth's stories,
in a suitable form for reading exercises for the younger classes of
the Lowell schools, in the use of which the teachers were carefully
instructed.

In May, 1827, he was elected a Fellow of the American Academy of
Sciences. For several years he was a member of the Examining Committee
for Mathematics at Harvard College.

He was a member of the Superintending School Committee of Lowell; and so
busy were he and his coworkers that they were repeatedly obliged to hold
their meetings at six o'clock in the morning.

Warren Colburn was ardently admired--almost revered--by the teachers who
were trained to use his "Inductive Methods of Instruction" in teaching
elementary mathematics.

In personal appearance Mr. Colburn was decidedly pleasing. His height
was five feet ten, and his figure was well proportioned. His face
was one not to be forgotten; it indicated sweetness of disposition,
benevolence, intelligence, and refinement. His mental operations were
not rapid, and it was only by great patience and long continued thought
that he achieved his objects. He was not fluent in conversation; his
hesitancy of speech, however, was not so great when with friends as
with strangers. The tendency of his mind was toward the practical in
knowledge; his study was to simplify science, and to make it accessible
to common minds.

Mr. Colburn will live in educational history as the author of "Warren
Colburn's First Lessons," one of the very best books ever written, and
which, for a quarter of a century, was in almost universal use as a
text-book in the best common schools, not only in the primary and
intermediate grades, but also in the grammar school classes.

In accordance with the method of this famous book, the pupils were
taught in a natural way, a knowledge of the fundamental principles of
arithmetic. By its use they developed the ability to solve mentally and
with great facility all of the simple questions likely to occur in the
every day business of common life.

Undoubtedly Pestalozzi first conceived the idea of the true "inductive
method" of teaching numbers; but it was Mr. Colburn who adapted it to
the needs of the children of the common elementary schools. It has
wrought a great change in teaching, and placed Warren Colburn on the
roll as one of the educational benefactors of his age.

He died at Lowell, Mass., Sept. 13, 1883, at the age of 90
years.--_Journal of Education_.

       *       *       *       *       *




THURY'S DYNAMO-ELECTRIC MACHINE.


Thury's dynamo-electric machine, which presents some peculiarities,
has never to our knowledge been employed outside of Sweden and a few
neighboring regions; but this is doubtless due to some personal motive
or other of its constructors, since it has, it would seem, given
excellent results in every application that has been made of it. It is
represented in perspective in Fig. 1, and in longitudinal section and
elevation in Figs. 2 and 3.

As may be seen, it is a multipolar (6-pole) machine in which an attempt
has been made to utilize magnetically, as far as possible, all the iron
used in the frame. For this reason the system has been given the form of
a hexagonal prism, whose faces are formed of flat electro-magnets, A, A,
xxx, constituting the inductors.

The internal angles of this prism are filled by polar expansions, P, P,
xxx, alternately north and south, that thus form in the interior of the
apparatus an inscribed cylinder designed to receive the armature. This
latter belongs to the kinds that are wound upon a cylinder in which the
wire is external thereto.

The conductors are placed upon the iron drum longitudinally and parallel
with its axis. But instead of being connected with each other at the
posterier end of the armature, as in the Siemens system, they are
connected according to chords that correspond to a fourth, a sixth,
or any equal fraction whatever of the circumference. Fig. 4 gives a
perspective view of the cylinder, upon which the conductors 1, 2, 3,
4, and so on, are placed according to generatrices. The armature is
supposed to be divided into six parts, each conductor passing over the
bases of the drum through a chord equal to the radius, that is to say,
corresponding to a sixth of the circumference.

Three conductors are all connected together in such a way as to form
but a single circuit closed upon itself. Conductor 1, for example, is
connected with No. 6 in such a way that the end issuing from 1 becomes
the end that enters No. 6. Conductor No. 3 is connected in the same way
with No. 8, and so on, up to the last conductor, which is connected in
its turn with the end that enters the first.

As the figure shows, the conductor before passing from 3 to 8, for
example, returns several times upon itself in following 6 and 3, and the
same is the case with all the rest of the winding.

[Illustration: FIG. 1. PERSPECTIVE VIEW OF THE THURY MACHINE.]

In this way the cylinder becomes inclosed within nine rectangular wire
frames, each of which is connected with the following one by a conductor
that is at the same time connected with one of the nine plates of
the collector. The number of the rubbers corresponds to that of the
inducting poles. They may be coupled in different ways, but they are in
most cases united for quantity.

It will be seen that the Thury armature resembles, in the system of
winding, those of the Siemens machines and their derivatives. But it
differs from these, however, in the details connected with the coupling
of the wires, from the very fact that the features of a two-pole machine
are not found exactly in a multipolar one.

[Illustration: FIGS. 2 AND 3.]

This latter kind of machine is considered advantageous by its inventors,
in that there is no need of revolving it with much velocity. It must not
be forgotten, however, that although we reduce the velocity by this mode
of construction, we are, on another hand, obliged to increase the size
of the machine, so that, according to the circumstances under which we
chanced to be placed, the advantage may now be on the one side and now
on the other.

[Illustration: FIGS. 4 AND 5.]

It goes without saying that Fig. 4 is essentially diagrammatic, and is
designed to give a clearer idea of the mode of winding the armature. In
practice the number of the frames, and consequently that of the plates
of the conductor, is much greater, and the arrangement that we have
described is repeated a certain number of times, the conducter always
forming a circuit that is closed upon itself.

The Thury machines are constructed in different styles. No. 1 is a
100-lamp (16 candles and 100 volts) machine, and Nos. 2 and 3 are
nominally 250-lamp ones, but may be more. Their weight is 1,100
kilogrammes, and their velocity, for 100 volts, is from 400 to 500
revolutions, according to the mode of coupling.

A later type, now in course of construction, is to furnish from 750 to
2,000 lamps, with 250 revolutions, for 100 volts, and is not to weigh
more than 2,000 kilogrammes. Let us add that Messrs. Meuron and Cuenod,
the manufacturers, have likewise applied their mode of winding to
conductors arranged radially upon the surface of a circle. Fig. 5 shows
this arrangement.

In this case the inductors will, it is unnecessary to say, be arranged
laterally as in all flat ring machines. The arrangement will recall, for
example, that of the Victoria machines (Brush-Mordey).

We do not think that the inventors have applied this radial arrangement
practically, for it does not appear to be advantageous. The parts of
conductors which are perpendicular to the radius, and which can be only
inert (even if they do not become the seat of disadvantageous currents),
have, in fact, too great an importance with respect to the radial
parts.--_A. Guerout, in La Lumiere Electrique_.

       *       *       *       *       *




BREGUET'S TELEPHONE.


Prof. G. Forbes gives the following description: The instrument which
I call Breguét's telephone is founded upon the instrument which was
described by Lipmann, called the capillary electrometer. The phenomenon
may be shown in a variety of ways. One of the easiest methods to show it
is by taking a long glass tube and bending it into two glasses of dilute
acid, and, the tube being filled with acid itself, a piece of mercury
is placed in the center of the tube. Then if one pole of a battery is
connected with one vessel of acid, and the other pole of the battery is
connected with the other vessel of acid, at the moment of connection the
bit of mercury will be seen to travel to the right or left, according to
the direction of the current. M. Lipmann explained the action by showing
that the electro-motive force which is generated tends to alter the
convexity of the surface of the mercury. The surface of the mercury,
looked at from one side, has a convex form, which is altered by the
electro-motive force set up when connection is made with the battery.
The equilibrium of the mercury is dependent upon the convexity, and
consequently when the convexity is disturbed the mercury moves to one
side or the other. Lipmann also showed that if a tube containing a bit
of mercury, and tapering to a point, is taken and dipped into acid, and
then the tube filled with acid, on one pole of a battery being dipped
into the tube and another into the acid the mercury will move up or
down, showing similar action to that which I have just described.

Lipmann further showed the reverse effect, that if a piece of mercury be
forcibly pressed, so as to alter the convexity of its surface, such
as by bringing it into a narrower part of the tube, then there is an
electro-motive force produced.

It occurred to me, and no doubt it did to Breguet also, that if we speak
either against the surface of the glass tube, and caused the tube to
vibrate, or if the mercury were caused to vibrate in the manner I have
shown, we ought to be able to introduce a varying current in the wires
which might have sufficient electro-motive force to produce audible
speech in a Bell telephone. Further, the same instrument, since varying
electro-motive force affected the drop of mercury and produced varying
displacement, ought also to act as a receiving instrument, and should
vibrate in accordance with the currents that arrive. My experiments
have only been in the way of using the instrument as a transmitter; but
Breguét, I find, used it as a receiver as well as a transmitter, though
I am not aware that M. Breguet made any actual experiments so as to
produce articulate speech. I presume that this was done, although I have
not come across any description of the experiments, and it was for that
reason that I thought possibly some account of my own experiments might
be interesting to the members of the Society. The first tubes that I
used were bits of glass tube about a centimeter diameter, and simply
drawn out to a tapering point. I have the tubes here. The first
experiment I tried was by tapping the glass tube so as to mechanically
shift the position of the mercury, and by listening on the telephone for
the effect. For a long time, at least an hour, I could get no effect at
all. At last I got a sound, but could not understand how it was that at
one time of tapping I could not hear, while at another time it was quite
loud.

At the top I always got sound, but at the side I got no sound, although
the mercury was shaking. I then tried to see how feeble a current was
audible in the telephone. An assistant tapped the tube while I stood out
of the way, and where I could not see. I got him to tap it gentler and
gentler, and could hear the most feeble tap. A pellet of paper was next
dropped from various heights down to an inch, and each tap was perfectly
audible in the telephone. I tried many methods, and one, purely
accidentally chosen, was a piece of glass tube which I had drawn out
into a tube about 2 mm. diameter, and then nearly closed the end of
it. I have that tube here, and you will see what an ill-shapen and
ugly-looking tube it is, but it is one of the best tubes I ever got; and
finally, I found that small bits of thermometer tube, which were simply
closed at their ends with a blow-pipe, gave very good results, and I was
able to make them useful for various purposes. I then tried mounting a
tube on the end of a speaking-trumpet and speaking to the mercury, but
got no effect. In every place where I attached the glass tube itself
to a sounding-board I got a very accurate reproduction. I put one on a
piece of ferrotype plate, and that gave really the best result I ever
got. The tube was fastened with sealing-wax, and with it I got excellent
speech heard in a Bell receiver. I tried putting in a large number of
these tubes, all in quantity, on the bottom of a ferrotype plate, but
with no advantage. I have not yet tried putting them in series, one
behind the other, so as to increase the electro-motive force, but I
think that probably would be an improvement; of course it would require
many vessels of acidulated water to dip into. The most distinct
articulate speech was obtained from an ordinary ferrotype telephone
plate, secured at the edges, and one of the glass tubes you see here
attached to it.

       *       *       *       *       *




MUNRO'S TELEPHONIC EXPERIMENTS.


Mr. J. Munro, whose name is well known not only as a very clear writer
upon electrical subjects, but as an original investigator, has recently,
with the assistance of Mr. Benjamin Warwick, been conducting a most
interesting experimental investigation of the action of the microphone
as a telephonic transmitter, with the result of proving that metals may
advantageously be employed in the place of carbon in a transmitting
instrument, a practical development of one of the very earliest of
Professor Hughes' microphones. The fact that metallic electrodes can
practically be employed in microphonic transmitters has been denied of
late with so much assurance and in such high quarters, that Mr. Munro's
successful applications of that portion of Professor Hughes' discovery
possess an especial interest, and must to a considerable extent affect
the aspect of litigation in future contests in which the discovery of
the microphone and the invention of the carbon transmitter are vital
points at issue.

In investigating the properties of metallic conductors employed in the
construction of microphones, Mr. Munro's first experiments were made
with wires. These, in some cases, were caused by the action of a
diaphragm, to rub the one on the other in such a manner as to make the
point of contact vary (under the influence of the vibrations of the
diaphragms) on one side or other of a position of normal potential, so
that by the movement of a wire attached to a vibrating tympan along a
fixed wire conveying a current from a battery, and thereby shunting the
current at various positions along the length of the fixed wire, the
strength of the current in the derived circuit, in which was included a
suitable receiver, was varied accordingly. In other experiments mercury
was employed, either as a sliding-drop, inclosing the fixed wire, or as
an oscillating column; but these experiments, though instructive and
interesting, did not for various reasons give encouraging results with a
view to the practical application of the principle.

They, however, led Mr. Munro to proceed with compound wire structures,
such as gratings resting upon or rubbing against one another, and one of
the first experiments in this direction proved very successful, and led
Mr. Munro to the construction of his gauze telephone, which is the most
characteristic and efficient of his practical apparatus.

This instrument consists essentially of two pieces of iron-wire gauze,
the one fixed in a vertical plane, and the other resting more or less
lightly against it, the pressure between them being regulated by an
adjustable spring or weight. These gauze plates are so connected in a
telephonic circuit as to constitute the electrodes of a microphone; for
touching one another lightly in several points, they allow the current
to be transmitted between them in inverse proportion to the resistance
offered to it in its passage from one to the other. Under the influence
of sonorous vibrations the one plate dances more or less on the other,
thus varying the resistance; and very perfect articulation is produced
in a telephonic receiver included in the circuit. The gauze transmitter
so constructed may be fixed within a wall-box with or without a
mouthpiece; but as the sound waves acting directly upon the gauze plates
set them into agitation through their sympathetic vibration or by direct
impact, no sort of diaphragm or equivalent device is necessary, and none
is employed.

[Illustration: FIG. 1.]

A convenient form of this apparatus is shown in Fig. 1, and to which the
name of "The Lyre Telephone" has been given from its resemblance to that
impossible musical instrument. In this apparatus, G¹ is a plate of iron
wire gauze stretched vertically between two horizontal wires attached to
a lyre-shaped framework of mahogany; against the plate rests the smaller
plate, G², the normal pressure between them being regulated by an
adjustable spring acting in opposition to a weighted lever, W. The two
plates are connected respectively with the attachment screws, X and
Y, by which the instrument is placed in a circuit with a battery and
telephonic circuit.

[Illustration: FIG. 2.]

A modification of this apparatus is shown in the diagram sketch, Fig.
2, which will probably be a more practical form. In this instrument the
electrodes consist of two circular disks of iron wire gauze of different
diameters, the larger disk, G¹, which is fixed, being pierced with holes
of smaller diameter than the smaller disk, G². In the diagram the two
disks are shown separated for the purpose of explanation, but in reality
they rest the one against the other; the smaller and movable disk,
G², is held up against G¹ with greater or less pressure by the spiral
spring, S, the tension of which can be adjusted by a screw or other
suitable device at N. This form of the apparatus is more suitable for
inclosure in a wall box with or without a mouthpiece, but it does not
require the employment of any kind of diaphragm or tympan. Mr. Munro
can employ with all his instruments an induction coil for installations
where the resistance of the line wire makes it desirable to do so; the
microphone and battery being included in the primary circuit and the
telephones in the secondary.

[Illustration: FIG. 3.]

Fig. 3 is an ingenious arrangement devised by Mr. Munro, in which the
adjusting spring or weight is substituted by a magnet which may be
either a permanent or an electro-magnet. The figure shows an arrangement
in which the fixed gauze, g¹, is perforated as in the apparatus
illustrated in Fig. 2, and the movable electrode, g, is bent or dished
so as to press upon g¹ around its edge. E is a magnet which by its
attractive influence upon g holds t up against g¹ with a pressure
dependent upon its magnetic intensity and upon its distance from the
gauze. By making E an electro-magnet, and including its coil in the
telephonic circuit, an instrument may be constructed in which the normal
pressure between the electrodes can be automatically adjusted to the
strength of the current, and in cases where an induction coil is
employed the magnet, E, may be the core of such a coil.

[Illustration: FIG. 4.]

Fig. 4 illustrates an apparatus devised by Mr. Munro, and to which the
name thermo-microphone might be given, as it is a microphone in which
thermo-electric currents are employed in the place of voltaic currents,
its special feature of interest lying in the fact that the heated
junction of the thermo-electric couple is identical with the microphone
contacts of the two electrodes. In this very elegant experiment a piece
of iron wire gauze, G, is supported in a horizontal position by a light
metallic support, B. To another support. A, is loosely hinged a frame,
which at its further extremity carries a little coil of German silver
wire, C, which by its weight rests upon the center of the gauze plate,
G; and in contact therewith, and to increase the pressure of contact, a
little bar weight is laid within the convolutions of the core. The
two electrodes, the gauze, and the coil are connected, as shown, to a
receiving telephone, T. Upon the application of heat, as from the flame
of a spirit lamp placed below, a thermo-electric current is set up
throughout the circuit; in this condition the apparatus becomes a very
perfect microphone, and when the pressure between the electrodes is
properly adjusted it is a very efficient telephonic transmitter,
transmitting articulate speech and musical sounds with remarkable
clearness and fidelity.

[Illustration: FIG. 5]

Mr. Munro is, with the aid of Mr. Warwick's manipulative skill,
extending this portion of his investigation further by experimenting
with gauzes and coils of various metals forming other couples in
the thermo-electric series, as well as with iron and other gauzes
electrotyped with bismuth and other metals, and we hope in due time to
lay the results of those experiments before our readers.

Mr. Munro has, moreover, observed that if two pieces of gauze of
identical material and in microphonic contact be heated, a peculiar
sighing sound is heard in a telephone connected with them and with a
battery, and he attributes this phenomenon to the electrical discharge
between the gauze plates being facilitated and increased by the
action of heat, but we are rather inclined to trace the effect to the
mechanical action of the one gauze moving over the other under the
influence of expansion and contraction of the metals by the variable
temperature of the flame and convection currents of heated air, such
movement producing the sounds just as would be produced if one of the
electrodes of an ordinary microphone were as delicately moved by the
hand or other agent.

[Illustration: FIG. 6]

Figs. 5 and 6 illustrate another and distinct form of metallic
microphone transmitter designed by Mr. Munro and Mr. Warwick, in which
a small chain, preferably of iron, forms the microphonic portion of the
apparatus. In Fig. 5, A is a plate of sonorous wood forming a diaphragm
or collector of the sonorous waves; to the back of this is attached a
short length of chain, C, the opposite ends of which are by the wires, X
and Y, included in the telephonic circuit. The points of junction of the
links with one another constitute the variable microphonic contacts, and
the normal pressure between them is adjusted by the spiral spring, S,
the tension of which may be varied by the cord and winding pin, B. Fig.
6 is the section of a transmitter constructed upon this principle, and
in which two chains, c and c', are employed attached at one end by a
wire, f, to a diaphragm mouthpiece, N, and at their opposite extremities
to the adjusting springs, s and s'; an induction coil, D, may be
employed if the resistance of the line render it advantageous.

[Illustration: FIG. 7]

Fig. 7 is a form of pencil microphone experimented with by Mr. Munro,
which differs from some of the Hughes' transmitters adopted by Crossley,
Gower, Ader, and many others only in the material of which it is
composed, Mr. Munro's being of cast iron, while the others to which we
have referred are of carbon rods such as are used in electric lighting.
In Fig. 7 a light cast-iron bar, i², of the form shown, is supported in
holes drilled in two blocks of cast iron, i i', and the pressure between
the bar and the blocks can be adjusted by a regulating spring, s. In
connection with this apparatus Mr. Munro has observed that rust has no
appreciable effect upon the efficiency of the instrument unless it be
to such an extent as to cause the two to adhere, or to be "rusted up"
together.

[Illustration: FIG. 8]

We now come to another class of metallic transmitters with which Mr.
Munro and his associate have been making experiments, and to which he
has given the name "Grain transmitter," since it consists of a box
having metallic sides, e e', to which terminal screws, t t', are
attached and filled in between with iron or brass filings, granules of
spongy iron, or indeed small metallic particles in any form; one of the
most efficient transmitters being a box such as is shown in Fig. 8,
filled with a quantity of ¼ in. screws.

[Illustration: FIG. 9]

The results of Mr. Munro's experiments have led him to the opinion
that the action of the microphone must be attributed to the action
of sonorous vibrations upon the air or gaseous medium separating the
so-called contact-points of the electrodes, and that across these
spaces, or films of gaseous matter, silent electrical discharges take
place, the strengths of which, being determined by the thickness of the
gaseous strata through which they pass, vary with the motion of the
electrodes; and as, according to this hypothesis, the distances of the
electrodes from one another is determined by the sound-waves, the sound
in that way controls the current.--_Engineering_.

       *       *       *       *       *




APPARATUS FOR MANEUVRING BICHROMATE OF POTASSA PILES FROM A DISTANCE.


Bichromate of potassa piles, especially those single liquid ones that
are applied to domestic lighting, all present the grave defect of
consuming almost as much zinc in open as in closed circuit, and of
becoming rapidly exhausted if care be not taken to remove the zinc from
the liquid when the battery is not in use. This operation, which is a
purely mechanical one, has hitherto required the pile to be located near
the place where it was to be used, or to have at one's disposal a system
of mechanical transmission that was complicated and not very ornamental.

In order to do away with this inconvenience, which is inherent to all
bichromate piles, Mr. G. Mareschal has invented and had constructed an
ingenious system that we shall now describe.

[Illustration: FIG. 1.--BICHROMATE OF POTASSIUM PILE, WITH MANEUVERING
APPARATUS.]

Mr. Mareschal's plan consists in suspending the frame that carries all
the battery zincs (Fig. 1) from the extremity of a horizontal beam, and
balancing them by means of weights at the other extremity.

The system, being balanced, the lifting or immersion of the zincs then
only requires a slight mechanical power, such as may be obtained from
an ordinary kitchen jack through a combination that will be readily
understood upon reference to Fig. 2. The axis, M, of the jack,
on revolving, carries along a crank, MD, to which is fixed a
connecting-rod, A, whose other extremity is attached to the horizontal
beam that supports the zincs and counterpoises. If the axle, M, be given
a continuous revolution, it will communicate to the rod, A, an upward
and downward motion that will be transmitted to the beam and produce an
alternate immersion and emersion of the zincs.

Upon stopping the jack at certain properly selected positions of the
rod, MD, the zincs may, at will, be kept immersed in the liquids, or
_vice versa_. This is brought about by Mr. Mareschal in the following
way: The jack carries along in its motion a horizontal fly-wheel, V,
against whose rim there bears an iron shoe, F, placed opposite an
electro-magnet, E. In the ordinary position, this shoe, which is fixed
to a spring, bears against the felly of the wheel and stops the jack
through friction. When a current is sent into the electro-magnet, E, the
brake shoe, F, is attracted, leaves the fly wheel, and sets free the
jack, which continues to revolve until the current ceases to pass into
the electro.

[Illustration: FIG. 2.--PRINCIPLE OF THE APPARATUS.]

The problem, then, is reduced to sending a current into the electro and
in shutting it off at the proper moment. This result is obtained very
simply by means of an auxiliary Leclauche pile. (The piles got up for
house bells will answer.) The current from this pile is cut off from
the electro, F, by means of a button, B, when it is desired to light or
extinguish the lamps. In a position of rest, for example, the crank, MD,
is vertical, as shown in the diagram to the right in Fig. 2. The circuit
is open between M and N through the effect of the small rod, C, which
separates the spring, R, from the spring, R'. As soon as the circuit has
been closed, be it only for an instant, the crank leaves its vertical
position, the rod, C, quits the bend, S, and the spring, R, by virtue of
its elasticity, touches the spring, R', and continues its contact until
the crank, MD, having made a half revolution, the rod, C', repulses the
spring, R, and breaks the circuit anew. The brake then acts, and the
crank stops after making a revolution of 180°, and immersing the
zincs to a maximum depth. In order to extinguish the lamp, it is only
necessary to press the button, B, again. The axle, M, will then make
another half revolution, and, when it stops, the zinks will be entirely
out of the liquid. The depth of immersion is regulated by fixing the
crank-pin. D, in the apertures, T1, or T2, of the connecting rod. This
permits the travel, and consequently the degree of immersion, to be
varied.

The device requires three wires, two for connecting the lamp with the
battery, and one for maneuvering the apparatus through a closing of the
contact, B.

With Mr. Mareschal's system, bichromate of potassa piles may be utilized
in a large number of cases where a light of but short duration is
required until the battery is exhausted, without the tedious maneuvering
of a winch and without inconvenience. The jack permits of a large number
of lightings and extinctions being effected before it becomes necessary
to wind up its clockwork movement. This operation, however, is very
simple, and may be performed every time the battery is visited in order
to see what state it is in.

We regard Mr. Mareschal's apparatus as an indispensable addition to
every case of domestic electric lighting in which bichromate of potassa
piles are used, and, in general, to all cases where the pile becomes
uselessly exhausted in open circuit. It will likewise find an
application in laboratories, where the bichromate pile is in much demand
because of its powerful qualities, and where it is often necessary to
order it from quite a distant point.--_La Nature_.

       *       *       *       *       *




MAGNETIC ROTATIONS.

By E. L. VOICE.


The remarkable researches and experiments of Professor Hughes clearly
show that magnetism is totally independent of iron, and that its
molecules, particles, or polarities are capable of rotation in that
metal. It would also appear that by reason of the friction between
magnetism and iron, the molecules of the latter are only partially
moved, such movement being the result of the tendency of iron to retard
magnetic change.

I have found that the magnetic molecules also possess inertia, that they
are capable of acquiring momentum, and that their rotation continues
for a considerable time after the exciting cause of their rotation has
ceased.

These facts may be proved in a very evident manner, inasmuch as induced
electric currents are generated by this _after_ rotation, which may be
made to light incandescent lamps.

In this case the magnetic rotations are produced in an electro magnet by
means of alternate currents supplied by alternating Gramme machine.

In order to better explain the action, it will be necessary to refer
to a new electro-motor, which was the subject of an article in the
_Electrical Review_ of February 19 last. It is of that type of motor in
which the field magnet and armature poles are alternately arranged, and
which requires a periodical reversibility of magnetism in the armature
to cause the latter to revolve, as in the Griscom motor. The insulating
strips in the commutator are sufficiently wide to demagnetize the whole
of the machine before reversibility in the armature takes place, and
this demagnetization sets up a _direct_ induced current, which is caught
in a shunt circuit by the aid of a second commutator, which only comes
into action when the first commutator goes out.

When this motor is supplied by a continuous current, it is easy to
understand that the induced current which passes through the shunt
circuit, and which is caused by the demagnetization, is proportional
to the mass of iron and wire of which the machine is composed, or
proportional to its inductive capacity. This current is purely a
secondary effect, of short duration, and only occurs once at each break
of the commutator.

The motor is of such a size that when supplied with a continuous current
of proper strength the induced electrical effect in the shunt circuit
will light one incandescent lamp. If, however, it is supplied with an
alternating current of the same power, it will light eight lamps, and
the mechanical power given off is even more than with a continuous
current, provided that the alternations from the dynamo do not exceed
6,000 a minute.

At first I was considerably puzzled by this great difference, because in
both cases it is impossible for the lamp circuit to be acted upon by the
main current. It occurred to me, however, that the rapid alternations
of the exciting current from the dynamo, and the consequent speed of
magnetic molecular rotation, gave the latter a certain momentum, and
that by widening the insulating strips of the first or main current
commutator, and proportionately increasing the width of conducting
surface in the shunt commutator up to certain limits, this effect would
be increased. I found such to be the case, from which I inferred that
the increase of induced current in the shunt circuit was on account of
its longer duration, by reason of the acquired momentum of the magnetic
molecular rotations _after_ the alternating exciting current had ceased.

[Illustration]

Those who have facilities for carrying out experiments may prove it in
the following manner:

E, in the inclosed drawing, is an electro-magnet whose brushes press on
two metallic bands, B and B¹, fixed to but insulated from the spindle,
A. The band, B, is in electrical circuit with the shunt commutator, S,
and the main commutator, M; while the band, B¹, is in contact with
shunt commutator, S¹, and main commutator, M¹. This contact is made
by conducting rods, as indicated. The commutators, as regards their
brushes, are so arranged that when M and M¹ are in action, S and S¹ are
out of action, and _vice versa_. The spindle and commutators are rotated
by the pulley, P. L is an incandescent lamp in the shunt circuit.

Let us now suppose the apparatus at rest, and the brushes in electrical
contact with the main commutators, M and M¹. The current from an
alternating dynamo passes into the magnet, E, and rapidly reverses its
polarity. By actuating the pulley, P, the commutators are rotated, when
M and M¹ go out of, and the shunt commutators, S and S¹, come into
action, enabling the _after_ current set up in the magnet to light the
lamp, L, in the shunt circuit.

In order to make comparative tests, the same apparatus may be supplied
with continuous instead of alternating currents. The after current in
the former case, however, is much smaller, consisting of one electrical
impulse only at each break of the commutator, whereas in the alternating
system these impulses are practically continued; the result being that,
all things being equal, a far greater number of lamps may be used in the
shunt than when supplied by continuous current only, and it would
appear that this difference can only be attributed to the fact that the
rotatory motion of magnetic molecules, or polarity of the magnet, E,
acquires momentum when acted upon by a suitable physical cause, such as
alternating currents of electricity; this momentum lasting a sensible
time after the cessation of the acting cause.

If we had the gift of magnetic sight, and could see what is going on in
the electro-magnet when it is excited by alternating currents, we should
probably see the molecules or polarities tumbling over each other at an
enormous rate. I do not think, however, that we should see anything but
a vibratory motion as regards the iron molecules.--_Elec. Review_.

       *       *       *       *       *

[AMER. MICROSCOP. JOUR.]




LIGHTON'S IMMERSION ILLUMINATOR


The following extremely simple plan for an immersion illuminator was
first brought to the notice of microscopists a few years ago, and,
in the absence of the inventor, was kindly described by Prof. Albert
McCalla, at the meeting of the American Society of Microscopists, at
Columbus, O. It consists of a small disk of silvered plate glass, c,
about one-eighth of an inch thick, which is cemented by glycerine
or some homogeneous immersion medium to the under surface of the
glass-slide, s. Let r represent the silvered surface of the glass disk,
b, the immersion objective, f, the thin glass cover. It will be easily
seen that the ray of light, h, from the mirror or condenser above the
stage will enter the slide and thence be refracted to the silvered
surface of the illuminator, r, whence it is reflected at a corresponding
angle to the object in the focus of the objective. A shield to prevent
unnecessary light from entering the objective can be made of any
material at hand, by taking a strip one inch long and three-fourths
of an inch wide and turning up one end. A hole not more than
three-sixteenths of an inch in diameter should be made at the angle. The
shield should be placed on the upper surface of the slide, so that the
hole will cover the point where the light from the mirror enters the
glass. With this illuminator Möller's balsam test-plate is resolved
with ease, with suitable objectives. Diatoms mounted dry are shown in
a manner far surpassing that by the usual arrangement of mirror,
particularly with large angle dry objectives.

Ottumwa, Ia.

WM. LIGHTON.

[Illustration: LIGHTON'S ILLUMINATOR.]

       *       *       *       *       *




FOUCAULT'S PENDULUM EXPERIMENTS.

By RICHARD A. PROCTOR.


Science owes to M. Foucault the suggestion that the motions of a
pendulum so suspended as to be free to swing in any vertical plane
might be made to give ocular demonstration of the earth's rotation. The
principle of proof may be easily exhibited, though, like nearly all of
the evidences of the earth's rotation, the complete theory of the
matter can only be mastered by the aid of mathematical researches of
considerable complexity. Suppose A B (Fig. 1) to be a straight rod in a
horizontal position bearing the free pendulum C D suspended in some such
manner as is indicated at C; and suppose the pendulum to be set swinging
in the direction of the length of the rod A B, so that the bob D remains
throughout the oscillations vertically under the rod A B. Now, if A B be
shifted in the manner indicated by the arrows, its horizontality being
preserved, it will be found that the pendulum does not partake in this
motion. Thus, if the direction of A B was north and south at first, so
that the pendulum was set swinging in a north and south direction, it
will be found that, the pendulum will still swing in that direction,
even though the rod be made to take up an east and west position.

[Illustration: Fig. 1.]

Nor will it matter if we suppose B (say) fixed and the rod shifted by
moving the end A horizontally round B. Further, as this is true whatever
the length of the rod, it is clear that the same fixity of the plane
of swing will be observed if the rod be shifted horizontally as though
forming part of a radial line from a point E in its length. In these
cases the plane of the pendulum's swing will indeed be shifted _bodily_,
but the direction of swing will still continue to be from north to
south.

Now, let P O P' represent the polar axis of the earth; a b a horizontal
rod at the pole bearing a pendulum, as in Fig. 1. It is clear that if
the earth is rotating about P O P' in the direction shown by the arrow,
the rod a b is being shifted round, precisely as in the case first
considered. The swinging pendulum below it will not partake in its
motion; and thus, through whatever arc the earth rotates from west to
east, through the same arc will the plane of swing of the pendulum
appear to travel from east to west under a b.

But we cannot set up a pendulum to swing at the pole of the earth. Let
us inquire, then, whether the experiment ought to have similar results
if carried out elsewhere.

Suppose A B to be our pendulum-bearing rod, placed (for convenience of
description merely) in a north and south position. Then it is clear that
A B produced meets the polar axis produced (in E, suppose), and when,
owing to the earth's rotation, the rod has been carried to the position
A' B', it still passes through the point E. Hence it has shifted through
the angle A E A', a motion which corresponds to the case of the motion
of A B (in Fig. 1) about the point E,[1] and the plane of the pendulum's
swing will therefore show a displacement equal to the angle A E A'. It
will be at once seen that for a given arc of rotation the displacement
is smaller in this case than in the former, since the angle A E A' is
obviously less than the angle A K A'.[2] In our latitude a free pendulum
should seem to shift through one degree in about five minutes.

[Footnote 1: In reality A E moves to the position A' E over the surface
of a cone having E P' as axis, and E as vertex; but for any small part
of its motion, the effect is the same as though it traveled in a plane
through E, touching this cone; and the sum of the effects should clearly
be proportioned to the sum of the angular displacements.]

[Footnote 2: In fact, the former angle is less than the latter, in the
same proportion that A K is less than A E, or in the proportion of the
sine of the angle A E P, which is obviously the same as the sine of the
latitude.]

It is obvious that a great deal depends on the mode of suspension. What
is needed is that the pendulum should be as little affected as possible
by its connection with the rotating earth. It will surprise many,
perhaps, to learn that in Foucault's original mode of suspension the
upper end of the wire bearing the pendulum bob was fastened to a metal
plate by means of a screw. It might be supposed that the torsion of
the wire would appreciably affect the result. In reality, however, the
torsion was very small.

[Illustration: Fig. 2.]

Still, other modes of suspension are obviously suggested by the
requirements of the problem. Hansen made use of the mode of suspension
exhibited in Fig. 3. Mr. Worms, in a series of experiments carried out
at King's College, London, adopted a somewhat similar arrangement, but
in place of the hemispherical segment he employed a conoid, as shown in
Fig. 4, and a socket was provided in which the conoid could work freely.
From some experiments I made myself a score of years ago, I am inclined
to prefer a plane surface for the conoid to work upon. Care must be
taken that the first swing of the pendulum may take place truly in one
plane. The mode of liberation is also a matter of importance.

[Illustration: Fig.3.]

Many interesting experiments have been made upon the motions of a
free pendulum, regarded as a proof of the earth's rotation, and when
carefully conducted, the experiments have never failed to afford the
most satisfactory results. Space, however, will only permit me to dwell
on a single series of experiments. I select those made by Mr. Worms in
the Hall of King's College, London, in the year 1859:

"The bob was a truly turned ball of brass weighing 40 lb.; the
suspending medium was a thick steel wire; the length of the pendulum was
17 feet 9 inches. The amplitude of the first oscillation was 6° 42', and
during the time of the experiment--about half an hour--the arcs were
not much diminished. As I had to demonstrate to a large number of
spectators, I encountered considerable difficulty," says Mr. Worms, "in
rendering the small deviations of the plane of oscillation visible to
all. I accomplished it in three different ways." These he proceeds
to describe. He had first a set of small cones set up, which were
successively knocked down as the change in the plane of the pendulum
slowly brought the pointer under the bob to bear on cone after cone.
Secondly, a small cannon was so placed that the first touch of the
pendulum pointer against a platinum wire across the touch-hole completed
a galvanic circuit, and so fired the cannon. Lastly, a candle was placed
so as to throw the shadow of the pendulum bob upon a ground-glass
screen, and so to exhibit the gradual change of the plane of swing.

The results accorded most satisfactorily with the deductions from the
theory of the earth's rotation.

[Illustration: Fig.4.]

       *       *       *       *       *




A NEW LUNARIAN.

By Prof. C. W. MACCORD, Sc.D.


The construction of apparatus for illustrating the motions of the
heavenly bodies has often occupied the attention of both mathematicians
and mechanicians, who have produced many very ingenious, and in some
cases very complicated, combinations. These may be divided into two
classes; the object of the first being to represent _exactly_ what
occurs--to reproduce the precise movements of the various bodies
represented in their true proportions and relations to each other, in
respect to distances, magnitudes, times, and phases. When the absolute
complexity of the movements of the bodies composing the solar system
is considered, it is not so much a matter of wonder that a planetarium
which shall thus imitate them is a very delicate and complicated machine
as that it should lie within the limits of human ingenuity.

In the second class, the object is to show the nature and the causes
of specific phenomena, without regard to others perhaps, and without
necessarily paying attention to exact proportions of distances and
dimensions. Indeed, it is often the case that the illustration is made
clearer by exaggerating some of these and reducing others; thus, for
example, the causes of the variation in the lengths of the days and
nights, and of the changes in the seasons, can be exhibited to much
better advantage by an apparatus in which the diameter of the sun and
its distance from the earth are enormously reduced than they possibly
could be were they of their proper proportionate magnitudes; nor is the
presence of any other planet, or the attendance of a satellite, at all
necessary or even desirable for the purpose named.

It is apparent that machines of this class can be made much more simple
than those of the first, while at the same time it may safely be
asserted that for educational purposes they are far more useful.

In both classes, the action involves the use of some sort of epicyclic
train, since the motions to be explained are both orbital and axial. The
planetary body is carried round by a train-arm, and its rotation about
its axis is usually given it by a train of gearing, the inner or
central wheel of which is stationary, being fastened to the fixed frame
supporting the whole.

[Illustration: AN IMPROVED LUNARIAN.]

The lunarian which we herewith present belongs to the second of the
classes above named; in its construction an attempt has been made to
show by as simple means and in as clear a manner as possible the nature
of the following phenomena, viz.:

1. Apogee and perigee.

2. The moon's phases.

3. The rotation on her axis, by reason of which she always presents
nearly the same face to the earth.

4. The inclination of her axis to the plane of her orbit, and her
consequent libration in latitude.

5. Her varying angular velocity, and consequent libration in longitude.

The mechanism consists of a train-arm, T, which turns upon the vertical
pivot, P, fixed in the stand. In this arm, T, are the bearings of two
cranks, B and C. equal in length to each other and to a third crank, A,
which is stationary, being fixed to the pivot, P, by a pin, p. To the
crank-pin of A is secured a reverted arm, A', which supports the earth,
E, and keeps it also stationary. The three cranks are connected by the
rod, R, like the parallel rod of a locomotive: to which is fastened by a
steady-pin, o, the bevel wheel, D, concentric with the crank-pin, b. The
head of this crank-pin is first made spherical, then faced off at an
angle with the axis of b, and in the sloping face is firmly fixed the
long screw, S, forming the support for the moon, M, which is caused
to rotate about the axis of S, by means of the wheel, F, equal to
and engaging with D. The upper end of S projects slightly through a
perforation in the moon, and to it the hemispherical black shell or cap,
G, is fixed by the screw, K; this cap represents the unilluminated part
of the moon, and since G, s, b, and B, are in effect but one piece, the
cap moves precisely as the crank does.

Now as the train-arm, T, is carried round, the cranks, B and C, will
turn in their bearings; but by their connection with A, they are
compelled to remain always parallel to themselves, and thus the axis of
the moon receives a motion of translation. But since during this action
the wheel D turns relatively to the pin b, the moon evidently rotates
about its axis with an angular velocity precisely equal to that of its
orbital motion.

The black shell however has the motion of translation only, and thus
exhibits the phases of the moon, on the supposition that the source
of light is infinitely remote and the rays come always in the same
direction, which is not strictly true, of course; but the reasons of the
varying appearance are as clearly shown as if it were absolutely exact.
The same may be said in regard to the phenomena of libration; the
inclination of the moon's axis to the plane of her orbit is really
small, but is purposely exaggerated in this apparatus in order to make
the results apparent; in the position represented, it is quite obvious
that an observer upon the earth can see a little past one pole, and
cannot quite see the other, as well as that this condition will be
reversed after half a revolution.

The action in reference to the phases is clearly shown in the small
diagram on the right. The one on the left illustrates the manner in
which the libration in longitude is made apparent. It will be noted that
the center of M is not directly over the axis of the bearing of the
crank, B, so that after half a revolution the moon will be farther from
the earth than she is here shown. Her orbit here is circular, whereas,
in fact, it is an ellipse; but the earth not being in the center, her
angular velocity in relation to the earth is variable, the result
of which is that, when she is near her quadrature, the actual force
presented to the earth is slightly different from that presented when in
conjunction or opposition.

Thus these various peculiarities of the motion of our satellite are
exhibited by comparatively simple means--the number of moving parts
being, it is believed, as small as it can be made; and the substitution
of a crank motion for the usual train of wheels, we think, is a new
device.

       *       *       *       *       *




THE UPRIGHT ATTITUDE OF MANKIND.


Every one must have heard or have read of the supposed perfect
adaptation of the human frame to bipedal locomotion and to an upright
attitude, as well as the advantages which we gain by this erect
position. We are told, and with perfect truth, that in man the occipital
foramen--the aperture through which the brain is connected with the
spinal cord--is so placed that the head is nearly in equilibrium when he
stands upright. In other mammalia this aperture lies further back, and
takes a more oblique direction, so that the head is thrown forward,
and requires to be upheld partly by muscular effort and partly by the
ligamentum nuchæ, popularly known in cattle as the "pax-wax."

Again, the relative lengths of the bones of the hinder extremities in
man form an obstacle to his walking on all-fours. If we keep the legs
straight we may touch the ground in front of our feet with the tips of
the fingers, but we cannot place the palms of the hands upon the ground
and use them to support any part of our weight in walking. Not a few
other points of a similar tendency have been so often enlarged upon, in
works of a teleological character, that there can be no need even to
specify them at present.

But till lately it has never been asked, "Is man's adaptation to
an upright posture perfect?" and "Is this posture attended with no
drawbacks?" These questions have been raised by Dr. S. V. Clevenger in a
lecture delivered before the Chicago University Club, on April 18, 1882,
and recently published in the _American Naturalist_. This lecture,
we may add, cost the speaker the chair of Comparative Anatomy and
Physiology at the Chicago University!

Dr. Clevenger first discusses the position of the valves in the veins.
The teleologists have long told us that the valves in the veins of
the arms and legs assist in the return of blood to the heart against
gravitation. But what earthly use has a man for valves in the
intercostal veins which carry blood almost horizontally backward to the
azygos veins? When recumbent, these valves are an actual obstacle to
the free flow of the blood. The inferior thyroid veins which drop their
blood into the innominate are obstructed by valves at their junction.
Two pairs of valves are situate in the external jugular, and another
pair in the internal jugular, but they do not prevent regurgitation of
blood upward.

An anomaly exists in the absence of valves from parts where they are
most needed, such as the venæ cavæ, the spinal, iliac, hæmorrhoidal, and
portal veins.

But if we place man upon all-fours these anomalies disappear, and a law
is found regulating the presence or absence of valves, and, according to
Dr. Clevenger, it is applicable to all quadrupeds and to the so-called
Quadrumana. Veins flowing toward the back, i.e., against gravitation in
the all-fours posture--are fitted with valves; those flowing in
other directions are without. For the few exceptions a very feasible
explanation is given.

Valves in the hæmorrhoidal veins would be useless to quadrupeds; but to
man, in his upright position, they would be very valuable. "To their
absence in man many a life has been and will be sacrificed, to say
nothing of the discomfort and distress occasioned by the engorgement
known as piles, which the presence of valves in their veins would
obviate."

A noticeable departure from the rule obtaining in the vascular system of
mammalia also occurs to the exposed situation of the femoral artery in
man. The arteries lie deeper than the veins, or are otherwise protected,
for the purpose--as a teleologist would say--of preventing serious loss
of blood from superficial cuts. Translating this view into evolutionary
language, it appears that only animals with deeply placed arteries can
survive and transmit their structural peculiarities to their offspring.
The ordinary abrasions to which all animals are exposed, not to mention
their onslaughts upon each other, would quickly kill off species with
superficially placed arteries. But when man assumed the upright posture
the femoral artery, which in the quadrupedal position is placed out of
reach on the inner part of the thigh, became exposed. Were not this
defect greatly compensated by man's ability to protect this part in ways
not open to brutes, he, too, might have become extinct. As it is, this
exposure of so large an artery is a fruitful cause of trouble and death.

We may here mention some other disadvantages of the upright position
which Dr. Clevenger has omitted. Foremost comes the liability to fall
due to an erect posture supported upon two feet only. Four-footed
animals in their natural haunts are little liable to fall; if one foot
slips or fails to find hold, the other three are available. If a fall
does occur on level ground, there is very little danger to any mammal
nearly approaching man in bulk and weight. Their vital parts, especially
the heart and the head, are ordinarily so near the ground that to them
the shock is comparatively slight. To human beings the effects of a
fall on smooth, level ground are often serious, or even deadly. We need
merely call to mind the case of the illustrious physicist whom we have
so recently and suddenly lost.

The upright attitude involves a further sourge of danger. In few parts
(if any) of the body is a blow more fatal than over what is popularly
called the "pit of the stomach." In the quadruped this part is little
exposed either to accidental or intentional injuries. In man it is quite
open to both. A blow, a kick, a fall among stones, etc., may thus easily
prove fatal.

Another point is the exposure and prominence of the generative organs,
which in most other animals are well protected. Leaving danger out of
the question, it may be asked whether we have not here the origin of
clothing? The assumption of the upright posture may have made primitive
man aware of his nakedness.

Returning to the illustrations furnished by Dr. Clevenger, we are
reminded that another disadvantage which occurs from the upright
position of man is his greater liability to inguinal hernia. In
quadrupeds the main weight of the abdominal viscera is supported by the
ribs and by strong pectoral and abdominal muscles. The weakest part of
the latter group of muscles is in the region of Poupart's ligament,
above the groin. Inguinal hernia is rare in other vertebrates because
this weak part is relieved by the pressure of the viscera. In man the
pelvis receives almost the entire load of the intestines, and hence Art
is called in to compensate the deficiencies of nature, and an immense
number of trusses have to be manufactured and used. It is calculated
that 20 per cent. of the human family suffer in this way. Strangulated
hernia frequently causes death. The liability to femoral hernia is in
like manner increased by the upright position.

Now, if man has always been erect from his creation--or, if that term be
disliked, from his origin--we have evidently nothing to hope from the
future in the way of an amendment of this and other defects. But if we
have sprung from a quadrupedal animal, and have by degrees adopted
an upright position, to which we are as yet imperfectly adapted, the
muscular tissues of the abdomen will doubtless in the lapse of ages
become strengthened to meet the demand made upon them, so that the
liability to rupture will decrease. In like manner the other defects
above enumerated may gradually be rendered less serious.

A most important point remains; the peritoneal ligaments of the uterus
fully subserve suspensory functions. The anterior, posterior, and
lateral ligaments are mainly concerned in preventing the gravid uterus,
in quadrupeds, from pitching too far forward toward the diaphragm. The
round ligaments are utterly unmeaning in the human female, but in the
lower animals they serve the same purpose as the other ligaments.
Prolapsus uteri, from the erect position and the absence of supports
adapted to the position, is thus rendered common, destroying the health
and happiness of multitudes.

As a simple deduction from mechanical laws, it would readily follow that
any animal or race of men which had for the longest time maintained an
erect position would have straighter abdomens, wider pelvic brims with
contracted pelvic outlets, and that the weight of the spinal column
would force the sacrum lower down. This, generally speaking, we find to
be the case. In quadrupeds the box-shaped pelvis, which admits of easy
parturition, is prevalent. Where the position of the animal is such as
to throw the weight of the viscera into the pelvis, the brim necessarily
widens, these weighty organs sink lower, and the beads of the
thigh-bones acting as fulcra permit the crest of the ilium to be
carried outward, while the lower part of the pelvis is at the same time
contracted.

In the innominate bones of a young child the box-shape exists, while its
prominent abdomen resembles that of the gorilla. The gibbon exhibits
this iliac expansion through the sitting posture which developed his
ischial callosities. Similarly iliac expansion occurs in the chimpanzee.
The megatherium had wide iliacal expansions due to its semi-erect
habits; but as its weight was in great part supported by the huge tail,
and as the fermora rested in acetabula placed far forward, the leverage
necessary to contract the lower portion of the pelvis was absent.

Prof. Weber, of Bonn, quoted in Karl Vogt's "Vorlesungen ueber den
Mensohen," distinguishes four chief forms of the pelvis in mankind--the
oval in Aryans, the round among the Red Indians, the square in the
Mongols, and the wedge-shaped in the Negro. Examining this question
mechanically it would seem that the longer a race had remained in
an upright position the lower is the sacrum, and the greater is the
tendency to approximate to the larger lateral diameter of the European
female. The front to back diameter of the ape's pelvis is usually
greater than the measurement from side to side. A similar condition
affords the cuneiform, from which it may be inferred that the erect
position in the Negro has not been maintained so long as in the Mongol,
whose pelvis has assumed the quadrilateral shape owing to persistence
of spinal axis weight for a greater time. This pressure has finally
culminated in forcing the sacrum of the European nearer the pubes, with
consequent lateral expansion and contraction of the diameter from
front to back. From the marsupials to the lemurs the box-shaped pelvis
remains. With the wedge-shape occasioned in the lowest human types there
occurs a further remarkable phenomenon in the increased size of the
foetal head accompanying the contraction of the pelvic outlet. While the
marsupial head is about one-sixth the size of the narrowest part of the
bony parturient canal, the moment we pass to erect animals the greater
relative increase is there seen in cranial size, with a coexisting
decrease in the area of the outlet. This altered condition of things
has caused the death of millions of otherwise perfectly healthy and
well-formed human mothers and children. The palæontologist might tell us
if some such case of ischial approximation by natural mechanical causes
has not caused the probable extinction of whole genera of vertebrates.
"If we are to believe that for our original sin the pangs and labor
of childbirth were increased, and if we also believe in the
disproportionate contraction of the pelvic space being an efficient
cause of the same difficulties of parturition, the logical inference is
that man's original sin consisted in his getting upon his hind legs."

This subject is not without direct applications. Accoucheurs cause their
patients to assume what is called the knee-chest position, a prone one,
for the purpose of restoring the uterus to something near a natural
position. Brown-Sequard recommends, in myelitis, or spinal congestion,
drawing away the blood from the spine by placing the patient on his
abdomen or side, with hands and feet somewhat hanging down. The
liability to _spina bifida_ is greatest in the human infant, through
the stress thrown on the spine. The easy parturition in the lower human
races is due to the discrepancy between cranial and pelvic sizes not
having been as yet reached by those races. The Sandwich Island mother
has a difficult delivery only when her child is half white, and has
consequently a longer head than the unmixed native strain.

At present the world goes on in its blindness, apparently satisfied
that everything is all right because its exists, ignorant of the evil
consequences of apparently beneficial pecularities, vaunting man's
erectness and its advantages, while ignoring the disadvantages.

The observation that the lower the animal the more prolific (not
universally true!) would warrant the belief that the higher the animal
the more difficulties encompass its propagation and development. The
cranio-pelvic difficulty may perhaps settle the Malthusian question as
far as the higher races of men are concerned by their extinction.

[If the facts brought forward by Dr. Clevenger cannot be controverted,
they seem to prove that man must have originated by gradual development
from a four-footed being. Had he been created an erect, bipedal animal,
as we find him, his structure would have been not in partial, but in
perfect, adaptation to the conditions of that attitude. That some of the
peculiarities of his structure are better in harmony with a horizontal
than a vertical position of the spinal column, is perhaps the strongest
argument against the theory of direct creation and the radical _toto
coelo_ distinction between man and beast that has yet been advanced. We
cannot at the moment lay our hands upon any thorough and trustworthy
account of the valves in the veins of the sloth: as that animal spends
its life hanging, back downward, the structure of the veins would be
interesting in this connection.--ED. J. S.]--_Journal of Science_.

       *       *       *       *       *




OUR ENEMIES, THE MICROBES.


We have seen the microbes, as our servants[1], often performing,
unbeknown to us, the work of purifying and regenerating the soil and
atmosphere. Let us now examine our enemies, for they are numerous.
Everywhere frequent--in the air, in the earth, in the water--they only
await an occasion to introduce themselves into our body in order to
engage in a contest for existence with the cells that make up our
tissues; and, often victorious, they cause death with fearful rapidity.
When we have named charbon, septicæmia, diphtheria, typhoid fever, pork
measles, etc., we shall have indicated the serious affections that
microbes are capable of engendering in the animal organism.

[Footnote 1: SUPPLEMENT, No. 446, page 7125.]

We call those diseases "parasitic" that are occasioned by the
introduction of a living organism into the bodies of animals. Although a
knowledge of such diseases is easy where it concerns parasites such as
acari and worms, it becomes very difficult when it is a question of
diseases that are caused by the Bacteriaceæ. In fact, the germs of these
plants exist in the air in large quantities, as is shown by the analysis
of pure air by a sunbeam, and we are obliged to take minute precautions
to prevent then from invading organic substances. If, then, during an
autopsy of an individual or animal, a microscopic examination reveals
the presence of microbes, we cannot affirm that the latter were the
cause of the affection that it is desired to study, since they might
have introduced themselves during the manipulation, and by reason of
their rapid vegetation have invaded the tissues of the dead animal in
a very short time. The presumption exists, nevertheless, that when
the same form of bacteria is present in the same tissue with the same
affection, it is connected with the disease. This was what Davaine was
the first to show with regard to _Bacillus anthracis_, which causes
charbon. He, in 1850, having examined the blood of an animal that had
died of this disease, found therein amid the globules (Fig. 1), small,
immovable, very narrow rods of a length double that of the blood
corpuscles. It was not till 1863 that he suspected the active role of
these organisms in the charbon malady, and endeavored to demonstrate it
by experiments in inoculation. Is the presence of these little rods in
the blood of an animal that has died of charbon sufficient of itself to
demonstrate the parasitic nature of the affection? No; in order that
the demonstration shall be complete, the bacteria must be isolated,
cultivated in a state of purity in proper liquids, and then be used
to inoculate animals with. If the latter die with all the symptoms
of charbon, the demonstration will be complete. Davaine did, indeed,
perform some experiments in inoculation that were successful, but his
results were contradicted by the experiments of Messrs. Jaillard and
Leplat, and those of Mr. Bert concerning the toxic influence of oxygen
at high tension upon microbes. As Davaine was unable to explain the
contradiction between his results and those of Messrs. Jaillard, Leplat,
and Bert, minds were not as yet convinced, notwithstanding the support
that his ideas received from Mr. Koch's researches.

In 1877 Mr. Pasteur took up Davaine's experiments, and confirmed his
affirmations step by step by employing the method of culture that he had
used with such success in his studies upon fermentation. He isolated
Davaine's bacterium by cultivating it in a decoction of beer yeast that
had been previously sterilized (Fig. 2); and after from ten to twenty
cultures, he found that a portion of the liquid containing a few
bacteria, when used for inoculating a rabbit, quickly caused the latter
to die of charbon, while the same liquid, when filtered through plaster
or porcelain, became harmless.

Davaine's bacterium develops exclusively in the blood, and is never
found at any depth in the tissues. This is due to the fact that the
alga, having need of oxygen in order to live, borrows its flow from the
blood, and thus extracts from the globules that which they should have
carried to the tissue. The animal therefore dies asphyxiated. It is on
account of the absence of oxygen in the blood that the latter assumes
the blackish-brown color that characterizes the malady, and that has
given its name of _charbon_ (coal).

The parasitic nature of charbon was therefore absolutely demonstrated,
first, by the constant presence of _Bacillus anthracis_ in the blood of
anthracoid animals, and second, by the pure culture of the parasite and
the inoculation of animals with charbon by means of it.

Davaine began the demonstration in 1863, and Pasteur finished it in
1877. These facts are now incontestable; yet, to show how slowly truth
is propagated, even in these days of telegraphs and telephones, there
might have been read a few months ago, in an interesting article on
microbes, by Dr. Fol, a distinguished savant, the statement that charbon
and tuberculosis were discovered by Dr. Koch!

New parasitic affections, whose existence was suspected, were soon
discovered and scientifically demonstrated, such, for example, as
septicæmia, or the putrefaction which occurs in living animals, which in
ambulances causes so fearful havoc among the wounded, and which proceeds
from _Bacillus septicus_. This parasite exhibits itself under the form
of little articulated rods that live isolated from oxygen in the mass of
the tissues, and disorganize the latter in disengaging a large quantity
of putrid gas. Other parasites of this class are the _micrococcus_ of
chicken cholera (Fig. 3), the _micrococcus_ of hog measles, and the
_Spirochoete Obermeieri_ of recurrent fever, discovered by Obermeier
(Fig. 5).

Besides these, there are a certain number of maladies that seem as if
they must be due to the Bacteriaceæ, although a demonstration of the
fact by the method of cultures and inoculation has not as yet been
attempted. Among such, we may cite typhoid fever, diphtheria, murrain,
tuberculosis (Fig. 4), malarial fever (Fig. 6), etc.

As may be seen, the list is already a long one, and it tends every day
to still further increase. All the progress that has been made in so
few years in our knowledge of contagious or epidemic diseases is due
exclusively to M. Pasteur and the scientific method that he introduced
through his remarkable labors on fermentation. Now that we know our most
formidable enemies, how shall we defend ourselves against them?

As we have seen, bacteria exist everywhere, mixed with the dust that
interferes with the transparency of the air and covers all objects; and
they are likewise found in water.

Under normal conditions, our body is closed to these organisms through
the epidermis and epithelium, and, as has been shown by Mr. Pasteur, no
bacteria are found in the blood and tissues of living animals. But let a
rupture or wound occur, and bacteria will enter the body, and, when once
the enemy is in place, it will be too late. One sole chance of safety
remains to us, and that is that in the warfare that it is raging against
our tissues the enemy may succumb. M. Pasteur has shown that the blood
corpsucles sometimes engage in the contest against bacterides and
come off victorious. In fact, chickens are proof against poisoning by
charbon, because, owing to the high temperature of their blood, the
bacterides are unable to extract oxygen from the corpuscles thereof.
But, if the chickens be chilled, the conditions are changed, and they
will die of charbon just as do cattle and sheep; but, as the result of
the contest cannot always be foreseen, it is necessary at any cost to
prevent bacterides from entering the body.

[Illustration: I. Bacteria of charbon (_Bacillus antracis_.) II. The
same cultivated in yeast. III. The _Micrococcus_ of chicken cholera. IV.
The _Bacillus_ of tuberculosis. V. The _Spirillun_ of recurrent fever.
VI. The _Bacillus_ of malaria.]

Under ordinary circumstances a severe hygiene will suffice to preserve
us; if a wound is received it should be washed with water mixed with
antiseptics, such as phenic acid, borax, or salicylic acid. If water is
impure, it must be boiled and then aerated before it is drunk. If the
air is the vehicle of the germs of the disease, it will have to be
filtered by means of a muslin curtain kept wet with a hygroscopic
solution, glycerine for example. Finally, when, after an epidemic,
contaminated apartments are to be occupied, the walls and floor and the
clothing must be washed with antiseptic solutions whose nature will vary
according to circumstances--steam charged with phenic acid, water mixed
with a millionth part of sulphuric acid, boric acid, ozone, chlorine,
etc.

These preventives only prove efficient on condition that they be used
persistently. Let our vigilance be lacking for an instant, and the enemy
will enter to work destruction, for it only requires a spore less than
a hundredth of a millimeter in diameter to produce the most serious
affections.

Fortunately, and it is again to Mr. Pasteur that we owe these wonderful
discoveries, the parasitic microbes themselves, which sow sickness and
death, may, through proper culture, become true vaccine viri that are
capable of preserving the organism against any future attack of the
disease that they were capable of producing; such vaccine matters have
been discovered for charbon, chicken cholera, the measles of swine, etc.

When the _micrococcus_ of chicken cholera (Fig. 3.) is cultivated, it
is seen that the activity of the microbe in cultures exposed to the air
gradually diminishes. While a drop of the liquid would, in twenty-four
hours, have killed all the chickens that were inoculated with it, its
effect after two, three, or four days considerably diminishes, and an
inoculation with it produces nothing more than a slight indisposition in
the animal, and one that is never followed by a serious accident. It is
then said that the virulence of the microbe is attenuated.

The air is the agent of this transformation that gradually renders the
bacteria benign, for in cultures made under the same circumstances as
the preceding, but with the absence of air, the activity of these algæ
is preserved for days or weeks, and they will then cause death just as
surely as they would have done at the end of one day.

What is remarkable is that animals inoculated with the attenuated
_micrococcus_ become for a varying length of time refractory to the
action of the most formidable parasites of this kind. Mr. Pasteur has
discovered two such vaccine viri--one for chicken cholera and the other
for charbon. His results have not been accepted without a struggle, and
it required nothing less than public experiment in vaccination, both in
France and abroad, to convince the incredulous. There are still people
at the present time who assert that Mr. Pasteur's process of vaccination
has not a great practical range! And yet, here we have the results; more
than 400,000 animals have been vaccinated since 1881, and it has been
found that the mortality is ten times less in these than in those that
have not been vaccinated!

An impetus has now been given, and we can look to the future with
confidence, for, if our enemies are numerous, the use of a severe
hygiene and preventive vaccination will permit us to gradually free
humanity from the terrible scourges that sap the sources of fortune and
life.--_Science et Nature_.

       *       *       *       *       *




THE WINE FLY.


At the last meeting of the New York Microscopical Society, a paper
was read by Dr. Samuel Lockwood, secretary of the New Jersey State
Microscopical Society. His subject was the Wine Fly, _Drosophila
ampelophila_. The paper was a contribution to the life-history of this
minute insect. He had given in part three years to its study, beginning
in September, 1881, when nothing whatever of its life-history seemed to
have been known. In October the flies attacked his Concords. He found
upon a grape which he was inspecting with a pocket-lens an extremely
small white egg; but lost it. The grapes when brought on the table were
infested by the flies, which proved to be the above mentioned species.
When driven from the grapes they would fly to the window, where he
captured two of them These were placed in a jar with a grape for food.
In two days he found one egg on the outer skin of the grape. The laying
was kept up for four or five days, until there were about thirty, some
on the outside of the grape and some at an opening where the two flies
had fed. The egg had a pair of curious suspenders near the end where
the mouth of the larva would develop. These suspenders were attached at
their ends to the grape, but where the egg was laid in the soft part of
the fruit the suspenders were spread out at the surface; thus the larva
would emerge clean from the shell. The egg was 0.5 mm. in length, and
about a fourth of that in width. The larva when grown was at least four
times as long as the egg. As the larva burrowed in the juices of the
fruit, two quite prominent breathing tubes at the posterior end were
kept in the air. Between these cardinal tubes were several teat-like
points, much smaller, but having a similar function.

The larvae appeared in five days after the eggs were laid. In about as
many more days the puparium state would be entered, and in about six
days more the fly or imago would appear. In ovipositing the suspensors
would leave the oviparous duct last. The paper claimed that the curious
shape of the egg compelled the female to oviposit slowly, as it took
time for the egg to assume its form; hence, the eggs were not laid in
strings or masses, but singly and at considerable intervals.

The flies are very hairy, especially the females. The neck and even the
eyes are very hirsute. The eyes are red, quite large and pretty, though
somewhat _outre_ under the microscope, for from between the little
lenses are projecting, straight, stiff hairs. As the insect is quite
active, it must be that this fringing of the tiny eyelets with hair does
not materially obscure its vision. When the minuteness of this singular
arrangement is considered, it is surely remarkable. This general
hairiness of the female especially, and that about the head, neck, and
forward part of the thorax, stands correlated to a beautiful structure
found only in the male, which has on the tarsus of each leg in the
forward pair what the lecturer called a sexual comb. It is a beautiful
comb of a very dark brown color, each comb having ten pointed and strong
teeth. In the nuptial embrace these combs are fixed in the hairy front
of the thorax of the female, thus becoming little grapnels.

The flies love any vegetable substance in fermentation, whether acetic
or vinous. Hence it will abound about cider mills, swarm on preserves in
the pantry, and in cellars or places where wine is being made or stored.
The paper showed the tendency of the glucose in the over-ripe grape
to the vinous ferment, and that the fly delighted in it. A singular
accident showed how they loved even the very high spirits. In making
some of the mounts shown to the society, Dr. Lockwood had left a bottle
of 90 per cent. alcohol uncorked over night. Next morning he was
astonished to find his alcohol of a beautiful amethystine color, and the
cork out. Inspection showed a number of these tiny creatures, which,
when filled with the purple juice of the grape, had smelt the alcohol
in the open bottle, and had gone in to drink. They had ignominiously
perished, and had given color to the liquid.--_Micro. Journal_.

       *       *       *       *       *

[NATURE.]




THE "POTETOMETER," AN INSTRUMENT FOR MEASURING THE TRANSPIRATION OF
WATER BY PLANTS.


In view of the interest now attaching to recent advances in vegetable
physiology, it seems not unlikely that a description of the instrument
bearing the above name, lately published by Moll (_Archives
Neerlandaises_, t. xviii.), will serve as useful purpose. The apparatus
was designed to do away with certain sources of error in Sachs'
older form of the instrument, described in his "Experimental
Physiologie"--errors chiefly due to the continual alteration of pressure
during the progress of the experiment.

As shown in the diagram, the "potetometer" consists essentially of a
glass tube, a d, open at both ends, and blown out into a bulb near the
lower end; an aperture also exists on either side of the bulb at or
about its equator. The two ends of the main tube are governed by the
stopcocks, a and d, and the greater length of the tube is graduated. A
perforated caoutchouc stopper is fitted into one aparture of the bulb,
e, and the tube, g k, fits hermetically to the other. This latter tube
is dilated into a cup at h to receive the caoutchouc stopper, into which
the end of the shoot to be experimented upon is properly fixed.

The fixing of the shoot is effected by caoutchouc and wire or silk, as
shown at i, and must be performed so that the clean-cut end of the
shoot is exactly at the level of a tube passing through the perforated
stopper, e, of the bulb; this is easily managed, and is provided for by
the bending of the tube, g h. The tube, f, passing horizontally through
the caoutchouc stopper, e, is intended to admit bubbles of air, and so
equalize the pressure and at the same time afford a means of measuring
the rapidity of the absorption of water by the transpiring shoot. This
tube (see Fig. 2, f) is a short piece of capillary glass tubing, to
which is fixed a thin sheath of copper, b', which slides on it, and
supports a small plate of polished copper, a', in such a manner that the
latter can be held vertically at a small distance from the inner opening
of the tube, and so regulate the size of the bubble of air to be
directed upward into the graduated tube, a b.

[Illustration]

The apparatus is filled by placing the lower end of the main tube under
water, closing the tubes, f and i (with caoutchouc tubing and clips),
and opening the stopcocks, a and d. Water is then sucked in from a, and
the whole apparatus carefully filled. The cocks are then turned, and the
cut end of the shoot fixed into i, as stated; care must be taken that no
air remains under the cut end at i, and the end of the shoot must be at
the level, k l. This done, the tube, f, may then be opened.

The leaves of the shoot transpire water, which is replaced through the
stem at the cut end in i from the water in the apparatus. A bubble of
air passes through the tube, f, and at once ascends into the graduated
tube, a c. The descent of the water-level in this tube--which may
conveniently be graduated to measure cubic millimeters--enables the
experimenter at once to read off the amount of water employed in a given
time.

It is not necessary to dwell on obvious modifications of these
essentials, nor to speak of the slight difficulties of manipulation
(especially with the tube, f). Of course the apparatus might be mounted
in several ways; and excellent results for demonstration in class could
be obtained by arranging the whole on one of the pans of a sensitive
balance. H. MARSHALL WARD.

Botanical Laboratory, Owens College.

       *       *       *       *       *




BOLIVIAN CINCHONA FORESTS.


The great progress made in the acclimation of cinchona trees in India,
Ceylon, and elsewhere has awakened the governments of countries where
the plants are indigenous to the necessity of conserving from reckless
destruction, and replanting denuded forests, so as to be able to keep up
the supply of this valuable product.

In Bolivia, since 1878, according to the report of the Netherlands
Consul, private individuals and land owners have taken up the question
with great earnestness, and at the present time on the banks of the
Mapiri, in the department of La Paz, there are over a million of young
trees growing.

New plantations have also sprung up in various other localities, either
on private ground or that owned by Government. The competition of India
and Ceylon in supplying the markets has had also the effect of inducing
more care in collecting and also of revisiting old spots, often with the
result of a rich harvest of bark which had been left on partly denuded
trunks, and the opening up of new localities. The new shoots springing
up from the old stumps have yielded much quill bark, and the root bark
of the old stumps has also been utilized.

The replanting entails very little expense. The Indian tenant on an
estate has a house and land from the owner (hacienda) of the estate. For
this he binds himself to work for two to four days a week, at from 28 to
36 cents per day, women and children obtaining 16 to 21 cents per day.
Thus the planting, weeding, etc., during the first two years is
but nominal in expense; after this period the trees may be left to
themselves.

On Government land the expense is greater, as, after an application
being made, the land is put up to public auction, and may fetch a
very low or higher price according to the bidding. The land secured,
contracts are made with natives of the lower class to clear the forest
and plant cinchona. The contracts are often sublet to Indians. The
young plants are planted from five to six feet apart, with banana trees
between, on account of their rapid growth and the shade the latter
afford. From March to June, after the wet season is over, is the best
time for planting, and the contractor keeps the plantation free from
weeds and in good order for twelve months, when it is handed over to the
owner. The following is given as the cost of the Mapiri River plantation
of an area from 60 or more miles in extent:

  Ground.                                   $1,200
  300,000 plants at $0.14.                  42,000
  Superintendent, buildings, etc.            4,400
  Interest.                                  4,800
                                           -------
  Total.                                   $52,400

Till the plants are above two years of age, they are liable to die from
drought or the attacks of ants, and during 1878 many thousands died from
these causes. At the end of the fourth year some proprietors begin to
collect the quill bark by the method of coppicing.

It is feared by some that, should this new venture be successful, it
will prove a dangerous rival to the plantations of India, Ceylon, and
Java, and lower the price of bark considerably.--_Jour. Society of
Arts_.

       *       *       *       *       *




FERNS.


_N. Davallioides Furcans._--Among the many crested ferns in cultivation,
this, of which the annexed is an illustration, is one of the most
distinct; so different indeed it is from the type, that it is
questionable if it really is a form of it; the most essential
characteristic, that of the fructification at the extreme edge of the
lobes of the pinnæ, is altogether absent, and the whole habit of the
plant is also thoroughly distinct. It is of equally robust growth,
but its handsomely arching fronds, which are from 3 feet to 4 feet
in length, are produced in great abundance from a central tuft or
agglomeration of crowns. Its most distinct characteristic is the
furcation of the pinnæ, which are all of the same dimensions, whether
sterile or fertile; they are all opposite and closely set along the
mid-rib, whereas those of N. davallioides are set much further apart.
In the barren pinnæ which are only situated on the lower portion of the
frond, and which generally are only few in number, the furcation is
rudimentary; in the fertile pinnæ it is twice and even three times
repeated in the extremities of the first division, becoming more complex
toward the point of the frond, where it often forms quite a large
tassel, whose weight gives the fronds quite an elegant, arching habit.
On that account this plant is valuable for growing in baskets of large
dimensions, in which it shows itself off to good advantage, and never
fails to prove attractive. Although it produces spores freely, it is
best to propagate it by means of the young plants produced from rhizomes
in the ordinary way, on account of the extreme variations which take
place among the seedlings, a small percentage only of which are
possessed of the true character of the parent plant. Stove.--_The
Garden._

[Illustration: NEPHROLEPIS DAVALLIOIDES FURCANS.]

_N. Duffi_.--This pretty, neat-habited species, of which an
illustration, kindly lent us by Mr. Bull, appears in another place, is a
native of the Duke of York's Island, in the South Pacific Ocean, and is
undoubtedly one of the most interesting of the whole genus. Its compact
habit, its comparatively small dimensions, and the bright, glossy color
of its beautifully tasseled fronds render it a most welcome addition to
a group of ferns naturally rich in decorative plants. Its curiously and
irregularly pinnate fronds are borne on slender stalks, terete toward
the base, and covered with reddish brown, downy scales, instead of being
produced loosely, as in most other Nephrolepises; these are densily
crowded, and the outcome of closely clustered crowns. They measure from
15 inches to 18 inches long, and are terminated by very handsome massive
crests, which vary in size according to the temperature in which the
plant is grown. We have at different times heard complaints of these
fronds being simply furcate, when the same plant, after being subjected
to a greater amount of heat and moisture, produced fronds very heavily
tasseled, and partaking of an elegant vase-shaped appearance. In fact,
nothing short of the moist heat of a stove will induce it to show its
characters in their best condition. The pinnæ, which are small, of
different sizes, rounded and serrated at the edges, are produced in
pairs, one overlying the other, and, curiously enough, those on the top
are the largest. The pairs are sometimes opposite, but mostly alternate,
distant toward the base, approximate higher up, and crowded and
quite overlapping in the crested portion of the frond. This, being
a thoroughly barren kind, can only be propagated by division of the
crowns, an operation easily done at any time of the year, but most
safely in early spring and by young plants produced from the rhizomes,
which, however, are produced much more sparingly than in any other
species. It is also one of the best adapted for pot or pan culture, its
somewhat upright habit making it less suitable for baskets, brackets,
and wall covering than other species. Stove.--_The Garden_.

[Illustration: NEPHROLEPIS DUFFI.]

       *       *       *       *       *




FORMATION OF SUGAR.


A paper on "The Formation of Sugar in the Sugar-cane" was recently read
by M. Aimé Girard before the Paris Academy of Sciences. By comparative
investigations of the amount of cane sugar and grape sugar in different
parts of the sugar-cane in the afternoon and before sunrise, the author
has found that only in the substance of the leaves does this quantity
vary, and that the quantity of cane sugar sinks during the night to
one-half, while the quantity of reducing sugar remains almost unaltered.
He finds further that the quantity of sugar-cane in the leaves increases
with the illumination, on very bright days reaching nearly one per
cent., considerably less on dull ones, and in either case diminishing
during the night by one-half. From this the author concludes that the
formation of saccharose from glucose takes place entirely in the leaves
under the influence of sunlight, and that the saccharose thereupon
ascends the cane through the petioles, etc., and collects there.

       *       *       *       *       *

A catalogue, containing brief notices of many important scientific
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PATENTS.


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