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SCIENTIFIC AMERICAN SUPPLEMENT NO. 324




NEW YORK, MARCH 18, 1882

Scientific American Supplement. Vol. XIII, No. 324.

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.    ENGINEERING AND MECHANICS--Machine Tools for Boiler Makers.
      2 figures.--Improved boiler plate radial drill.--Improved
      boiler plate bending roller.

      Modern Ordnance. By COLONEL MAITLAND.--Rifled cannon.--Built
      guns.--Steel castings.--Breech loading.--Long guns.--Slow
      burning of powder.--Breech closers.--Projectiles.--Destructive
      power of guns.

      Oscillating Cylinder Locomotive. 2 figures.--Shaw's oscillating
      cylinder locomotive.

      Gas Motors and Producers. By C. W. SIEMENS--2 figures.

      The Bazin System of Dredging. By A. A. LANGLEY.--3 figures.

II.   CHEMISTRY.--On the Mydriatic Alkaloids. By ALBERT LADENBERG.
      --I. Atropine.--II. The Atropine of Datura Stramonium.
      --III. Hyoscyamine from Hyoscyamus.

      Detection of Small Quantities of Morphia. By A. JORISSEN.

      The Estimation of Manganese by Titration. By C. G. SARNSTROM.

      On the Estimation and Separation of Manganese. By NELSON
      H. DARTON.

      Delicate Test for Oxygen.

      Determination of Small Quantities of Arsenic in Sulphur. By H.
      SCHAEPPI.

III.  BIOLOGY, ETC.--Researches on Animals Containing Chlorophyl.
      --Abstract of a long and valuable paper "On the Nature and Functions
      of the Yellow Cells of Radiolarians and Coelenterates," read
      to the Royal Society of Edinburgh. By PATRICK GEDDES.

      The Hibernation of Animals, An interesting review of the winter
      habits of some of our familiar animals, insects, etc.

IV.   HORTICULTURE, SILK CULTURE, ETC.--How to Plant Trees.
      By N. ROBERTSON.

      The Growth of Palms.

      The Future of Silk Culture in the United States. Report of
      United States Consul Peixotto, of Lyons. A valuable and encouraging
      summary of the conditions and prospects of silk culture
      in the United States.

V.    TECHNOLOGY, ETC.--Compressed Oil Gas for Lighting Cars,
      Steamboats, and Buoys. An elaborate description of the apparatus
      and appliances of the Pintsch system of illumination. 14
      figures. Elevation and plan of works.--Cars.--Locomotive and car
      lamps.--Buoys.--Regulations, etc.

VI.   ART, ARCHITECTURE, ETC.--Cast Iron in Architecture.

VII.  ELECTRICITY, MAGNETISM, ETC.--On the Mechanical Production
      of Electric Currents. 12 figures.

      Rousse's Secondary Battery.

VIII. MISCELLANEOUS.--Dangers from Lightning in Blasting.

      The Tincal Trade of Asia.

      Sir W. Palliser. Obituary and summary of his inventions.

      The Tides. Influence of the tides upon the history of the earth.

      Drilling Glass.

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MACHINE TOOLS FOR BOILER-MAKERS.


We give this week an engraving of a radial drilling machine designed
especially for the use of boiler-makers, this machine, together with the
plate bending rolls, forming portion of a plant constructed for Messrs.
Beesley and Sons, boiler makers, of Barrow-in-Furness.

[Illustration: IMPROVED BOILER PLATERADIAL DRILL.]

This radial drill, which is a tool of substantial proportions, is
adapted not only for ordinary drilling work, but also for turning the
ends of boiler shells, for cutting out of flue holes tube boring, etc.
As will be seen from our engraving, the pillar which supports the radial
arm is mounted on a massive baseplate, which also carries a circular
table 6 ft. in diameter, this table having a worm-wheel cast on it
as shown. This table is driven by a worm gearing into the wheel just
mentioned. On this table boiler ends up to 8 ft. in diameter can be
turned up, the turning tool being carried by a slide rest, which is
mounted on the main baseplate, as shown, and which is adjustable
vertically and radially.

For cutting out flue holes a steel boring head is employed, this head
having a round end which fits into the center of the table. When this
work is being done the radial arm is brought into the lowest position.
Flue holes 40 in. in diameter can thus be cut out.

The machine has a 4 in. steel spindle with self-acting variable feed
motion through a range of 10 in., and the radial arm is raised or
lowered by power through a range of 2 ft. 8 in. When the arm is in its
highest position there is room for a piece of work 4 ft. high between
the circular table and the lower end of the spindle. The circular
table serves as a compound table for ordinary work, and the machine is
altogether a very useful one for boiler-makers.

The plate-bending rolls, which are illustrated on first page, are 10 ft.
long, and are made of wrought iron, the top roll being 12 in. and the
two bottom rolls 10 in. in diameter. Each of the bottom rolls carries
at its end a large spur-wheel, these spur-wheels, which are on opposite
sides of the machine, each gearing into a pinion on a shaft which runs
from end to end below the rolls, and which is itself geared to the shaft
carrying the belt pulleys, as shown. This is a very simple and direct
mode of driving, and avoids the necessity for small wheels on the rolls.
There is no swing frame, but the top roll is arranged to draw through
between the arms of the spur-wheels, a very substantially framed machine
being thus obtained.

[Illustration: IMPROVED BOILER PLATE BENDING ROLLER.]

The chief novelty in the machine is the additional roll provided
under the ordinary bottom rolls. This extra roll, which is used for
straightening old plates and for bending small tubes, pipes, etc., is
made of steel, and is 7 in. in diameter by 5 ft. long. It is provided
with a swing frame at one end to allow of taking-off pipes when bent,
etc., and it is altogether a very useful addition.

The machine we illustrate weighs 11 tons, and is all self-contained, the
standards being mounted on a strong bedplate, which also carries the
bearings for the shaft with fast and loose pulleys, belt gear, etc. Thus
no foundation is required.--_Engineering_.

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MODERN ORDNANCE.

[Footnote: A paper read Feb. 8, 1882, before the Society of Arts,
London.]

By COLONEL MAITLAND.


A great change has lately been taking place throughout Europe in the
matter of armaments. Artillery knowledge has been advancing "by leaps
and bounds;" and all the chief nations are vying with each other in the
perfection of their _matériel_ of war. As a readiness to fight is the
best insurance for peace, it behooves us to see from time to time how we
stand, and the present moment is a peculiarly suitable one for taking
stock of our powers and capabilities. I propose, therefore, to give you,
this evening, a brief sketch of the principles of manufacture of
modern guns, at home and abroad, concluding with a few words on their
employment and power.

The introduction of rifled cannon into practical use, about twenty years
ago, caused a complete revolution in the art of gun-making. Cast iron
and bronze were found no longer suitable for the purpose. Cast iron was
too brittle to sustain the pressure of the powder gas, when its duration
was increased by the use of elongated projectiles; while the softness of
bronze was ill adapted to retain the nicety of form required by accurate
rifling.

From among a cloud of proposals, experiments, and inventions, two
great systems at length disentangled themselves. They were the
English construction of built-up wrought iron coils, and the Prussian
construction of solid steel castings.

Wrought-iron, as you are all aware, is nearly pure iron, containing but
a trace of carbon. Steel, as used for guns, contains from 0.3 to 0.5 per
cent of carbon; the larger the quantity of carbon, the harder the steel.
Since the early days of which I am now speaking, great improvement has
taken place in the qualities of both materials, but more especially in
that of steel. Still the same general characteristics were to be noted,
and it may be broadly stated, that England chose confessedly the weaker
material, as being more under control, cheaper, and safer to intrust
with the lives of men; while Prussia selected the stronger but less
manageable substance, in the hope of improving its uniformity, and
rendering it thoroughly trustworthy. The difference in strength, when
both are sound, is great. Roughly, gun steel is about twice as strong as
wrought iron.

I must now say a few words on the nature of the strains to which a piece
of ordnance is subjected when fired. Gunpowder is commonly termed an
explosive, but this hardly represents its qualities accurately. With a
true explosive, such as gun-cotton, nitro glycerine and its compounds,
detonation and conversion of the whole into gas are practically
instantaneous, whatever the size of the mass; while, with gunpowder,
only the exterior of the grain or lump burns and gives off gas, so that
the larger the grain the slower the combustion. The products consist of
liquids and gases. The gas, when cooled down to ordinary temperature,
occupies about 280 times the volume of the powder. At the moment of
combustion, it is enormously expanded by heat, and its volume is
probably somewhat about 6,000 times that of the powder. I have here a
few specimens of the powders used for different sizes of guns, rising
from the fine grain of the mountain gun to the large prisms and
cylinders fired in our heavy ordnance. You will readily perceive that,
with the fine-grained powders, the rapid combustion turned the whole
charge into gas before the projectile could move far away from its seat,
setting up a high pressure which acted violently on both gun and shot,
so that a short, sharp strain, approximating to a blow, had to be
guarded against.

With the large slow-bursting powders now used, long heavy shells move
quietly off under the impulse of a gradual evolution of gas, the
presence of which continues to increase till the projectile has moved a
foot or more; then ensues a contest between the increasing volume of the
gas, tending to raise the pressure, and the growing space behind the
advancing shot, tending to relieve it. As artillery science progresses,
so does the duration of this contest extend further along the bore
of the gun toward the great desideratum, a low maximum pressure long
sustained.

When quick burning powder was used for ordnance, the pressures were
short and sharp; the metal in immediate proximity to the charge was
called upon to undergo severe strains, which had scarcely time to reach
the more distant portions of the gun at all; the exterior was not nearly
so much strained as the interior. In order to obviate this defect, and
to bring the exterior of the gun into play, the system of building up
guns of successive tubes was introduced. These tubes were put one over
the other in a state of tension produced by "shrinkage." This term is
applied to the process of expanding a tube by the application of heat,
and in that condition fitting it over a tube larger than the inner
diameter of the outer tube when cold. When the outer tube cools it
contracts on the inner tube and clutches it fast. The wrought-iron guns
of England have all been put together in this manner.

Prussia at first relied on the superior strength of solid castings
of steel to withstand the explosive strain, but at length found the
necessity for re-enforcing them with hoops of the same material, shrunk
on the body of the piece.

The grand principle of shrinkage enables the gunmaker to bring into play
the strength of the exterior of the gun, even with quick powders, and to
a still greater extent as the duration of the strain increases with the
progress of powder manufacture. Thus, taking our largest muzzle-loaders
designed a few years ago, the thin steel lining tube, which forms an
excellent surface, is compressed considerably by the wrought-iron breech
coil holding it, which, in its turn, is compressed by the massive
exterior coil. When the gun is fired, the strain is transmitted at once,
or nearly at once, to the breech coil, and thence more slowly to the
outer one. Now, as the duration of the pressure increases, owing to the
use of larger charges of slower burning powder, it is evident that the
more complete and effective will be the transmission of the strain to
the exterior, and, consequently, the further into the body of the
gun, starting from the bore, and traveling outward, does it become
advantageous to employ the stronger material. Hence, in England, we
had reason to congratulate ourselves on the certainty and cheapness
of manufacture of wrought iron coils, as long as moderate charges
of comparatively quick burning powder were employed, and as long as
adherence to a muzzle-loading system permitted the projectiles to move
away at an early period of the combustion of the charge. Then the
pressures, though sharp, were of short duration, and were not thoroughly
transmitted through the body of the gun, so that the solidity, mass,
and compression of the surrounding coils proved usually sufficient to
support the interior lining. Now that breech-loading and slow powders
have been introduced, these conditions have been changed. The strains,
though less severe, and less tending to explosive rupture, last longer,
and are more fully transmitted through the body of the gun. Sheer
strength of material now tells more, and signs have not been wanting
that coils of wrought iron afford insufficient support to the lining.
It becomes, therefore, advantageous to thicken the inner tube, and to
support it with a steel breech piece. Carrying this principle further,
we shall be led to substitute the stronger for the weaker metal
throughout the piece. This has been done by the Germans in the first
instance, and recently by the French also. It is probable that we shall
follow the same course. When I say "probable," I intentionally guard
myself against uttering a prediction. It is never safe to prophesy,
unless you know, as the American humorist puts it. And in this case we
do not know, for a very dangerous rival, once defeated, but now full of
renewed vigor, has entered the lists against forged steel as a material
for ordnance. This rival's name is _wire_. Tempered steel wires can
be made of extraordinary strength. A piece of round section, only one
thirty-fifth of an inch in diameter, will just sustain a heavy man.

If, now, a steel tube, suitable for the lining of a gun, be prepared by
having wire wound round it very tightly, layer over layer, it will be
compressed as the winding proceeds, and the tension of the wire will act
as shrinkage. You will readily understand that a gun can be thus formed,
having enormous strength to resist bursting. Unfortunately, the wires
have no cohesion with one another, and the great difficulty with
construction of this kind is to obtain what gun-makers call end
strength. It is of but little use to make your walls strong enough, if
the first round blows the breech out. In the early days of wire this was
what happened, and Mr. Longridge, who invented the system, was compelled
to abandon it.

Lately, methods have been devised in France, by M. Schultz; at Elswick,
by Sir W.G. Armstrong & Co.; and at Woolwich, by ourselves, for getting
end strength with wire guns. They are all in the experimental stage;
they may prove successful; but I prefer not to prophesy at present.

The diagrams on the wall show the general construction of the modern
German, French, and English heavy breech-loading guns. The Germans have
a tube, a jacket, and hoops. The French, a thick tube or body, and
hoops. The English, a tube, a jacket, and an overcoat, as it may be
called. In each system of construction, the whole of the wall of the gun
comes into play to resist the transverse bursting strain of the charge.

The longitudinal or end strength varies: thus, in the German guns, the
tube and hoops do nothing--the jacket is considered sufficient. The
French construction relies entirely on the thick body, while the English
method aims at utilizing the whole section of the gun, both ways.
Of course, if the others are strong enough, there is no particular
advantage in this; and it is by no means improbable that eventually we
shall find it cheaper, and equally good, to substitute hoops for the
"overcoat."

I fear I have detained you a long time over construction, but it is both
instructive and interesting to note that certain well defined points
of contact now exist between all the great systems. Thus, a surface of
steel inside the bore is common to all, and the general use of steel is
spreading fast. Shrinkage, again, is now everywhere employed, and
such differences as still exist are matters rather of detail than of
principle, as far as systems of construction are concerned.

We now come to a part of the question which has long been hotly debated
in this country, and about which an immense quantity of matter has been
both spoken and written on opposite sides--I mean muzzle loading and
breech-loading. The controversy has been a remarkable one, and, perhaps,
the most remarkable part of it has been the circumstance that while
there is now little doubt that the advocates of breech-loading were on
the right side, their reasons were for the most part fallacious. Thus,
they commonly stated that a gun loaded at the breech could be more
rapidly fired than one loaded at the muzzle. Now, this was certainly not
the case, at any rate, with the comparatively short guns which were
made on both systems a few years ago. The public were acquainted with
breech-loaders only in the form of sporting guns and rifles, and argued
from them. The muzzle-loading thirty eight ton guns were fired in a
casemate at Shoeburyness repeatedly in less than twenty minutes for ten
rounds, with careful aiming. No breech-loader of corresponding size has,
I think, ever beaten that rate. With field-guns in the open, the No. 1
of the detachment can aim his muzzle loader while it is being loaded,
while he must wait to do so till loading at the breech is completed.
Again, it was freely stated that, with breech-loaders greater protection
was afforded to the gunners than with the muzzle-loaders. This entirely
depends on how the guns are mounted. If in siege works or _en
barbette_, it is much easier to load a muzzle loader under cover than a
breech-loader. But I need not traverse the old ground all over again. It
is sufficient for me to say here, that the real cause which has rendered
breech-loading an absolute necessity is the improvement which has been
made in the powder. You witnessed a few minutes ago the change which
took place in the action of fired gunpowder when the grains were
enlarged. You will readily understand that nearly the whole of a quick
burning charge was converted into gas before the shot had time to start;
suppose for the moment that the combustion was really instantaneous.
Then we have a bore, say sixteen diameters long, with the cartridge
occupying a length of, say, two diameters.

The pressure of the gas causes the shot to move. The greater the
pressure, the greater the impulse given. As the shot advances, the
pressure lessens; and it lessens in proportion to the distance the shot
proceeds. Thus, when the shot has proceeded a distance equal to the
length of the cartridge, the space occupied by the gas is doubled, and
its original pressure is halved. As the shot travels another cartridge
length, the space occupied by the gas is trebled, and its pressure will
be but one-third of the original amount. When the shot arrives at the
muzzle--that is, at eight times the length of the cartridge from the
breech--the pressure will be but one ninth of that originally set up.
Remember, this is on the supposition that the powder has been entirely
converted into gas before the shot begins to move.

Now, suppose the powder to be of a slow-burning kind, and assume that
only one-third of it has been converted into gas before the shot starts,
then the remaining two-thirds will be giving off additional gas as the
shot travels through the bore. Instead, therefore, of the pressure
falling rapidly, as the shot approaches the muzzle, the increasing
quantity of gas tends to make up for the increasing space holding it.
You will at once perceive that the slower the combustion of the powder
the less difference there will be in the pressure exerted by the gas at
the breech and at the muzzle, and the greater will be the advantage,
in point of velocity, of lengthening the bore, and so keeping the shot
under the influence of the pressure. Hence, all recent improvement has
tended toward larger charges of slower burning powder, and increased
length of bore. And it is evident that the longer the bore of the gun,
the greater is the convenience of putting the charge in behind, instead
of having to ram it home from the front. I may here remark, that the
increased length of gun necessary to produce the best effect is causing
even those who have possessed breech-loaders for many years to rearm,
just as completely as we are now beginning to do. All the old short
breech loading guns are becoming obsolete. Another great advantage of
breech-loading is the facility afforded for enlarging the powder chamber
of the gun, so that a comparatively short, thick cartridge may be I
employed, without any definite restriction due to the size of the bore.

There is yet one more point in which breech-loading has recently been
found, in the Royal Gun Factory, to possess a great advantage over
muzzle-loading as regards ballistic effect. With a shot loaded from the
front, it is clear that it must be smaller all over than the bore, or it
would not pass down to its seat. A shot thrust in from behind, on the
contrary, may be furnished with a band or sheath of comparatively soft
metal larger than the bore; the gas then acting on the base of the
projectile, forces the band through the grooves, sealing the escape,
entering the projectile, and, to a great extent, mitigating the erosion
of surface. This is, of course, universally known. It is also pretty
generally known among artillerists that the effect of the resistance
offered by the band or sheathing on the powder is to cause more complete
combustion of the charge before the shot moves, and therefore to raise
the velocity and the pressure. But I believe it escaped notice, till
observed in May, 1880, in the Royal Gun Factory, that this circumstance
affords a most steady and convenient mode of regulating the consumption
of the charge, so as to obtain the best results with the powder
employed.

Supposing the projectile to start, as in a muzzle loader, without
offering any resistance beyond that due to inertia, it is necessary to
employ a powder which shall burn quickly enough to give off most of
its gas before the shot has proceeded far down the bore; otherwise the
velocity at the muzzle will be low. To control this comparatively quick
burning powder, a large air space is given to the cartridge, which,
therefore, is placed in a chamber considerably too big for it.
Supposing, on the other hand, the projectile to be furnished with a
stout band, giving a high resistance to initial motion, a much slower
powder can be used, since the combustion proceeds as if in a closed
vessel, until sufficient pressure is developed to overcome the
resistance of the band. This enables us to put a larger quantity of
slower burning powder into the chamber, and in fact to use, instead of a
space filled with air, a space filled with powder giving off gas, which
comes into play as the projectile travels down the bore. Thus, while not
exceeding the intended pressure at the breech, the pressure toward the
muzzle is kept up, and the velocity very materially increased. Following
this principle to this conclusion, it will be found that the perfect
charge for a gun will be one which exactly fills the chamber, and which
is composed of a powder rather too slow to give the pressure for which
the gun is designed, supposing the shot to move off freely. The powder
should be so much too slow as to require for its full development the
holding power of a band which is just strong enough to give rotation to
the shot.

Having settled that the gun of the future is to be a breech-loader,
we have next to consider what system of closing the breech is to be
adopted.

The German guns are provided with a round backed wedge, which is pushed
in from the side of the breech, and forced firmly home by a screw
provided with handles; the face of the wedge is fitted with an easily
removable flat plate, which abuts against a Broad well ring, let into
a recess in the end of the bore. On firing, the gas presses the ring
firmly against the flat plate, and renders escape impossible as long as
the surfaces remain uninjured. When they become worn, the ring and
plate can be exchanged in a few minutes. Mr. Vavasseur, of Southwark,
constructs his guns on a very similar plan. In the French guns, and our
modern ones, the bore is continued to the rear extremity of the piece,
the breech end forming an intermittent screw, that is, a screw having
the threads intermittently left and slotted away. The breech block has
a similarly cut screw on it, so that when the slots in the block
correspond with the untouched threads in the gun, the block can be
pushed straight in, and the threads made to engage by part of a
revolution. In the French Marine the escape of gas is stopped very much
as in Krupp's system; a Broadwell ring is let into a recess in the end
of the bore, and a plate on the face of the breech-block abuts against
it.

In the French land service the escape is sealed in quite a different
manner. A stalk passes through the breech-block, its foot being secured
on the exterior. The stalk has a mushroom-shaped head projecting into
the bore. Round the neck of the stalk, just under the mushroom, is a
collar of asbestos, secured in a canvas cover; when the gun is fired,
the gas presses the mushroom against the asbestos collar, and squeezes
it against the walls of the bore. It is found that this cuts off all
escape.

We are at present using the Elswick method, which consists of a
flat-backed cup, abutting against the slightly rounded face of the
breech plug. The lips of the cup rest against a copper ring let in the
walls of the bore. On firing, the gas presses back the cup against the
rounded end of the breech-block, and thus forces the lips hard against
the copper ring.

It is difficult to compare the excellence of these various systems, so
much depends on the care of the gunners, and the nicety of manufacture.
The German and French marine methods permit the parts to be quickly
exchanged when worn, but it is necessary to cut deeply into the walls
of the gun, and to make the wedge, or breech-screw, considerably larger
than the opening into the chamber.

The Elswick plan is decidedly better in this last respect, but it
requires several hours to extract and renew the copper ring where worn.

The French land service (_De Bange_) arrangement requires no cutting
into the gun, and no enlargement of the breech screw beyond the size of
the chamber, while it is renewable in a few minutes, merely requiring a
fresh asbestos pad when worn. As regards durability, there is probably
no great difference. I have been informed that with a light gun as many
as 3,000 rounds have been fired with one asbestos pad. But usually
it may be considered that a renewal will be required of the wearing
surfaces of any breech-loader after a number of rounds, varying from six
or seven hundred, with a field gun, to a hundred or a hundred and fifty
with a very heavy gun. Full information is wanting on this point.

Having now decided on the material of which the gun is to be composed,
and the manner in which it is to be constructed, and having, moreover,
settled the knotty point of how it is to be loaded, we come to the
general principles on which a gun is designed. It must not be overlooked
that a gun is a machine which has to perform a certain quantity of work
of a certain definite kind, and, like all other machines, must be formed
specially for its purpose. The motive power is gunpowder, and the
article to be produced is perhaps a hole in an armor-plate, perhaps a
breach in a concealed escarp, or perhaps destructive effect on troops.
These articles are quite distinct, and though all guns are capable of
producing them all to some extent, no gun is capable of producing more
than one in the highest state of excellence.

Thus, for armor piercing, a long pointed bolt, nearly solid, is
required. It must strike with great velocity, and must therefore be
propelled by a very large charge of powder. Hence an armor-piercing gun
should have a large chamber and a comparatively small bore of great
length.

For breaching fortifications, on the other hand, curved fire is
necessary; the escarps of modern fortresses are usually covered from
view by screens of earth or masonry in front, so that the projectiles
must pass over the crest of the screen, and drop sufficiently to strike
the wall about half-way down, that is to say, at an angle of 15° to 20°.
To destroy the wall, shell containing large bursting charges of powder
are found to be particularly well adapted. Now it is clear that, for a
shell to drop at an angle of 15° or 20° at the end of a moderate range,
the velocity at starting must be low. Hence, for pieces intended for
breaching no enlarged powder chamber is wanted; the effect on the wall
is due to the shell, which must be made of a shape to hold the most
powder for a given weight; and, therefore, rather short and thick. This
gives us a large bore, which need not be long, as little velocity is
required.

For producing destructive effect among troops, a third kind of
projectile is employed. It is called shrapnel, and it consists of a thin
shell, holding a little powder and a large quantity of bullets. The
powder is ignited by a fuse, which is set to act during flight, or on
graze, when the shell is nearing the object. The explosion bursts the
shell open, and liberates the bullets, which fly forward, actuated by
the velocity of the shell at the moment of bursting. Hence, to render
the bullets effective, a considerable remaining velocity is requisite.
The gun must therefore take a large powder charge, while, as the shell
has to hold as many bullets as possible, the bore must be large enough
to take a short projectile of the given weight. Thus, the proportions
of the shrapnel gun will be intermediate between those of the
armor-piercing gun and the shell gun.

There are certain axioms known from experience, which should be
mentioned here. First, the length of the powder chamber should not
be more than three and a half or four times its diameter, if it can
possibly be avoided, because, with longer charges, the inflamed powder
gas is apt to acquire rapid motion, and to set up violent local
pressures. Next, the strength of a heavy gun, as reckoned on the
principle of all the metal being sound and well in bearing, should not
be less than about four times the strain expected.

Again, though there are several opinions as to the best weight of shot
for armor piercing, in proportion to diameter, yet among the most
advanced gun-makers, there is a growing tendency toward increased
weight. The value of w/d³, that is, the weight in pounds divided by the
cube of the diameter in inches, as this question is termed, is in the
hands of the Ordnance Committee, and it is to be confidently hoped that
efforts will shortly be made to arrive at a solution. In the meantime,
from about 0.45 to 0.5 appears to be a fairly satisfactory value, and is
adopted for the present.

Lastly, it may be broadly stated, that with suitable powders, a charge
of one-third the weight of the shot demands for most profitable use a
length of bore equal to about twenty-six calibers; a charge equal to
half the weight of the shot should be accommodated with a bore of about
thirty calibers; while a charge of two-thirds the weight of the shot
will be best suited by a bore thirty-five calibers long. Of course, in
each case, greater length of bore will give increased velocity, but it
will be gained at the expense of additional weight, which can be better
utilized elsewhere in the gun.

The amount of work performed by gunpowder, when exploded in a gun, is a
subject which has engaged a vast quantity of attention, and some highly
ingenious methods of calculating it have been put forward. Owing,
however, to the impossibility of ascertaining how fast the combustion
of large grains and prisms proceeds, a very considerable amount of
experience is required to enable the gunmaker to apply the necessary
corrections to these calculations; but, on the whole, it may be said
that, with a given charge and weight of shot, the muzzle velocity may
now be predicted with some accuracy.

You now have the chief data on which the designer bases his proposals,
and lays down the dimensions of the gun to suit such conditions as it
may be required to fulfill. In actual practice, the conditions are
almost always complicated, either by necessities of mounting in
particular places, such as turrets and casemates; or by the advantages
attending the interchangeability of stores, or other circumstances;
and it requires great watchfulness to keep abreast of the ever-growing
improvements of the day.

I will now conclude with a few words on the power of heavy guns, when
employed in various ways. The first consideration is accuracy of fire.
No matter how deadly the projectile may be, it is useless if it does
but waste itself on air. Accuracy is of two kinds--true direction and
precision of range. All modern guns are capable of being made to shoot
straight; but their precision of range depends partly on the successful
designing of the gun and ammunition, so as to give uniform velocities,
and partly on the flatness of the trajectory. The greater the velocity,
the lower the trajectory, and the greater the chance of striking the
target. Supposing a heavy gun to be mounted as in the fortresses round
our coasts, and aimed with due care, the distance of the object being
approximately known, we may fairly expect to strike a target of the size
of an ordinary door about every other shot, at a range of a mile and a
half. Here we have carriages mounted on accurately leveled platforms; we
have men working electric position finders, and the gunners live on the
spot, and know the look of the sea and land round about.

Now, consider the case of guns mounted in ships. You at once perceive
the difficulties of the shooter. Even supposing the ship to be one of
our magnificent ironclads, solid, steady, yielding little to the motion
of the water, yet she is under steam, the aim of her guns is altered
every moment, some oscillation is unavoidable, and she can only estimate
the range of her adversary. Great skill is required, and not only
required, I am glad to say, but ready to hand, on the part of the seamen
gunners; and low trajectory guns must be provided to aid their skill.

If we go to unarmored ships of great tonnage and speed, we shall
find these difficulties intensified; and if we pass on to the little
gunboats, advocated in some quarters for attacking ironclads in a swarm,
we shall find that unsteadiness of platform in a sea-way renders them a
helpless and harmless mark for the comparatively accurate practice of
their solitary but stately foe.

The destructive power of guns is little known to the general public, and
many wild statements are sometimes put forward. Guns and plates have
fought their battle with varying success for many years. One day the
plate resists, another day the gun drives its bolt through. But it is
frequently overlooked that the victory of a plate is a complete victory.
If the shot does not get through, it does practically nothing. On the
other hand, the victory of the gun is but a partial triumph; it is
confined to a small arc. I mean that, when the plate is struck at an
angle exceeding 30° or so, the shot glances harmlessly off; while, even
when perforation is obtained, it is at the expense of the more deadly
qualities of the projectile, which must be a nearly solid bolt, unable
to carry in with it heavy bursting charges of powder or destructive
masses of balls.

About six years ago, an experiment carried out at Shoeburyness taught a
lesson which seems to be in danger of being forgotten. We hear sometimes
that unarmored vessels are a match for ironclads and forts; and I will
conclude this paper with a short extract from the official account of
the results of firing shrapnel shell at an unprotected ship's side. I
shall say nothing of boilers and magazines, but shall state simply the
damage to guns and gunners.

A target was built representing the side of a certain class of unarmored
ships of war; behind this target, as on a deck, were placed some
unserviceable guns, mounted on old carriages, and surrounded by wooden
dummies, to represent the men working the guns. The attacking gun was a
twelve-ton nine-inch muzzle-loader, of the old despised type, and the
projectiles were shrapnel shell. The charges were reduced to represent
the striking force at a range of 500 yards. Two rounds did the following
damage inside, besides tearing and ripping the ship's side in all
directions.

1st Gun.--Seven men of detachment killed.

2d Gun.--Carriage destroyed. Six men blown to pieces, all the remainder
of the detachment severely hit.

3d Gun.--No damage to gun or carriage. Five men killed, one blown to
bits, and one wounded in leg.

4th Gun.--Gun dismounted. The whole of the gun detachment blown to
pieces.

That is the amount of destruction achieved in an unarmored ship by two
rounds of shrapnel shell.

       *       *       *       *       *




OSCILLATING CYLINDER LOCOMOTIVE.


This locomotive is the design of Mr. Henry F. Shaw, of Boston.

This engine has oscillating cylinders placed between the driving-wheels.
Fig. 2 represents a section of one of these cylinders, from which it
will be seen that each has two pistons and piston-rods, which are
connected directly to the crank-pins. His invention is described as
follows in his specification:

"Midway between each set of wheels, e and f, is located the oscillating
steam-cylinder, g, having its journals, g' and g", supported in the
stationary arm, h, which is secured in a suitable manner to the frame,
c. To each cylinder, g, is secured or cast in one piece therewith a
balanced vibratory beam or truss, i, as shown. Within the cylinder, g,
are two movable pistons, k and k', Fig. 2, provided with piston-rods, l
and l', and cross-heads, m and m', as shown.

"n n are slides for the cross-head, m, on the insides of one end of the
truss or beam, i, and n' n', are similar slides in the other end of
said truss or beam, for the cross-head, m'. To the driving-wheel, e,
is attached a crank-pin, passing through the cross-head, m, and to the
driver-wheel, f, is attached a similar crank-pin, F, that passes through
the cross-head, m'. o is the slide-valve within the steam-chest,
G, which slide-valve is operated forward and back by means of the
valve-rod, o¹, the outer end of which is hinged to the upper end of
the slotted lever, o², Fig. 1, that is hung at o³, on the end of the
balanced and vibratory beam of truss, i, as shown. On the crank, F, is
secured an eccentric, that works within the slot of the slotted lever,
o², during the revolution of the crank, F, and in this manner imparts
the requisite motion to the slide valve, o, to admit the steam into the
cylinder, g, alternately between the pistons, k and k', and at the ends
of said cylinder, g, so as to alternately force the pistons, k and k',
from and toward each other, and thus, in combination with the vibratory
motion of the truss, i, impart a rotary motion to the driving-wheels, e
and f.

[Illustration: SHAWS OSCILLATING CYLINDER LOCOMOTIVE.]

"The steam is admitted to and from the cylinder, g, as follows: When
the pistons, k and k', are at the outer ends of their stroke the steam
enters through the channel, p, back of the piston, k, and at the same
time through the channel, p', back of the piston, k', and thus causes
both pistons to move toward each other, the steam between them being
at the same time exhausted through the channels, q and q', the former
communicating with the exhaust, r, by means of the space, s, in the
valve, o, and the latter communicating with the exhaust, r', through the
channel, s', in the said valve, o. The steam that passes to the back of
the piston, k, comes direct from the steam-chest, G, through the open
end of the channel, p, the valve, o, being at this time moved to one
side to leave the port, p, open. The steam is admitted to the back end
of the piston, k', from the steam-chest, G, through the channel, s", in
the valve, o, and from thence to the channel, p'. When the pistons, k
and k', have reached their inner positions the live steam is admitted
through the channels, q and q', direct from the steam-chest, G, to the
former, and through the recess, s³, and channel, s', in the valve, o, to
the latter, the exhaust steam back of the piston, K, passing out through
the channel, p, to the recess, s, in the valve, o, and thence to the
exhaust, r, the exhaust steam back of the piston, k, passing out through
channel, p', and through channel, s", in the valve, o, and thence to the
exhaust, r'.

"The valve-rod, o', is to be connected to a link and reversing lever as
usual, such being, however, omitted in the drawings."

The advantages claimed for it are that "it is composed of very few
parts, and it is very powerful on account of its having a separate steam
actuating piston for each of its driving-wheels. It has great strength
and resistance, owing to the fact that no pressure is exerted on the
journals on which the steam cylinders oscillate, and all the pressure
from the steam pistons is directly transferred to the crank-pins on the
driving-wheels. The engine is perfectly balanced in any position during
the stroke, and it may therefore be run at a much higher speed than the
common engines now in use."

       *       *       *       *       *




GAS MOTORS AND PRODUCERS.

By C.W. SIEMENS, London.


The cylinder of the engine--assuming that it has only a single-acting
one, placed with its axis vertical--consists of two parts; the upper hot
part being lined with plumbago, fire-clay, or other refractory material,
and the lower part kept cool by a water casing. The cylinder has a trunk
piston working in the lower part, and on its upper side a shield that
almost fills the hot part of the cylinder when the piston is at the
extreme of its upstroke. The trunk-rod of the piston passes through a
stuffing-box in the cylinder bottom, and is connected to a crank on the
engine-shaft; and this (unless multiple cylinders are employed) carries
a heavy fly-wheel. From the lower end of the cylinder there is a passage
which, by means of a rotating or reciprocating slide, is alternately
put in communication with inlets for gas and air (regulated by suitable
cocks or valves) and with a strong receptacle. As the piston, makes its
upstroke, air and gas are drawn into the annular space surrounding its
trunk, and the mixed air and gas are compressed by the downstroke of
the piston, and delivered into the receptacle, in which considerable
pressure is maintained. The receptacle is made of cylindrical form, with
a domed cover of thin sheet metal; so that in case of excessive internal
pressure it can operate as a safety-valve to save the body of the
receptacle from damage. From the upper end of the cylinder there is
a passage that, by means of a rotating or reciprocating slide, is
alternately put in communication with the receptacle and with a
discharge outlet. In this passage are fixed a number of wire gauze
screens or pieces of metal with interstices. These constitute a
regenerator of heat, and also prevent a communication of flame from the
cylinder to the receptacle. In the upper end of the cylinder or of the
piston shield are provided electrodes which give an electric spark, or
a platinum wire which is rendered incandescent by a current from an
inductor or other source of electricity to ignite the combustible charge
of the cylinder. After the engine has been for some time at work,
the heat at the upper part of the cylinder may suffice for effecting
ignition without provision of other means for this purpose.

In combining such an engine with means for generating the combustible
gas, a gas producer is employed. In this producer a current of heated
air is introduced into the heart of a body of kindled fuel, and
the gases produced--partly by distillation and partly by imperfect
combustion of the fuel--are conveyed to the gas inlet of the cylinder
or pump of the engine. As the gas in leaving the producer is hot, it is
caused to pass through regenerating apparatus, to which it delivers a
large portion of its heat before it reaches the engine, and the air
which supplies the producer is made to pass through this regenerating
apparatus so as to take up the heat abstracted from the gas.

In the accompanying engravings, Fig. 1 shows a front elevation (partly
in section) of a pair of engines constructed according to this
invention. The lower part, A, of each cylinder is cooled by water
circulating through its casing. The upper part, B, is lined with
refractory material, such as fire-clay. The trunk piston, C, is made
hollow, and formed with a shield covered by refractory material to
protect the packing of the piston and the surface of the lower part of
the cylinder from heat. The pistons of the two cylinders are connected
by rods, D, to opposite cranks on the shaft, E. This shaft, by means of
bevel gear, F, works a revolving cylindrical valve, G, situated in a
casing between the two cylinders. The lowest part of this casing is
supplied with combustible gas and with air, in proportions capable of
being regulated by stopcocks or valves. The highest part of the casing
communicates with a discharge-pipe; and the middle part of it with a
reservoir which can be cut off from communication by a stopcock, so that
the charge in the reservoir may be retained when the engine is stopped.
The middle space of the hollow valve, G, communicates, by a number of
holes, with the middle space of the slide casing. It also, by means of a
port at its lower part, communicates alternately with the annular spaces
of the two cylinders; this communication in each case being made when
the piston is performing the latter part of its downstroke. The interior
of the slide also, by means of a second port at its upper part,
communicates alternately with the tops of the two cylinders; this
communication being in each case made while the piston is performing the
first portion of its downstroke. During the upstroke of each piston the
slide, by means of another port, makes communication alternately to each
cylinder from the bottom of the slide casing, and by means of a fourth
port make communication alternately from each cylinder to the top of the
slide casing. In the passage connecting the top of the slide casing
to each cylinder is placed a regenerator, consisting of a number of
perforated metal plates or sheets of wire gauze.

[Illustration: SIEMENS' GAS PRODUCER AND GAS MOTOR. Fig 1.]

In order that gas of poor quality or gas diluted with a large proportion
of air may be utilized, an igniting arrangement is employed which
operates as follows: I is a vessel containing a supply of hydrocarbon
oil, preferably of volatile character. From this vessel pipes lead to
two cocks, one for each cylinder; these corks being caused to revolve in
time with the engine-shaft by a chain, M, communicating motion from a
wheel on the engine shaft to a chain-wheel of equal size on the spindle
of the two cocks. The plug of each cock has on its side a small hollow,
which during one part of its revolution presents itself under the
oil-pipe, and receives a charge of oil. During another part of its
revolution, which is timed to correspond with the flow of gaseous
mixture to the cylinder, the hollow of the plug presents itself to the
bend of a pipe leading from the top of the cylinder to a port opening
into the cylinder below the regenerator, in which port are situated
two wires of platinum. These wires are connected with the brushes of a
commutator, K, on the engine-shaft, which commutator is in electrical
connection with the poles of a battery, dynamo-electric machine, or
other source of electricity. Instead of two wires to produce a spark, a
single wire may be arranged to become incandescent at the proper time
for ignition.

The operation of the engine is as follows: Each piston as it ascends
draws into the annular space under it a supply of gas and air in
proportion regulated by the cocks or valves, and as it descends it
forces this charge into the interior of the revolving valve and its
casing, and into the reservoir which communicates therewith. When either
piston is at the top of its stroke, the revolving valve admits to the
upper part of the cylinder a supply of the gaseous mixture from the
reservoir and valve casing, and this passes through the generator. At
the same time a portion of the charge passes by the pipe, and becomes
enriched by admixture of the hydrocarbon oil delivered to it by the
cock. The enriched mixture, in passing the platinum wires, which at that
time give an electrical spark, is ignited, and ignites the charge that
is passing through the regenerator into the cylinder. The mixture thus
ignited expands, and acting on the full area of the piston propels it
downward, the under side of the piston being at that time subject to
pressure only on its annular area. When the piston has completed its
down-stroke the passage is opened to the discharge-pipe, and the
expanded products of combustion then pass from the cylinder through the
regenerator, and are discharged. In their passage they give out to the
regenerator a large portion of their heat, which the charge entering
the cylinder for the next stroke receives in passing through the
regenerator.

[Illustration: SIEMENS' GAS PRODUCER AND GAS MOTOR. Fig 2.]

Fig. 2 is a vertical section of a gas producer and scrubber, which, as
stated above, may be employed in combination with engines such as have
been described for supplying them with combustible gas. The producer
is a vessel lined with refractory material. At the top it has a supply
opening covered by a cap, U, having a flange dipping into a sand joint.
At the bottom it has an opening surrounded by inclined bars, V, which
rest upon a water-pipe perforated with small holes, by which water
issues to cool the bars and generate vapor. This vapor rises along
with a limited supply of air through the incandescent fuel above, and
combustible gas is produced, which collects in the annular space, and
is led thence by a pipe to the scrubber. The scrubber is a vessel
containing in its lower part water, W, supplied by a pipe, and having an
overflow. By means of a perforated deflecting plate the gas is caused
to bubble through the water, whereby it is cleansed and cooled, and it
passes by a pipe, X, to supply the engine. The upper end of the vertical
pipe of the scrubber is made open and covered by a cap sealed in water
while the producer is at work. In starting the producer this cap is
removed and a chimney pipe put in its place, so as to give a draught for
kindling the fuel in the producer. When the fuel is kindled the chimney
is removed and the cap substituted, whereupon the suction of the engine
continues the draught as required.

       *       *       *       *       *




THE BAZIN SYSTEM OF DREDGING.

By MR. A.A. LANGLEY.


This paper, lately read before the Institution of Mechanical Engineers,
London, is a description of the construction and working of a dredger
on M. Bazin's system, as used by the author for the past three years in
dredging sand and other material in Lowestoft Harbor. The dredger is
represented in its general features on next page, Fig. 1. The total
length of the hull is 60 ft., with 20 ft. beam. In the after part of the
hold is placed a horizontal boiler, A, which supplies steam to a pair
of inverted vertical engines, B. These engines drive, through belts and
overhead pulleys, a centrifugal pump, C, which discharges into the open
trough, H. The suction pipe, D, of this pump passes through the side of
the dredger, and then forms an elbow bent downward at an angle of 45
deg. To this elbow is attached a flexible pipe, E, 12 in. in diameter
and 25 ft. long, made of India-rubber, with a coil of iron inside
to help it to keep its shape. At the lower end of this pipe is an
elbow-shaped copper nozzle which rests on the bottom, and is fitted with
a grating to prevent stones getting into the pump and stopping the work.
The flexible tube is supported by chains that pass over the head of a
derrick, F, mounted at the stern of the dredger, and then round the
barrel of a steam winch. By this means the depth of the nozzle is
altered, as required to suit the depth of water.

A man stands at the winch, and lifts or lowers the pipe as is required,
judging by the character of the discharge from the pump. If the liquid
discharged is very dark and thick the nozzle is too deep in the sand
or gravel; if of a light color the pipe must be lowered. The best
proportion of water to sand is 5 to 1. When loose sand is the only
material to be dealt with, it can be easily sucked up, even if the
nozzle is deeply buried; but at other times stones interfere with the
work, and the man in charge of the flexible tube has to be very careful
as to the depth to which the nozzle may be buried in the sand. The pump
is shown in Figs. 2 and 3. The fan is 2 ft. diameter, and has only two
blades, a larger number being less efficient. The faces of the blades,
where they come in contact with the sand, are covered with flaps of
India-rubber. Small doors are provided at the side of the pump for
cleaning it out, extracting stones, etc. The fan makes 350 revolutions
per minute, and at that speed is capable of raising 400 tons of sand,
gravel, and stones per hour, but the average in actual work may be taken
at 200 tons per hour. This is with a 10-horse power engine, and working
in a depth of water varying from 7 ft. to 25 ft. The great advantage of
this dredger is its capability of working in disturbed water, where the
frames of a bucket dredger would be injured by the rise and fall of the
vessel.

[Illustration: THE BRAZIN SYSTEMEM OF DREDGING.]

Thus at Lowestoft bucket dredgers are used inside the harbor, and the
Bazin dredger at the entrance, where there are sand and gravel, and
where the water is more disturbed. The dredger does not succeed very
well in soft silt, because, owing to its slow precipitation, it runs
over the sides of the hopper barges without settling. Nor does it do for
dredging solid clay. It gives, however, excellent results with sand and
gravel, and for this work is much superior to the bucket dredger. The
experience in working was then described, showing that a great many very
discouraging failures preceded successful working, about a year being
expended in getting good results.


COST OF WORKING.

The vessel or barge for carrying the machinery and pumps cost £600, and
the contract price of the machinery and pumps was £1,200. But before the
dredger was taken over by the company the alterations before enumerated
had cost about £300, bringing the total for barge and dredger up to
£2,100. In building a second dredger this might of course be greatly
reduced. The cost of repairs for one month's working has been only £5.
The contractor receives for labor alone 1-1/8d. per ton, being at the
rate of about 1¾d. for the dredging and 3/8d. for taking to sea--a lead
of two miles--all materials being supplied to him. The consumption of
coal is at the rate of about 1 ton for 1,000 tons of sand dredged. At
Lowestoft Harbor the total amount of dredging has been about 200,000
tons yearly, but this is now much reduced in consequence of the pier
extension recently constructed by the author, which now prevents the
sand and shingle from the sea blocking the mouth of the harbor. The
total cost of working has been 2.572d. per ton. which with 10 per cent
interest on capital, 0.240d., makes the total cost per ton 2.812d. The
repairs to steam tug, hopper, barges, and dredger have averaged about
2d. per ton.

Before the discussion on the paper commenced, Mr. Langley remarked that
attempts had been made to connect the engine direct to the pump of a
Bazin dredger, but this arrangement failed, and the belt acted as a
safety arrangement and prevented breakage by slipping when the pump was
choked in any way. A new lock was constructed near Lowestoft a short
time ago, and the dredger pump was used to empty it; when half empty the
men placed a net in front of the delivery pipe and caught a cartload of
fish, many of which where uninjured. In the discussion Mr. Wallick, who
had superintended the use of the dredger at Lowenstoft, gave some of his
experience there, and repeated the information and opinions given by Mr.
Langley in the paper.

Mr. Ball, London agent for M. Bazin, said that as devised by M. Bazin
the pump was placed below water level, so that the head of water outside
should be utilized; but he--Mr. Ball--now placed the pump considerably
above water level, as no specially formed craft was thus necessary. He
also described some of the steps by which he had arrived at the present
arrangements of the whole plant, and gave some particulars of its
working. Mr. Crampton asked some questions, in reply to which Mr. Ball
said the longest distance they had carried the material was 1,200 yards
in two relays--namely, a second pump on a floating barge with special
engine. The distance to which they could carry the material depended
upon its character. Fine sand would travel well; mud would not, bowlders
would not, though gravel would. To give the water a rotary motion he had
inserted a helical piece of angle iron, and so prevented deposition.

       *       *       *       *       *




DANGER FROM LIGHTNING IN BLASTING.


Although the accident in the tunnel in process of construction at Union
Hill by the New York, Ontario, and Western Railroad Company, which took
place on Tuesday afternoon, was happily attended with no loss of life or
serious injuries to the men employed in the shaft, it reads a new lesson
as to the firing of charges of powder by electricity, and one that
should be carefully noted by railway and civil engineers, and even
by the torpedo service of the United States. The exact cause of the
explosion has scarcely been fully and accurately set forth by the
various reports of the affair.

It appears that the wires usually employed lo supply the electric lamps
in the excavation were used for the purpose of firing the charges, being
disconnected from the electric light system for the moment and connected
with the explosives. As a rule, six charges were fired together, those
of the afternoon relay of men being exploded at very regular hours--the
last usually at 5:45 P.M. There were only sixteen men in the shaft,
and the work of connecting the wires had commenced, when the flash of
lightning that occurred at 5:42 P.M., suddenly charged the conductors
and produced the explosion.

There were two flashes of lightning between the hours of 5 and 6 o'clock
Tuesday afternoon, the first taking place at 5:23, and the second
nineteen minutes later. The former, according to testimony elicited by
our reporter, simply caused a slight perturbation of the lights in the
tunnel, but did not extinguish them. Five minutes later the work of
disconnection and reconnection began, but only two of the six charges
were ready for the pressure of the button when the last flash
interrupted the proceedings. The fact that the time of the explosion
corresponded to the second with that of the aerial electrical discharge
furnishes indubitable evidence that the accident was not caused by any
carelessness on the part the electrician in charge, and exonerates
all parties from blame. At the same time it should be remembered by
engineers in of such work that atmospheric electricity cannot be
altogether disregarded in such cases, and that as a source of accident
it may at any time prove dangerous. The concurrence of circumstances on
Tuesday was particularly fortunate. In the first instance only two of
the six charges had been connected with the firing battery, and in the
second the rock in which the charges were inserted was so peculiarly
soft and porous as to deaden the force of the eight pounds of giant
powder thus prematurely set off. Had the cartridges been set in the
harder and more solid rock of the east heading, instead of the west, and
the explosion taken place there, probably not a man in the shaft would
have escaped destruction. The lesson to engineers is one of no less
importance than if the whole number of men had been killed, and should
lead to the exercise of great care and precaution at times when the air
is charged with electrical energy.--_New York Times_.

       *       *       *       *       *



CAST IRON IN ARCHITECTURE.


Whatever may be the misgivings entertained by many engineers respecting
the future use of cast iron for structures of certain kinds, it is clear
that for architectural purposes this material is likely to be employed
to an extent hardly contemplated by many who have looked upon it with
disfavor. At the present moment many buildings may be seen in London, in
which cast iron has been introduced instead of stone for architectural
features, and the substitution of cast iron for façades in many
warehouses and commercial buildings seems to show that, notwithstanding
the prejudices of the English architect against the importation of the
iron architecture of our transatlantic brethren, there is a prospect of
its being largely employed for frontages in which ample lighting and
strength are needed. The extensive window space necessary in narrow city
thoroughfares, and the difficulty of employing brick in large masses,
such as pilasters and lintels, have chiefly led to the adoption of
material having less of the uncertain durability and strength of either
stone or terra-cotta in its favor. Architects would gladly resort to the
last-named material if it could be procured in sufficient size and mass
without the difficulties attendant upon shrinkage in the burning, and
the winding and unevenness of the lines thereby caused. They have also
an even more tractable material in concrete ready to their hand, if they
would seriously bring themselves to the task of stamping an expressive
art upon it, instead of going on designing concrete houses as if they
were stone ones. Cast iron has the advantage of being a tried material;
it is well adapted for structures not liable to sudden weights or
to vibration, and so it has come to be used for features of an
architectural kind, by a sort of tacit acknowledgment in its favor.
Those who are desirous of seeing examples of its employment in fronts
of warehouses will find instances in Queen Victoria Street, Southwark
Street, and Bridge Road, and Theobalds Road, where the whole or portions
of fronts have been constructed of cast iron. At some corner premises in
Southwark, the piers as well as the windows are formed of cast iron,
the former being made to assume the appearance of projecting pilasters.
There is nothing to which the most captious critic could object in the
treatment adopted here; the pilasters and other features have plain
moulded members, and there is no principle of design in cast work which
has been violated--the only question being the purely aesthetic one--is
it justifiable to copy features in cast iron which have generally been
constructed in stone or marble? The answer is obvious: Certainly not,
when those features suggest the mass and proportions or treatment
proper only for stone or marble; but when they do not so represent the
material, it is quite optional for the architect to build up his front
with castings, if by so doing he can obtain greater rigidity of bearing,
strength, and durability. He ought, of course, to vary the proportions
of his pilasters and horizontal lintels, and make them more in accord
with the material. It is the wholesale reproduction of the more costly
and ornamental features, such as we see in many buildings of New York
and Philadelphia, where whole fronts are manufactured of cast iron and
sheet-metal, which has shocked the minds of architects of culture and
sensitive feeling. Such imitations and cheap displays outrage the artist
by the attempt to produce in cast or rolled metal what properly belongs
to a stone front.

Bearing this distinction in mind, we are not presuming too much to
assert that architects have in cast iron, when properly employed under
certain restrictions, a material which might be turned to account in
narrow fronts where the use of brick or stone piers would encroach too
much upon the space for light. For warehouse fronts, we have evidence
for thinking that the employment of iron might be attended with
advantage, especially in combination with brickwork for the main
vertical piers. Plain classic mouldings, capitals and bases of the Doric
or Tuscan order, are well suited for cast-iron supports to lintels or
girders. In one attempt to make use of the structural features of the
latter, the fronts of the girders between the piers are divided into
panels, the flanges and stiffening pieces to the webs forming an
effective framework for cast or applied ornament to be introduced. The
iron framework thus constructed lends itself to the minor divisions of
the window openings, which can be of wood. In the new Leaden Hall and
Metropolitan Fruit and Vegetable Markets, cast-iron fronts have
been largely employed, consisting of stanchions cast in the form of
pilasters, with horizontal connections and other architectural members.

Regarding the more constructive aspects of cast iron, the employment of
it in fronts having numerous points of support and small bearings is
clearly within the capabilities of the material. So long as it is used
in positions in which its resistance to compression is the chief office
it has to fulfill, cast iron is in its right place. In the fronts of
buildings, therefore, where it is made to carry the floors and rolled
joists, and the lintels of openings, either as piers, pilasters, or
simply as mullions of windows, it is strictly within its legitimate
functions. So with regard to lintels and heads of openings where short
spans exist, cast iron is free from the objection that can be urged
against it for long girders. In fact, no position is better fitted for a
brittle, granular material than that of a vertical framework to receive
windows and ornamentation, and for such purposes cast iron is, to our
minds, admirably suited.

For bridge-building the value of this metal has lately been much
disputed, though we have several notable examples of its use in the
earlier days for such structures. In fact, the use of cast iron for
structural purposes is not older than the time of Smeaton, who in 1755
employed it for mill construction, and about the same time the great
Coalbrookdale Viaduct was erected across the Severn near Broseley, which
gave an impetus to the use of cast iron for bridge construction. The
viaduct had a span of 100 feet, and was composed of ribs cast in two
pieces; it was erected from castings designed by Mr. Pritchard, of
Shrewsbury, an architect, and this circumstance is worthy of note as
showing that an architect really was the first to employ this material
for important structural work, and that the same profession was the
first to reject it upon traditional grounds. It is quite certain,
however, the bridge-builder lost no time in trying his hand upon so
tractable a material; for not long after Telford erected a bridge at
Buildwas of even a greater span, and the famous cast-iron bridge over
the river Wear at Sunderland was erected from the designs of Thomas
Paine, the author of the "Age of Reason." Iron bridges quickly followed
upon these early experiments, for we hear of several being built on
the arched system, and large cotton-mills being erected upon fireproof
principles at the commencement of the present century, the iron girders
and columns of one mill being designed by Boulton and Watt. A little
later, Eaton Hodgkinson proved by experiments the uncertainty of cast
iron with regard to tensile strength, which he showed to be much less
than had been stated by Tredgold. Cast iron was afterwards largely
adopted by engineers. The experiments of Hodgkinson supplied a safe
foundation of facts to work upon, and cast iron has ever since retained
its hold. Thomas Paine's celebrated bridge at Sunderland had a span of
236 feet and a rise of 34 feet, and was constructed of six ribs, and is
remarkable from the fact that the arched girder principle used in the
Coalbrookdale and Buildwas bridges was rejected, that the ribs were
composed of segments or voussoirs, each made up of 125 parts, thus
treating the material in the manner of stone. Each voussoir was a
cast-iron framed piece two feet long and five feet in depth, and these
were bolted together. The Southwark bridge over the Thames, by Sir
John Rennie, followed, in which a similar principle of construction is
adopted. There is much to be said in favor of a system which puts each
rib under compression in the manner of a stone arch, and which builds up
a rib from a number of small pieces. At least, it is a system based on
the legitimate use of cast iron for constructive purposes. The large
segmental castings used in the Pimlico bridge, and the new bridge
over the Trent at Nottingham, from Mr. M. O. Tarbotton's design, are
excellent examples of the arched girder system. The Nottingham bridge
has each rib made up of three I-shaped segments bolted together and
united transversely; the span is 100 feet in each of the three openings,
and the ribs are three feet deep at the springing, diminishing about six
inches at the crown. We have yet to learn why engineers have abandoned
the arched bridge for the wrought iron girder system, except that the
latter is considered more economical, and better fitted for bearing
tensile stress. Cast-iron bridges constructed as rigid arches, subject
to compression and composed of small parts, have all the mechanical
advantages of stone without some of its drawbacks, while artistically
they can be made satisfactory erections.--_Building News_.

       *       *       *       *       *




SIR W. PALLISER.


We announce with regret the death of Major Sir William Palliser, which
took place suddenly on February 4, 1882. Sir William had been suffering
from disease of the heart for a considerable period, but we believe that
no one anticipated that the end was so near. For some twenty years Sir
William had devoted himself to the improvement of guns, projectiles,
and armor. To him is attributed the invention of the chilled-headed
projectiles which are known by his name. There seems to be no doubt that
chilled projectiles were suggested at Woolwich Arsenal, and even made,
before Sir William took the matter up, but there is excellent reason to
believe that Sir William knew nothing of this, and that the invention
was original with him; at all events, he, aided by the efforts of the
foundry and the laboratory at Woolwich, brought these projectiles to
perfection, and unless steel-faced armor defeat them they cannot be
said to have as yet met their match. A most valuable invention of the
deceased officer was the cut-down screw bolt for securing armor plates
to ships and ports. It was at one time feared that no fastening could be
got for armor plates, as on the impact of a shot the heads or the nuts
always flew off the bolts. The fracture usually took place just at the
point where the screw-thread terminated. Sir William adopted the bold
course of actually weakening the bolt in the middle of its length by
turning it down, so that the screw stands raised up instead of being cut
into the bolt, and by this simple device he changed the whole face of
affairs, and the expedient applied in other ways, such as by drilling
holes longitudinally down bolts, has since been extensively adopted
where great immunity from fracture is required.

It is, however, for the well-known converted gun that Sir William
Palliser's name will be best remembered. When our smooth-bore cast iron
guns became obsolete they were converted into the rifled compound guns
by a process which led to their being known as Palliser guns. The plan
was to bore out a cast iron gun and then to insert a wrought iron rifled
barrel consisting of two tubes of coiled iron one inside the other.
By the firing of a proof charge the wrought iron barrel was tightened
inside the cast iron casing. By this means we obtained a converted gun
at one-third of the cost of a new gun, and saved £140 on a 64-pounder
and £210 on an 80-pounder. The process of conversion involved no change
in the external shape of the gun, and it could, therefore, be replaced
upon the carriage and platform to which it formerly belonged. The
converted guns were placed upon wooden frigates and corvettes and upon
the land fronts of fortifications, and were adopted for the defense of
harbors. The many services Sir William Palliser had rendered to the
science of artillery secured him the Companionship of the Bath in 1868,
and knighthood in 1873. In 1874 he received a formal acknowledgment from
the Lords of the Admiralty of the efficiency of his armor bolts for
ironclad ships. His guns have been largely made in America and elsewhere
abroad; and in 1875 he received from the King of Italy the Cross of
Commander of the Crown of Italy. The youngest son of Lieutenant Colonel
Wray Palliser--Waterford Militia--he was born in Dublin in 1830, and was
therefore only fifty-two years of age. He was educated successively at
Rugby, at Trinity College, Dublin, and at Trinity Hall, Cambridge, and,
finally passing through the Staff College at Sandhurst, he entered the
Rifle Brigade in 1855, and was transferred to the Eighteenth Hussars in
1858. He remained in the service to the end of 1871, when he retired by
the sale of his commission. At the general election of 1880, Sir William
Palliser was returned as a Conservative at the head of the poll for
Taunton. In the House of Commons Sir William gave his chief attention
to the scientific matters on which his authority was so generally
recognized. Under the many disappointments and "unkind cuts," which
fall to the lot of the most successful inventors, Sir William Palliser
displayed qualities that won hearty admiration. The confidence with
which he left his last well-known experiment to be carried out in his
own absence almost under the directions of those whose professional
opinions were adverse to his own, may be called chivalrous. His
liberality and kindness of Colonel of the second Middlesex Artillery
Volunteers had gained him the affection of the entire corps; in short,
where it might naturally be expected that he should win respect, he won
the love of those who were thrown with him.--_The Engineer_.

       *       *       *       *       *

THE CEDARS OF LEBANON.--Regulations were lately issued by Rustem Pasha
for the guidance of travelers and others visiting the Cedars of Lebanon.
These venerable trees have now been fenced in, but, with certain
restrictions, they will continue to be accessible to all who wish to
inspect them. In future no encampments will be permitted within the
enclosure, except in the part marked out for that purpose by the keeper,
nor may any cooking or camp fires be lighted near the trees.

       *       *       *       *       *




ON THE MECHANICAL PRODUCTION OF ELECTRIC CURRENTS.


The object of these articles is to lay down in the simplest and most
intelligible way the principles which are concerned in the mechanical
production of electric currents. Every one knows now that electric
lights are produced from powerful currents of electricity generated in
a machine containing magnets and coils of wire, and driven by a steam
engine, or gas engine, or water-wheel. But of the thousands who have
heard that a steam engine can thus provide us with electric currents,
how many are there who comprehend the action of the generator or
dynamo-electric machine? How many, of engineers even, can explain where
the electricity comes from, or how the mechanical power is converted
into electrical energy, or what the magnetism of the iron magnets has
to do with it all? Take any one of the dynamo-electric machines of
the present date--the Siemens, the Gramme, the Brush, or the Edison
machine--of each of these there exist descriptions excellent in their
way, and sufficient for men already versed in the technicalities of
electric science. But to those who have not served an apprenticeship to
the technicalities--to all but professed electricians--the action
of these machines is almost an unknown mystery. As, however, an
understanding of the how and the why of the dynamo-electric machine or
generator is the very A B C of electrical engineering, an exposition
of the fundamental principles of the mechanical production of electric
currents demands an important place in the current science of the day.
It will be our endeavor to expound these principles in the plainest
terms, while at the same time sacrificing nothing in point of scientific
accuracy or of essential detail.

The modern dynamo-electric machine or generator may be regarded as
a combination of iron bars and copper wires, certain parts of the
machinery being fixed, while other parts are driven round by the
application of mechanical forces. How the movement of copper wires and
iron bars in this peculiar arrangement can generate electric currents is
the point which we are proposing to make clear. Friction has nothing
to do with the matter. The old-fashioned spark-producing "electrical
machine" of our youthful days, in which a glass cylinder or disk was
rotated by a handle while a rubber of silk pressed against it, has
nothing in common with the dynamo-electric generator, except that in
both something turns upon an axis as a grindstone or the barrel of
a barrel-organ may do. In the modern "dynamo" we cannot help having
friction at the bearings and contact pieces, it is true, but there
should be no other friction. The moving coils of wire or "armatures"
should rotate freely without touching the iron pole-pieces of the fixed
portion of the machine. In fact friction would be fatal to the action of
the "dynamo." How then does it act? We will proceed to explain without
further delay. There are, however, three fundamental principles to be
borne in mind if we would follow the explanation clearly from step to
step, and these three principles must be laid down at the very outset.

1. The first principle is that the existence of the energy of electric
currents, and also the energy of magnetic attractions, must be sought
for not so much _in the wire_ that carries the current, or _in the bar_
of steel or iron that we call a magnet, as _in the space that surrounds_
the wire or the bar.

2. The second fundamental principle is that the electric current is, in
one sense, quite as much a _magnetic_ fact as an electrical fact; and
that the wire which carries a current through it has magnetic properties
(so long as the current flows) and can attract bits of iron to itself as
a steel magnet does.

3. The third principle to be borne in mind is that to do work of any
kind, whether mechanical or electrical, requires the expenditure of
energy to a certain amount. The steam engine cannot work without its
coal, nor the laborer without his food; nor will a flame go on burning
without its fuel of some kind or other. Neither can an electric current
go on flowing, nor an electric light keep on shedding forth its beams,
without a constant supply of energy from some source or other.

[Illustration: Fig. 1.]

The last of these three principles, involving the relation of electric
currents to the work they can do and to the energy expended in their
production, will be treated of separately and later. Meantime we resume
the task of showing how such currents can be produced mechanically, and
how magnetism comes in in the process.

[Illustration: Fig. 2]

Surrounding every magnet there is a "field" or region in which the
magnetic forces act. Any small magnet, such for example as a compass
needle, when brought into this field of force, exhibits a tendency to
set itself in a certain direction. It turns so as to point with its
north pole toward the south pole of the magnet, and with its south pole
toward the north pole of the magnet; or if it cannot do both these
things at once, it takes up an intermediate position under the joint
action of the separate forces and sets in along a certain line. Such
lines of force run through the magnetic "field" from one pole of the
magnet to the other in curves. If we define a line of force as being the
line along which a free north-seeking magnetic pole would be urged, then
these lines will run from the north pole of the magnet round to the
south pole, and pass through the substance of the magnet itself. In Fig.
1 a rough sketch is given of the lines of magnetic force as they emerge
from the poles of a bar magnet in tufts. The arrow heads show the
direction in which a free north pole would move. These lines of forces
are no fiction of the imagination, like the lines of latitude and
longitude on the globe; they exist and can be rendered visible by the
simplest of expedients. When iron filings are sprinkled upon a card or
a sheet of glass below which a magnet is placed, the filings set
themselves--especially if aided by a gentle tap--along the lines of
force. Fig. 2 is a reproduction from nature of this very experiment, and
surpasses any attempt to draw the lines of force artificially. It
is impossible to magnetize a magnet without also in this fashion
magnetizing the space surrounding the magnet; and the space thus filled
with the lines of force possesses properties which ordinary unmagnetic
space does not possess. These lines give us definite information about
the magnetic condition of the space where they are. Their direction
shows us the direction of the magnetic forces, and their density shows
us the strength of the magnetic forces; for where the force is strongest
there we have the lines of force most numerous and most strongly
delineated in the scattered filings. To complete this first
consideration of the magnetic field surrounding a magnet, we will take a
look at Fig. 3, which reproduces the lines of filings as they settle in
the field of force opposite the end of a bar magnet. The repulsion of
the north pole of the magnet upon the north poles of other magnets would
be, of course, in lines diverging radially from the magnet pole.

[Illustration: Fig. 3]

We will next consider the space surrounding a wire through which a
current of electricity is flowing. This wire has magnetic properties so
long as the current continues, and will, like a magnet, act on a compass
needle. But the needle never tries to point toward the wire; its
tendency is always to set itself broadside to the current and at right
angles to it. The "field" of a current flowing up a straight wire is,
in fact, not unlike the sketch shown in Fig. 4, where instead of tufted
groups we have a sort of magnetic whirl to represent the lines of force.
The lines of force of the galvanic field are, indeed, circles or curves
which inclose the conducting wire, and their number is proportional
to the strength of the current. In the figure, where the current is
supposed to be flowing up the wire (shown by the dark arrows), the
little arrows show the direction in which a free north pole would be
urged round the wire;[1] a south pole would, of course, be urged round
the wire in the contrary direction. Now, though when we look at the
telegraph wires, or at any wire carrying a current of electricity, we
cannot _see_ these whirls of magnetic force in the surrounding space,
there is no doubt that they exist there, and that a great part of the
energy spent in starting an electric current is spent in producing these
magnetic whirls in the surrounding space. There is, however, one way of
showing the existence of these lines of force; similar, indeed, to
that adopted for showing the lines of force in the field surrounding a
magnet. Pass the conducting wire up through a hole in a card or a plate
of glass, as shown in Fig. 5, and sprinkle filings over the surface.
They will, when the glass is gently tapped, arrange themselves in
concentric circles, the smallest and innermost being the best defined
because the magnetic force is strongest there. Fig 6 is an actual
reproduction of the circular lines produced in this fashion by iron
filings in the field of force surrounding an electric current.

[Footnote 1: It will not be out of place here to recall Ampere's
ingenious rule for remembering the direction in which a current urges
the pole of a magnetic needle. "Suppose a man swimming in the wire with
the current, and that he turns so as to face the needle, then the north
pole of the needle will be deflected toward his left hand."]

[Illustration: Fig. 4]

This experimental evidence must suffice to establish two of the three
fundamental points stated at the outset, for they prove conclusively
that the electric current may be treated as a magnetic phenomenon, and
that both in the case of the pole of a magnet, and in that of the wire
which carries a current, a portion, at any rate, of the energy of the
magnetic forces exists outside the magnet or the current, and must be
sought in the surrounding space.

[Illustration: Fig. 5]

[Illustration: Fig. 6]

Having grasped these two points, the next step in our argument is to
establish the relation between the current and the magnet, and to show
how one may produce the other.

[Illustration: Fig. 7]

If we wind a piece of copper wire into a helix or spiral, as in Fig. 7,
and pass a current of electricity through it, the magnetic whirls in the
surrounding space are modified, and the lines of force are no longer
small circles wrapping round the conducting wire. For now the lines of
force of adjacent strands of the coil merge into one another, and run
continuously through the helix from one end to the other. Compare this
figure with Fig. 1, and the similarity in the arrangement of the lines
of force is obvious. The front end of the helix acts, in fact, like the
north pole of a magnet, and the further end like the south pole. If a
small bar of iron be now pushed into the interior of this helix, the
lines of force will run through it and magnetize it, converting it into
an _electro-magnet_. The magnetic "field" of such an electro-magnet is
shown in Fig. 8, which is reproduced from the actual figure made by iron
filings. To magnetize the iron bar of the electro-magnet as strongly as
possible the wire should be coiled many times round, and the current
should be as strong as possible. This mode of making an iron rod or bar
into a powerful magnet is adopted in every dynamo-electric machine. For,
as will be presently explained, very powerful magnets are required, and
these magnets are most effectively made by sending the electric currents
through spiral coils of wire wound (as in Fig. 8) round the bars that
are to be made into magnets.

[Illustration: Fig. 8]

The reader will at this point probably be ready to jump to the
conclusion that magnets and currents are alike surrounded by a sort of
magnetic atmosphere, and such a view may help those to whom the subject
is fresh to realize how such actions as we have been describing can be
communicated from one magnet to another, or from a current to a magnet.
Nevertheless such a conclusion would be both premature and inaccurate.
Even in the most perfect vacuum these actions still go on, and the lines
of force can still be traced. It is probably more correct to conclude
that these magnetic actions are propagated through space not by special
magnetic atmospheres, but by there being movements and pressures and
tensions in the _ether_ which is believed to pervade all space as a
very thin medium more attenuated than the lightest gas, and which when
subjected to electro-magnetic forces assumes a peculiar state, and
gives rise to the actions which have been detailed in the preceding
paragraphs.

[Illustration: Fig. 9.]

The next point to be studied is the magnetic property of a single loop
of the wire through which an electric current flows. Fig. 9 represents
a single voltaic cell containing the usual plates of zinc and copper
dipping into acid to generate a current in the old-fashioned way. This
current flows from the zinc plate through the liquid to the copper
plate, and from thence it flows round the wire ring or circuit back to
the zinc plate. Here the lines of magnetic force in the surrounding
space are no longer only whirls like those drawn in Fig. 4 and 6, for
they react on one another and become nearly parallel where they pass
through the middle of the ring. The thick arrows show the direction of
the electric current, the fine arrows are the lines of magnetic force,
and show the paths along which a free north pole would be urged. All the
front face, where the arrow-heads are, will be like the north pole of a
magnet. All the other face of the ring will be like the south pole of a
magnet. Our ring resembles a flat magnet, one face all north pole the
other face all south pole. Such a magnet is sometimes called a "magnetic
shell."[1]

[Footnote 1: The rule for telling which face of the magnetic shell (or
of the loop circuit) is north and which south in its magnetic properties
is the following: If as you look at the circuit the current is flowing
in the same apparent direction as the hands of a clock move, then the
face you are looking at is a south pole. If the current flows the
opposite way round to the hands of a clock, then it is the north pole
face that you are looking at.]

Since the circuit through which the current is flowing has these
magnetic properties, it can attract other magnets or repel them
according to circumstances.

[Illustration: Fig. 10.]

If a magnet be placed near the circuit, so that its north pole, N, is
opposite that side of the circuit which acts as a south pole, the magnet
and the circuit will attract one another. The lines of force that
radiate from the end of the magnet, curve round and coalesce with
some of those of the circuit. It was shown by the late Professor
Clerk-Maxwell, that every portion of a circuit is acted upon by a force
urging it in such a direction as to make it inclose within its embrace
the greatest possible number of lines of force. This proposition, which
has been termed "Maxwell's Rule," is very important, because it can be
so readily applied to so many cases, and will enable one so easily
to think out the actual reaction in any particular case. The rule is
illustrated by the sketch shown in Fig. 10, where a bar magnet has been
placed with its north pole opposite the south face of the circuit of
the cell. The lines of force of the magnet are drawn into the ring and
coalesce with those due to the current. According to Faraday's mode of
regarding the actions in the magnetic field there is a tendency for the
lines of force to shorten themselves. This would occur if either the
magnet were pulled into the circuit, or the circuit were moved up toward
the magnet. Each attracts the other, and whichever of them is free to
move will move in obedience to the attraction. And the motion will in
either case be such as to increase the total number of lines of force
that pass through the circuit. Lest it should be thought that Fig. 10 is
fanciful or overdrawn, we reproduce an actual magnetic "field" made in
the manner described in the preceding article. Fig. 11 is a kind of
sectional view of Fig. 10, the circuit being represented merely by two
circular spots or holes above and below the middle line, the current
flowing toward the spectator through the lower spot, and passing in
front of the figure to the upper hole, where it flows down. Into this
circuit the pole, N, is attracted, the tendency being to draw as many
lines of force as possible into the embrace of the circuit.

[Illustration: Fig. 11.]

So far as the reasoning about these mutual actions of magnets and
currents is concerned, it would therefore appear that the lines of force
are the really important feature to be understood and studied. All our
reasons about the attractions of magnets could be equally well thought
out if there were no corporeal magnets there at all, only collections
of lines of force. Bars of iron and steel may be regarded as convenient
conductors of the lines of force; and the poles of magnets are simply
the places where the lines of force run out of the metal into the air or
_vice versa_. Electric currents also may be reasoned about, and their
magnetic actions foretold quite irrespective of the copper wire that
acts as a conductor; for here there are not even any poles; the lines
of force or magnetic whirls are wholly outside the metal. There is an
important difference, however, to be observed between the case of the
lines of force of the current, and that of the lines of force of the
magnet. The lines of force of the magnet are the magnet so far as
magnetic forces are concerned; for a piece of soft iron laid along the
lines of force thereby becomes a magnet and remains a magnet as long
as the lines of force pass through it. But the lines of force crossing
through a circuit are not the same thing as the current of electricity
that flows round the circuit. You may take a I loop of wire and put the
poles of magnets on each side of it so that the lines of force pass
through in great numbers from one face to the other, but if you have
them there even for months and years the mere presence of these lines
of force will not create an electric current even of the feeblest kind.
There must be _motion_ to induce a current of electricity to flow in a
wire circuit.

Faraday's great discovery was, in fact, that when the pole of a magnet
is moved into, or moved out of, a coil of wire, the motion produces,
while it lasts, currents of electricity in the coil. Such currents are
known as "induced currents;" and the action is called magneto-electric
"induction." The momentary current produced by plunging the magnet pole
into the wire coil or circuit is found to be in the opposite direction
to that in which a current must be sent if it were desired to attract
the magnet pole into the coil. If the reader will look back to Fig. 10
he will see that a north magnet pole is being attracted in from behind
into a circuit round which, as he views it, the current flows in an
opposite sense to that in which the hands of a clock move round. Now,
compare this figure with Fig. 12, which represents the generation of a
momentary induced current by the act of moving the north pole, N, toward
a wire ring, which is in this case connected with a little detecter
galvanometer, G. The momentary current flows round the circuit (as seen
by the spectator from the front) in the _same_ sense as the movement of
the hands of a clock. The induced current which results from the motion
is found, then, to be in a direction exactly opposed to that of the
current that would itself produce the same movement of the magnet pole.
If the north pole, instead of being moved toward or into the circuit,
were moved away from the circuit, this motion will also induce a
transient current to flow round the wire, but this time the current will
be in the same sense as that in Fig. 10, in the opposite sense to that
in Fig. 12. Pulling the magnet pole away sets up a current in the
reverse direction to that set up by pushing the pole nearer. In both
cases the currents only last while the motion lasts.

[Illustration: Fig. 12.]

Now in the first article it was pointed out that the lines of force of
the magnet indicate not only the direction, but the strength of the
magnetic forces. The stronger the pole of the magnet is, the greater
will be the _number of lines of force_ that radiate from its poles. The
strength of the current that flows round a circuit is also proportional
to the number of lines of force which are thereby caused to pass (as in
Fig. 9) through the circuit. The stronger the current, the more numerous
the lines of force that thread themselves through the circuit. When a
magnet is moved near a circuit near it, it is found that any alteration
in the number of lines of force that cross the circuit is accompanied
by the production of a current. Referring once more to Fig. 10, we will
call the direction of the current round the circuit in that figure the
_positive_ direction; and to define this direction we may remark that if
we were to view the circuit from such a point as to look along the lines
of force in their own direction, the direction of the current round
the circuit will appear to be the same as that of the hands of a clock
moving round a dial. If the magnet, N S, be now drawn away from the
circuit so that fewer of its lines of force passed through the circuit,
experiment shows the result that the current flowing in circuit will be
for the moment increased in strength, the _increase_ in strength being
proportional to the rate of _decrease_ in the number of lines of force.
So, on the other hand, if the magnet were pushed up toward the circuit,
the current in the circuit would be momentarily reduced in strength, the
decrease in strength in the current being proportional to the rate of
increase in the number of lines of force.

Similar considerations apply to the case of the simple circuit and the
magnet shown in Fig. 12. In this circuit there is no current flowing so
long as the magnet is at rest; but if the magnet be moved up toward
the circuit so as to _increase_ the number of lines of force that pass
through the circuit, there will be a momentary "inverse" current induced
in the circuit and it will flow in the _negative_ direction. While if
the magnet were moved away the _decrease_ in the number of lines of
force would result in a transient "direct" current, or one flowing in
the _positive_ direction.

It would be possible to deduce these results from an abstract
consideration of the matter from the point of view of the principle of
conservation of energy. But we prefer to reserve this point until a
general notion of the action of dynamo-electric machines has been given.

The following principles or generalized statements follow as a matter of
the very simplest consequence from the foregoing considerations:

(a) To induce a current in a coil of wire by means of a magnet there
must be relative motion between coil and magnet.

(b) Approach of a magnet to a coil or of a coil to a magnet induces
currents in the opposite direction to that induced by recession.

(c) The stronger the magnet the stronger will be the induced currents in
the coils.

(d) The more rapid the motion the stronger will be the momentary
current induced in the coils (but the time it lasts will, of course, be
shorter).

(e) The greater the number of turns in the coil the stronger will be the
total current induced in it by the movement of the magnet.

These points are of vital importance in the action of dynamo electric
generators. It remains, however, yet to be shown how these transient and
momentary induction currents can be so directed and manipulated as to be
made to combine into a steady and continuous supply. To bring a magnet
pole up toward a coil of wire is a process which can only last a very
limited time; and its recession from the coil also cannot furnish a
continuous current since it is a process of limited duration. In the
earliest machines in which the principle of magneto-electric induction
was applied, the currents produced were of this momentary kind,
alternating in direction. Coils of wire fixed to a rotating axis were
moved past the pole of a magnet. While the coil was approaching the
lines of force were increasing, and a momentary inverse current was set
up, which was immediately succeeded by a momentary direct current as the
coil receded from the pole. Such machines on a small scale are still to
be found in opticians' shops for the purpose of giving people shocks. On
a large scale alternate current machines are still employed for certain
purposes in electric lighting, as, for example, for use with the
Jablochkoff candle. Large alternate-current machines have been devised
by Wilde, Gramme, Siemens, De Meritens, and others.--_Engineering_.

       *       *       *       *       *




ON THE UNIT WEIGHT AND MODE OF CONSTITUTION OF COMPOUNDS.


Dr. Odling delivered a lecture on the above before the Chemical Society,
London, February 2, 1882.

The lecturer said that it had been found useful to occasionally bring
forward various points of chemical doctrine, on which there were
differences of opinion, to be discussed by the society. On this occasion
he wished not so much to demonstrate certain conclusions, or to make a
declaration of his opinions, as to invite discussion and a thoughtful
consideration of questions of importance to chemists. Originally three
questions were proposed: First, Is there any satisfactory evidence
deducible of the existence of two distinct forms of chemical combination
(atomic and molecular)? Second, Is the determination of the vapor
density of a body alone sufficient to determine the weight of the
chemical molecule? Third, In the case of an element forming two or more
distinct series of compounds, e.g., ferrous and ferric salts, is the
transition from one series to another necessarily connected with the
addition or subtraction of an even number of hydrogenoid atoms? He
would, however, limit himself to the first of these questions; at the
same time the three questions were so closely associated with one
another that in discussing the first it was difficult to know where to
begin. The answer to this question (Is there any satisfactory
evidence deducible of the existence of two distinct forms of chemical
combination?) depends materially on the view we take of the property
called in text-books valency or atomicity; and before discussing the
question it is important to have a clear idea of what these words
valency and atomicity really mean. It is necessary, too, to start with
some propositions which must be taken for granted. These propositions
are: First, that in all chemical changes, those kinds of matter which we
commonly call elementary, do not suffer decomposition. Second, That the
atomic weights of the elements as received are correct, i.e., that they
do really express with great exactitude the relative weights of the
atoms of the individual elements. If we accept these two propositions,
it follows that hydrogen can be replaced atom for atom by other elements
not only by the hydrogens but by alkali metals, etc. Hydrogen is, it may
here be remarked, an element of unique character; not only can it be
replaced by the elements of the widely different classes represented by
chlorine and sodium, but it is the terminal of the series of paraffins,
C_{n}H_{2n}; C_{3}H_{6}, C_{2}H_{4}, H_{2}. The third proposition which
must be taken for granted is, that the groups of elements, C_{2}H_{5},
CH_{3}, behave as elements, and that these radicals, ethyl, methyl,
etc., do not suffer decomposition in many chemical reactions.

Now as to valency or atomicity, accepting the received atomic weights of
the elements, it is certain that there are at least four distinct types
of hydrogen compounds represented by ClH, OH_{2}, NH_{3}, CH_{4}. The
recognition of these types, and their relations to each other as
types, was one of the most important and best assured advances made in
theoretical chemistry. When we compare the formula of water with that of
hydrochloric acid, we find that there is twice as much hydrogen combined
with one atom of oxygen as there is combined with one atom of chlorine;
and in a great many other instances, we find that we can replace two
atoms of chlorine by one atom of oxygen, so that we get an idea of the
exchangeable value of these elements, and we say that one atom of oxygen
is worth two of chlorine, or is bivalent; similarly, nitrogen is said to
be trivalent. The meaning attached to the word "valency," is simply one
of interchangeability, just as we say a penny is worth two halfpennies
or four farthings. The question next arises, is the valency of an
element fixed or variable? If the word be defined as above, it is
absolutely certain that the valency varies. Thus, tin may be trivalent,
SnCl_{2}, or tetravalent, SnCl_{4}. Accordingly elements have been
classed as monads, dyads, triads, etc. The lecturer objected most
strongly to the word "atomicity;" he could not conceive of one atom
being more atomic than another; he could understand the atomicity of
a molecule or the equivalency of an atom, but not the atomicity of an
atom; the expression seemed to him complete nonsense. He next considered
the possibility of assigning a fixed limit to this valency or adicity of
an atom, and concluded that the adicity was not absolutely fixed, but
was fixed in relation to certain elements, e.g., C never combines with
more than four atoms of H; O never more than two atoms of H, etc. The
adicity of an element when combined with two or more elements is usually
higher than when combined with only one, e.g., NH_{3}, NH_{4}Cl. The
term "capacity of saturation," may be used as a synonym for adicity, if
care be taken to distinguish it from other kinds of saturation, such as
an acid with an alkali, etc. Adicity is, however, quite distinct from
combining force; the latter is indicated by the amount of heat evolved
in the combination.

The lecturer then proceeded to criticise a statement commonly found
in text books, that chemical combination suppresses altogether the
properties of the combining bodies. The reverse of this statement is
probably true. To take the case commonly given of the combination of
copper and sulphur when heated; this is good as far as it goes, but
there are numerous instances, as ClI, SSe, etc., where the original
properties and characters of the combining elements do not completely
disappear. The real statement is that the original properties of the
elements disappear more or less, and least when the combination is weak
and attended with the evolution of a slight amount of heat, and in every
case some properties are left which can be recognized. So with reference
to the question of atomic and molecular combination, as atomic
combination does not necessarily produce change, it does not differ in
this respect from what is usually called molecular combination.

The lecturer then referred to an important difference in the adicity of
chlorine and oxygen. Chlorine can combine with methyl or ethyl singly.
Oxygen can combine with both and hold them together in one molecule. The
recognition of this fundamental difference between chlorine and oxygen,
this formation of double oxides as opposed to single chlorides, marks an
epoch in scientific chemistry.

The lecturer then considered the subject of chemical formulæ; it is the
bounden duty of every formula to express clearly the number of atoms of
each kind of elementary matter which enters into the constitution of the
molecule of the substance. A formula may do much more than this. If we
attempt to express too much by a complex formula we may veil the number
of atoms contained in it. This difficulty may be avoided by using two
formulæ, a synoptic formula giving the number of atoms present, and a
complex formula perhaps covering half a page, giving the constitution
of the molecule. But between the purely synoptic formula and the very
elaborate formula there are others--contracted formulæ--which labor
under the disadvantage, as a rule, of being one-sided, and so create a
false impression as to the nature of the substance. Thus, for instance,
to take the formula of sulphuric acid, H_{2}SO_{4}. This suggests that
all the oxygen is united to the S; (HO)_{2}SO_{2} suggests that two
atoms of hydroxyl exist in the molecule; then, again, we might write the
formula HSO_{2}OH, or H_{2}OSO_{3}. All of these are justifiable, and
each might be useful to explain certain reactions of sulphuric acid, but
to use one only creates a false impression. The only plan is to use them
variously and capriciously, according to the reaction to be explained.
Again, ethyl acetate may be written--

          H_{3}C\
          H_{2}C/
                \
                 O
                /
              OC\
          H_{3}C/

Or condensed--

          H_{5}C_{2} \
                      }O
          H_{3}C_{2}O/

Or H_{5}C_{2}O.C_{2}H_{3}O, or H_{5}C_{2}.C_{2}H_{3}O_{2}. Now each
of these two latter formulæ is a partial formula, each represents a
one-sided view; it is justifiable if you use both, but unfair if you use
only one.

We now come to the question as to the existence or non-existence of
two distinct classes of compounds, one in which the atoms are combined
directly or indirectly with each other, and the other in which a group
of atoms is combined as an integer with some other group of atoms,
without any atomic connection by so-called molecular combination. These
two modes of combination are essentially distinct. The question is not
one of degree. Are there any facts to support this theory that one set
of compounds is formed in one way, another in a different way? Take the
case of the sulphates: Starting with SO_{3}, we can replace one atom
of O by HO_{2}, and obtain SO_{2}(HO)_{2} or H_{2}SO_{4}; replacing a
second atom, we get SO(HO)_{4} or H_{4}SO_{5}, glacial sulphuric acid, a
perfectly definite body corresponding to a definite class of sulphates,
e.g., H_{2}MgSO_{5}, Zn_{2}SO_{5}, etc. By replacing the third atom of O
we get S(HO)_{6} or H_{6}SOH_{6}; this corresponds to a class of salts,
gypsum, H_{4}CaSO_{6}, etc. These are admitted without dispute to be
atomic compounds. Are we to stop here? We may write the above compounds
thus: H_{2}SO_{4}, H_{2}SO_{4}H_{2}O, H_{2}SO_{4}2H_{2}O. If we measure
the heat evolved in the formation of the two latter compounds, it is,
for H_{2}SO_{4}+H_{2}O, 6.272; H_{2}SO_{4}+2H_{2}O, 3.092. But if we now
take the compound H_{2}SO_{4}+3H_{2}O we have heat evolved 1.744; so we
can have H_{2}SO_{4}4H_{2}O, etc. Where are we to draw the line between
atomic and molecular combination, and why? It comes to this: All
compounds which you can explain on your views of atomicity are atomic,
and all that you cannot thus explain are molecular. Similarly with
phosphates, arsenates, etc. In all these compounds it is impossible to
lay one's finger on any distinction as regards chemical behavior between
the compounds called atomic and those usually called molecular.

Two points remain to be mentioned: The first is the relationship between
alteration of adicity and two series (ous and ic) of compounds. Tin is
usually said to be dyad in stannous compounds and a tetrad in stannic
compounds, but in a compound like SnCl_{2}AmCl, is not tin really a
tetrad?

                 {Cl
                 {Cl
              Sn {Cl
                 {NH_{4}

and yet it is a stannous compound, and gives a black precipitate with
H_{2}S; so that valency does not necessarily go with the series. The
second point is that an objection may be urged, as, for example, in
ammonium chloride (the lecturer stated above that here N was a pentad,
the addition of the chlorine having caused the N to assume the pentadic
character), it may be said, why should you not suppose that it is the
chlorine "which has altered its valency, and that the compound should be
written:

                 {H
                 {H
               N { \
                 {H--Cl
                 {H/

There is something to be said for this view, but on the whole the
balance of the evidence is in favor of nitrogen being a pentad.

In conclusion the lecturer stated that his principal object was to
direct the attention of chemists, and especially of young chemists, to
the question: Is there or is there not any evidence derived from
the properties, the decompositions, or the relative stabilities of
substances to warrant us in believing that two classes of compounds
exist: one class in which there is interatomic connection alone, and
another in which the connection is molecular?

       *       *       *       *       *




FRENCH TOILET ARTICLES.


Mr. Martenson, of St. Petersburg, who, it will be remembered, was one of
the Russian delegates to the International Pharmaceutical Congress, has
been analyzing a number of French preparations for the toilet, most of
which are familiar to our readers, at any rate by name and repute.

1. _Eau de Fleurs de Lys_--(Planchon and Riet, Paris.)--An infallible
banisher of freckles, etc., etc. The bottle contains 100 grammes of
a milky fluid, made up of 97 per cent. of water, 2.5 per cent. of
precipitated calomel, and a small quantity of common salt and corrosive
sublimate, and scented with orange flower water.

2. _Eau de Blanc de Perles_.--The bottle contains 120 grammes of a weak
alkaline solution, with a thick deposit of 15 per cent. of carbonate of
lead, and scented with otto of roses and geranium.

3. _Nouveau Blanc de Perle, Extra Fin_.--(Lubin, Paris.)--The bottles
contains 35 grammes of a liquid consisting of water, holding in
suspension about equal parts of zinc oxide, magnesic carbonate, and
powdered talc, perfumed with otto of roses.

4. _Lait de Perles_.--A close imitation of No. 3, the bottle holding
nearly three times the quantity for the same price. The amount of the
precipitate in this case is 20 per cent.

5. _Lait de Perles_.--(Legrand, Paris).--The bottles contain 65 grammes
of a thick white fluid, the precipitate from which consists of zinc
oxide and bismuth oxychloride, and is scented with rose water.

6. _Lait Antiphélique_.--(Candès and Co., Paris.)--Each bottle contains
140 grammes of a milky fluid, smelling strongly of camphor, and having
an acid reaction. It contains alcohol, camphor, ammonic chloride,
half per cent. of corrosive sublimate, albumen, and a little free
hydrochloric acid.

7. _Lait de Concombres_.--The bottle contains 160 grammes of a very
inelegantly made emulsion, smelling of very common rose-water, with an
unpleasant twang about it, and giving a strongly alkaline reaction.
It consists of soap, glycerin, and cotton seed oil, made into a
semi-emulsion.

8. _Crême de Fleurs des Lys; Blanc de Ville Onctueux_.--About 30 grammes
of a kind of weak ointment contained in a small pomatum pot prettily
ornamented. It is simply a salve made of wax oil, and possibly lard,
mixed with a large proportion of zinc oxide, and smelling of inferior
otto of roses.

9. _Páte de Velonas_.-This paste consists of almond, and possibly other
meal mixed with soap powder, and has a strong alkaline reaction. It is
scented with orris-root.

10. _Rouge Végétal_.--The box contains 8½ grammes of raspberry colored
powder, consisting chiefly of China clay and talc, tinted to the proper
depth with extract of cochineal.

11. _Rouge Extra Fin Foncé_.--A small square bottle containing 11
grammes of a deep red solution, smelling of otto of roses and ammonia.
It consists of a solution of carmine in ammonia, with an addition of a
certain amount of alcohol.

12. _Rouge de Dorin_.--_Extract des Fleurs des Indes_.--A round pot
containing a porcelain disk, covered with about 6 grammes of a bright
red paste, which is a mixture of carthamin or safflower with talc. This
rouge, which differs from all the others, is harmless and effectual,
but must bear a high profit seeing that the ingredients cost only a few
half-pence, while it sells in St. Petersburg at about 4s. 9d. a pot.

13. _Etui Mystérieux ou Boite de Maintenon_.--A prettily got-up box
containing red and white paint, and two sticks of black and blue
cosmetic for the eyebrows and veins, with camel's hair pencils for
applying the latter. Sells in St. Petersburg at 6s. 4d.

14. _Philidore_.--_Remède Specifique pour oter les Pellicules de la
tête, etc_.--The bottle contains 100 grammes of a strong alkaline
solution smelling strongly of ammonia, and containing potash, ammonia,
alcohol, glycerin, and eau de cologne.

15. _Colorigène Rigaud_.--A blue bottle containing 160 grammes of a
clear fluid with a slight black deposit, consisting of a mixture of
equal parts of a 14 per cent. solution of sodic hyposulphate, and a 4
per cent. solution of lead acetate. Of course the longer this solution
is kept the more lead sulphate it deposits. It sells in St. Petersburg
at 8s. per bottle. It is also stated to be much more powerful if used
in conjunction with the _Pommade Miranda Rigaud_. This beats Mrs.
Allen completely out of the field.--_Pharmaceutische Zeitschrift für
Russland_.

       *       *       *       *       *




ON THE MYDRIATIC ALKALOIDS.

By ALBERT LADENBURG.


We translate the following important article, says the _Chemists'
Journal_, from the _Moniteur Scientifique_ of last month. It may be
explained for the sake of our student readers that the word _mydriatic_
is derived from the Greek _mudriasis_, which means paralysis of the
pupil.

The synthetical researches which I have undertaken with a view to
explain the constitution of atropine have shown me the necessity of
studying the connection of atropine with the other alkaloids, which have
an analogous physiological action. According to the early researches we
could not discover any of these relationships which only become evident
when we come to study the new discoveries which have been made in
connection with the tropines, to which class belong both duboisine
and hyoscyamine, which, although differing from atropine, are equally
mydriatic in their action.


I.--ATROPINE.

Discovered by Mein in 1831 in the roots of belladonna. More thoroughly
studied some time after by Geiger and Hesse, who confirmed Mein's
results. Liebig next published an analysis of the alkaloid, which was
afterward shown to be incorrect. He consequently modified his
formula, and gave the following as the composition of atropine;
C_{17}H_{23}NO_{3}. Liebig's amended analysis was afterward confirmed by
Planta, who further showed that the alkaloid itself melted at 194° F.,
and its double gold salt at 275° F. It is worthy of remark that the
first figure was considered correct until my researches proved the
contrary. The physiological action of atropine, especially in relation
to the eye, has been most carefully studied by several celebrated
ophthalmologists, such as Graef, Donders, Bezold, and Bloebaum. Its
chemical properties have also been the object of very extensive
researches by Pfeiffer, Kraut, and Lassen. Pfeiffer first discovered
that benzoic acid was one of the products of decomposition of atropine,
and Kraut split atropine by means of baryta water into atropic
acid, C_{9}H_{6}O_{2}, and tropine, C_{8}O_{15}NO. Lassen, who used
hydrochloric acid, discovered the true products of the splitting up of
atropine, viz., tropic acid, C_{9}H_{8}O_{3}, and tropine, C_{8}H_{15}N,
and proved at the same time that atropic acid is easily formed by the
action of boiling baryta water on tropic acid, while hydrochloric acid
at all temperatures forms isatropic acid, an isomer of atropic acid.
Kraut confirmed these results, and showed that atropic acid as well as
cinnamic acid gives benzoic acid by oxidation, and hydratropic acid (the
isomer of phenylpropionic acid) by reduction with sodium amalgam. These
results are sufficient to show that tropic acid may have one of the
following two formulae.

          I                       II

         CH_{2}OH                    CH_{3}
        /                         /
C_{4}H_{5}CH           or    C_{8}H_{5}--C--OH
        \                         \
         OOHO                      COOH

Fittig and Wurster, who discovered atrolactic acid, C_{2}H_{10}O_{3},
an isomer of tropic acid, gives tropic acid the second formula, while
Burgheimar and myself have shown that it is the true formula of
atrolactic acid. Lately we have succeeded in performing the complete
synthesis of atropic acid, and the artificial preparation of atropine
has been greatly facilitated since I have shown that we can easily
reconstruct atropine by starting from its products of decomposition,
tropic acid, and tropine.

Before my researches nothing was known of the constitution of tropine.
New unpublished researches into this problem have shown that it closely
resembles neurine,[1] a body which I hope will speedily lead us to the
complete synthesis of atropine.

[Footnote 1: As we shall probably hear a great deal about this alkaloid,
it may be as well to state that, although found in the brain and liver,
it may be prepared synthetically by the action of ethylene oxide,
(CH_{2})_{2}O, water, H_{2}O, and trimethyiamine, N(CH_{3})_{3}. Its
constitution is that of trimethyl-ethylene-hydrate-ammonic-hydrate, and
has the following constitutional formula:

   { (CH_{2})_{2}OH
   { CH_{3}
N  { CH_{3}
   { CH_{3}
   { OH

or in other words, it is the hydrate of
trimethyl-hydrethylene-ammonium.]

The fusing point of atropine is not 194° F., as stated by Planta, but
237° F. Crystallized from not too dilute alcohol it forms crystals
which are aggregations of prisms. Toluene, alcohol, and chloroform all
dissolve atropine readily. Its double gold salt is very characteristic.
It is generally precipitated in the form of an oil which solidifies
rapidly and may be crystallized from hot water after the addition of a
little hydrochloric acid. This clouds in cooling, and after a certain
time it separates in small crystals of indeterminate form which unite in
warty concretions. After drying the salt forms a dull powder, melting
between 275° F. and 280° F. It also melts in boiling water, and its
aqueous solution exposed to the light is partially reduced, 100 grammes
of water acidulated with 10 cubic centimeters of 1.190° solution of
hydrochloric acid dissolves 0.137 gramme of the gold salt at 136° F. to
140° F.

I should fancy that the above particulars are sufficent to completely
differentiate atropine from all the other mydriatic alkaloids.


II.--THE ATROPINE OF DATURA STRAMONIUM.

Planta has already tried to show that atropine is identical with the
daturine obtained by Geiger and Hesse, founding his opinion on facts
which we nowadays look upon as doubtful. This identity was generally
admitted by all chemists. The pharmacologists, headed by Soubeiran,
Erhardt, Schroff, and Poehl, were much more reserved in their judgment.
I thought it as well, therefore, to recommence the study of daturine,
the more so as I had already determined the incorrectness of the
long accepted point of fusion of atropine, and that my researches on
hyoscyamine convinced me that this base is an isomer of atropine,
although very analogous to it. I have also shown that Merck's daturine
differs from atropine, and is merely pure hyoscyamine. A short time
afterward there appeared a paper by Schmidt which again asserted the
identity of daturine and atropine. I therefore requested Mr. Merck, of
Darmstadt, to send me all the bases which he obtained from datura. This
eminent manufacturer was good enough to comply with my request, and sent
me two products, one of which was marked "light daturine," the other
"heavy daturine," the separation of which was effected in the following
manner: The solution of crude daturine in concentrated alcohol was mixed
with a little hot water; this treatment caused the deposition of the
"heavy daturine," while the "light daturine" remained in the mother
liquor. The "heavy daturine," of which only a small quantity is
obtainable, is far from being a body of definite composition, that is to
say, it is a mixture of atropine and hyoscyamine. If we convert the base
into a double gold salt we obtain by a single crystallization a dull
looking salt, melting at from 275° F. to 280° F., the appearance of
which is very different to that of atropine. I have succeeded
in splitting up "heavy daturine" by two different methods. By
recrystallizing the gold salt six times from boiling water, the salt of
hyoscyamine, which melts at from 316° F. to 323° F., crystallizes our
first, and by the successive evaporation of the mother liquor at last
obtain the pure gold salt of atropine, which melts at 275° F. to 280° F.
If we only want to isolate the atropine, it is better to crystallize the
free base two or three times from alcohol at 50 per cent., always taking
the earliest formed crystals.

These facts prove the presence of atropine in datura; but while Planta
and Schmidt assert that only this alkaloid is found in the plant, I have
proved that the proportion of atropine in it is but small, while its
richness in hyoscyamine is great. I think, therefore, that both Planta
and Schmidt must have worked with a mixture of atropine and hyoscyamine.
It is true that Schmidt had received pure atropine under the name
of daturine, for I have proved most conclusively that the so-called
daturine supplied by Trommsdorff, of Erfurt, is pure atropine and
nothing else. It has no action whatever on polarized light.


III.--HYOSCYAMINE FROM HYOSCYAMUS.

Discovered by Geiger and Hesse in 1833. It was first obtained in the
form of needles, which were much more soluble than atropine. In the pure
state it forms a viscous mass with a repulsive odor. These researches
were repeated by Thibout, Kletinski, Ludwig, Lading, Bucheim, Wagymar,
and Renard.

Hoehn and Reichardt have recently studied hyoscyamine in a very complete
manner. They have obtained the body in the form of warty concretions as
soft as wax, and melting at 194° F., having a formula according to them
of C_{15}H_{23}NO_{3}. They have also studied the splitting up of the
alkaloid by means of baryta water, and have obtained an acid which they
have named hyoscinic acid, and which melts at about 219° F., and a basic
body, hyoscine, C_{6}H_{13}N. They represent the reaction as follows:

C_{15}H_{23}NO_{3} = C_{9}H_{10}O_{3} + C_{6}H_{13}N.

According to this view hyoscyamine ought to be the hyoscinate of
hyoscine, or at any rate an isomer of this body. It is to be remarked
that they compare hyoscinic acid not with tropic acid, of which it
possesses the composition, but with atropic acid, C_{9}H_{8}O_{2}. I
have worked with the hyoscyamine of both Merck and Trommsdorff, as well
as with a product which I obtained from hyoscyamus seeds myself. The
best way of purifying the alkaloid is by recrystallizing its gold salt
several times, so as to obtain it in brilliant yellow plates, melting
at 320° F. By passing a stream of hydrosulphuric acid gas through the
liquor the gold is precipitated in the form of sulphide. The liquid is
filtered and evaporated, precipitated by an excess of a strong solution
of potassium carbonate, and the alkaloid extracted by chloroform.
The solution is dried over carbonate of potassium, and part of the
chloroform is distilled off. By leaving the solution to evaporate
spontaneously the alkaloid is obtained in silky crystals. The crystals
are then dissolved in alcohol, which, on being poured into water, parts
with them in the same form.

Hyoscyamine crystallizes in the acicular form, with greater difficulty
even than atropine, it also forms less compact crystals. Its fusing
point is 149.6° F. I have not yet succeeded in crystallizing any of
its more simple salts. The double platinum salt melts at 392° F., with
decomposition. The double gold salt, which has been described above,
does not melt in boiling water, and its aqueous solution is reduced
neither by boiling nor by long exposure to light. By leaving the hot
saturated solution to cool it does not cloud, but the double salt
separates pretty rapidly in the form of plates.

One liter of water containing 10 cubic centimeters of hydrochloric acid
at 1.19° dissolves 65 centigrammes of the salt at 146° F.

These characteristics allow us to differentiate atropine and
hyoscyamine, the reactions of which are almost identical, as will be
seen from the following table, which shows the action of weak solutions
of the acids named on the hydrochlorates of the bases:

_Reagents_.         _Hyoscyamine_.        _Atropine_.

Picric acid.        An oil solidifying    Crystalline precipitate.
                    immediately into
                    tabular crystals.

Mercuropotassic     White cheesy          Same.
iodide.             precipitate.

Iodized potassic    An immediate          A brown oil crystallizing
iodide.             precipitate of        after a time.
                    periodate.

Mercuric chloride.  Same as picric acid.  Same.

Tannic acid.        Slight cloud.         Cloud hardly visible.

Platinum chloride.  O.                    O.

_(To be continued.)_

       *       *       *       *       *




DETECTION OF SMALL QUANTITIES OF MORPHIA.

By A. JORISSEN.


The solution of morphia, free from foreign bodies, is evaporated to
dryness, and the residue is heated on the water bath with a few drops
of sulphuric acid. A minute crystal of ferrous sulphate is then added,
bruised with a glass rod, stirred up in the liquid, heated for a minute
longer, and poured into a white porcelain capsule, containing 2 to 3
c.c. strong ammonia. The morphia solution sinks to the bottom, and where
the liquids touch there is formed a red color, passing into violet at
the margin, while the ammoniacal stratum takes a pure blue. The reaction
is very distinct to 0.0006 grm. Codeine does not give this reaction. If
sulphuric acid at 190° to 200° is allowed to act upon morphia, there is
ultimately formed an opaque black green mass. If this is poured dropwise
into much water, the mixture turns bluish, and if it is then shaken up
with ether or chloroform, the form takes a purple and the latter a very
permanent blue. Codeine gives the same reaction, but no other of the
alkaloids. This reaction can be obtained very distinctly with 0.0004
grm. of morphia.

       *       *       *       *       *




ON THE ESTIMATION OF MANGANESE BY TITRATION.

[Footnote: _From Jernkontorets Annaler_, vol. xxxvi.--_Iron_.]

By C. G. SARNSTROM.


If we dissolve black oxide of manganese, permanganate of potash, or any
other compound of manganese of a higher degree of oxidation than the
protoxide in hydrochloric acid, we obtain, as is well known, a dark
colored solution of perchloride of manganese, which, when heated to
boiling loses color pretty rapidly, chlorine being given off, until
finally only protochloride remains. This decomposition also proceeds at
the common temperature, though much more slowly, and we may therefore
say that manganese when dissolved in hydrochloric acid always tends to
descend to its lowest, and, considered as a base, strongest degree of
oxidation, which is not raised to a higher degree even by chameleon
solution. In slightly acid, neutral, or alkaline solutions on the other
hand, protoxide of manganese absorbs oxygen with great avidity and
forms with it different compounds, according to the means of oxidation
employed. Thus, for example, manganese is slowly deposited from an
ammoniacal solution, when it is permitted to take up oxygen from the
air, as hydrated sesquioxide, and from neutral or alkaline solutions,
as hydrated peroxide on the addition of chlorine, bromine, or chameleon
solution. For if to an acid solution of protochloride of manganese we
add a solution of bicarbonate of soda, as long as carbonic acid escapes
or till the free acid is saturated and the protochloride of manganese
converted into carbonate of protoxide of manganese, which forms with
bicarbonate of soda a soluble double salt, resembling the carbonate of
lime and magnesia, we obtain a solution which is, indeed, acid from free
carbonic acid, but has a slight alkaline reaction with litmus paper, and
with the greatest ease deprives chameleon solution of its color, the
permanganic acid being reduced and the protoxide of manganese being
oxidized to peroxide, which is precipitated as hydrate. This reaction
proceeds according to the formula,

3MnCO_{3} + 2KMnO_{4} + H_{2}O = 2KHCO_{3} + 5MnO_{2} + CO_{2}

and it may be employed for estimating the content of manganese by
titration. As follows from the formula two equivalents of permanganate
of potash are required for the titration of three equivalents of
protoxide of manganese, which has also been established by direct
experiments, as well as that the escape of carbonic acid indicated
by the formula actually takes place. The precipitate of manganese is
dissolved either in water to which 0.5 per cent. of hydrochloric acid
has been added, or in boiling nitric acid. When manganese occurs along
with iron, which in general is the case, we must take care that the iron
in the solution is in the state of peroxide, which is precipitated on
the addition of the bicarbonate of soda, and is allowed to remain as a
precipitate, because it does not affect the titration injuriously. The
removal of this precipitate by filtering would be more loss than gain,
partly because there would be a risk of losing manganese in this way,
partly because the precipitate of manganese, which occurs immediately on
the addition of the chameleon solution, proceeds both more rapidly and
with greater completeness in the presence of the iron precipitate than
otherwise. This appears to be caused by the iron precipitate as it
were inclosing, and mechanically drawing down the light manganese
precipitate, provided a weak chemical union between the two precipitates
does not even take place, depending on the tendency of peroxide of
manganese to behave toward bases, as, for instance, hydrate of lime
as an acid. Hence it thus follows that it ought to be arranged that
a sufficient quantity of iron[1] (at least the same quantity as of
manganese) be present in the liquid at titration, also that time be
given for the precipitate to fall, so that the color of the solution may
be observed between every addition of chameleon solution.

[Footnote 1: For this in case of need a solution of perchloride of iron
free of manganese may be employed.]

When the content of manganese is large, it is sometimes rather long
before the solution is ready for titration. The reason of this appears
to be that a part of the manganese is first precipitated as hydrated
sesquioxide, which is afterward oxidized to hydrated peroxide, for the
upper portion of the liquid may sometimes be colored by chameleon, while
the lower portion, which is in closer contact with the precipitate,
is less colored or absolutely colorless. From this we also see how
advisable it is to stir the liquid frequently during titration. Toward
the close of it, it is also advantageous, when the contents of manganese
are large, to warm the solution to about 50° C., because the removal of
color is thereby hastened. When the fluid, which is well stirred after
each addition of chameleon, has obtained from it a perceptible color,
which does not disappear after several stirrings, the whole of the
manganese is precipitated and the color of the solution remains almost
unchanged after the lapse of at least twelve hours.

When the content of manganese is large the solution may be divided into
two equal portions, one of which is first to be roughly titrated to
ascertain its content approximately, after which the whole is to be
mixed together and the titration completed, which can thus be performed
with greater speed and certainty. If too much chameleon has been added,
one may titrate back with an accurately estimated solution of manganese,
which is prepared most easily by evaporating fifteen cubic centimeters
chameleon solution down to two or three cubic centimeters, boiling with
two to three cubic centimeters hydrochloric acid so long as the smell
of chlorine is observed, and then diluting the solution to ten cubic
centimeters, when one cubic centimeter of it corresponds to the same
measure of chameleon.

With respect to the delay which must take place during the titration in
order to give the precipitate time to fall, it is advantageous, in order
to save time, to work with several samples; but it is, in such a case,
desirable to have a separate burette for each sample, in order to avoid
noting every addition of the chameleon solution and afterward adding
them up. If burettes are wanting, and one must be used for several
samples, a Mohr's burette with glass cock is the most convenient to
use. For the titration of iron with chameleon solution, the latter is
commonly used of such a strength that 0.01 gramme of iron corresponds to
about one cubic centimeter of chameleon solution, which is obtained
by dissolving 5.75 grammes permanganate of potash in 1,000 cubic
centimeters water. The titration is determined by means of iron, a salt
of iron or oxalic acid. A drop of such a solution, corresponding to
about one-twentieth cubic centimeter, or 0.0001 gramme Mn, is sufficient
to give a perceptible reddish color to 200 cubic centimeters of water.

As what takes place in the titration of iron with chameleon is indicated
by the following formula,

10FeO + 2KMnO_{4} = 5Fe_{2}O_{3} + K_{2}O + 2MnO_{2},

it appears, on making a comparison with the formula given above, that
ten equivalents of iron correspond to three equivalents of manganese,
and that there is thus required for three equivalents manganese as
much chameleon solution as for ten equivalents iron. When we know the
titration of the chameleon solution for iron, that for manganese is
obtained by multiplying the former by (3 x 55)/(10 x 56) =0.295. If, for
instance, one cubic centimeter chameleon solution corresponds to 0.01
gramme iron, the figure for manganese is 0.01 x 0.295 = 0.00295 gramme
per cubic centimeter.

We can of course also determine the titration for manganese in a
chameleon solution with the greatest certainty by titrating a compound
of manganese with an accurately estimated content of it, for instance, a
spiegeleisen or ferromanganese; the test is carried out in the following
way: The substance, which is to be examined for manganese, is dissolved
by means of hydrochloric acid. If the manganese, as in slags, be
combined with silica, it is frequently necessary first to fuse the
specimen with soda. Iron ores and refinery cinders may indeed, if they
are reduced to a very fine state of division, be commonly decomposed by
boiling with hydrochloric acid with or without the addition of sulphuric
acid, but the undissolved silica is generally rendered impure by
manganese, which can only be removed by fusion with soda.

The dissolving of the fused mass in hydrochloric acid does not need to
be carried to dryness for the separation of the soluble silica, but the
boiling, after the addition of a little nitric acid, is only kept
up until the iron passes into perchloride and the manganese into
protochloride. The quantity, which ought to be taken for the test,
depends on the accuracy with which it is desired to have the manganese
estimated.

Of ferromanganese and other very manganiferous substances, in which the
manganese need not be determined with greater exactness than to 0.1 per
cent., only 0.01 gram. is taken for a test; but of common pig, wrought
iron, steel, iron ore, slags, etc., there is taken 0.5 to 1 gramme
according to the supposed content of manganese and the desired exactness
of the estimation. For instance one gramme iron, which has passed
through a metal sieve with holes half a millimeter in diameter, is
placed in a beaker 125 mm. in height and 60 mm. in diameter, and has
added to it twenty cubic centimeters of hydrochloric acid of 1.12
specific gravity, which, with a well-fitting glass cover, is boiled for
half an hour, in order that the combined carbon may be driven off in the
shape of gas. After at least the half of the hydrochloric acid has been
boiled away, there are added at least five cubic centimeters nitric acid
of 1.2 specific gravity, partly to bring the iron to peroxide, partly to
destroy the organic matters formed from the carbon, which might possibly
be remaining and might tend to remove the color of the chameleon
solution. The boiling is now continued till near dryness, when five
cubic centimeters hydrochloric acid are added, after which the solution
is boiled as long as any reddish-yellow vapors of nitrous acid are
observed. When these have disappeared a drop of the liquid taken up on
a small glass rod is tested with an newly prepared solution of red
prussiate of potash (2 grammes in 100 cubic centimeters water), to
ascertain whether there is any protoxide of iron remaining. First, when
no indication of blue or green is visible, the test shows a pure yellow,
it is certain that there are no reducing substances in the solution.

If a trace of protoxide of iron remains in the solution another cubic
centimeter of nitric acid ought to be added and the boiling continued so
long as any reddish-yellow vapors are visible, more hydrochloric acid
also being added to keep the solution from being dried up. The process
is continued in this way until two tests have given no reaction of
protoxide of iron, when the solution is diluted with water; but no
dilution should take place until the oxidation is complete, because
in the course of it the solution ought to be kept as concentrated as
possible. Silica, and graphite when it is present, need not be removed
by filtration, if it is not intended to estimate them, or there be no
fear that the graphite is accompanied by any humous substance, or that
any oily, viscous compound has been deposited on the sides of the
beaker. In the last mentioned case the solution should be transferred
into another beaker, and filtered, if graphite be present. When the
solution is evaporated to dryness, the remainder has five cubic
centimeters hydrochloric acid added to it, and the liquid is then
brought to boiling in order that the perchloride of manganese
possibly formed during the evaporation to dryness may be reduced to
protochloride, after which the solution is diluted with water till it
measures about 100 cubic centimeters. To this is now added in small
portions and with constant stirring as much of a saturated solution of
bicarbonate of soda (thirteen parts water dissolve one part salt), that
all the iron is precipitated, after which, when the escape of carbonic
acid has ceased, the solution is diluted with water till it measures 200
cubic centimeters and is then ready for titration.

A large excess of bicarbonate ought to be avoided, because in a solution
of pure protochloride of manganese it renders the liquid milky and
turbid; the addition of more water, however, makes it clear. The
solution of bicarbonate must be free from organic substances which may
tend to remove the color of the chameleon solution. To ascertain this,
the latter is added to the former drop by drop so long as the color is
removed.

If it be desired to estimate the silica in the same test, the iron, as
when it is analyzed for silica, may be also dissolved in sulphuric acid,
and afterward oxidized with nitric acid, after which the solution is
boiled to near dryness, so that the organic substances are completely
destroyed. In order afterward, to drive off the nitric acid and get the
manganese with certainty reduced to protoxide, the solution is boiled
with a little hydrochloric acid. In this way the solution goes on
rapidly and conveniently, but the titration takes longer time than when
the iron is dissolved in hydrochloric acid, because the iron precipitate
is more voluminous, and, in consequence, longer in being deposited. To
diminish this inconvenience the solution ought to be made larger. In
such a case the rule for dissolving is, one gramme iron (more if the
content of silica is small) is dissolved in a mixture of two cubic
centimeters sulphuric acid of 1.83 specific gravity and twelve cubic
centimeters of water in the way described above, and boiled until salt
of iron begins to be deposited on the bottom of the beaker. Five cubic
centimeters hydrochloric acid are now added, and the solution tested
with red prussiate of potash for protoxide of iron, and the boiling
continued till near dryness, when all the nitric acid is commonly driven
off. Should nitrous acid still show itself, some more hydrochloric acid
is added and the boiling continued.

As in dissolving in hydrochloric acid and oxidizing with nitric acid the
solution ought to be twice tested for protoxide of iron, even although
at the first test none can be discovered. The silica is taken upon
a filter, dried, ignited, and weighed. The filtrate is treated with
bicarbonate of soda, and titrated with chameleon solution in the way
described above. If the content of manganese is small (under 0.5 per
cent.) it is not necessary to warm the liquid before titration; but
in proportion as the content of manganese is larger there is so much
greater reason to hasten the removal of color by warming and constant
stirring toward the close of the titration.

       *       *       *       *       *




ON THE ESTIMATION AND SEPARATION OF MANGANESE.

[Footnote: Read before the American Chemical Society, Dec. 16, 1881]

By NELSON H. DARTON.


The element manganese having many peculiarities in its reactions
with the other elements, is now extensively used in the arts, its
combinations entering into and are used in many of the important
processes; it is consequently often brought before the chemist in his
analysis, and has to be determined in most cases with considerable
accuracy. Many methods have been proposed for this, all of them of more
or less value; those yielding the best results, however, requiring a
considerable length of time for their execution, and involving so large
an amount of manipulatory skill as to render them fairly impracticable
to a chemist at all pressed for time, and receiving but a mere trifle
for the results.

As I have had to make numerous estimations of manganese in various
compounds, as a public analyst, I have been induced to investigate the
volumetric methods at present in use to find their comparative values,
and if possible to work out a new one, setting aside one or more of the
difficulties met with in the use of the older ones. This paper is a part
summary of the results. First, I will detail my process of estimation,
then on the separation.

From all compounds of manganese, excepting those containing cobalt and
nickel, the manganese is precipitated as binoxide; those containing
these two elements are treated with phosphoric acid, or as noted under
Separation.

A.--The Estimation. The binoxide of commerce, as taken from the mine, is
well sampled, powdered, and dried at 100°C. 0.5 gramme of this is taken
and placed in a 250 c.c. flask; in analysis the binoxide on the filter,
from the treatments noted under separation is thoroughly washed with
warm water; it is then washed down in a flask, as above, after breaking
the filter paper; sufficient water is added to one-third fill the flask,
and about twice the approximate weight of the binoxide in the flask of
oxalate of potassa; these are agitated together. A twice perforated
stopper is fitted to this flask, carrying through one opening a 25 c c.
pipette nearly filled with sulphuric acid, sp. gr. 1.4, the lower point
of which just dips below the mixture in the flask, and the upper end,
carrying a rubber tube and pinch cock to control the flow of acid.
Through the other opening passes a glass tube bent at an acute angle
and connected by a short rubber tube to an adjoining flask, two-thirds
filled with decinormal baryta solutions. These connections are all made
air tight. Sulphuric acid is allowed in small portions at a time to
flow into the mixture. Carbonic acid is evolved, and, passing into
the adjoining flask, is absorbed by the baryta, precipitating it as
carbonate. To prevent the precipitate forming around or choking up the
entrance tube, the flask must be agitated at short intervals to break it
off. The reaction so familiar to us in other determinations is expressed
thus:

MnO_{2}+KO,C_{2}O_{3}+2SO_{3} = MnO,SO_{3}+KO.SO_{3}+2CO_{2},

When no more carbonic acid is evolved, another tube from this last flask
is connected with the aspirator, the pinch-cock of the pipette open, and
air drawn through the apparatus for about half a minute, and thus all
the carbonic acid evolved absorbed, or the flasks may be slightly
heated. If danger of more carbonic acid being absorbed from the air is
feared, and always in very accurate analysis, a potassa tube may be
connected to the pipette before drawing the air through. The precipitate
formed is allowed to settle, 50 c.c. of the supernatant solution
is removed with a pipette and transferred to a beaker; 50 c.c. of
decinormal nitric acid and some water is added with sufficient cochineal
tincture. It is then titrated back with decinormal soda; from this is
now readily deducted the amount of carbonic acid, and from that the
MnO_{2}, holding in view that 44 parts of carbonic acid is equivalent to
43.5 of MnO_{2} or 98.87 per cent, and that 1 c.c. of the N/10 baryta
solution is equivalent to 0.0022 grm. of CO_{2}.

If a carbonate, chloride, or nitrate, be present in the native binoxide,
it must be removed with some sulphuric acid. This is afterward
neutralized with a little caustic soda. This method yields the
following results for its value in amount of manganese to 100:
99.91-99.902-99.895, and can be executed in about twenty minutes.
Fifteen determinations can be carried on at once without loss of time,
this, however, depending on the operator's skill. I have made many
assays, and assays by this method with similarly excellent results.

Of the other methods, Bunsen's is acknowledged to be the most accurate,
but is, of course, too troublesome to be used in technical work,
although it is used in scientific analysis. Ordinary samples are not
sufficiently accurate to allow the use of this method.

The methods of reducing with iron and titrating this with chromate of
potassa, etc., have given a constant average of from 98.60-99.01. These
results are fair, but hard to obtain expeditiously.

Of the methods of precipitating the compounds of the protoxide and
estimating the acid, that of the phosphate is by far the most accurate,
titrating with uranium solution; 99.82 is a nearly constant average
with me, much depending on the operator's familiarity with the uranium
process.

The methods of Lenssen, or ferricyanide of potassium method, yields very
widely differing results. I have found the figures of Fresenius about
the same as my own in this case; that is from 98.00-100.10.

B.--On the Separation. First, from its soluble simple combinations with
the acids or bases containing no iron or cobalt; if they are present, it
is treated as is noted later. If sulphuric acid is present it must be
separated by treating the solution of the compound with barium chloride
and filtering. A nearly neutral solution is prepared in water or
hydrochloric acid and placed in a flask. Here it is treated with
chlorine by passing a current of that gas through it as long as
it causes a precipitate and for some time afterward. It is then
discontinued, the mixture allowed to deposit for a few moments, and
about two-thirds of the supernatant solution decanted; it is mixed with
some more water, and these decantations repeated until they pass away
without reaction, or by filtering it and washing on the filter; it is
then dissolved in hot hydrochloric acid, this nearly neutralized, a
solution of sesquichloride of iron is added, and again treated with an
excess of chlorine. After washing it is transferred to the flasks of
the apparatus mentioned in the first part of this paper, and estimated.
Myself and several others have found this always to be a true MnO_{2},
and not a varying mixture of protosesquioxide and binoxide, and will
thus yield accurate results. This reprecipitation may sometimes be
dispensed with by adding the iron salt before the first precipitation,
but it of course depends upon the other elements present.

From Compounds containing Cobalt, Cobalt and Nickel, Iron and group
III., together or with other elements.--Group III. and sesqui. iron are
separated by agitation with baryta carbonate, some chloride of ammonia
being added to prevent nickel and cobalt precipitation traces, and
filtering. If cobalt is present we treat this filtrate with nitrite
of potassa, etc., to separate it (that is, if it and nickel are to
be separated and estimated in the same sample; but if they are to be
estimated as one, or not separated, the treatment with nitrite, etc.,
is not used). The filtrate from this last is directly treated with
chlorine. If nickel and cobalt are not to be estimated in this sample,
the solution, as chlorides, is mixed with some chloride of ammonium
and ammonia, then with a fair excess of phosphoric acid, a sufficient
quantity more of ammonia to render the mixture alkaline. The precipitate
formed is transferred to the filter and well washed with water
containing NH_{3}Cl and NH_{4}O, then dissolved in hydrochloric acid
and reprecipitated with ammonia, filtering and washing as before. It is
again dissolved in HCl and titrated with uranium solution, or decomposed
by tin, as noted below, and the manganese precipitated as binoxide with
chlorine, and determined. The latter method is hardly practicable, and
I never have time to use it, as the titration and all together yields a
value of 99.80 in most cases, if accurately executed.

From the bases of groups V. and VI. these are separated by hydrogen
sulphide, from iron in alloys, ores, etc., and in general the iron is
separated as basic acetate, and the manganese afterward precipitated
with chlorine. Bromine is generally used in place of chlorine, the use
of which chemists claim as troublesome; but in a number of examinations
I have found it to yield more satisfactory results than bromine, which
is much more expensive.

From the acids in insoluble and a few other compounds, chromic, arsenic,
and arsenious acids, by fusion with carbonate of soda in presence of
carbonic acid gas; borate of manganese is readily decomposed when the
boracic acid is to be determined by boiling with solution of potassa,
dissolving the residue in hydrochloric acid and precipitating the
manganese as binoxide. This boiling, however, is seldom needed, as the
borate is soluble in HCl.

From phosphoric acid I always use Girard's method of treatment with
tin, using it rasped, and it yields much more accurate results with but
little manipulation. When the other acids mentioned above are present in
the compound, we treat it as directed there.

From silicic acid, by evaporation with hydrochloric acid.

From sulphur or iodine, by decomposing with sulphuric acid and
separating this with baryta chloride.

       *       *       *       *       *




RESEARCHES ON ANIMALS CONTAINING CHLOROPHYL.

[Footnote: Abstract of a paper "On the Nature and Functions of the
'Yellow Cells' of Radiolarians and Coelenterates," read to the Royal
Society of Edinburgh, on January 14, 1882, and published by permission
of the Council.--_Nature_.]


It is now nearly forty years since the presence of chlorophyl in certain
species of planarian worms was recognized by Schultze. Later observers
concluded that the green color of certain infusorians, of the common
fresh water hydra and of the fresh water sponge, was due to the same
pigment, but little more attention was paid to the subject until 1870,
when Ray Lankester applied the spectroscope to its investigation. He
thus considerably extended the list of chlorophyl containing animals,
and his results are summarized in Sachs' Botany (Eng. ed.). His list
includes, besides the animals already mentioned, two species of
Radiolarians, the common green sea anemone (_Anthea cereus_, var.
_Smaragdina_), the remarkable Gephyrean, _Bonellia viridis_, a Polychæte
worm, _Chætoperus_, and even a Crustacean, _Idotea viridis_.

The main interest of the question of course lies in its bearing on the
long-disputed relations between plants and animals; for, since neither
locomotion nor irritability is peculiar to animals; since many
insectivorous plants habitually digest solid food; since cellulose, that
most characteristic of vegetable products, is practically identical with
the tunicin of Ascidians, it becomes of the greatest interest to know
whether the chlorophyl of animals preserves its ordinary vegetable
function of effecting or aiding the decomposition of carbonic anhydride
and the synthetic production of starch. For although it had long been
known that _Euglena_ evolved oxygen in sunlight, the animal nature of
such an organism was merely thereby rendered more doubtful than ever.
In 1878 I had the good fortune to find at Roscoff the material for
the solution of the problem in the grass-green planarian, _Convoluta
schultzii_, of which multitudes are to be found in certain localities on
the coast, lying on the sand, covered only by an inch or two of water,
and apparently basking in the sun. It was only necessary to expose
a quantity of these animals to direct sunlight to observe the rapid
evolution of bubbles of gas, which, when collected and analyzed, yielded
from 45 to 55 per cent. of oxygen. Both chemical and histological
observations showed the abundant presence of starch in the green cells,
and thus these planarians, and presumably also _Hydra spongilla_, etc.,
were proved to be truly "vegetating animals."

Being at Naples early in the spring of 1879, I exposed to sunlight some
of the reputedly chlorophyl containing animals to be obtained there,
namely, _Bonellia viridis_ and _Idotea viridis_, while Krukenberg had
meanwhile been making the same experiment with _Bonellia_ and _Anthea_
at Trieste. Our results were totally negative, but so far as _Bonellia_
was concerned this was not to be wondered at since the later
spectroscopic investigations of Sorby and Schenk had fully confirmed
the opinion of Lacaze-Duthiers as to the complete distinctness of
its pigment from chlorophyl. Krukenberg, too, who follows these
investigators in terming it _bonellein_, has recently figured the
spectra of Anthea-green, and this also seems to differ considerably from
chlorophyl, while I am strongly of the opinion that the pigment of
the green crustaceans is, if possible, even more distinct, having not
improbably a merely protective resemblance.

It is now necessary to pass to the discussion of a widely distinct
subject--the long outstanding enigma of the nature and functions of the
"yellow cells" of Radiolarians. These bodies were first so called by
Huxley in his description of _Thallassicolla_, and are small bodies of
distinctly cellular nature, with a cell wall, well defined nucleus,
and protoplasmic contents saturated by a yellow pigment. They multiply
rapidly by transverse division, and are present in almost all
Radiolarians, but in very variable number. Johnnes Muller at first
supposed them to be concerned with reproduction, but afterward gave up
this view. In his famous monograph of the Radiolarians, Haeckel suggests
that they are probably secreting cells or digestive glands in the
simplest form, and compares them to the liver-cells of Amphioxus, and
the "liver-cells" described by Vogt in _Velella_ and _Porpita_. Later
he made the remarkable discovery that starch was present in notable
quantity in these yellow cells, and considered this as confirming his
view that these cells were in some way related to the function of
nutrition. In 1871 a very remarkable contribution to our knowledge of
the Radiolarians was published by Cienkowski, who strongly expressed the
opinion that these yellow cells were parasitic algæ, pointing out that
our only evidence of their Radiolarian nature was furnished by their
constant occurrence in most members of the group. He showed that they
were capable not only of surviving the death of the Radiolarian, but
even of multipying, and of passing through an encysted and an amoeboid
state, and urged their mode of development and the great variability of
their numbers within the same species as further evidence of his view.

The next important work was that of Richard Hertwig, who inclined to
think that these cells sometimes developed from the protoplasm of the
Radiolarian, and failing to verify the observations of Cienkowski,
maintained the opinion of Haeckel that the yellow cells "fur den
Stoffwechsel der Radiolarien von Bedeutung sind." In a later publication
(1879) he, however, hesitates to decide as to the nature of the yellow
cells, but suggests two considerations as favoring the view of
their parasitic nature--first, that yellow cells are to be found in
Radiolarians which possess only a single nucleus, and secondly, that
they are absent in a good many species altogether.

A later investigator, Dr. Brandt, of Berlin, although failing to confirm
Haeckel's observations as to the presence of starch, has completely
corroborated the main discovery of Cienkowski, since he finds the yellow
cells to survive for no less than two months after the death of the
Radiolarian, and even to continue to live in the gelatinous investment
from which the protoplasm had long departed in the form of swarm-spores.
He sum up the evidence strongly in favor of their parasitic nature.

Meanwhile similar bodies were being described by the investigators
of other groups. Haeckel had already compared the yellow cells of
Radiolarians to the so-called liver-cells of _Velella_; but the brothers
Hertwig first recalled attention to the subject in 1879 by expressing
their opinion that the well-known "pigment bodies" which occur in the
endoderm cells of the tentacles of many sea-anemones were also parasitic
algæ. This opinion was founded on their occasional occurrence outside
the body of the anemone, on their irregular distribution in various
species, and on their resemblance to the yellow cells of Radiolarians.
But they did not succeed in demonstrating the presence of starch,
cellulose, or chlorophyl. The last of this long series of researches is
that of Hamann (1881), who investigates the similar structures which
occur in the oral region of the Rhizostome jelly-fishes. While agreeing
with Cienkowski as to the parasitic nature of the yellow cells of
Radiolarians, he holds strongly that those of anemones and jelly-fishes
are unicellular glands.

In the hope of clearing up these contradictions, I returned to Naples
in October last, and first convinced myself of the accuracy of the
observation of Cienkowski and Brandt as to the survival of the yellow
cells in the bodies of dead Radiolarians, and their assumption of the
encysted and the amoeboid states. Their mode of division, too, is
thoroughly algoid. One finds, not unfrequently, groups of three and four
closely resembling _Protococcus_. Starch is invariably present; the wall
is true plant-cellulose, yielding a magnificent blue with iodine and
sulphuric acid, and the yellow coloring matter is identical with that
of diatoms, and yields the same greenish residue after treatment with
alcohol. So, too, in Velella, in sea-anemones, and in medusæ; in all
cases the protoplasm and nucleus, the cellulose, starch, and chlorophyl,
can be made out in the most perfectly distinct way. The failure of
former observers with these reactions, in which I at first also shared,
has been simply due to neglect of the ordinary botanical precautions.
Such reactions will not succeed until the animal tissue has been treated
with alcohol and macerated for some hours in a weak solution of caustic
potash. Then, after neutralizing the alkali by means of dilute acetic
acid, and adding a weak solution of iodine, followed by strong sulphuric
acid, the presence of starch and cellulose can be successively
demonstrated. Thus, then, the chemical composition, as well as the
structure and mode of division of these yellow cells, are those of
unicellular algæ, and I accordingly propose the generic name of
_Philozoon_, and distinguish four species, differing slightly in size,
color, mode of division, behavior with reagents, etc., for which the
name of _P. radiolarum, P. siphonophorum, P. actiniarum_, and _P.
medusarum_, according to their habitat, may be conveniently adopted.
It now remains to inquire what is their mode of life, and what their
function.

I next exposed a quantity of Radiolarians (chiefly _Collozoum_) to
sunshine, and was delighted to find them soon studded with tiny
gas-bubbles. Though it was not possible to obtain enough for a
quantitative analysis, I was able to satisfy myself that the gas was not
absorbed by caustic potash, but was partly taken up by pyrogallic acid,
that is to say, that little or no carbonic acid was present, but that a
fair amount of oxygen was present, diluted of course by nitrogen.
The exposure of a shoal of the beautiful blue pelagic Siphonophore,
_Velella_, for a few hours, enabled me to collect a large quantity of
gas, which yielded from 24 to 25 per cent. of oxygen, that subsequently
squeezed out from the interior of the chambered cartilaginous float,
giving only 5 per cent. But the most startling result was obtained
by the exposure of the common _Anthea cereus_, which yielded great
quantities of gas containing on an average from 32 to 38 per cent. of
oxygen.

At first sight it might seem impossible to reconcile this copious
evolution of oxygen with the completely negative results obtained from
the same animal by so careful an experimenter as Krukenberg, yet the
difficulty is more apparent than real. After considerable difficulty I
was able to obtain a large and beautiful specimen of _Anthea cereus_,
var. _smaragdina_, which is a far more beautiful green than that with
which I had been before operating--the dingy brownish-olive variety,
_plumosa_. The former owes its color to a green pigment diffused chiefly
through the ectoderm, but has comparatively few algæ in its endoderm;
while in the latter the pigment is present in much smaller quantity;
but the endoderm cells are crowded by algæ. An ordinary specimen of
_plumosa_ was also taken, and the two were placed in similar vessels
side by side, and exposed to full sunshine; by afternoon the specimen of
_plumosa_ had yielded gas enough for an analysis, while the larger and
finer _smaragdina_ had scarcely produced a bubble. Two varieties of
_Ceriactis aurantiaca_, one with, the other without, yellow cells, were
next exposed, with a precisely similar result. The complete dependence
of the evolution of oxygen upon the presence of algæ, and its complete
independence of the pigment proper to the animal, were still further
demonstrated by exposing as many as possible of those anemones known
to contain yellow cells (_Aiptasia chamæleon, Helianthus troglodytes_,
etc.) side by side with a large number of forms from which these are
absent (_Actinia mesembryanthemum, Sagastia parasitica, Cerianthus_,
etc.). The former never failed to yield abundant gas rich in oxygen,
while in the latter series not a single bubble ever appeared.

Thus, then, the coloring matter described as chlorophyl by Lankester
has really been mainly derived from that of the endodermal algæ of the
variety _plumosa_, which predominates at Naples; while the anthea-green
of Krukenberg must mainly consist of the green pigment of the ectoderm,
since the Trieste variety evidently does not contain algæ in any great
quantity. But since the Naples variety contains a certain amount of
ordinary green pigment, and since the Trieste variety is tolerably sure
to contain some algæ, both spectroscopists have been operating on a
mixture of two wholly distinct pigments--diatom-yellow and anthea-green.

But what is the physiological relationship of the plants and animal thus
so curiously and intimately associated? Every one knows that all the
colorless cells of a plant share the starch formed by the green
cells; and it seems impossible to doubt that the endoderm cell or the
Radiolarian, which actually incloses the vegetable cell, must similarly
profit by its labors. In other words, when the vegetable cell dissolves
its own starch, some must needs pass out by osmose into the surrounding
animal cell; nor must it be forgotten that the latter possesses
abundance of amylolytic ferment. Then, too, the _Philozoon_ is
subservient in another way to the nutritive function of the animal, for
after its short life it dies and is digested; the yellow bodies supposed
by various observers to be developing cells being nothing but dead algæ
in progress of solution and disappearance.

Again, the animal cell is constantly producing carbonic acid and
nitrogenous waste, but these are the first necessities of life to our
alga, which removes them, so performing an intracellular renal function,
and of course reaping an abundant reward, as its rapid rate of
multiplication shows.

Nor do the services of the _Philozoon_ end here; for during sunlight
it is constantly evolving nascent oxygen directly into the surrounding
animal protoplasm, and thus we have actually foreign chlorophyl
performing the respiratory function of native hæmoglobin! And the
resemblance becomes closer when we bear in mind that hæmoglobin
sometimes lies as a stationary deposit in certain tissues, like the
tongue muscles of certain mollusks, or the nerve cord of _Aphrodite_ and
Nemerteans.

The importance of this respiratory function is best seen by comparing
as specimens the common red and white Gorgonia, which are usually
considered as being mere varieties of the same species, _G. verrucosa_.
The red variety is absolutely free from _Philozoon_, which could not
exist in such deeply colored light, while the white variety, which I am
inclined to think is usually the larger and better grown of the two, is
perfectly crammed. Just as with the anemones above referred to, the
red variety evolves no oxygen in sunlight, while the white yields
an abundance, and we have thus two widely contrasted _physiological
varieties_, as I may call them, without the least morphological
difference. The white specimen, placed in spirit, yields a strong
solution of chlorophyl; the red, again, yields a red solution, which was
at once recognized as being tetronerythrin by my friend M. Merejkowsky,
who was at the same time investigating the distribution and properties
of that remarkable pigment, so widely distributed in the animal kingdom.
This substance, which was first discovered in the red spots which
decorate the heads of certain birds, has recently been shown by
Krukenberg to be one of the most important of the coloring matter of
sponges, while Merejkowsky now finds it in fishes and in almost all
classes of invertebrate animals. It has been strongly suspected to be an
oxygen-carrying pigment, an idea to which the present observation seems
to me to yield considerable support. It is moreover readily bleached
by light, another analogy to chlorophyl, as we know from Pringsheim's
researches.

When one exposes an aquarium full of _Anthea_ to sunlight, the
creatures, hitherto almost motionless, begin to wave their arms, as if
pleasantly stimulated by the oxygen which is being developed in their
tissues. Specimens which I kept exposed to direct sunshine for days
together in a shallow vessel placed on a white slab, soon acquired a
dark, unhealthy hue, as if being oxygenated too rapidly, although I
protected them from any undue rise of temperature by keeping up a flow
of cold water. So, too, I found that Radiolarians were killed by a day's
exposure to sunshine, even in cool water, and it is to the need for
escaping this too rapid oxidation that I ascribe their remarkable habit
of leaving the surface and sinking into deep water early in the day.

It is easy, too, to obtain direct proof of this absorption of a great
part of the evolved oxygen by the animal tissues through which it has to
pass. The gas evolved by a green alga (_Ulva_) in sunlight may contain
as much as 70 per cent. of oxygen, that evolved by brown algae
(_Haliseris_) 45 per cent., that from diatoms about 42 per cent.; that,
however, obtained from the animals containing _Philozoon_ yielded a very
much lower percentage of oxygen, e.g. _Velella_ 24 per cent., white
_Gorgonia_ 24 per cent., _Ceriactis_ 21 per cent., while Anthea, which
contains most algæ, gave from 32 to 38 per cent. This difference is
naturally to be accounted for by the avidity for oxygen of the animal
cells.

Thus, then, for a vegetable cell no more ideal existence can be imagined
than that within the body of an animal cell of sufficient active
vitality to manure it with carbonic acid and nitrogen waste, yet of
sufficient transparency to allow the free entrance of the necessary
light. And conversely, for an animal cell there can be no more ideal
existence than to contain a vegetable cell, constantly removing
its waste products, supplying it with oxygen and starch, and being
digestible after death. For our present knowledge of the power of
intracellular digestion possessed by the endoderm cells of the lower
invertebrates removes all difficulties both as to the mode of entrance
of the algæ, and its fate when dead. In short, we have here the relation
of the animal and the vegetable world reduced to the simplest and
closest conceivable form.

It must be by this time sufficiently obvious that this remarkable
association of plant and animal is by no means to be termed a case of
parasitism. If so, the animals so infested would be weakened, whereas
their exceptional success in the struggle for existence is evident.
_Anthea cereus_, which contains most algæ, probably far outnumbers all
the other species of sea-anemones put together, and the Radiolarians
which contain yellow cells are far more abundant than those which are
destitute of them. So, too, the young gonophores of Velella, which
bud off from the parent colony and start in life with a provision of
_Philozoon_ (far better than a yolk-sac) survive a fortnight or more in
a small bottle--far longer than the other small pelagic animals. Such
instances, which might easily be multiplied, show that the association
is beneficial to the animals concerned.

The nearest analogue to this remarkable partnership is to be found in
the vegetable kingdom, where, as the researches of Schwendener, Bornet,
and Stahl have shown, we have certain algæ and fungi associating
themselves into the colonies we are accustomed to call lichens, so that
we may not unfairly call our agricultural Radiolarians and anemones
_animal lichens_. And if there be any parasitism in the matter, it is
by no means of the alga upon the animal, but of the animal, like the
fungus, upon the alga. Such an association is far more complex than
that of the fungus and alga in the lichen, and indeed stands unique in
physiology as the highest development, not of parasitism, but of the
reciprocity between the animal and vegetable kingdoms. Thus, then, the
list of supposed chlorophyl containing animals with which we started,
breaks up into three categories; first those which do not contain
chlorophyl at all, but green pigments of unknown function (_Bonelia<,
Idotea_, etc.); secondly, those vegetating by their own intrinsic
chlorophyl (_Convoluta_, _Hydra_, _Spongilia_); thirdly, those
vegetating by proxy, if one may so speak, rearing copious algae in their
own tissues, and profiting in every way by the vital activities of
these.

PATRICK GEDDES.

       *       *       *       *       *




COMPRESSED OIL GAS FOR LIGHTING CARS, STEAMBOATS, AND BUOYS.


We give in the accompanying figures the arrangement of the different
apparatus necessary for the manufacture and compression of illuminating
gas on the system of Mr. Pintsch, as well as the arrangements adopted by
the inventor for the lighting of railway cars and buoys. This system has
been adopted to some extent in both Germany and England, and is also
being introduced into France.

[Illustration: WORKS FOR THE MANUFACTURE OF OIL GAS.--ELEVATION AND
PLAN.]

The Pintsch gas is prepared by the distillation of heavy oils in a
furnace composed of two superposed retorts. The oil to be volatilized
is contained in a vertical reservoir B, which carries a bent pipe that
enters the upper retort, A. The flow of the oil is regulated in this
conduit by means of a micrometer screw which permits of varying the
supply according to the temperature of the retorts. In order to
facilitate the vaporization, the flow of oil starts from a cast-iron
trough, C, and from thence spreads in a thin and uniform layer in the
retort. The residua of distillation remain almost entirely in the
reservoir, O, from whence they are easily removed. The vapor from the
oil which is disengaged in the vessel, A, goes to the lower retort, D,
in which the transformation of the matter is thoroughly completed. On
leaving the latter, the gas enters the drum, E, at the lower part of
the furnace. To prevent the choking up of the pipe, R, the latter is
provided with a joint permitting of dilatation. The gas on leaving E
goes to the condenser, G G, where it is freed from its tar. The latter
flows out, and the gas proceeds to the washer, J, and the purifiers, I
and I, to be purified. The amount of production is registered by the
meter, L.

When the gas is to be utilized for lighting railway cars or buoys, it
is compressed in the accumulators, T, which are large cylindrical
reservoirs of riveted or welded iron plate.

Compression is effected by means of a pump, F or F', which sucks the
gas into a desiccating cylinder, M, connected with the gasometer of the
works The pump, F, which is used when the production is larger than
usual, has two compressing cylinders of different diameters, one
measuring 170 millimeters and the other 100. The piston has a stroke of
320 millimeters. The two compressing cylinders are double acting,
and communicate with each other by valves so arranged as to prevent
injurious spaces. The gas drawn from the gasometer is first compressed
in the larger cylinder to a pressure of about 4 atmospheres; then
it passes into the second cylinder, whence it is forced into the
accumulators under a pressure varying from 10 to 12 atmospheres.

For a not very large production, the small pump suffices. This has a
single compressing cylinder connected directly with the piston rod, upon
which acts the steam coming from the boiler, K. This pump compresses the
gas to a pressure of 10 atmospheres, and is capable of storing seven
cubic meters of it per hour.

The carburets of hydrogen which separate in a liquid state through the
effect of the compression of the gas are retained in a cylindrical
receptacle, V, which is located between the pump and the accumulators,
T.

Besides the necessary safety apparatus, there is disposed in front of
the condensers a special valve, N, which allows the gas to escape into
the air if the retorts or the purifying apparatus get choked up.

When the oil gas is not compressed it possesses an illuminating power
four times greater than that obtained from coal gas; and, while the
latter loses the greater part of its luminous power by compression, the
former loses only an eighth. It is this property that renders the oil
gas eminently fitted for lighting cars, and it is for this reason that
several large European railway companies have adopted it.


APPLICATION TO CARS.

We show in the accompanying engravings the mode of installation that
the inventor has finally adopted for railway purposes. Each car
is furnished, perpendicularly to its length, with a reservoir, a,
containing the supply of gas under a pressure of 6 or 7 atmospheres. The
gas is introduced into this reservoir by means of a valve, which is
put in communication with the mouths of supply pipes placed along a
platform. The pipes are provided with a stopcock and their mouths are
closed by a cap. To fill the car reservoir it is only necessary to
connect the mouths of the supply pipes with the valves of the cars by
means of rubber tubing--an operation which takes about one minute for
each car.

[Illustration: LIGHTING OF RAIWAY CARS]

When it is necessary to supply cars at certain points where there are
no gas works, there is attached to the train a special car on which are
placed two or three accumulators, which thus transport a supply of the
compressed gas to distances that are often very far removed from the
source of supply.

The reservoir of each car, containing a certain supply of gas,
communicates with a regulator, b, the importance of which we scarcely
need point out. This apparatus consists: (1) of a cast-iron cup, A,
closed at the top by a membrane, B, which is impervious to gas; (2) of a
rod, C, connected at one end with the membrane, and at the other with
a lever, D; (3) of a regulating valve resting on the lever, and of a
spring, E, which renders the internal mechanism independent of the
motions of the car. The lever, acting for the opening and closing of the
valve, serves to admit gas into the regulator through the aperture, F.
This latter is so calculated as to allow the passage of a quantity of
gas corresponding to a pressure of 16 millimeters. As soon as such a
pressure is reached in the regulator, the membrane rises and acts on the
lever, and the latter closes the valve. When the pressure diminishes,
as a consequence of the consumption of gas, the spring, E, carries the
lever to its initial position and another admission of gas takes place.
Communication between the regulator and the lamps is effected by means
of a pipe, z, of 7 millimeters diameter (provided with a cock, d, which
permits of extinguishing all the lamps at once, and by special branches
for each lamp. The lamps used differ little in external form from those
at present employed. The body is of cast-iron; the cover, funnel, and
chimney are of tin; and the burner is of steatite. The products of
combustion are led outside through a flattened chimney, t, resting at o
on the center of the reflector. The air enters through the cover of
the lamp and reaches the interior through a series of apertures in the
circumference of the cast-iron bell which supports the reflector. There
is no communication whatever between the interior of the lamp and the
interior of the car, and thus there is no danger of passengers being
annoyed by the odor of gas. By means of a peculiar apparatus, f, the
flame may be reduced to a minimum without being extinguished. This
arrangement is at the disposition of the conductor or within reach of
the passengers. For facilitating cleaning, the lamps are arranged so as
to turn on a hinge-joint, m; so that, on removing the reflector, o, it
is only necessary to raise the arm that carries the burner, r in order
to clean the base, s, without any difficulty.

On several railways both the palace and postals cars are also heated by
compressed oil gas; and lately an application has been made of the gas
for supplying the headlights of locomotives (see figure), and for the
signals placed at the rear of trains. But one of the most interesting
applications of oil is that of


LIGHTING BUOYS,

in which case it is compressed into large reservoirs placed on a boat.
The buoys employed are generally of from 90 to 285 cubic feet capacity,
affording a lighting for from 35 to 100 days.

To the upper part of the buoy there is affixed a firmly supported tube
carrying at its extremity the lantern, c. The gas compressed to 6 or 7
atmospheres in the body of the buoy passes, before reaching the burner,
into a regulator analogous to the one installed on railway cars, but
modified in such a way as to operate with regularity whatever be the
inclination of the buoy. In the section showing the details of the
lantern on a large scale the direction taken by the air is indicated by
arrows, as is also the direction taken by the products of combustion.
These latter escape at m, through apertures in the cap of the apparatus.

[Illustration: COMPRESSED OIL GAS FOR LIGHTING CARS STEAMBOTS, AND
BUOYS.]

The regulator, B, in the interior of the lantern, brings to a uniform
pressure the inclosed gas, whose pressure continues diminishing as a
consequence of the consumption. The lantern is protected against wind
and waves by very thick convex glasses set into metallic cross-bars, c.
The flame is located in the focus of a Fresnel lens, b, consisting
of superposed prismatic rings, and adjusted at its lower part with a
circle, d, while a conical ring, e makes a joint at its other extremity.
This ring is held by the top piece of the lantern through the
intermedium of six spiral springs, c' c''. Under the focus of the flame
there is placed a conical reflector of German silver, t.

The buoy is filled through an aperture, k, in the side of the upper
tube. This aperture is provided with a valve which allows of the buoy
being charged by connecting it with the accumulators located on a boat
built especially for this service. As soon as the gas reaches 6 or 7
atmospheres the cocks of the buoy and reservoir are closed, and the
connecting tube is removed. The consumption of gas in the lantern
is. 1,230 cubic inches per hour. This being known it is very easy to
calculate from the capacity of the buoy how often it is necessary to
charge it.

A large number of buoys on the Pintsch system are already in use.

The oil gas is likewise applicable to the illumination of lighthouses,
and among those that are now being lighted in that way we may cite the
one in the port of Pillau, near Königsberg. Several large steamers are
likewise being lighted on this plan. In such an application of oil gas
the management of the apparatus is very easy, and the permanence of the
illuminating power of the gas gives every facility for the lighting of
the boat, whatever be the duration of the trip.

Although Mr. Pintsch's process of manufacture has been but recently
introduced into France, it has received a number of applications that
permits us to foresee the future that is in store for it. The Railway
Company of the West has contracted for the lighting of 250 first-class
cars that run within the precincts of the city; the State Railways have
56 cars lighted in this way running between Nantes and Bordeaux and
between Saintes and Limoges; and the Line of the East has just applied
the system to 80 of its cars.

       *       *       *       *       *




DELICATE TEST FOR OXYGEN.


T. W. Engelmann proposes, in the _Botanische Zeitung_, a new test, of an
extremely delicate nature, for determining the presence of very minute
quantities of oxygen, namely: its power of exciting the motility of
bacteria. If any of the smaller species, especially _Bacterium termo_,
are brought to rest, and then introduced into a fluid in which there is
the minutest trace of free oxygen, they will immediately begin to move
about freely; and if the oxygen is gradually introduced, their motion
will be set up only in those parts of the drop which the oxygen reaches.
In this way Engelmann was able to determine the evolution of oxygen by
_Euglena_ and by chlorophyl granules.

       *       *       *       *       *




DETERMINATION OF SMALL QUANTITIES OF ARSENIC IN SULPHUR.

By H SCHÆPPI.


Ten grms. of sulphur, pulverized as finely as possible, are covered
with hot water and a few drops of nitric acid digested for some time,
filtered, and washed till the washings have no longer an acid reaction.
Thus calcium chloride and sulphate are removed, and calcium sulphide, if
present, is destroyed. The sulphur thus prepared is covered with water
at 70° to 80°, a few drops of ammonia are added, and the mixture is
digested for a quarter of an hour. All the arsenic present as sulphide
is dissolved, and the ammoniacal liquid is variously treated
according to the degree of accuracy required. For perfectly accurate
determinations the ammoniacal solution is mixed with silver nitrate, and
all the sulphur present in the state of arsenic sulphide is thrown down
as silver sulphide, acidified with nitric acid, filtered, and washed.
The precipitate of silver sulphide is dissolved in hot nitric acid and
determined as silver chloride. From the weight of the latter the arsenic
sulphide is calculated. As a less accurate but more rapid method, the
ammoniacal solution of arsenic sulphide is cautiously neutralized with
pure dilute nitric acid and considerably diluted. It is then titrated
with decinormal silver nitrate till a drop of the solution is turned
brown with neutral chromate. The arsenic is easily calculated from the
quantity of silver nitrate consumed. For very rough determinations it is
sufficient to treat ten grms. of finely-ground sulphur with nitric acid,
to extract with ammonia, and to add silver nitrate. From the intensity
of the color, or the quantity of the precipitate of silver sulphide,
it may be judged if the sulphur is approximately free from arsenic or
strongly contaminated. The author states that, contrary to the general
belief, reddish yellow sulphur is more free from arsenic than such as is
of a full yellow color.

       *       *       *       *       *




HOW TO PLANT TREES.

By N. ROBERTSON, Government Grounds, Ottawa.


A great deal has been written and said about tree planting. Some advise
one way, some another. I will give you my method, with which I have been
very successful, and, as it differs somewhat from the usual mode, may be
interesting to some of your readers. I go into the woods, select a place
where it is thick with strong, young, healthy, rapid growing trees. I
commence by making a trench across so as I will get as many as I want.
I may have to destroy some until I get a right start. I then undermine,
taking out the trees as I advance; this gives me a chance not to destroy
the roots. I care nothing about the top, because I cut them into what
is called poles eight or ten feet long. Sometimes I draw them out by
hitching a team when I can get them so far excavated that I can turn
them down enough to hitch above where I intend to cut them off; by this
method I often get almost the entire root. I have three particular
points in this; good root, a stem without any blemish, and a rapid
growing tree. This is seldom to be got where most people recommend trees
to be taken from--isolated ones on the outside of the woods; they are
generally scraggy and stunted; and to get their roots you would have to
follow along way to get at the fibers on their points, without which
they will have a hard struggle to live. Another point recommended is to
plant so that the tree will stand in the direction it was before being
moved; that I never think about, but always study to have the longest
and most roots on the side where the wind will be strongest, which is
generally the west, on an open exposure.

For years I was much against this system of cutting trees into poles,
and fought hard against one of the most successful tree planters in
Canada about this pole business. I have trees planted under the system
described that have many strong shoots six and eight feet long--hard
maple, elm, etc., under the most unfavorable circumstances. In planting,
be particular to have the hole into which you plant much larger than
your roots; and be sure you draw out all your roots to their length
before you put on your soil; clean away all the black, leafy soil about
them, for if that is left, and gets once dry, you will not easily wet it
again. Break down the edges of your holes as you progress, not to leave
them as if they were confined in a flower pot; and when finished, put
around them a good heavy mulch, I do not care what of--sawdust, manure,
or straw. This last you can keep by throwing a few spadefuls of soil
over; let it pass out over the edges of your holes at least one foot.

I have no doubt that the best time to plant is the fall, as, if left
till spring, the trees are too far advanced before the frost is put of
the ground; and by fall planting the soil gets settled about the roots,
and they go on with the season.

Trees cut like poles have another great advantage. For the first season
they require no stakes to guard against the wind shaking them, which is
a necessity with a top; for depend upon it, if your tree is allowed to
sway with the wind, your roots will take very little hold that season,
and may die, often the second year, from this very cause.

All who try this system will find out that they will get a much prettier
headed tree, and much sooner see a tree of beauty than by any other,
as, when your roots have plenty of fibrous roots, and are in vigorous
health, three years will give you nice trees.--_The Canadian
Horticulturist_.

       *       *       *       *       *




THE GROWTH OF PALMS.


In a paper (Russian) recently read before the Botanical Section of the
St. Petersburg Natural History Society, Mr. K. Friderich describes in
detail the anatomical structures to be met with in the aerial roots of
_Acanthorhiza aculeata_, these roots presenting a remarkable example of
roots being metamorphosed into spines. Supplementing this, E. Regel made
the following remarks:

Palm trees, grown from seed, thicken their stems for a succession of
years, like bulbs, only at the base. Many palms continue this primary
growth (i.e., the growth they first started with) for fifty to sixty
years before they form their trunk. During this time new roots are
always being developed at the base of the stem, in whorls, and these
always above the old roots. This even takes place in old specimens,
especially in those planted in the open ground which have already formed
a trunk, In such cases the cortex layer, where the roots break through,
is sprung off. In conservatories, under the influence of the damp air,
this root formation, on which indeed the further normal growth of the
palm depends, takes place without any special assistance. When the palm
is grown in a sitting room, one must surround the base of the trunk with
moss, which is to be kept damp, in order to favor the development of the
roots. When the base of the palm trunk has almost reached its normal
thickness, then begins the upward development of the trunk, which takes
place more slowly in those species whose leaves grow close together than
in those whose leaves are further apart. In specimens of many species of
Cocos and Syagrus, whose leaves are particularly far apart, the stems
grow so quickly when planted in the open ground that they increase by
five to six feet in height per annum. The stem of those palms which
develop a terminal inflorescence have ended their apical growth by doing
so, and wither gradually, In addition to this (withering) in the case,
e.g. of _Arenga saccharifera_, new inflorescences are developed from the
original axils _(Blattachseln)_ from above downward, so that one sees at
last the already leafless trunk still developing inflorescences in the
direction toward the base of the trunk. Almost all palms with this
latter kind of growth develop offshoots in their youth at the base of
their trunks, which shoot up again into trunks after the death of the
primary trunk, if they are not taken off before. As to the structure of
the palm trunks out of unconnected wood bundles, the assertion has been
made that the palm stem does not grow thicker in the course of time, and
that this is the explanation of the columnar almost evenly thick trunk.
But careful measurements that were made for years have led Regel to the
conclusion that a thickening of the trunk actually takes place, which
probably amounts to an increase of about a third over the original
circumference of the trunk.

       *       *       *       *       *




THE FUTURE OF SILK CULTURE IN THE UNITED STATES.

Report by CONSUL PEIXOTTO, of Lyons.


In my dispatch, No. 140, dated September 1, 1880, I referred to the fact
that new machinery for reeling silk had been invented, which, in my
opinion, was destined to be of great importance, and to make this
industry extremely valuable and profitable in our country. I beg now
to submit some additional observations upon this subject, and for the
purpose of being definite, to entitle them


THE FUTURE OF SILK CULTURE IN THE UNITED STATES.

Silk reeling is at present accomplished by the use of appliances which
differ only in detail from those in use many centuries ago, and which
can scarcely be called machines, being rather of the nature of apparatus
depending entirely upon the skill and knowledge of the operative for the
results produced. In fact, even the most perfect of French and Italian
reels bear about the same relation to automatic machinery that an
old-fashioned spinning wheel does to our modern spinning machines.

Since the date of my previous dispatch upon this subject, the new
reeling machine of Mr. E. W. Serrell, jr., of New York (who still
continues in Lyons), has been undergoing improvement and development,
and it is with the hope of facilitating the introduction and culture of
silk, and of enabling our people to adopt the best means to that end,
and to avoid errors which have been disastrous in the past and are
likely to be extremely expensive in the near future, that I now
communicate with the department, which is equally interested in securing
new sources of industry and wealth for our people at home as for the
promotion and extension of their commerce abroad.

It will be recollected that from about 1834 to 1839 there raged a great
speculation in mulberry trees of a certain species (_Morus multicaulis_)
destined for feeding silk worms. This speculation led to a total loss
of all the time and money devoted to it, partly because of its wild and
utterly unsound character, and partly because the little silk which was
actually produced could not be reeled to advantage. As a result, silk
culture fell into utter disrepute and for nearly a generation was
scarcely thought of as a practical thing in the United States. Time,
however, showed clearly where the great obstacle lay, and although many
may have imagined that other difficulties led to its abandonment in
1839-40, those who have studied the matter are unanimously of the
opinion that the want of reeling machinery has alone prevented the
success of sericulture in those parts of the Union which are suitable
for it. Believing this obstacle to be removed, it remains to set forth
in a brief manner some of the points upon which, it appears to me, the
successful introduction of silk raising will depend.

For the success of silk culture in our country two things are now
requisite--the acquisition on the part of those about to engage in it
of sound knowledge of its processes and requirements, and proper
organization.

The details of the work of silk culture are of such a nature that they
may be readily understood, and I apprehend that there will be little
difficulty found by those who engage in it in mastering them, after some
little experience. The point at which it seems to me that there is the
most danger is at the very beginning.

In order to avoid delays and losses, the person who begins silk culture
should have a pretty clear idea of the scale of operations which are
likely to be most profitable; of the trees, or rather shrubs, which must
be obtained; of the apparatus and fixtures necessary, and of the results
which may be reasonably expected from the labor and expense required.
All of these items will be found to vary in different parts of the
country, and I fear that general rules, broad deductions, and such
information as would apply under all circumstances and in all places
would be extremely difficult to formulate, and too vague for practical
use at any given point.

In fact, as far as information which may be considered perfectly general
is concerned, I have, for the time being, only one point to put forward
in addition to what has already been published in the United States,
which is to repeat and show as emphatically as possible that the use
of the reels at present employed for the filature of silk is entirely
impracticable in our country, and that the raiser must sell his cocoons.

This has been so often said and so clearly shown that I should consider
it unnecessary to repeat it had not my attention been called to the fact
that the success of several people and associations in the United States
in raising cocoons has again made it a temptation to endeavor to reel
silk, and during the past year I have received applications from people
in different States for information as to the kind of silk reel employed
here which would be most suitable for use by them.

I am aware, also, that estimates have been made and published by some
eminent authorities tending to show that this work could be done on a
paying basis in some places in America. So far as I have seen them,
however, these estimates are fatally defective in that they do not allow
for differences in quality of silk reeled by competent or incompetent
people, and under circumstances favorable or otherwise, but seem to
assume that any silk reeled in our country would be a first rate
article, and paid for accordingly.

While this might be true in isolated cases, it could not be true in
general, as with present appliances the art of reeling _good_ silk is
only to be acquired and retained by years of apprenticeship and constant
practice joined to a natural talent for the work. So true is this, that
even in districts where the work has been largely carried on for many
generations, quite a large proportion of women who try for years find it
impossible to become good reelers.

Now, there is a considerable difference in price between well reeled and
poorly reeled silk--a difference so great that silk not well reeled in
every way is not worth as much as the cocoons from which it is derived.
It is, therefore, quite a hopeless task to reel silk unless the reeler
is skilled. Even if it could be done to advantage--which I do not think
it could--there exists in America no means of training reelers. In
Europe they are taught by degrees in the filatures, working first at
the easier stages of the operations, and afterward being helped forward
under the eyes and guidance of experienced operatives.

Another grave defect in the estimates alluded to is that all the profit
is assumed to be paid to the reeler. This can evidently only be the case
when each reeler runs her own reel, owns and cares for her own cocoons,
sells her own silk, and furnishes her own capital. Now, even supposing
that persons so fortunately placed as to be able to fulfill all these
conditions should wish to engage in silk reeling, which is in the
highest degree improbable, there exists an almost insuperable obstacle
to the production of good silk except by an establishment large enough
to use the cocoons of many producers.

Nearly every silk crop as raised by the individual growers contains
three or four grades of cocoons, and to produce good and uniform silk,
these must be separated and each sort reeled by itself, producing
several grades of silk.

Without going into detail, it is enough to say that this is not
practical for those who attempt to reel their own cocoons, and that for
this reason, and many others, hand reels and single basins have been
nearly abandoned even in Italy; the women finding so much difficulty
that they prefer to sell their cocoons and work in large establishments
where the work is done to more advantage.

It is evident, therefore, that, from the estimates made, there should be
a considerable deduction for poor workmanship, and another for use of
capital, organization, selling expenses, superintendence, insurance,
repairs, deterioration, etc. In fact, I do not see in what way the
reeling of silk in the United States, by the ordinary method, could be
made to bear a much higher charge for labor than that borne by European
filatures, which barely pay with labor at one franc per diem of thirteen
hours.

To be able, then, to reel silk by the ordinary reels, it would first be
necessary to find a sufficiency of highly skilled operatives willing
to labor in a factory thirteen hours per day for twenty cents each. I
sincerely believe and hope that this can never be done. I have enlarged
somewhat upon this difficulty for the purpose of showing that the
growers, or at any rate individual growers of cocoons, should not
attempt to do the reeling, but by no means with an idea of discouraging
the raising of silk worms, which is and should be an entirely separate
matter. To use a rough comparison, I should esteem it as wasteful, even
if possible, for each grower to attempt to reel his own cocoons as for
each farmer to grind his own wheat upon his farm and endeavor to sell
the flour.

It is, therefore, clear that the object of the sericulturist should be
to raise and market as good a crop of cocoons as possible to the best
advantage, and with the least possible expense and risk.

After what has been said, it may be very properly asked, if, seeing that
the hopes which have been entertained of reeling by the usual method
have proved fallacious, and as no radically new system of raising silk
worms is under consideration, it is not very possible that all hopes of
profit from rearing the worm may prove fallacious also.

In fact, not only has the question been asked, but an argument of
great apparent strength and much plausibility has been formulated and
extensively circulated, tending to show that the difficulty of cheap
labor, which it has been shown stood in the way of reeling without
improved machinery, will make the raising of cocoons also a hopelessly
unprofitable task.

Briefly summarized, this argument may be stated as follows:

First. To raise silk worms to advantage much time and attention are
required.

Second. Time and attention are more costly in the United States than in
other countries.

Third. Consequently, cocoons can be more cheaply raised in other
countries than in the United States.

Fourth. The United States possess no special advantages as a market for
cocoons, and therefore they must be sold as cheaply as elsewhere, and
the labor costing more, there is less profit.

Fifth. The profits made by raisers in Europe are not very great, and as
they would be less in the United States, it is not worth while to try to
raise cocoons in that country.

It must be acknowledged that upon the surface this all appears to be
very sound and almost unanswerable, but I hope to be able to show that
there is in reality not the slightest real foundation for the conclusion
to which this argument points.

Taking the points cited in order, I would say, as regards the first and
second, that although labor and time are required to raise cocoons, I
am convinced that the labor and time of the kind necessary will not be
found more expensive in our country than in Europe, for the following
reasons:

The work is a home industry. It can be carried on without severe manual
labor except for a few days, at the end of the season, when large crops
are raised.

Now, nothing is better known than that there exists in many of our
States an enormous number of wives and daughters of country people of
a class entirely different from any to be found elsewhere, except,
perhaps, to a limited extent, in England. I refer to the "well-to-do"
but not wealthy agricultural and manufacturing classes in small
villages.

One or two generations ago the farmers' and mechanics' wives and
daughters found plenty of work in spinning, weaving, dyeing, cutting,
and making the linen and clothes of the family. This has entirely ceased
as a domestic industry with the exception of the "sewing" of the women's
clothes and men's underwear. As a consequence, the women of the family
are condemned to idleness, or to the drudgery of the whole household
work.

Upon a proper occasion I think that much might be said of the evils and
dangers which are likely within a short time to arise from the fact that
perhaps a large majority of American women find themselves, because
of the present organization of society and industry, almost unable to
contribute to the family income except by going away from home, or in
doing the most menial and severe labor as household workers from one end
of the year to the other. I shall at present, however, only point out
that in hundreds of thousands of homes in the country an opportunity of
gaining a very moderate sum in addition to the present income by the
expenditure of some weeks of care and light work would be hailed as a
Godsend, and that, too, in families where the feeling of self-respect
and the desire to keep the family together are far too strong to permit
the women to go away from home in any way to earn money.

Let any one who doubts this consider the dairy work and similar
industries, and try to calculate how much per diem the women thus
occupied at home gain in money. It may be said with entire accuracy
that, as a rule, anything in which the women can engage at home, by
which something may be earned, will in general be regarded as net profit
through out many sections of the land. In the silk districts of Europe,
agricultural machinery is very much less employed than with us, and in
general every woman who can possibly be spared from other work is a
field laborer and valuable as such. So that time taken for raising silk
must be deducted from her other productive work and charged to the cost
of the silk crop. I think that there can be no doubt that this one fact
is quite sufficient to make the question of the cost of caring for the
worms really as much in favor of the United States as at first glance it
appears to be the other way; it being the case that in our country many
who would be glad to do the work have spare time to give to it, whereas
in Europe every hour that is given to silk worms would otherwise be
spent in the field.

In the South there are very large masses of inhabitants who are unable
to work in the fields, both men and women, and who would also find in a
yearly crop of silk worms a very comfortable addition to their
yearly gains, and one which could be derived from time not otherwise
convertible into money. Land is very much dearer, and taxes are higher
in the European silk districts than with us, and every little crop of
cocoons has to pay its share, which adds a considerable percentage to
its cost.

The buildings possessed by peasants and used for the raising of silk
worms are, in general, small, close, and miserable. Throughout America
the roomy barns which are empty at the cocoon season, will, with little
preparation, be much preferable, and enable the raisers to work to very
much better advantage.

In Europe diseases of several kinds have become more or less prevalent,
and in some cases have diminished the production of whole districts.

Notwithstanding the fact that many experiments have been made in
America, and in Georgia particularly, and silk has been raised
continuously for over a century, these diseases (_maladies des vers a
soile_) have never made their appearance.

The people of our country are, as a rule, much better educated than
those in Southern France and Italy, and will undoubtedly use their
intelligence in such a way as to derive a benefit from it, and economize
their labor by proper appliances, etc.

Taking all these facts into consideration, I am convinced that that
there will be no difficulty in raising cocoons for the same cost in
labor in the United States as in Europe, and I am inclined to think that
the work can be much more cheaply done.

It is true that the United States is not an especially good market for
cocoons; in fact up to this time there has been scarcely any market
at all for them; but with the organization of the industry and the
introduction of reeling machinery, the market will be at least as good
there as elsewhere. As to whether it will be "worth while" for our
people to raise silk worms, I would say that though the amount of money
to be paid by any one family is certainly not very large, it is nearly
all clear profit, and under the circumstances which I have above pointed
out, and which exist so generally, I am sure that the sum to be realized
will be regarded as very important by a vast number of people. As in
other points, it is extremely difficult to make any exact estimates on
such a subject which would be generally applicable to a country so large
and so various in climate, soil, and social habit as ours. I am inclined
to think, however, that were the members of an average family, under
average circumstances, to raise a crop of cocoons, the amount
which could be advantageously reared should produce, according to
circumstances, from seventy-five to two hundred dollars. Scarcely
any "paying" result can be hoped for, however, without more or less
organization of the work, as sericulture is an industry which is very
sensitive to the evils of a want of proper co-operation among those
who carry on its various processes. After some reflection, I am of the
opinion that individual growers will have great difficulty in selling
cocoons if they are isolated from others, and I therefore doubt the
wisdom of encouraging sporadic and ill-directed efforts, which,
however well meant and earnestly pursued, are much more apt to end in
disappointment, discouragement, and discredit to the newly developing
industry than in anything else. It seems to me to be neither wise nor
fair to furnish estimates of returns, which presuppose an organization
of the industry, without mentioning the difficulties which must be
encountered where the organization is lacking. The great difficulty
is in selling the cocoons after they are raised, and this can only be
practically overcome by such a development of the culture as will
result in the production, within the limits of a given neighborhood, of
sufficient quantities of cocoons to make it practicable to prepare and
forward them to market. It is as well known as any other fact in trade,
that small transactions are much more costly in proportion than large
ones, and this general rule is especially applicable to the cocoon
market. The product of two or three isolated families in the interior of
our country could not be marketed to advantage. Whereas, were several
hundreds engaged on the work in the same vicinity the charge of
marketing their joint crop would be only a small percentage of its
value.

Silk raising is the work of an organized people, and before it can
become successful in our country must possess proper channels for its
trade, just as much as wool, or cotton, or wheat. The machinery of this
organization, however, need not be either complicated or expensive. What
is required is a system of nuclei in towns or large villages, which may
serve as centers of information and as gathering receptacles for the
crops of surrounding producers.

The details of organization must be left, and I think may safely be left
to the good sense of the people of different sections, who will work
out the problem in different ways, according to their different
circumstances. Even were the need of organization not made evident to
those undertaking sericulture in the beginning, it would soon become so,
as it has, in fact, in several parts of the country. I have therefore
deemed it proper to call attention to this matter, on the principle that
a "stitch in time saves nine." I am informed that there exist already
in the United States several associations devoted to acquiring and
disseminating knowledge of the art of sericulture. This is a very great
step in the right direction, and cannot be too heartily commended. If
conducted with prudence and wisdom these societies will be of great
service, and I would respectfully suggest that any encouragement which
the government may think proper to afford would in all probability be
extremely useful and profitable to the country in the future. Provided,
always, that such societies are really devoted to the dissemination of
information and the careful organization of the industry, and are not
merely visionary and impractical cultivators of misapplied enthusiasm.

It would, I think, be of importance so far as possible, to direct
the attention of county and State agricultural societies, "village
improvement clubs," and in general the intelligent and careful portion
of our rural population to this matter. It is beyond doubt that the time
when sericulture can be begun and carried on profitably in our country
has arrived. Its successful introduction would result in a very
important yearly revenue and increase in the public wealth, for I think
that within a comparatively few years it could be made to be worth at
least fifty or sixty millions of dollars per annum, and perhaps much
more. This, however, is a less advantage than the fact that by supplying
a new home industry it would do much toward conserving home ties and
interests, and thereby help to strengthen and perpetuate good morals and
home living among our people.

       *       *       *       *       *




THE HIBERNATION OF ANIMALS.


"Don't black bears sleep through the winter?" questioned the writer of
an attendant who was dealing out mid-day rations of bread and milk at
the park.

"That's the general impression," was the rejoinder, "but we have never
noticed any attempts at hibernation here. Bears are unusually lively
during the cold months, and demand their food as regularly as do the
lions and other feline animals. I don't know that any observations of
value on this question have ever been made on animals in confinement.
I have had some experience with outside animals, and a great many go
through what is called a winter's sleep; and in warm countries there is
what might be called a summer sleep. Bears begin in the fall to look out
for a soft nest; and if it's possible for them to eat more at one time
than another they do it then, and when the cold weather sets in they
are fat and in prime condition. According to some authorities, the fat
produces the carbon that in some way tends to induce somnolency. The
stomach of a bear at this time becomes empty, and naturally shrivels
or draws into a very small space, and is rendered totally useless by
a substance called 'tappen' that clogs it and the intestines; this is
formed of pine leaves and other material that the animal takes from
ants' nest and the trunks of trees in its search after honey. They lie
asleep in this condition for about six months, generally snowed in; but
you can tell the place, as the heat of the bear, what there is left,
keeps an air hole up through the snow. The bear seems to live on its
fat, the tappen preventing its too rapid consumption; and if you run
across them during this time--even along in March just before they wake
up--they are about as fat as when they went in. I have taken a slice of
fat from a black bear six inches thick--regular blubber. I remember,"
continued the man, "one winter I was 'log hauling' in the western part
of this State. We had our eyes on a big tree, and one morning when it
was about ten degrees below zero I tackled it to warm up. I hammered
away for about five hours at it and finally started her, and over she
came--slowly at first, and then as if she was going right through. The
snow was nearly three feet deep, and as the tree struck it flew up for
about twenty feet and half blinded me, and when I came to there was the
biggest black bear I ever saw standing along side of me, looking about
as mixed as I did. I had lost my ax, and the first move I made she
started, and on taking a look I found that she had a nest in the trunk
and had probably turned in for the winter. It was about twenty feet from
the ground, and was built with moss, leaves, and all kinds of truck, and
as warm and as snug as you please--a good place to spend a winter in."

The brown and polar bears have the same habit of lying up for the
winter. An Esquimau informed Captain Lyon that in the first of the
winter the pregnant bears are always fat and solitary. When a heavy fall
of snow sets in the animal seeks some hollow place in which she can lie
down, and remains quiet while the snow covers her. Sometimes she will
wait until a quantity of snow has fallen and then digs herself a cave;
at all events it seems necessary that she should be covered up by the
snow. She now goes to sleep and does not wake until the spring sun is
pretty high, when she brings forth two cubs. The cave by this time has
become much larger by the effect of the animal's warmth and breath, so
that the cubs have room enough to move, and they acquire considerable
strength by continually sucking. The dam at length becomes so thin and
weak that it is with great difficulty she extricates herself, which she
does when the sun is powerful enough to throw a strong glare through
the snow which roofs the den. Then the family comes out, and will take
anything that comes along in the way of food. During the long sleep
the temperature of the bear's blood is reduced to almost that of
the surrounding air. The power of will over the muscles seems to be
suspended, respiration is hardly noticeable, and most of the vital
functions are at a complete standstill--the entire body sleeping, as it
were. The male grizzly bear never hibernates. The young and the females,
however, build nests, one of which measured ten feet high, five feet
long, and six feet wide.

Bats are great winter sleepers, and in most of the known caves they can
be found during the cold months clinging to the walls and to each other.
During hibernation their respiration ceases almost entirely, and only
the most careful use of a stethoscope can reveal it. The air that has
surrounded numbers of them has been carefully examined and not the
slightest evidence found of its having been breathed; and, stranger yet,
they can exist in this condition in gas, that, were they awake, would
prove instantly fatal. A machine has been invented to examine these and
other animals while in this condition. A delicate index records the
slightest pulsation, while a thermometer shows the rise and fall of the
temperature at every moment during the period; and by an arrangement
of the wing, the circulation of the blood is recorded. A more delicate
experiment can hardly be imagined, as a strong breath, a sneeze, or a
footfall will cause the subject of the experiment to recover enough to
respire several times; and the effect of this on the machine can be
imagined when it is known that though, while in this condition, they
produce no effect upon the oxygen of the air about them, they consume
when respiring more than four cubic inches of oxygen an hour.

The common marmot is a great underground sleeper. They build large
storehouses, sometimes eight feet in diameter, and from the latter part
of September to April they lie in them, and, like the bears, give birth
to their young during this period.

The dormouse is a remarkable sleeper. Even in their ordinary sleep they
can be taken from the nest and handled without waking them. Toward
winter they acquire a great deal of fat, and stow away a vast amount of
provision around about their nest, and then go to sleep within; but they
rarely awake to use this food unless a very warm period comes around
before the regular breaking up of cold weather.

The hedgehog is a sound winter sleeper, and has been the subject of
an infinite number of experiments while in this condition. One
experimentalist, believing that cold was the cause of their curious
condition, surrounded one with a freezing mixture, and froze it
to death. By increasing the cold about another that was already
hibernating, it was made to wake up; and walked off.

If an animal is suddenly decapitated while in this hibernating
condition, the action of the heart is not affected for some time, a
second life seeming to outlive the one taken. An experiment has been
made in which the brain of the sleeper was removed, then the entire
spinal cord, but for two hours hardly any change was noticeable upon the
action of the heart; and a day after that organ contracted when touched
by the operator.

The writer has the winter nest of a family of ants. A piece of fence
rail was found beneath an old pile of boards and brought into a warm
room for the sake of a rich fungus growing upon it, and several hours
after the table and chairs were found to be covered with ants. Where
they came from was a mystery, until the old rail was accidentally jarred
and a number fell from it. A section was cut down through it, and the
winter home of the tribe destroyed--probably the work of weeks, perhaps
months. The interior of the wood was completely riddled by tunnels and
passages, some being large and holding several hundred ants, while
others contained only a few. In some of the interior passages the ants
had not been affected by the heat, and were packed in great masses and
evidently fast asleep; they soon recovered, however, and walked off
slowly in different directions, as if wondering if an earthquake or
spring had come.

A great number of insects go through a period of hibernation, especially
spiders. The young of the latter are often covered by the parent; first,
by coarse strings of silk, as if to hold them in place, and then by
a white, silvery web worked over them, which forms probably a sure
protection from wind and weather.

The writer has a cherry-stone in which is coiled up an insect, best
known as the sowbug. A squirrel had probably eaten out the meat and
opened the way, and in this snug retreat we found the little hibernater
snugly rolled up, as is also its habit when alarmed. The mouth of the
hole was stopped by black soil, but whether from accident or by the
animal itself we could not tell.

Some fishes and reptiles are hibernaters. Frogs and toads sleep out the
winter at the bottom of ponds or in holes in the ground. Tree toads, if
kept in a cage in the winter and provided with soil, will endeavor to
cover themselves with it, showing how strong the instinct or habit
is. Some fishes are so insensible to heat or cold that when in this
condition they can be frozen and carried for a number of days and then
be brought back to an active condition. The pond snail passes into a
winter sleep as soon as the temperature of the water is below 14° Cent.,
that is, they will not digest food or grow until the temperature of the
water is at least up to 15° Cent. Those who have watched the Harlem
River from McComb's Dam Bridge cannot have failed to notice the curious
appearance of the muddy shores of the river and creeks at low tide.
If the sun shines brightly, the dismal beach seems to quiver and
scintillate in a most beautiful manner, reflecting the light like so
many diamonds. If we draw nearer, this shore is seen to be entirely
covered in places with little snails, that, left by the tide, are
forging through the mud to regain the water, and the sunlight striking
on them is reflected by the glass-like secretion with which they are
covered, producing the curious effect noticed. This could be seen in the
warm months, but now, not a snail of the countless millions can be seen.
They have gone down in search of "hard-pan," there to hibernate until
next April. The land snail (_Helix pomatia_) sleeps four months during
the year, and does not throw off the calcareous lid that protects it
during this time until the day temperature has reached 12° Cent. Prairie
dogs feel the effect of temperature as low as this.

In Cuba reptiles hibernate between 7° and 24° Cent., according to the
species. In warmer countries, snakes, lizards, frogs, etc., fall into a
state called chill coma that precisely resembles winter sleep, but their
temperature is far above that at which hibernating animals of the north
are still active. The state of hibernation is not the direct result of
an extreme of heat or cold, but rather is caused by a departure from the
optimum. In the snail its normal temperature is about the same as the
water, and being a poor heat producer it is not surprising that when
the water grows colder the animal is forced to succumb; but it is
a remarkable fact that warm-blooded animals like many of the
above-mentioned, whose bodies are maintained by internal processes at a
high temperature of 26° to 38°, are incapable of resisting the lowering
influence of cold. The fall in temperature in some is wonderful; as an
example, the high body temperature of warm-blooded animals may be said
to oscillate between 36° and 43° Cent. (this includes man). Experiments
made with the zizel show that during hibernation this animal's
temperature is only 2° Cent., the lowest known; and a thermometer
introduced into the animal indicated the same, showing that warm-blooded
animals in hibernating become truly cold blooded animals. If a rabbit's
temperature reaches 15° Cent., it will die. The germs of bryozoa or of
the fresh water sponges resist any amount of cold, but the full grown
forms die at the first cold turn. Insects are destroyed, but their eggs
live, though of the greatest possible delicacy. Salmon eggs have been
carried from this State to Australia, and there hatched. In fact, some
animals live in the ice, as the glacier flea and several others.

As it is not the direct result of extremes of heat or cold that produces
sleep, neither is the awakening from hibernation directly caused by
a rise of temperature. In experiments made upon weasels, which are
sometimes caught asleep, one came to life in about three hours, during
which the temperature of the room remained the same as it had been
during the entire hibernation, viz., 10° Cent. In another weasel, during
the awakening, the body temperature rose very rapidly--and more so in
the second part of the period than in the first. In the first hour and
fifty-five minutes of the awakening the body temperature rose 6.6° Cent,
and in the following fifty minutes it rose 17° Cent. This remarkable
increase took place without any vigorous movements on the part of the
weasel. Even its breathing showed no increase in proportion to the rise.
These cases show that though, at certain seasons, animals relax as it
were and lie dormant, and recover, seemingly at the will of the weather,
yet, in point of fact, the rise and fall of temperature has no direct
effect upon them. The cause is an internal one, awaiting discovery.--C.
F. HOLDER, in _Forest and Stream_.

       *       *       *       *       *

What is described as the largest steel sailing ship afloat was lately
launched at Belfast, Ireland. It registers 2,220 tons, and has been
named the Garfield. It will be employed in the Australian and California
trade.

       *       *       *       *       *




THE TIDES.


London _Nature_, in a recent issue, says: From a scientific point of
view, the work done by the tides is of unspeakable importance. Whence is
this energy derived with which the tides do their work? If the tides are
caused by the moon, the energy they possess must also be derived from
the moon. This looks plain enough, but unfortunately it is not true.
Would it be true to assert that the finger of the rifleman which pulls
the trigger supplies the energy with which the rifle bullet is animated?
Of course it would not. The energy is derived from the explosion of
gunpowder, and the pulling of the trigger is merely the means by which
that energy is liberated.

In somewhat similar manner the tidal wave produced by the moon is the
means whereby a part of the energy stored in the earth is compelled to
expend itself in work. Let me illustrate this by a comparison between
the earth rotating on its axis and the fly-wheel of an engine: The fly
wheel is a sort of reservoir, into which the engine pours its power at
each stroke of the piston. The various machines in the mill merely draw
off the power from the store accumulated in the fly-wheel. The earth
is like a gigantic fly-wheel detached from the engine, though still
connected with the machines in the mill. In that mighty fly-wheel a
stupendous quantity of energy is stored up, and a stupendous quantity of
energy would be given out before that fly-wheel would come to rest. The
earth's rotation is a reservoir from whence the tides draw the energy
they require for doing work. Hence it is that though the tides are
caused by the moon, yet whenever they require energy they draw on the
supply ready to hand in the rotation of the earth. The earth differs
from the fly-wheel of an engine in a very important point. As the energy
is withdrawn from the fly-wheel by the machines in the mill, so it is
restored thereto by the power of the steam engine, and the fly runs
uniformly. But the earth is merely the fly-wheel without the engine.
When the work by the tides withdraws energy from the earth, that energy
is never restored. It, therefore, follows that the earth's rotation
must be decreasing. This leads to a consequence of the most wonderful
importance. It tells us that the speed with which the earth rotates on
its axis is diminishing. We can state the result in a manner which has
the merits of simplicity and brevity. The tides are increasing the
length of the day. At present, no doubt, the effect of the tides
in changing the length of the day is very small. A day now is not
appreciably longer than a day a hundred years ago. Even in a thousand
years the change in the length of the day is only a fraction of a
second. But the importance arises from the fact that the change, slow
though it is, lies always in one direction. The day is continually
increasing. In millions of years the accumulated effect becomes not only
appreciable, but even of startling magnitude.

The change in the length of the day must involve a corresponding change
in the motion of the moon. If the moon acts on the earth and retards the
rotation of the earth, so, conversely, does the earth react upon the
moon. The earth is tormented by the moon, so it strives to drive away
its persecutor. At present the moon revolves around the earth at a
distance of about 240,000 miles. The reaction of the earth tends to
increase this distance, and to force the moon to revolve in an orbit
which is continually growing larger and larger. As thousands of years
roll on, the length of the day increases second by second, and the
distance of the moon increases mile by mile. A million years ago the
day, probably, contained some minutes less than our present day of
twenty-four hours. Our retrospect does not halt here; we at once project
our view back to an incredibly remote epoch which was a crisis in the
history of our system. It must have been at least 50,000,000 years ago.
It may have been very much earlier. This crisis was the interesting
occasion when the moon was born. The length of the day was only a very
few hours. If we call it three hours we shall not be far from the truth.
Purhaps you may think that if we looked back to a still earlier epoch,
the day would become still less, and finally disappear altogether. This
is, however, not the case. The day can never have been much less than
three hours in the present order of things. Everybody knows that the
earth is not a sphere, but there is a protuberance at the equator, so
that, as our school books tell us, the earth is shaped like an orange.
It is well known that this protuberance is due to the rotation of
the earth on its axis, by which the equatorial parts bulge out by
centrifugal force. The quicker the earth rotates the greater is the
protuberance. If, however, the rate of rotation exceeds a certain limit,
the equatorial portion of the earth could no longer cling together. The
attraction which unites them would be overcome by centrifugal force, and
a general break up would occur. It can be shown that the rotation of the
earth, when on the point of rupture, corresponds to a length of the day
somewhere about the critical value of three hours, which we have already
adopted. It is, therefore, impossible for us to suppose a day much
shorter than three hours.

Let us leave the earth for a few minutes and examine the past history
of the moon. We have seen the moon revolve around the earth in an
ever-widening orbit, and consequently the moon must, in ancient times,
have been nearer the earth than it is now. No doubt the change is slow.
There is not much difference between the orbit of the moon a thousand
years ago and the orbit in which the moon is now moving. But when we
rise to millions of years, the difference becomes very appreciable.
Thirty or forty millions of years ago the moon was much closer to the
earth than it is at present; very possibly the moon was then only half
its present distance. We must, however, look still earlier, to a certain
epoch not less than fifty million of years ago. At that epoch the moon
must have been so close to the earth that the two bodies were almost
touching. Everybody knows that the moon revolves now around the earth
in a period of twenty-seven days. The period depends upon the distance
between the earth and the moon. In earlier times the month must have
been shorter than our present month. Some millions of years ago the moon
completed its journey in a week instead of taking twenty-eight days as
at present. Looking back earlier still, we find the month has dwindled
down to a day, then down to a few hours, until at that wondrous epoch
when the moon was almost touching the earth, the moon spun around the
earth once every three hours.

In those ancient times I see our earth to be a noble globe, as it is as
present. Yet it is not partly covered with oceans and partly clothed
with verdure. The primeval earth seems rather a fiery and half-molten
mass, where no organic life can dwell. Instead of the atmosphere which
we now have, I see a dense mass of vapors in which perhaps, all the
oceans of the earth are suspended as clouds. I see that the sun still
rises and sets to give the succession of day and of night, but the
day and the night together only amounted to three hours, instead of
twenty-four. Almost touching the chaotic mass of the earth is another
much smaller and equally chaotic body. Around the earth I see this small
body rapidly rotating, the two revolving together, as if they were bound
by invisible bands. The smaller body is the moon.

       *       *       *       *       *




DRILLING GLASS.


The _Revue Industrielle_ gives the following method of drilling holes
in glass: First, prepare a saturated solution of gum camphor in oil of
turpentine. Then take a lance-shaped drill, heat it to a white heat, and
dip it into a bath of mercury, which will render it extremely hard. When
sharpened and dipped into the above-named camphor solution, the tool
will enter the glass as if the latter were as soft as wood. If care be
taken to keep the spot being drilled constantly wet with the solution,
the operation will proceed rapidly, and there will rarely be any need of
sharpening the tool.

       *       *       *       *       *

A catalogue, containing brief notices of many important scientific
papers heretofore published in the SUPPLEMENT, may be had gratis at this
office.

       *       *       *       *       *




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