



Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland,
Charles Franks and the DP Team





[Illustration]




SCIENTIFIC AMERICAN SUPPLEMENT NO. 531




NEW YORK, MARCH 6, 1886

Scientific American Supplement. Vol. XXI, No. 531.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.


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TABLE OF CONTENTS.

I.   CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By
     WM. LAWSON

     Aluminum.--By J.A. PRICE.--Iron the basis of civilization.--
     Aluminum the metal of the future.--Discovery of aluminum.--Art
     of obtaining the metal.--Uses and possibilities

II.  ENGINEERING AND MECHANICS.--The Use of Iron in Fortification.
     --Armor-plated casements.--The Schumann-Gruson chilled iron
     cupola.--Mougin's rolled iron cupola.--With full page
     of engravings

     High Speed on the Ocean

     Sibley College Lectures.--Principles and Methods of Balancing
     Forces developed in Moving Bodies.--Momentum and centrifugal
     force.--By CHAS.T. PORTER.--3 figures

     Compressed Air Power Schemes.--By J. STURGEON.--Several
     figures

     The Berthon Collapsible Canoe.--2 engravings

     The Fiftieth Anniversary of the Opening of the First German
     Steam Railroad.--With full page engraving

     Improved Coal Elevator.--With engraving

III. TECHNOLOGY.--Steel-making Ladles.--4 figures

     Water Gas.--The relative value of water gas and other gases as
     Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With
     tables and 1 figure

     Japanese Rice Wine and Soja Sauce.--Method of making

IV.  ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating
     that Electricity develops only on the Surface of Conductors.--1
     figure

     The Colson Telephone.--3 engravings

     The Meldometer.--An apparatus for determining the melting
     points of minerals

     Touch Transmission by Electricity in the Education of Deaf
     Mutes.--By S. TEFFT WALKER.--With 1 figure

V.   HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By
     C.F. HOLDER.--With 2 engravings

     How Plants are reproduced.--By C.E. STUART.--A paper read
     before the Chemists' Assistants' Association

VI.  MISCELLANEOUS--The Origin of Meteorites.--With 1 figure

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THE USE OF IRON IN FORTIFICATION.


Roumania is thinking of protecting a portion of the artillery of the
forts surrounding her capital by metallic cupolas. But, before deciding
upon the mode of constructing these formidable and costly affairs, and
before ordering them, she has desired to ascertain their efficacy and
the respective merits of the chilled iron armor which was recently in
fashion and of rolled iron, which looks as if it were to be the fashion
hereafter.

[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.]

The Krupp works have recommended and constructed a cupola of
casehardened iron, while the Saint Chamond works have offered a turret
of rolled iron. Both of these recommend themselves by various merits,
and by remarkably ingenious arrangements, and it only remains to be seen
how they will behave under the fire of the largest pieces of artillery.

[Illustration: FIG. 2.]

We are far in advance of the time when cannons with smooth bore were
obliged to approach to within a very short range of a scarp in order to
open a breach, and we are far beyond that first rifled artillery which
effected so great a revolution in tactics.

[Illustration: FIG. 3.]

To-day we station the batteries that are to tear open a rampart at
distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch
cannon that arms them has for probable deviations, under a charge of 20
pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16
inches in direct fire and 8 inches in curved.

The weight of the projectile is 88 pounds, and its remanent velocity at
the moment of impact is 1,295 feet. Under this enormous live force, the
masonry gradually crumbles, and carries along the earth of the parapet,
and opens a breach for the assaulting columns.

[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF
THIRTY-SEVEN 6 IN. PROJECTILES.]

In order to protect the masonry of the scarp, engineers first lowered
the cordon to the level of the covert-way. Under these circumstances,
the enemy, although he could no longer see it, reached it by a curved or
"plunging" shot. When, in fact, for a given distance we load a gun with
the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is
as depressed as possible, and the angles, a and a', at the start and
arrival are small, and we have a direct shot. If we raise the chase of
the piece, the projectile will describe a curve in space which would be
a perfect parabola were it not for the resistance of the air, and the
summit of such curve will rise in proportion as the angle so increases.
So long as the falling angle, a, remains less than 45 deg., we shall have a
curved shot. When the angle exceeds this, the shot is called "vertical."
If we preserve the same charge, the parabolic curve in rising will meet
the horizontal plane at a greater distance off. This is, as well known,
the process employed for reaching more and more distant objects.

[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE
OF A VOUSSOIR.]

The length of a gun depends upon the maximum charge burned in it, since
the combustion must be complete when the projectile reaches the open
air. It results from this that although guns of great length are capable
of throwing projectiles with small charges, it is possible to use
shorter pieces for this purpose--such as howitzers for curved shots and
mortars for vertical ones. The curved shot finds one application in the
opening of breaches in scarp walls, despite the existence of a covering
of great thickness. If, from a point, a (Fig. 3), we wish to strike the
point, b, of a scarp, over the crest, c, of the covert-way, it will
suffice to pass a parabolic curve through these three points--the
unknown data of the problem, and the charge necessary, being
ascertained, for any given piece, from the artillery tables. In such
cases it is necessary to ascertain the velocity at the impact, since the
force of penetration depends upon the live force (mv squared) of the
projectile, and the latter will not penetrate masonry unless it have
sufficient remanent velocity. Live force, however, is not the sole
factor that intervenes, for it is indispensable to consider the angle at
which the projectile strikes the wall. Modern guns, such as the Krupp 6
inch and De Bange 6 and 8 inch, make a breach, the two former at a
falling angle of 22 deg., and the latter at one of 30 deg.. It is not easy to
lower the scarps enough to protect them from these blows, even by
narrowing the ditch in order to bring them near the covering mass of the
glacis.

The same guns are employed for dismounting the defender's pieces, which
he covers as much as possible behind the parapet. Heavy howitzers
destroy the _materiel_, while shrapnel, falling nearly vertically, and
bursting among the men, render all operations impossible upon an open
terre-plein.

[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12
INCH BALL.]

The effect of 6 and 8 inch rifled mortars is remarkable. The Germans
have a 9 inch one that weighs 3,850 pounds, and the projectile of which
weighs 300. But French mortars in nowise cede to those of their
neighbors; Col. De Bange, for example, has constructed a 101/2 inch one of
wonderful power and accuracy.

Seeing the destructive power of these modern engines of war, it may well
be asked how many pieces the defense will be able to preserve intact for
the last period of a siege--for the very moment at which it has most
need of a few guns to hold the assailants in check and destroy the
assaulting columns. Engineers have proposed two methods of protecting
these few indispensable pieces. The first of these consists in placing
each gun under a masonry vault, which is covered with earth on all sides
except the one that contains the embrasure, this side being covered with
armor plate.

The second consists in placing one or two guns under a metallic cupola,
the embrasures in which are as small as possible. The cannon, in a
vertical aim, revolves around the center of an aperture which may be of
very small dimensions. As regards direct aim, the carriages are
absolutely fixed to the cupola, which itself revolves around a vertical
axis. These cupolas may be struck in three different ways: (1) at right
angles, by a direct shot, and consequently with a full charge--very
dangerous blows, that necessitate a great thickness of the armor plate;
(2) obliquely, when the projectile, if the normal component of its real
velocity is not sufficient to make it penetrate, will be deflected
without doing the plate much harm; and (3) by a vertical shot that may
strike the armor plate with great accuracy.

General Brialmont says that the metal of the cupola should be able to
withstand both penetration and breakage; but these two conditions
unfortunately require opposite qualities. A metal of sufficient
ductility to withstand breakage is easily penetrated, and, conversely,
one that is hard and does not permit of penetration does not resist
shocks well. Up to the present, casehardened iron (Gruson) has appeared
to best satisfy the contradictory conditions of the problem. Upon the
tempered exterior of this, projectiles of chilled iron and cast steel
break upon striking, absorbing a part of their live force for their own
breakage.

In 1875 Commandant Mougin performed some experiments with a chilled iron
turret established after these plans. The thickness of the metal
normally to the blows was 231/2 inches, and the projectiles were of cast
steel. The trial consisted in firing two solid 12 in. navy projectiles,
46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed
ones, 12 in. in diameter. The 6 inch projectiles were fired from a
distance of 3,280 feet, with a remanent velocity of 1,300 feet. The
different phases of the experiment are shown in Figs. 4, 5, and 6. The
cupola was broken; but it is to be remarked that a movable and
well-covered one would not have been placed under so disadvantageous
circumstances as the one under consideration, upon which it was easy to
superpose the blows. An endeavor was next made to substitute a tougher
metal for casehardened iron, and steel was naturally thought of. But
hammered steel broke likewise, and a mixed or compound metal was still
less successful. It became necessary, therefore, to reject hard metals,
and to have recourse to malleable ones; and the one selected was rolled
iron. Armor plate composed of this latter has been submitted to several
tests, which appear to show that a thickness of 18 inches will serve as
a sufficient barrier to the shots of any gun that an enemy can
conveniently bring into the field.

[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING
NINETY-SIX SHOTS.]

_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron
casemate after a vigorous firing. The system that we are about to
describe is much better, and is due to Commandant Mougin.

[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.]

The gun is placed under a vault whose generatrices are at right angles
to the line of fire (Fig. 8), and which contains a niche that traverses
the parapet. This niche is of concrete, and its walls in the vicinity of
the embrasure are protected by thick iron plate. The rectangular armor
plate of rolled iron rests against an elastic cushion of sand compactly
rammed into an iron plate caisson. The conical embrasure traverses this
cushion by means of a cast-steel piece firmly bolted to the caisson, and
applied to the armor through the intermedium of a leaden ring.
Externally, the cheeks of the embrasure and the merlons consist of
blocks of concrete held in caissons of strong iron plate. The
surrounding earthwork is of sand. For closing the embrasure, Commandant
Mougin provides the armor with a disk, c, of heavy rolled iron, which
contains two symmetrical apertures. This disk is movable around a
horizontal axis, and its lower part and its trunnions are protected by
the sloping mass of concrete that covers the head of the casemate. A
windlass and chain give the disk the motion that brings one of its
apertures opposite the embrasure or that closes the latter. When this
portion of the disk has suffered too much from the enemy's fire, a
simple maneuver gives it a half revolution, and the second aperture is
then made use of.

_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is
dome-shaped, and thus offers but little surface to direct fire; but it
can be struck by a vertical shot, and it may be inquired whether its top
can withstand the shock of projectiles from a 10 inch rifled mortar. It
is designed for two 6 inch guns placed parallel. Its internal diameter
is 191/2 feet, and the dome is 8 inches in thickness and has a radius of
161/2 feet. It rests upon a pivot, p, around which it revolves through the
intermedium of rollers placed in a circle, r. The dome is of relatively
small bulk--a bad feature as regards resistance to shock. To obviate
this difficulty, the inventor partitions it internally in such a way as
to leave only sufficient space to maneuver the guns. The partitions
consist of iron plate boxes filled with concrete. The form of the dome
has one inconvenience, viz., the embrasure in it is necessarily very
oblique, and offers quite an elongated ellipse to blows, and the edges
of the bevel upon a portion of the circumference are not strong enough.
In order to close the embrasure as tightly as possible, the gun is
surrounded with a ring provided with trunnions that enter the sides of
the embrasure. The motion of the piece necessary to aim it vertically is
effected around this axis of rotation. The weight of the gun is balanced
by a system of counterpoises and the chains, l, and the breech
terminates in a hollow screw, f, and a nut, g, held between two
directing sectors, h. The cupola is revolved by simply acting upon the
rollers.

[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.]

_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1)
is that of a cylindrical turret. It is 123/4 feet in diameter, and rises
31/4 feet above the top of the glacis. It has an advantage over the one
just described in possessing more internal space, without having so
large a diameter; and, as the embrasures are at right angles with the
sides, the plates are less weakened. The turret consists of three plates
assembled by slit and tongue joints, and rests upon a ring of strong
iron plate strengthened by angle irons. Vertical partitions under the
cheeks of the gun carriages serve as cross braces, and are connected
with each other upon the table of the hydraulic pivot around which the
entire affair revolves. This pivot terminates in a plunger that enters a
strong steel press-cylinder embedded in the masonry of the lower
concrete vault.

The iron plate ring carries wheels and rollers, through the intermedium
of which the turret is revolved. The circular iron track over which
these move is independent of the outer armor.

The whole is maneuvered through the action of one man upon the piston of
a very small hydraulic press. The guns are mounted upon hydraulic
carriages. The brake that limits the recoil consists of two bronze pump
chambers, a and b (Fig. 10). The former of these is 4 inches in
diameter, and its piston is connected with the gun, while the other is 8
inches in diameter, and its piston is connected with two rows of 26
couples of Belleville springs, d. The two cylinders communicate through
a check valve.

When the gun is in battery, the liquid fills the chamber of the 4 inch
pump, while the piston of the 8 inch one is at the end of its stroke. A
recoil has the effect of driving in the 4 inch piston and forcing the
liquid into the other chamber, whose piston compresses the springs. At
the end of the recoil, the gunner has only to act upon the valve by
means of a hand-wheel in order to bring the gun into battery as slowly
as he desires, through the action of the springs.

[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.]

For high aiming, the gun and the movable part of its carriage are
capable of revolving around a strong pin, c, so placed that the axis of
the piece always passes very near the center of the embrasure, thus
permitting of giving the latter minimum dimensions. The chamber of the 8
inch pump is provided with projections that slide between circular
guides, and carries the strap of a small hydraulic piston, p, that
suffices to move the entire affair in a vertical plane, the gun and
movable carriage being balanced by a counterpoise, q.

The projectiles are hoisted to the breech of the gun by a crane.

Between the outer armor and turret sufficient space is left for a man to
enter, in order to make repairs when necessary.

Each of the rolled iron plates of which the turret consists weighs 19
tons. The cupolas that we have examined in this article have been
constructed on the hypothesis than an enemy will not be able to bring
into the field guns of much greater caliber than 6 inches.--_Le Genie
Civil_.

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HIGH SPEED ON THE OCEAN.


_To the Editor of the Scientific American_:

Although not a naval engineer, I wish to reply to some arguments
advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of
Jan. 2, 1886, in regard to high speed on the ocean.

Capt. Giles argues that because quadrupeds and birds do not in
propelling themselves exert their force in a direct line with the plane
of their motion, but at an angle to it, the same principle would, if
applied to a steamship, increase its speed. But let us look at the
subject from another standpoint. The quadruped has to support the weight
of his body, and propel himself forward, with the same force. If the
force be applied perpendicularly, the body is elevated, but not moved
forward. If the force is applied horizontally, the body moves forward,
but soon falls to the ground, because it is not supported. But when the
force is applied at the proper angle, the body is moved forward and at
the same time supported. Directly contrary to Capt. Giles' theory, the
greater the speed of the quadruped, the nearer in a direct line with his
motion does he apply the propulsive force, and _vice versa_. This may
easily be seen by any one watching the motions of the horse, hound,
deer, rabbit, etc., when in rapid motion. The water birds and animals,
whose weight is supported by the water, do not exert the propulsive
force in a downward direction, but in a direct line with the plane of
their motion. The man who swims does not increase his motion by kicking
out at an angle, but by drawing the feet together with the legs
straight, thus using the water between them as a double inclined plane,
on which his feet and legs slide and thus increase his motion. The
weight of the steamship is already supported by the water, and all that
is required of the propeller is to push her forward. If set so as to act
in a direct line with the plane of motion, it will use all its force to
push her forward; if set so as to use its force in a perpendicular
direction, it will use all its force to raise her out of the water. If
placed at an angle of 45 deg. with the plane of motion, half the force will
be used in raising the ship out of the water, and only half will be left
to push her forward.

ENOS M. RICKER.

Park Rapids, Minn., Jan. 23, 1886.

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SIBLEY COLLEGE LECTURES.

BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL
ENGINEERING.




PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES.

BY CHAS. T. PORTER.

INTRODUCTION.


On appearing for the first time before this Association, which, as I am
informed, comprises the faculty and the entire body of students of the
Sibley College of Mechanical Engineering and the Mechanic Arts, a
reminiscence of the founder of this College suggests itself to me, in
the relation of which I beg first to be indulged.

In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight
acquaintance with Mr. Sibley, whose home was then, as it has ever since
been, in that city. Nearly twelve years afterward, in the summer of
1861, which will be remembered as the first year of our civil war, I met
Mr. Sibley again. We happened to occupy a seat together in a car from
New York to Albany. He recollected me, and we had a conversation which
made a lasting impression on my memory. I said we had a conversation.
That reminds me of a story told by my dear friend, of precious memory,
Alexander L. Holley. One summer Mr. Holley accompanied a party of
artists on an excursion to Mt. Katahdin, which, as you know, rises in
almost solitary grandeur amid the forests and lakes of Maine. He wrote,
in his inimitably happy style, an account of this excursion, which
appeared some time after in _Scribner's Monthly_, elegantly illustrated
with views of the scenery. Among other things, Mr. Holley related how he
and Mr. Church painted the sketches for a grand picture of Mt. Katahdin.
"That is," he explained, "Mr. Church painted, and I held the umbrella."

This describes the conversation which Mr. Sibley and I had. Mr. Sibley
talked, and I listened. He was a good talker, and I flatter myself that
I rather excel as a listener. On that occasion I did my best, for I knew
whom I was listening to. I was listening to the man who combined bold
and comprehensive grasp of thought, unerring foresight and sagacity, and
energy of action and power of accomplishment, in a degree not surpassed,
if it was equaled, among men.

Some years before, Mr. Sibley had created the Western Union Telegraph
Company. At that time telegraphy was in a very depressed state. The
country was to a considerable extent occupied by local lines, chartered
under various State laws, and operated without concert. Four rival
companies, organized under the Morse, the Bain, the House, and the
Hughes patents, competed for the business. Telegraph stock was nearly
valueless. Hiram Sibley, a man of the people, a resident of an inland
city, of only moderate fortune, alone grasped the situation. He saw that
the nature of the business, and the demands of the country, alike
required that a single organization, in which all interests should be
combined, should cover the entire land with its network, by means of
which every center and every outlying point, distant as well as near,
could communicate with each other directly, and that such an
organization must be financially successful. He saw all this vividly,
and realized it with the most intense earnestness of conviction. With
Mr. Sibley, to be convinced was to act; and so he set about the task of
carrying this vast scheme into execution. The result is well known. By
his immense energy, the magnetic power with which he infused his own
convictions into other minds, the direct, practical way in which he set
about the work, and his indomitable perseverance, Mr. Sibley attained at
last a phenomenal success.

But he was not then telling me anything about this. He was telling me of
the construction of the telegraph line to the Pacific Coast. Here again
Mr. Sibley had seen that which was hidden from others. This case
differed from the former one in two important respects. Then Mr. Sibley
had been dependent on the aid and co-operation of many persons; and this
he had been able to secure. Now, he could not obtain help from a human
being; but he had become able to act independently of any assistance.

He had made a careful study of the subject, in his thoroughly practical
way, and had become convinced that such a line was feasible, and would
be remunerative. At his instance a convention of telegraph men met in
the city of New York, to consider the project. The feeling in this
convention was extremely unfavorable to it. A committee reported against
it unanimously, on three grounds--the country was destitute of timber,
the line would be destroyed by the Indians, and if constructed and
maintained, it would not pay expenses. Mr. Sibley found himself alone.
An earnest appeal which he made from the report of the committee was
received with derisive laughter. The idea of running a telegraph line
through what was then a wilderness, roamed over for between one and two
thousand miles of its breadth by bands of savages, who of course would
destroy the line as soon as it was put up, and where repairs would be
difficult and useless, even if the other objections to it were out of
the way, struck the members of the convention as so exquisitely
ludicrous that it seemed as if they would never be done laughing about
it. If Mr. Sibley had advocated a line to the moon, they would hardly
have seen in it greater evidence of lunacy. When he could be heard, he
rose again and said: "Gentlemen, you may laugh, but if I was not so old,
I would build the line myself." Upon this, of course, they laughed
louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen,
I will bar the years, and do it." And he did it. Without help from any
one, for every man who claimed a right to express an opinion upon it
scouted the project as chimerical, and no capitalist would put a dollar
in it, Hiram Sibley built the line of telegraph to San Francisco,
risking in it all he had in the world. He set about the work with his
customary energy, all obstacles vanished, and the line was completed in
an incredibly short time. And from the day it was opened, it has proved
probably the most profitable line of telegraph that has ever been
constructed. There was the practicability, and there was the demand and
the business to be done, and yet no living man could see it, or could be
made to see it, except Hiram Sibley. "And to-day," he said, with honest
pride, "to-day in New York, men to whom I went almost on my knees for
help in building this line, and who would not give me a dollar, have
solicited me to be allowed to buy stock in it at the rate of five
dollars for one."

"But how about the Indians?" I asked. "Why," he replied, "we never had
any trouble from the Indians. I knew we wouldn't have. Men who supposed
I was such a fool as to go about this undertaking before that was all
settled didn't know me. No Indian ever harmed that line. The Indians are
the best friends we have got. You see, we taught the Indians the Great
Spirit was in that line; and what was more, we proved it to them. It
was, by all odds, the greatest medicine they ever saw. They fairly
worshiped it. No Indian ever dared to do it harm."

"But," he added, "there was one thing I didn't count on. The border
ruffians in Missouri are as bad as anybody ever feared the Indians might
be. They have given us so much trouble that we are now building a line
around that State, through Iowa and Nebraska. We are obliged to do it."

This opened another phase of the subject. The telegraph line to the
Pacific had a value beyond that which could be expressed in money. It
was perhaps the strongest of all the ties which bound California so
securely to the Union, in the dark days of its struggle for existence.
The secession element in Missouri recognized the importance of the line
in this respect, and were persistent in their efforts to destroy it. We
have seen by what means their purpose was thwarted.

I have always felt that, among the countless evidences of the ordering
of Providence by which the war for the preservation of the Union was
signalized, not the least striking was the raising up of this remarkable
man, to accomplish alone, and in the very nick of time, a work which at
once became of such national importance.

This is the man who has crowned his useful career, and shown again his
eminently practical character and wise foresight, by the endowment of
this College, which cannot fail to be a perennial source of benefit to
the country whose interests he has done so much to promote, and which
his remarkable sagacity and energy contributed so much to preserve.

We have an excellent rule, followed by all successful designers of
machinery, which is, to make provision for the extreme case, for the
most severe test to which, under normal conditions, and so far as
practicable under abnormal conditions also, the machinery can be
subjected. Then, of course, any demands upon it which are less than the
extreme demand are not likely to give trouble. I shall apply this
principle in addressing you to-day. In what I have to say, I shall speak
directly to the youngest and least advanced minds among my auditors. If
I am successful in making an exposition of my subject which shall be
plain to them, then it is evident that I need not concern myself about
being understood by the higher class men and the professors.

The subject to which your attention is now invited is


THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING
BODIES.

This is a subject with which every one who expects to be concerned with
machinery, either as designer or constructor, ought to be familiar. The
principles which underlie it are very simple, but in order to be of use,
these need to be thoroughly understood. If they have once been mastered,
made familiar, incorporated into your intellectual being, so as to be
readily and naturally applied to every case as it arises, then you
occupy a high vantage ground. In this particular, at least, you will not
go about your work uncertainly, trying first this method and then that
one, or leaving errors to be disclosed when too late to remedy them. On
the contrary, you will make, first your calculations and then your
plans, with the certainty that the result will be precisely what you
intend.

Moreover, when you read discussions on any branch of this subject, you
will not receive these into unprepared minds, just as apt to admit error
as truth, and possessing no test by which to distinguish the one from
the other; but you will be able to form intelligent judgments with
respect to them. You will discover at once whether or not the writers
are anchored to the sure holding ground of sound principles.

It is to be observed that I do not speak of balancing bodies, but of
balancing forces. Forces are the realities with which, as mechanical
engineers, you will have directly to deal, all through your lives. The
present discussion is limited also to those forces which are developed
in moving bodies, or by the motion of bodies. This limitation excludes
the force of gravity, which acts on all bodies alike, whether at rest or
in motion. It is, indeed, often desirable to neutralize the effect of
gravity on machinery. The methods of doing this are, however, obvious,
and I shall not further refer to them.

Two very different forces, or manifestations of force, are developed by
the motion of bodies. These are


MOMENTUM AND CENTRIFUGAL FORCE.

The first of these forces is exerted by every moving body, whatever the
nature of the path in which it is moving, and always in the direction of
its motion. The latter force is exerted only by bodies whose path is a
circle, or a curve of some form, about a central body or point, to which
it is held, and this force is always at right angles with the direction
of motion of the body.

Respecting momentum, I wish only to call your attention to a single
fact, which will become of importance in the course of our discussion.
Experiments on falling bodies, as well as all experience, show that the
velocity of every moving body is the product of two factors, which must
combine to produce it. Those factors are force and distance. In order to
impart motion to the body, force must act through distance. These two
factors may be combined in any proportions whatever. The velocity
imparted to the body will vary as the square root of their product.
Thus, in the case of any given body,

  Let force 1, acting through distance 1,  impart velocity 1.
  Then  "   1,   "        "      "     4, will "     "     2, or
        "   2,   "        "      "     2,  "   "     "     2, or
        "   4,   "        "      "     1,  "   "     "     2;
  And   "   1,   "        "      "     9,  "   "     "     3, or
        "   3,   "        "      "     3,  "   "     "     3, or
        "   9,   "        "      "     1,  "   "     "     3.

This table might be continued indefinitely. The product of the force
into the distance will always vary as the square of the final velocity
imparted. To arrest a given velocity, the same force, acting through the
same distance, or the same product of force into distance, is required
that was required to impart the velocity.

The fundamental truth which I now wish to impress upon your minds is
that in order to impart velocity to a body, to develop the energy which
is possessed by a body in motion, force must act through distance.
Distance is a factor as essential as force. Infinite force could not
impart to a body the least velocity, could not develop the least energy,
without acting through distance.

This exposition of the nature of momentum is sufficient for my present
purpose. I shall have occasion to apply it later on, and to describe the
methods of balancing this force, in those cases in which it becomes
necessary or desirable to do so. At present I will proceed to consider
the second of the forces, or manifestations of force, which are
developed in moving bodies--_centrifugal force_.

This force presents its claims to attention in all bodies which revolve
about fixed centers, and sometimes these claims are presented with a
good deal of urgency. At the same time, there is probably no subject,
about which the ideas of men generally are more vague and confused. This
confusion is directly due to the vague manner in which the subject of
centrifugal force is treated, even by our best writers. As would then
naturally be expected, the definitions of it commonly found in our
handbooks are generally indefinite, or misleading, or even absolutely
untrue.

Before we can intelligently consider the principles and methods of
balancing this force, we must get a correct conception of the nature of
the force itself. What, then, is centrifugal force? It is an extremely
simple thing; a very ordinary amount of mechanical intelligence is
sufficient to enable one to form a correct and clear idea of it. This
fact renders it all the more surprising that such inaccurate and
confused language should be employed in its definition. Respecting
writers, also, who use language with precision, and who are profound
masters of this subject, it must be said that, if it had been their
purpose to shroud centrifugal force in mystery, they could hardly have
accomplished this purpose more effectually than they have done, to minds
by whom it was not already well understood.

Let us suppose a body to be moving in a circular path, around a center
to which it is firmly held; and let us, moreover, suppose the impelling
force, by which the body was put in motion, to have ceased; and, also,
that the body encounters no resistance to its motion. It is then, by our
supposition, moving in its circular path with a uniform velocity,
neither accelerated nor retarded. Under these conditions, what is the
force which is being exerted on this body? Clearly, there is only one
such force, and that is, the force which holds it to the center, and
compels it, in its uniform motion, to maintain a fixed distance from
this center. This is what is termed centripetal force. It is obvious,
that the centripetal force, which holds this revolving body _to_ the
center, is the only force which is being exerted upon it.

Where, then, is the centrifugal force? Why, the fact is, there is not
any such thing. In the dynamical sense of the term "force," the sense in
which this term is always understood in ordinary speech, as something
tending to produce motion, and the direction of which determines the
direction in which motion of a body must take place, there is, I repeat,
no such thing as centrifugal force.

There is, however, another sense in which the term "force" is employed,
which, in distinction from the above, is termed a statical sense. This
"statical force" is the force by the exertion of which a body keeps
still. It is the force of inertia--the resistance which all matter
opposes to a dynamical force exerted to put it in motion. This is the
sense in which the term "force" is employed in the expression
"centrifugal force." Is that all? you ask. Yes; that is all.

I must explain to you how it is that a revolving body exerts this
resistance to being put in motion, when all the while it _is_ in motion,
with, according to our above supposition, a uniform velocity. The first
law of motion, so far as we now have occasion to employ it, is that a
body, when put in motion, moves in a straight line. This a moving body
always does, unless it is acted on by some force, other than its
impelling force, which deflects it, or turns it aside, from its direct
line of motion. A familiar example of this deflecting force is afforded
by the force of gravity, as it acts on a projectile. The projectile,
discharged at any angle of elevation, would move on in a straight line
forever, but, first, it is constantly retarded by the resistance of the
atmosphere, and, second, it is constantly drawn downward, or made to
fall, by the attraction of the earth; and so instead of a straight line
it describes a curve, known as the trajectory.

Now a revolving body, also, has the same tendency to move in a straight
line. It would do so, if it were not continually deflected from this
line. Another force is constantly exerted upon it, compelling it, at
every successive point of its path, to leave the direct line of motion,
and move on a line which is everywhere equally distant from the center
to which it is held. If at any point the revolving body could get free,
and sometimes it does get free, it would move straight on, in a line
tangent to the circle at the point of its liberation. But if it cannot
get free, it is compelled to leave each new tangential direction, as
soon as it has taken it.

This is illustrated in the above figure. The body, A, is supposed to be
revolving in the direction indicated by the arrow, in the circle, A B F
G, around the center, O, to which it is held by the cord, O A. At the
point, A, it is moving in the tangential direction, A D. It would
continue to move in this direction, did not the cord, O A, compel it to
move in the arc, A C. Should this cord break at the point, A, the body
would move; straight on toward D, with whatever velocity it had.

You perceive now what centrifugal force is. This body is moving in the
direction, A D. The centripetal force, exerted through the cord, O A,
pulls it aside from this direction of motion. The body resists this
deflection, and this resistance is its centrifugal force.

[Illustration: Fig. 1]

Centrifugal force is, then, properly defined to be the disposition of a
revolving body to move in a straight line, and the resistance which such
a body opposes to being drawn aside from a straight line of motion. The
force which draws the revolving body continually to the center, or the
deflecting force, is called the centripetal force, and, aside from the
impelling and retarding forces which act in the direction of its motion,
the centripetal force is, dynamically speaking, the only force which is
exerted on the body.

It is true, the resistance of the body furnishes the measure of the
centripetal force. That is, the centripetal force must be exerted in a
degree sufficient to overcome this resistance, if the body is to move in
the circular path. In this respect, however, this case does not differ
from every other case of the exertion of force. Force is always exerted
to overcome resistance: otherwise it could not be exerted. And the
resistance always furnishes the exact measure of the force. I wish to
make it entirely clear, that in the dynamical sense of the term "force,"
there is no such thing as centrifugal force. The dynamical force, that
which produces motion, is the centripetal force, drawing the body
continually from the tangential direction, toward the center; and what
is termed centrifugal force is merely the resistance which the body
opposes to this deflection, _precisely like any other resistance to a
force_.

The centripetal force is exerted on the radial line, as on the line, A
O, Fig. 1, at right angles with the direction in which the body is
moving; and draws it directly toward the center. It is, therefore,
necessary that the resistance to this force shall also be exerted on the
same line, in the opposite direction, or directly from the center. But
this resistance has not the least power or tendency to produce motion in
the direction in which it is exerted, any more than any other resistance
has.

We have been supposing a body to be firmly held to the center, so as to
be compelled to revolve about it in a fixed path. But the bond which
holds it to the center may be elastic, and in that case, if the
centrifugal force is sufficient, the body will be drawn from the center,
stretching the elastic bond. It may be asked if this does not show
centrifugal force to be a force tending to produce motion from the
center. This question is answered by describing the action which really
takes place. The revolving body is now imperfectly deflected. The bond
is not strong enough to compel it to leave its direct line of motion,
and so it advances a certain distance along this tangential line. This
advance brings the body into a larger circle, and by this enlargement of
the circle, assuming the rate of revolution to be maintained, its
centrifugal force is proportionately increased. The deflecting power
exerted by the elastic bond is also increased by its elongation. If this
increase of deflecting force is no greater than the increase of
centrifugal force, then the body will continue on in its direct path;
and when the limit of its elasticity is reached, the deflecting bond
will be broken. If, however, the strength of the deflecting bond is
increased by its elongation in a more rapid ratio than the centrifugal
force is increased by the enlargement of the circle, then a point will
be reached in which the centripetal force will be sufficient to compel
the body to move again in the circular path.

Sometimes the centripetal force is weak, and opportunity is afforded to
observe this action, and see its character exhibited. A common example
of weak centripetal force is the adhesion of water to the face of a
revolving grindstone. Here we see the deflecting force to become
insufficient to compel the drops of water longer to leave their direct
paths, and so these do not longer leave their direct paths, but move on
in those paths, with the velocity they have at the instant of leaving
the stone, flying off on tangential lines.

If, however, a fluid be poured on the side of the revolving wheel near
the axis, it will move out to the rim on radial lines, as may be
observed on car wheels universally. The radial lines of black oil on
these wheels look very much as if centrifugal force actually did produce
motion, or had at least a very decided tendency to produce motion, in
the radial direction. This interesting action calls for explanation. In
this action the oil moves outward gradually, or by inconceivably minute
steps. Its adhesion being overcome in the least possible degree, it
moves in the same degree tangentially. In so doing it comes in contact
with a point of the surface which has a motion more rapid than its own.
Its inertia has now to be overcome, in the same degree in which it had
overcome the adhesion. Motion in the radial direction is the result of
these two actions, namely, leaving the first point of contact
tangentially and receiving an acceleration of its motion, so that this
shall be equal to that of the second point of contact. When we think
about the matter a little closely, we see that at the rim of the wheel
the oil has perhaps ten times the velocity of revolution which it had on
leaving the journal, and that the mystery to be explained really is, How
did it get that velocity, moving out on a radial line? Why was it not
left behind at the very first? Solely by reason of its forward
tangential motion. That is the answer.

When writers who understand the subject talk about the centripetal and
centrifugal forces being different names for the same force, and about
equal action and reaction, and employ other confusing expressions, just
remember that all they really mean is to express the universal relation
between force and resistance. The expression "centrifugal force" is
itself so misleading, that it becomes especially important that the real
nature of this so-called force, or the sense in which the term "force"
is used in this expression, should be fully explained.[1] This force is
now seen to be merely the tendency of a revolving body to move in a
straight line, and the resistance which it opposes to being drawn aside
from that line. Simple enough! But when we come to consider this action
carefully, it is wonderful how much we find to be contained in what
appears so simple. Let us see.

[Footnote 1: I was led to study this subject in looking to see what had
become of my first permanent investment, a small venture, made about
thirty-five years ago, in the "Sawyer and Gwynne static pressure
engine." This was the high-sounding name of the Keely motor of that day,
an imposition made possible by the confused ideas prevalent on this very
subject of centrifugal force.]

FIRST.--I have called your attention to the fact that the direction in
which the revolving body is deflected from the tangential line of motion
is toward the center, on the radial line, which forms a right angle with
the tangent on which the body is moving. The first question that
presents itself is this: What is the measure or amount of this
deflection? The answer is, this measure or amount is the versed sine of
the angle through which the body moves.

Now, I suspect that some of you--some of those whom I am directly
addressing--may not know what the versed sine of an angle is; so I must
tell you. We will refer again to Fig. 1. In this figure, O A is one
radius of the circle in which the body A is revolving. O C is another
radius of this circle. These two radii include between them the angle A
O C. This angle is subtended by the arc A C. If from the point O we let
fall the line C E perpendicular to the radius O A, this line will divide
the radius O A into two parts, O E and E A. Now we have the three
interior lines, or the three lines within the circle, which are
fundamental in trigonometry. C E is the sine, O E is the cosine, and E A
is the versed sine of the angle A O C. Respecting these three lines
there are many things to be observed. I will call your attention to the
following only:

_First_.--Their length is always less than the radius. The radius is
expressed by 1, or unity. So, these lines being less than unity, their
length is always expressed by decimals, which mean equal to such a
proportion of the radius.

_Second_.--The cosine and the versed sine are together equal to the
radius, so that the versed sine is always 1, less the cosine.

_Third_.--If I diminish the angle A O C, by moving the radius O C toward
O A, the sine C E diminishes rapidly, and the versed sine E A also
diminishes, but more slowly, while the cosine O E increases. This you
will see represented in the smaller angles shown in Fig. 2. If, finally,
I make O C to coincide with O A, the angle is obliterated, the sine and
the versed sine have both disappeared, and the cosine has become the
radius.

_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the
radius O C toward O B, then the sine and the versed sine both increase,
and the cosine diminishes; and if, finally, I make O C coincide with O
B, then the cosine has disappeared, the sine has become the radius O B,
and the versed sine has become the radius O A, thus forming the two
sides inclosing the right angle A O B. The study of this explanation
will make you familiar with these important lines. The sine and the
cosine I shall have occasion to employ in the latter part of my lecture.
Now you know what the versed sine of an angle is, and are able to
observe in Fig. 1 that the versed sine A E, of the angle A O C,
represents in a general way the distance that the body A will be
deflected from the tangent A D toward the center O while describing the
arc A C.

The same law of deflection is shown, in smaller angles, in Fig. 2. In
this figure, also, you observe in each of the angles A O B and A O C
that the deflection, from the tangential direction toward the center, of
a body moving in the arc A C is represented by the versed sine of the
angle. The tangent to the arc at A, from which this deflection is
measured, is omitted in this figure to avoid confusion. It is shown
sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large
angles, being 12 deg. and 24 deg. respectively. These large angles are used for
convenience of illustration; but it should be explained that this law
does not really hold in them, as is evident, because the arc is longer
than the tangent to which it would be connected by a line parallel with
the versed sine. The law is absolutely true only when the tangent and
arc coincide, and approximately so for exceedingly small angles.

[Illustration: Fig. 2]

In reality, however, we have only to do with the case in which the arc
and the tangent do coincide, and in which the law that the deflection is
_equal to_ the versed sine of the angle is absolutely true. Here, in
observing this most familiar thing, we are, at a single step, taken to
that which is utterly beyond our comprehension. The angles we have to
consider disappear, not only from our sight, but even from our
conception. As in every other case when we push a physical investigation
to its limit, so here also, we find our power of thought transcended,
and ourselves in the presence of the infinite.

We can discuss very small angles. We talk familiarly about the angle
which is subtended by 1" of arc. On Fig. 2, a short line is drawn near
to the radius O A'. The distance between O A' and this short line is 1 deg.
of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc.
The upper line of the Table of versed sines given below is the versed
sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular
space. These are a great many angles, but they do not make a circle.
They make a polygon. If the radius of the circumscribed circle of this
polygon is 1,296,000 feet, which is nearly 213 geographical miles, each
one of its sides will be a straight line, 6.283 feet long. On the
surface of the earth, at the equator, each side of this polygon would be
one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the
moon, at its mean distance from the earth, each of these straight sides
would be about 6,000 feet long.

The best we are able to do is to conceive of a polygon having an
infinite number of sides, and so an infinite number of angles, the
versed sines of which are infinitely small, and having, also, an
infinite number of tangential directions, in which the body can
successively move. Still, we have not reached the circle. We never can
reach the circle. When you swing a sling around your head, and feel the
uniform stress exerted on your hand through the cord, you are made aware
of an action which is entirely beyond the grasp of our minds and the
reach of our analysis.

So always in practical operation that law is absolutely true which we
observe to be approximated to more and more nearly as we consider
smaller and smaller angles, that the versed sine of the angle is the
measure of its deflection from the straight line of motion, or the
measure of its fall toward the center, which takes place at every point
in the motion of a revolving body.

Then, assuming the absolute truth of this law of deflection, we find
ourselves able to explain all the phenomena of centrifugal force, and to
compute its amount correctly in all cases.

We have now advanced two steps. We have learned _the direction_ and _the
measure_ of the deflection, which a revolving body continually suffers,
and its resistance to which is termed centrifugal force. The direction
is toward the center, and the measure is the versed sine of the angle.

SECOND.--We next come to consider what are known as the laws of
centrifugal force. These laws are four in number. They are, that the
amount of centrifugal force exerted by a revolving body varies in four
ways.

_First_.--Directly as the weight of the body.

_Second_.--In a given circle of revolution, as the square of the speed
or of the number of revolutions per minute; which two expressions in
this case mean the same thing.

_Third_.--With a given number of revolutions per minute, or a given
angular velocity[1] _directly_ as the radius of the circle; and

_Fourth_.--With a given actual velocity, or speed in feet per minute,
_inversely_ as the radius of the circle.

[Footnote 1: A revolving body is said to have the same angular velocity,
when it sweeps through equal angles in equal times. Its actual velocity
varies directly as the radius of the circle in which it is revolving.]

Of course there is a reason for these laws. You are not to learn them by
rote, or to accept them on any authority. You are taught not to accept
any rule or formula on authority, but to demand the reason for it--to
give yourselves no rest until you know the why and wherefore, and
comprehend these fully. This is education, not cramming the mind with
mere facts and rules to be memorized, but drawing out the mental powers
into activity, strengthening them by use and exercise, and forming the
habit, and at the same time developing the power, of penetrating to the
reason of things.

In this way only, you will be able to meet the requirement of a great
educator, who said: "I do not care to be told what a young man knows,
but what he can _do_." I wish here to add my grain to the weight of
instruction which you receive, line upon line, precept on precept, on
this subject.

The reason for these laws of centrifugal force is an extremely simple
one. The first law, that this force varies directly as the weight of the
body, is of course obvious. We need not refer to this law any further.
The second, third, and fourth laws merely express the relative rates at
which a revolving body is deflected from the tangential direction of
motion, in each of the three cases described, and which cases embrace
all possible conditions.

These three rates of deflection are exhibited in Fig. 2. An examination
of this figure will give you a clear understanding of them. Let us first
suppose a body to be revolving about the point, O, as a center, in a
circle of which A B C is an arc, and with a velocity which will carry it
from A to B in one second of time. Then in this time the body is
deflected from the tangential direction a distance equal to A D, the
versed sine of the angle A O B. Now let us suppose the velocity of this
body to be doubled in the same circle. In one second of time it moves
from A to C, and is deflected from the tangential direction of motion a
distance equal to A E, the versed sine of the angle, A O C. But A E is
four times A D. Here we see in a given circle of revolution the
deflection varying as the square of the speed. The slight error already
pointed out in these large angles is disregarded.

The following table will show, by comparison of the versed sines of very
small angles, the deflection in a given circle varying as the square of
the speed, when we penetrate to them, so nearly that the error is not
disclosed at the fifteenth place of decimals.

  The versed sine of   1" is 0.000,000,000,011,752
   "   "      "   "    2" is 0.000,000,000,047,008
   "   "      "   "    3" is 0.000,000,000,105,768
   "   "      "   "    4" is 0.000,000,000,188,032
   "   "      "   "    5" is 0.000,000,000,293,805
   "   "      "   "    6" is 0.000,000,000,423,072
   "   "      "   "    7" is 0.000,000,000,575,848
   "   "      "   "    8" is 0.000,000,000,752,128
   "   "      "   "    9" is 0.000,000,000,951,912
   "   "      "   "   10" is 0.000,000,001,175,222
   "   "      "   "  100" is 0.000,000,117,522,250

You observe the deflection for 10" of arc is 100 times as great, and for
100" of arc is 10,000 times as great as it is for 1" of arc. So far as
is shown by the 15th place of decimals, the versed sine varies as the
square of the angle; or, in a given circle, the deflection, and so the
centrifugal force, of a revolving body varies as the square of the
speed.

The reason for the third law is equally apparent on inspection of Fig.
2. It is obvious, that in the case of bodies making the same number of
revolutions in different circles, the deflection must vary directly as
the diameter of the circle, because for any given angle the versed sine
varies directly as the radius. Thus radius O A' is twice radius O A, and
so the versed sine of the arc A' B' is twice the versed sine of the arc
A B. Here, while the angular velocity is the same, the actual velocity
is doubled by increase in the diameter of the circle, and so the
deflection is doubled. This exhibits the general law, that with a given
angular velocity the centrifugal force varies directly as the radius or
diameter of the circle.

We come now to the reason for the fourth law, that, with a given actual
velocity, the centrifugal force varies _inversely_ as the diameter of
the circle. If any of you ever revolved a weight at the end of a cord
with some velocity, and let the cord wind up, suppose around your hand,
without doing anything to accelerate the motion, then, while the circle
of revolution was growing smaller, the actual velocity continuing nearly
uniform, you have felt the continually increasing stress, and have
observed the increasing angular velocity, the two obviously increasing
in the same ratio. That is the operation or action which the fourth law
of centrifugal force expresses. An examination of this same figure (Fig.
2) will show you at once the reason for it in the increasing deflection
which the body suffers, as its circle of revolution is contracted. If we
take the velocity A' B', double the velocity A B, and transfer it to the
smaller circle, we have the velocity A C. But the deflection has been
increasing as we have reduced the circle, and now with one half the
radius it is twice as great. It has increased in the same ratio in which
the angular velocity has increased. Thus we see the simple and necessary
nature of these laws. They merely express the different rates of
deflection of a revolving body in these different cases.

THIRD.--We have a coefficient of centrifugal force, by which we are
enabled to compute the amount of this resistance of a revolving body to
deflection from a direct line of motion in all cases. This is that
coefficient. The centrifugal force of a body making _one_ revolution per
minute, in a circle of _one_ foot radius, is 0.000341 of the weight of
the body.

According to the above laws, we have only to multiply this coefficient
by the square of the number of revolutions made by the body per minute,
and this product by the radius of the circle in feet, or in decimals of
a foot, and we have the centrifugal force, in terms of the weight of the
body. Multiplying this by the weight of the body in pounds, we have the
centrifugal force in pounds.

Of course you want to know how this coefficient has been found out, and
how you can be sure it is correct. I will tell you a very simple way.
There are also mathematical methods of ascertaining this coefficient,
which your professors, if you ask them, will let you dig out for
yourselves. The way I am going to tell you I found out for myself, and
that, I assure you, is the only way to learn anything, so that it will
stick; and the more trouble the search gives you, the darker the way
seems, and the greater the degree of perseverance that is demanded, the
more you will appreciate the truth when you have found it, and the more
complete and permanent your possession of it will be.

The explanation of this method may be a little more abstruse than the
explanations already given, but it is very simple and elegant when you
see it, and I fancy I can make it quite clear. I shall have to preface
it by the explanation of two simple laws. The first of these is, that a
body acted on by a constant force, so as to have its motion uniformly
accelerated, suppose in a straight line, moves through distances which
increase as the square of the time that the accelerating force continues
to be exerted.

The necessary nature of this law, or rather the action of which this law
is the expression, is shown in Fig. 3.

[Illustration: Fig. 3]

Let the distances A B, B C, C D, and D E in this figure represent four
successive seconds of time. They may just as well be conceived to
represent any other equal units, however small. Seconds are taken only
for convenience. At the commencement of the first second, let a body
start from a state of rest at A, under the action of a constant force,
sufficient to move it in one second through a distance of one foot. This
distance also is taken only for convenience. At the end of this second,
the body will have acquired a velocity of two feet per second. This is
obvious because, in order to move through one foot in this second, the
body must have had during the second an average velocity of one foot per
second. But at the commencement of the second it had no velocity. Its
motion increased uniformly. Therefore, at the termination of the second
its velocity must have reached two feet per second. Let the triangle A B
F represent this accelerated motion, and the distance, of one foot,
moved through during the first second, and let the line B F represent
the velocity of two feet per second, acquired by the body at the end of
it. Now let us imagine the action of the accelerating force suddenly to
cease, and the body to move on merely with the velocity it has acquired.
During the next second it will move through two feet, as represented by
the square B F C I. But in fact, the action of the accelerating force
does not cease. This force continues to be exerted, and produces on the
body during the next second the same effect that it did during the first
second, causing it to move through an additional foot of distance,
represented by the triangle F I G, and to have its velocity accelerated
two additional feet per second, as represented by the line I G. So in
two seconds the body has moved through four feet. We may follow the
operation of this law as far as we choose. The figure shows it during
four seconds, or any other unit, of time, and also for any unit of
distance. Thus:

  Time 1           Distance 1
    "  2               "    4
    "  3               "    9
    "  4               "   16

So it is obvious that the distance moved through by a body whose motion
is uniformly accelerated increases as the square of the time.

But, you are asking, what has all this to do with a revolving body? As
soon as your minds can be started from a state of rest, you will
perceive that it has everything to do with a revolving body. The
centripetal force, which acts upon a revolving body to draw it to the
center, is a constant force, and under it the revolving body must move
or be deflected through distances which increase as the squares of the
times, just as any body must do when acted on by a constant force. To
prove that a revolving body obeys this law, I have only to draw your
attention to Fig. 2. Let the equal arcs, A B and B C, in this figure
represent now equal times, as they will do in case of a body revolving
in this circle with a uniform velocity. The versed sines of the angles,
A O B and A O C, show that in the time, A C, the revolving body was
deflected four times as far from the tangent to the circle at A as it
was in the time, A B. So the deflection increased as the square of the
time. If on the table already given, we take the seconds of arc to
represent equal times, we see the versed sine, or the amount of
deflection of a revolving body, to increase, in these minute angles,
absolutely so far as appears up to the fifteenth place of decimals, as
the square of the time.

The standard from which all computations are made of the distances
passed through in given times by bodies whose motion is uniformly
accelerated, and from which the velocity acquired is computed when the
accelerating force is known, and the force is found when the velocity
acquired or the rate of acceleration is known, is the velocity of a body
falling to the earth. It has been established by experiment, that in
this latitude near the level of the sea, a falling body in one second
falls through a distance of 16.083 feet, and acquires a velocity of
32.166 feet per second; or, rather, that it would do so if it did not
meet the resistance of the atmosphere. In the case of a falling body,
its weight furnishes, first, the inertia, or the resistance to motion,
that has to be overcome, and affords the measure of this resistance,
and, second, it furnishes the measure of the attraction of the earth, or
the force exerted to overcome its resistance. Here, as in all possible
cases, the force and the resistance are identical with each other. The
above is, therefore, found in this way to be the rate at which the
motion of any body will be accelerated when it is acted on by a constant
force equal to its weight, and encounters no resistance.

It follows that a revolving body, when moving uniformly in any circle at
a speed at which its deflection from a straight line of motion is such
that in one second this would amount to 16.083 feet, requires the
exertion of a centripetal force equal to its weight to produce such
deflection. The deflection varying as the square of the time, in 0.01 of
a second this deflection will be through a distance of 0.0016083 of a
foot.

Now, at what speed must a body revolve, in a circle of one foot radius,
in order that in 0.01 of one second of time its deflection from a
tangential direction shall be 0.0016083 of a foot? This decimal is the
versed sine of the arc of 3 deg.15', or of 3.25 deg.. This angle is so small
that the departure from the law that the deflection is equal to the
versed sine of the angle is too slight to appear in our computation.
Therefore, the arc of 3.25 deg. is the arc of a circle of one foot radius
through which a body must revolve in 0.01 of a second of time, in order
that the centripetal force, and so the centrifugal force, shall be equal
to its weight. At this rate of revolution, in one second the body will
revolve through 325 deg., which is at the rate of 54.166 revolutions per
minute.

Now there remains only one question more to be answered. If at 54.166
revolutions per minute the centrifugal force of a body is equal to its
weight, what will its centrifugal force be at one revolution per minute
in the same circle?

To answer this question we have to employ the other extremely simple
law, which I said I must explain to you. It is this: The acceleration
and the force vary in a constant ratio with each other. Thus, let force
1 produce acceleration 1, then force 1 applied again will produce
acceleration 1 again, or, in other words, force 2 will produce
acceleration 2, and so on. This being so, and the amount of the
deflection varying as the squares of the speeds in the two cases, the
centrifugal force of a body making one revolution per minute in a circle
of

                              1 squared
  one foot radius will be ---------- = 0.000341
                           54.166 squared

--the coefficient of centrifugal force.

There is another mode of making this computation, which is rather neater
and more expeditious than the above. A body making one revolution per
minute in a circle of one foot radius will in one second revolve through
an arc of 6 deg.. The versed sine of this arc of 6 deg. is 0.0054781046 of a
foot. This is, therefore, the distance through which a body revolving at
this rate will be deflected in one second. If it were acted on by a
force equal to its weight, it would be deflected through the distance of
16.083 feet in the same time. What is the deflecting force actually
exerted upon it? Of

              0.0054781046
course, it is ------------.
                 16.083

This division gives 0.000341 of its weight as such deflecting force, the
same as before.

In taking the versed sine of 6 deg., a minute error is involved, though not
one large enough to change the last figure in the above quotient. The
law of uniform acceleration does not quite hold when we come to an angle
so large as 6 deg.. If closer accuracy is demanded, we can attain it, by
taking the versed sine for 1 deg., and multiplying this by 6 squared. This gives as
a product 0.0054829728, which is a little larger than the versed sine of
6 deg..

I hope I have now kept my promise, and made it clear how the coefficient
of centrifugal force may be found in this simple way.

We have now learned several things about centrifugal force. Let me
recapitulate. We have learned:

1st. The real nature of centrifugal force. That in the dynamical sense
of the term force, this is not a force at all: that it is not capable of
producing motion, that the force which is really exerted on a revolving
body is the centripetal force, and what we are taught to call
centrifugal force is nothing but the resistance which a revolving body
opposes to this force, precisely like any other resistance.

2d. The direction of the deflection, to which the centrifugal force is
the resistance, which is straight to the center.

3d. The measure of this deflection; the versed sine of the angle.

4th. The reason of the laws of centrifugal force; that these laws merely
express the relative amount of the deflection, and so the amount of the
force required to produce the deflection, and of the resistance of the
revolving body to it, in all different cases.

5th. That the deflection of a revolving body presents a case analogous
to that of uniformly accelerated motion, under the action of a constant
force, similar to that which is presented by falling bodies;[1] and
finally,

6th. How to find the coefficient, by which the amount of centrifugal
force exerted in any case may be computed.

[Footnote 1: A body revolving with a uniform velocity in a horizontal
plane would present the only case of uniformly accelerated motion that
is possible to be realized under actual conditions.]

I now pass to some other features.

_First_.--You will observe that, relatively to the center, a revolving
body, at any point in its revolution, is at rest. That is, it has no
motion, either from or toward the center, except that which is produced
by the action of the centripetal force. It has, therefore, this identity
also with a falling body, that it starts from a state of rest. This
brings us to a far more comprehensive definition of centrifugal force.
This is the resistance which a body opposes to being put in motion, at
any velocity acquired in any time, from a state of rest. Thus
centrifugal force reveals to us the measure of the inertia of matter.
This inertia may be demonstrated and exhibited by means of apparatus
constructed on this principle quite as accurately as it can be in any
other way.

_Second_.--You will also observe the fact, that motion must be imparted
to a body gradually. As distance, _through_ which force can act, is
necessary to the impartation of velocity, so also time, _during_ which
force can act, is necessary to the same result. We do not know how
motion from a state of rest begins, any more than we know how a polygon
becomes a circle. But we do know that infinite force cannot impart
absolutely instantaneous motion to even the smallest body, or to a body
capable of opposing the least resistance. Time being an essential
element or factor in the impartation of velocity, if this factor be
omitted, the least resistance becomes infinite.

We have a practical illustration of this truth in the explosion of
nitro-glycerine. If a small portion of this compound be exploded on the
surface of a granite bowlder, in the open air, the bowlder will be rent
into fragments. The explanation of this phenomenon common among the
laborers who are the most numerous witnesses of it, which you have
doubtless often heard, and which is accepted by ignorant minds without
further thought, is that the action of nitro-glycerine is downward. We
know that such an idea is absurd.

The explosive force must be exerted in all directions equally. The real
explanation is, that the explosive action of nitro-glycerine is so
nearly instantaneous, that the resistance of the atmosphere is very
nearly equal to that of the rock; at any rate, is sufficient to cause
the rock to be broken up. The rock yields to the force very nearly as
readily as the atmosphere does.

_Third_. An interesting solution is presented here of what is to many an
astronomical puzzle. When I was younger than I am now, I was greatly
troubled to understand how it could be that if the moon was always
falling to the earth, as the astronomers assured us it was, it should
never reach it, nor have its falling velocity accelerated. In popular
treatises on astronomy, such for example as that of Professor Newcomb,
this is explained by a diagram in which the tangential line is carried
out as in Fig. 1, and by showing that in falling from the point A to the
earth as a center, through distances increasing as the square of the
time, the moon, having the tangential velocity that it has, could never
get nearer to the earth than the circle in which it revolves around it.
This is all very true, and very unsatisfactory. We know that this long
tangential line has nothing to do with the motion of the moon, and while
we are compelled to assent to the demonstration, we want something
better. To my mind the better and more satisfactory explanation is found
in the fact that the moon is forever commencing to fall, and is
continually beginning to fall in a new direction. A revolving body, as
we have seen, never gets past that point, which is entirely beyond our
sight and our comprehension, of beginning to fall, before the direction
of its fall is changed. So, under the attraction of the earth, the moon
is forever leaving a new tangential direction of motion at the same
rate, without acceleration.

(_To be continued_.)

       *       *       *       *       *




COMPRESSED AIR POWER SCHEMES.

By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company.


In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec.
8 last, you state that you await with some curiosity my reply to certain
points in reference to the compressed air power schemes alluded to in
that article. I now, therefore, take the liberty of submitting to you
the arguments on my side of the question (which are substantially the
same as those I am submitting to Mr. Hewson, the Borough Engineer of
Leeds). The details and estimates for the Leeds scheme are not yet in a
forward enough state to enable me to give them at present; but the whole
case is sufficiently worked out for Birmingham to enable a fair
deduction to be made therefrom as regards the utility of the system in
other towns. In Birmingham, progress has been delayed owing to
difficulties in procuring a site for the works, and other matters of
detail. We have, however, recently succeeded in obtaining a suitable
place, and making arrangements for railway siding, water supply, etc.;
and we hope to be in a position to start early in the present year.

I inclose (1) a tabulated summary of the estimates for Birmingham
divided into stages of 3,000 gross indicated horse power at a time; (2)
a statement showing the cost to consumers in terms of indicated horse
power and in different modes, more or less economical, of applying the
air power in the consumers' engines; (3) a tracing showing the method of
laying the mains; (4) a tracing showing the method of collecting the
meter records at the central station, by means of electric apparatus,
and ascertaining the exact amount of leakage. A short description of the
two latter would be as well.

TABLE I.--_Showing the Progressive Development of the Compressed Air
System in stages of 3000 Indicated Horse Power (gross) at a Time, and
the Profits at each Stage_

_____________________________________________________________________________

Gross            |   3000    |   6000    |  9000     |   12,000  |   15,000  |
Indicated        |   Ind.    |   Ind.    |  Ind.     |    Ind.   |    Ind.   |
Horse Power      |   H.P.    |   H.P.    |  H.P.     |    H.P.   |    H.P.   |
at Central       |           |           |           |           |           |
Works:           |           |           |           |           |           |
-----------------------------------------------------------------------------

Thousands of     | 1,080,000 | 2,160,000 |3,240,000  | 4,320,000 |5,400,000  |
Cubic Feet at 45 |           |           |           |           |           |
lbs. pressure    |           |           |           |           |           |
at engines       |           |           |           |           |           |
Deduction for    |    17,928 |    70,927 |  154,429  |   267,529 |  409,346  |
friction and     |           |           |           |           |           |
leakage          |           |           |           |           |           |
Estimated net    | 1,062,072 | 2,089,073 |3,085,571  | 4,052,471 |4,990,654  |
delivery         |           |           |           |           |           |
-----------------------------------------------------------------------------

CAPITAL          |           |           |           |           |           |
EXPENDITURE--    |           |           |           |           |           |
Purchase and pre-| L12,500   | (amounts below apply to extension of works)   |
paration of land |           |           |           |           |           |
Machinery        |  27,854   |  L25,595  |  L25,595  |  L25,595  |  L25,595  |
Mains            |  10,328   |   10.328  |   10,328  |   10,328  |   10,328  |
Buildings        |   8,505   |    4,516  |    4,632  |    4,614  |    4,594  |
Parlimentary and |           |           |           |           |           |
general expenses,|  20,000   |       ..  |       ..  |      ..   |      ..   |
royalty, &c.     |           |           |           |           |           |
Engineering      |   3,268   |    1,820  |    1,825  |    1,824  |    8,823  |
  Previous Capit-|           |   82,455  |  124,714  |  167,094  |  209,455  |
  al Expenditure |      ..   |           |           |           |           |
Total Cap. Exp.  | L82,455   | L124,714  | L167,094  | L209,455  | L251,795  |
-----------------------------------------------------------------------------

ANNUAL CHARGES-- |           |           |           |           |           |
Salaries, wages, |           |           |           |           |           |
& general working|  L6,405   |   L7,855  |   L9,305  |  L10,955  |  L12,480  |
  expenses       |           |           |           |           |           |
Repairs, renewals|   2,780   |    5,198  |    7,622  |   10,045  |   12,467  |
&c.(reserve fund)|           |           |           |           |           |
Coal, water, &c. |   1,950   |    3,900  |    5,850  |    7,800  |    9,750  |
Rates            |     370   |      674  |      980  |    1,285  |    1,585  |
Contingencies of |           |           |           |           |           |
horse power = 5  |     575   |      881  |    1,187  |    1,504  |    1,814  |
per cent on above|           |           |           |           |           |
Total Ann. Exp.  | L12,080   |  L18,508  |  L24,944  |  L31,589  |  L38,096  |
-----------------------------------------------------------------------------

Revenue at 5d.   |           |           |           |           |           |
per 1000 cub. ft.|  22,126   |   43,522  |   64,282  |   84,426  |  103,971  |
(average)        |           |           |           |           |           |
Profit           |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.|
                 |= 10,046   | = 25,014  | = 39,338  | = 52,837  | = 65,875  |
-----------------------------------------------------------------------------

TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_.

Abbreviated column headings:

Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per
Hour.

Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet.

Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per
Cent.

Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet.

Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per
Cent.

Abbreviated row headings:

CASE 1.--Where air at 45 lbs. pressure is re-heated to 320 deg. Fahr., and
expanded to atmospheric pressure.

CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to
212 deg. Fahr., and expanded to atmospheric pressure.

CASE 3.--Where air is used expansively without re-heating, whereby
intensely cold air is exhausted, and may be used for ice making, &c.

CASE 4.--Where air is heated to 212 deg. Fahr., and the terminal pressure is
11.3 lbs. above that of the atmosphere

CASE 5.--Where the air is used without heating, and cut off at one-third
of the stroke, as in ordinary slide-valve engines

CASE 6.--Where the air is used without re-heating and without expansion.

  _____________________________________________________________________
          | Qty. Air | Cost/Hr.  | Cost/Hr. |  Cost/Yr.   |  Cost/Yr. |
          |          |           | w/rebate |             |  w/rebate |
          | Cub. Ft. |    d.     |    d.    |  L  s.  d.  |  L  s.  d.|
  ---------------------------------------------------------------------
   CASE 1 |  125.4   |   0.627   |   0.596  |  7   1   1  |  6  14  01/2|
   CASE 2 |  140.4   |   0.702   |   0.667  |  7  17  11  |  7  10  0 |
   CASE 3 |  178.2   |   0.891   |   0.847  | 10   0   51/2 |  9  10  51/2|
   CASE 4 |  170.2   |   0.851   |   0.809  |  9  11   51/2 |  9   1 101/2|
   CASE 5 |  258.0   |   1.290   |   1.226  | 14  10   3  | 13  15  9 |
   CASE 6 |  331.8   |   1.659   |   1.576  | 18  13   3  | 17  14  7 |
  _____________________________________________________________________

The great thing to guard against is leakage. If the pipes were simply
buried in the ground, it would be almost impossible to trace leakage, or
even to know of its existence. The income of the company might be
wasting away, and the loss never suspected until the quarterly returns
from the meters were obtained from the inspectors. Only then would it be
discovered that there must be a great leak (or it might be several
leaks) somewhere. But how would it be possible to trace them among 20 or
30 miles of buried pipes? We cannot break up the public streets. The
very existence of the concern depends upon (1) the _daily_ checking of
the meter returns, and comparison with the output from the air
compressors, so as to ascertain the amount of leakage; (2) facility for
tracing the locality of a leak; and (3) easy access to the mains with
the minimum of disturbance to the streets. It will be readily
understood, from the drawings, how this is effected. First, the pipes
are laid in concrete troughs, near the surface of the road, with
removable concrete covers strong enough to stand any overhead traffic.
At intervals there are junctions for service connections, with street
boxes and covers serving as inspection chambers. These chambers are also
provided over the ball-valves, which serve as stop-valves in case of
necessity, and are so arranged that in case of a serious breach in the
portion of main between any two of them, the rush of air to the breach
will blow them up to the corresponding seats and block off the broken
portion of main. The air space around the pipe in the concrete trough
will convey for a long distance the whistling noise of a leak; and the
inspectors, by listening at the inspection openings, will thus be
enabled to rapidly trace their way almost to the exact spot where there
is an escape. They have then only to remove the top surface of road
metal and the concrete cover in order to expose the pipe and get at the
breach. Leaks would mostly be found at joints; and, by measuring from
the nearest street opening, the inspectors would know where to break
open the road to arrive at the probable locality of the leak. A very
slight leak can be heard a long way off by its peculiar whistling sound.

[Illustration: COMPRESSED AIR POWER]

The next point is to obtain a daily report of the condition of the mains
and the amount of leakage. It would be impracticable to employ an army
of meter inspectors to take the records daily from all the meters in the
district. We therefore adopt the method of electric signaling shown in
the second drawing. In the engineer's office, at the central station, is
fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the
contact-making apparatus shown in Pig. 4, and in an enlarged form in
Figs. 5 and 6, by which a current is sent round the electro-magnet, D
(Fig. 1), attracting the armature, and drawing the disk forward
sufficiently for the roller at I to pass over the center of one of the
pins, and so drop in between that and the next pin, thus completing the
motion, and holding the disk steadily opposite the figure. This action
takes place on any meter completing a unit of measurement of (say) 1,000
cubic feet, at which point the contact makers touch. But suppose one
meter should be moving very slowly, and so retaining contact for some
time, while other meters were working rapidly; the armature at D would
then be held up to the magnet by the prolonged contact maintained by the
slow moving meter, and so prevent the quick working meters from
actuating it; and they would therefore pass the contact points without
recording. A meter might also stop dead at the point of contact on
shutting off the air, and so hold up the armature; thus preventing
others from acting. To obviate this, we apply the disengaging apparatus
shown at L (Fig. 4). The contact maker works on the center, m, having an
armature on its opposite end. On contact being made, at the same time
that the magnet, D, is operated, the one at L is also operated,
attracting the armature, and throwing over the end of the contact maker,
l, on to the non-conducting side of the pin on the disk. Thus the whole
movement is rendered practically instantaneous, and the magnet at D is
set at liberty for the next operation. A resistance can be interposed at
L, if necessary, to regulate the period of the operation. The whole of
the meters work the common dial shown in Fig. 1, on which the gross
results only are recorded; and this is all we want to know in this way.
The action is so rapid, owing to the use of the magnetic disengaging
gear, that the chances of two or more meters making contact at the same
moment are rendered extremely small. Should such a thing happen, it
would not matter, as it is only approximate results that we require in
this case; and the error, if any, would add to the apparent amount of
leakage, and so be on the right side. Of course, the record of each
consumer's meter would be taken by the inspector at the end of every
quarter, in order to make out the bill; and the totals thus obtained
would be checked by the gross results indicated by the main dial. In
this way, by a comparison of these results, a coefficient would soon be
arrived at, by which the daily recorded results could be corrected to an
extremely accurate measurement. At the end of the working day, the
engineer has merely to take down from the dial in his office the total
record of air measured to the consumers, also the output of air from the
compressors, which he ascertains by means of a continuous counter on the
engines, and the difference between the two will represent the loss. If
the loss is trifling, he will pass it over; if serious, he will send out
his inspectors to trace it. Thus there could be no long continued
leakage, misuse, or robbery of the air, without the company becoming
aware of the fact, and so being enabled to take measures to stop or
prevent it. The foregoing are absolutely essential adjuncts to any
scheme of public motive power supply by compressed air, without which we
should be working in the dark, and could never be sure whether the
company were losing or making money. With them, we know where we are and
what we are doing.

Referring to the estimates given in Table I., I may explain that the
item of repairs and renewals covers 10 per cent. on boilers and gas
producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per
cent. on mains. Considering that the estimates include ample fitting
shops, with the best and most suitable tools, and that the wages list
includes a staff of men whose chief work would be to attend to repairs,
etc., I think the above allowances ample. Each item also includes 5 per
cent. for contingencies.

I have commenced by giving all the preceding detail, in order to show
the groundwork on which I base the estimate of the cost of compressed
air power to consumers, in terms of indicated horse power per annum, as
given in Table II. I may say that, in estimating the engine power and
coal consumption, I have not, as in the original report, made purely
theoretical calculations, but have taken diagrams from engines in actual
use (although of somewhat smaller size than those intended to be
employed), and have worked out the results therefrom. It will, I hope,
be seen that, with all the safeguards we have provided, we may fairly
reckon upon having for sale the stated quantity of air produced by means
of the plant, as estimated, and at the specified annual cost; and that
therefore the statement of cost per indicated horse power per annum may
be fairly relied upon. Thus the cost of compressed air to the consumer,
based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary
from L6 14s. per indicated horse power per annum to L18 13s. 3d.,
according to circumstances and mode of application.

A compressed air motor is an exceedingly simple machine--much simpler
than an ordinary steam engine. But the air may also be used in an
ordinary steam engine; and in this case it can be much simplified in
many details. Very little packing is needed, as there is no nuisance
from gland leakage; the friction is therefore very slight. Pistons and
glands are packed with soapstone, or other self-lubricating packing; and
no oil is required except for bearings, etc. The company will undertake
the periodical inspection and overhauling of engines supplied with their
power, all which is included in the estimates. The total cost to
consumers, with air at an average of 5d. per 1,000 cubic feet, may
therefore be fairly taken as follows:

                                   Min.           Max.
  Cost of air used              L6 14  01/2      L18 13  3
  Oil. waste, packing, etc.      1  0  0         1  0  0
  Interest, depreciation,
    etc., 121/2 per cent. on
    L10, the cost of engine
    per indicated
    horse power                  1  5  0         1  5  0
                                --------       ---------
                                L8 19  01/2      L20 18  3

The maximum case would apply only to direct acting engines, such as
Tangye pumps, air power hammers, etc., where the air is full on till the
end of the stroke, and where there is no expansion. The minimum given is
at the average rate of 5d. per 1,000 cubic feet; but as there will be
rates below this, according to a sliding scale, we may fairly take it
that the lowest charge will fall considerably below L6 per indicated
horse power per annum.--_Journal of Gas Lighting_.

       *       *       *       *       *




THE BERTHON COLLAPSIBLE CANOE.


An endeavor has often been made to construct a canoe that a person can
easily carry overland and put into the water without aid, and convert
into a sailboat. The system that we now call attention to is very well
contrived, very light, easily taken apart, and for some years past has
met with much favor.

[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.]

Mr. Berthon's canoes are made of impervious oil-skin. Form is given them
by two stiff wooden gunwales which are held in position by struts that
can be easily put in and taken out. The model shown in the figure is
covered with oiled canvas, and is provided with a double paddle and a
small sail. Fig. 2 represents it collapsed and being carried overland.

[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.]

Mr. Berthon is manufacturing a still simpler style, which is provided
with two oars, as in an ordinary canoe. This model, which is much used
in England by fishermen and hunters, has for several years past been
employed in the French navy, in connection with movable defenses. At
present, every torpedo boat carries one or two of these canoes, each
composed of two independent halves that may be put into the water
separately or be joined together by an iron rod.

These boats ride the water very well, and are very valuable for
exploring quarters whither torpedo boats could not adventure without
danger.[1]--_La Nature_.

[Footnote 1: For detailed description see SUPPLEMENT, No. 84.]

       *       *       *       *       *




THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM
RAILROAD.


There was great excitement in Nuernberg on the 7th of December, 1835, on
which day the first German railroad was opened. The great square on
which the buildings of the Nuernberg and Furth "Ludwig's Road" stood, the
neighboring streets, and, in fact, the whole road between the two
cities, was filled with a crowd of people who flocked from far and near
to see the wonderful spectacle. For the first time, a railroad train
filled with passengers was to be drawn from Nuernberg to Furth by the
invisible power of the steam horse. At eight o'clock in the morning, the
civil and military authorities, etc., who took part in the celebration
were assembled on the square, and the gayly decorated train started off
to an accompaniment of music, cannonading, cheering, etc. Everything
passed off without an accident; the work was a success. The engraving in
the lower right-hand corner represents the engine and cars of this road.

It will be plainly seen that such a revolution could not be accomplished
easily, and that much sacrifice and energy were required of the leaders
in the enterprise, prominent among whom was the merchant Johannes
Scharrer, who is known as the founder of the "Ludwig's Road."

One would naturally suppose that such an undertaking would have met with
encouragement from the Bavarian Government, but this was not the case.
The starters of the enterprise met with opposition on every side; much
was written against it, and many comic pictures were drawn showing
accidents which would probably occur on the much talked of road. Two of
these pictures are shown in the accompanying large engraving, taken from
the _Illustrirte Zeitung_. As shown in the center picture, right hand,
it was expected by the railway opponents that trains running on tracks
at right angles must necessarily come in collision. If anything happened
to the engine, the passengers would have to get out and push the cars,
as shown at the left.

[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE
OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG]

Much difficulty was experienced in finding an engineer capable of
attending to the construction of the road; and at first it was thought
that it would be best to engage an Englishman, but finally Engineer
Denis, of Munich, was appointed. He had spent much time in England and
America studying the roads there, and carried on this work to the entire
satisfaction of the company.

All materials for the road were, as far as possible, procured in
Germany; but the idea of building the engines and cars there had to be
given up, and, six weeks before the opening of the road, Geo.
Stephenson, of London, whose engine, Rocket, had won the first prize in
the competitive trials at Rainhill in 1829, delivered an engine of ten
horse power, which is still known in Nuernberg as "Der Englander."

Fifty years have passed, and, as Johannes Scharrer predicted, the
Ludwig's Road has become a permanent institution, though it now forms
only a very small part of the network of railroads which covers every
portion of Germany. What changes have been made in railroads during
these fifty years! Compare the present locomotives with the one made by
Cugnot in 1770, shown in the upper left-hand cut, and with the work of
the pioneer Geo. Stephenson, who in 1825 constructed the first passenger
railroad in England, and who established a locomotive factory in
Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig,
whose great works at Moabit now turn out from 200 to 250 locomotives a
year, is to our time.

Truly, in this time there can be no better occasion for a celebration of
this kind than the fiftieth anniversary of the opening of the first
German railroad, which has lately been celebrated by Nuernberg and Furth.

The lower left-hand view shows the locomotive De Witt Clinton, the third
one built in the United States for actual service, and the coaches. The
engine was built at the West Point Foundry, and was successfully tested
on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug.
9, 1831.

       *       *       *       *       *




IMPROVED COAL ELEVATOR.


An illustration of a new coal elevator is herewith presented, which
presents advantages over any incline yet used, so that a short
description may be deemed interesting to those engaged in the coaling
and unloading of vessels. The pen sketch shows at a glance the
arrangement and space the elevator occupies, taking less ground to do
the same amount of work than any other mode heretofore adopted, and the
first cost of erecting is about the same as any other.

When the expense of repairing damages caused by the ravages of winter is
taken into consideration, and no floats to pump out or tracks to wash
away, the advantages should be in favor of a substantial structure.

The capacity of this hoist is to elevate 80,000 bushels in ten hours, at
less than one-half cent per bushel, and put coal in elevator, yard, or
shipping bins.

[Illustration: IMPROVED COAL ELEVATOR.]

The endless wire rope takes the cars out and returns them, dispensing
with the use of train riders.

A floating elevator can distribute coal at any hatch on steam vessels,
as the coal has to be handled but once; the hoist depositing an empty
car where there is a loaded one in boat or barge, requiring no swing of
the vessel.

Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and
builder, and has them in use in the U.S. engineering service.--_Coal
Trade Journal_.

       *       *       *       *       *




STEEL-MAKING LADLES.


The practice of carrying melted cast iron direct from the blast furnace
to the Siemens hearth or the Bessemer converter saves both money and
time. It has rendered necessary the construction of special plant in the
form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson &
Co., of Preston, make the construction of these ladles a specialty, and
by their courtesy, says _The Engineer_, we are enabled to illustrate
four different types, each steel works manager, as is natural,
preferring his own design. Ladles are also required in steel foundry
work, and one of these for the Siemens-Martin process is illustrated by
Fig. 1. These ladles are made in sizes to take from five to fifteen ton
charges, or larger if required, and are mounted on a very strong
carriage with a backward and forward traversing motion, and tipping gear
for the ladle. The ladles are butt jointed, with internal cover strips,
and have a very strong band shrunk on hot about half way in the depth of
the ladle. This forms an abutment for supporting the ladle in the
gudgeon band, being secured to this last by latch bolts and cotters. The
gearing is made of cast steel, and there is a platform at one end for
the person operating the carriage or tipping the ladle. Stopper gear and
a handle are fitted to the ladles to regulate the flow of the molten
steel from the nozzle at the bottom.

[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.]

Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It
requires no description. Fig. 3 shows a tremendous ladle constructed for
the North-Eastern Steel Company, for carrying molten metal from the
blast furnace to the converter. It holds ten tons with ease. It is an
exceptionally strong structure. The carriage frame is constructed
throughout of 1 in. wrought-iron plated, and is made to suit the
ordinary 4 ft. 81/2 in. railway gauge. The axle boxes are cast iron,
fitted with gun-metal steps. The wheels are made of forged iron, with
steel tires and axles. The carriage is provided with strong oak buffers,
planks, and spring buffers; the drawbars also have helical compression
springs of the usual type. The ladle is built up of 1/2 in. wrought-iron
plates, butt jointed, and double riveted butt straps. The trunnions and
flange couplings are of cast steel. The tipping gear, clearly shown in
the engraving, consists of a worm and wheel, both of steel, which can be
fixed on either side of the ladle as may be desired. From this it will
be seen that Messrs. Stevenson & Co. have made a thoroughly strong
structure in every respect, and one, therefore, that will commend itself
to most steel makers. We understand that these carriages are made in
various designs and sizes to meet special requirements. Thus, Fig. 4
shows one of different design, made for a steel works in the North. This
is also a large ladle. The carriage is supported on helical springs and
solid steel wheels. It will readily be understood that very great care
and honesty of purpose is required in making these structures. A
breakdown might any moment pour ten tons of molten metal on the ground,
with the most horrible results.

       *       *       *       *       *




APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE
SURFACE OF CONDUCTORS.


Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and
ingenious apparatus which permits of demonstrating that electricity
develops only on the surface of conductors. It consists (see figure)
essentially of a yellow-metal disk, M, fixed to an insulating support,
F, and carrying a concentric disk of ebonite, H. This latter receives a
hollow and closed hemisphere, J, of yellow metal, whose base has a
smaller diameter than that of the disk, H, and is perfectly insulated by
the latter. Another yellow-metal hemisphere, S, open below, is connected
with an insulating handle, G. The basal diameter of this second
hemisphere is such that when the latter is placed over J its edge rests
upon the lower disk, M. These various pieces being supposed placed as
shown in the figure, the shell, S, forms with the disk, M, a hollow,
closed hemisphere that imprisons the hemisphere, J, which is likewise
hollow and closed, and perfectly insulated from the former.

[Illustration]

The shell, S, is provided internally with a curved yellow-metal spring,
whose point of attachment is at B, and whose free extremity is connected
with an ebonite button, K, which projects from the shell, S. By pressing
this button, a contact may be established between the external
hemisphere (formed of the pieces, S and M), and the internal one, J. As
soon as the button is left to itself, the spring again begins to bear
against the interior surface of S, and the two hemispheres are again
insulated.

The experiment is performed in this wise: The shell, S, is removed. Then
a disk of steatite affixed to an insulating handle is rubbed for a few
instants with a fox's "brush," and held near J until a spark occurs.
Then the apparatus is grasped by the support, F, and an elder-pith ball
suspended by a flaxen thread from a good conducting support is brought
near J. The ball will be quickly repelled, and care must be taken that
it does not come into contact with J. After this the apparatus is placed
upon a table, the shell, S, is taken by its handle, G, and placed in the
position shown in the figure, and a momentary contact is established
between the two hemispheres by pressing the button, K. Then the shell,
S, is lifted, and the disk, M, is touched at the same time with the
other hand. If, now, the pith ball be brought near S, it will be quickly
repelled, while it will remain stationary if it be brought near J, thus
proving that all the electricity passed from J to S at the moment of
contact.--_La Lumiere Electrique_.

       *       *       *       *       *




THE COLSON TELEPHONE.


This apparatus has recently been the object of some experiments which
resulted in its being finally adopted in the army. We think that our
readers will read a description of it with interest. Its mode of
construction is based upon a theoretic conception of the lines of force,
which its inventor explains as follows in his Elementary Treatise on
Electricity:

"To every position of the disk of a magnetic telephone with respect to
the poles of the magnet there corresponds a certain distribution of the
lines of force, which latter shift themselves when the disk is
vibrating. If the bobbin be met by these lines in motion, there will
develop in its wire a difference of potential that, according to
Faraday's law, will be proportional to their number. All things equal,
then, a telephone transmitter will be so much the more potent in
proportion as the lines set in motion by the vibrations of the disk and
meeting the bobbin wire are greater in number. In like manner, a
receiver will be so much the more potent in proportion as the lines of
force, set in motion by variations in the induced currents that are
traversing the bobbin and meeting the disk, are more numerous. It will
consequently be seen that, generally speaking, it is well to send as
large a number of lines of force as possible through the bobbin."

[Illustration: FIG. 1.--THE COLSON TELEPHONE.]

In order to obtain such a result, the thin tin-plate disk has to be
placed between the two poles of the magnet. The pole that carries the
fine wire bobbin acts at one side and in the center of the disk, while
the other is expanded at the extremity and acts upon the edge and the
other side. This pole is separated from the disk by a copper washer, and
the disk is thus wholly immersed in the magnetic field, and is traversed
by the lines of force radiatingly.

This telephone is being constructed by Mr. De Branville, with the
greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig.
3). At A may be seen the magnet with its central pole, P, and its
eccentric one, P'. This latter traverses the vibrating disk, M, through
a rubber-lined aperture and connects with the soft iron ring, F, that
forms the polar expansion. These pieces are inclosed in a nickelized
copper box provided with a screw cap, C. The resistance of both the
receiver and transmitter bobbin is 200 ohms.

[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.]

The transmitter is 31/2 in. in diameter, and is provided with a
re-enforcing mouthpiece. It is regulated by means of a screw which is
fixed in the bottom of the box, and which permits of varying the
distance between the disk and the core that forms the central pole of
the magnet. The regulation, when once effected, lasts indefinitely. The
regulation of the receiver, which is but 21/4 in. in diameter, is
performed once for all by the manufacturer. One of the advantages of
this telephone is that its regulation is permanent. Besides this, it
possesses remarkable power and clearness, and is accompanied with no
snuffling sounds, a fact doubtless owing to all the molecules of the
disk being immersed in the magnetic field, and to the actions of the two
poles occurring concentrically with the disk. As we have above said,
this apparatus is beginning to be appreciated, and has already been the
object of several applications in the army. The transmitter is used by
the artillery service in the organization of observatories from which to
watch firing, and the receiver is added to the apparatus pertaining to
military telegraphy. The two small receivers are held to the lens of the
operator by the latter's hat strap, while the transmitter is suspended
in a case supported by straps, with the mouthpieces near the face (Fig.
1).

In the figure, the case is represented as open, so as to show the
transmitter. The empty compartment below is designed for the reception
and carriage of the receivers, straps, and flexible cords. This
arrangement permits of calling without the aid of special apparatus, and
it has also the advantage of giving entire freedom to the man on
observation, this being something that is indispensable in a large
number of cases.

[Illustration: FIG. 3.--RECEIVER TAKEN APART.]

In certain applications, of course, the receivers may be combined with a
microphone; yet on an aerial as well as on a subterranean line the
transmitter produces effects which, as regards intensity and clearness,
are comparable with those of a pile transmitter.

Stations wholly magnetic may be established by adding to the transmitter
and two receivers a Sieur phonic call, which will actuate them
powerfully, and cause them to produce a noise loud enough for a call. It
would be interesting to try this telephone on a city line, and to a
great distance on those telegraph lines that are provided with the Van
Rysselberghe system. Excellent results would certainly be obtained, for,
as we have recently been enabled to ascertain, the voice has a
remarkable intensity in this telephone, while at the same time perfectly
preserving its quality.--_La Nature_.

       *       *       *       *       *

[NATURE.]




THE MELDOMETER.


The apparatus which I propose to call by the above name
([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to
the mineralogical microscope, whereby the melting-points of minerals may
be compared or approximately determined and their behavior watched at
high temperatures either alone or in the presence of reagents.

As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide)
arranged to traverse the field of the microscope. The ribbon, clamped in
two brass clamps so as to be readily renewable, passes bridgewise over a
little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps
also take wires from a battery (3 Groves cells); and an adjustable
resistance being placed in circuit, the strip can be thus raised in
temperature up to the melting-point of platinum.

The disk being placed on the stage of the microscope the platinum strip
is brought into the field of a 1" objective, protected by a glass slip
from the radiant heat. The observer is sheltered from the intense light
at high temperatures by a wedge of tinted glass, which further can be
used in photometrically estimating the temperature by using it to obtain
extinction of the field. Once for all approximate estimations of the
temperature of the field might be made in terms of the resistance of the
platinum strip, the variation of such resistance with rise of
temperature being known. Such observations being made on a suitably
protected strip might be compared with the wedge readings, the latter
being then used for ready determinations. Want of time has hindered me
from making such observations up to this.

The mineral to be experimented on is placed in small fragments near the
center of the platinum ribbon, and closely watched while the current is
increased, till the melting-point of the substance is apparent. Up to
the present I have only used it comparatively, laying fragments of
different fusibilities near the specimen. In this way I have melted
beryl, orthoclase, and quartz. I was much surprised to find the last
mineral melt below the melting-point of platinum. I have, however, by me
as I write, a fragment, formerly clear rock-crystal, so completely fused
that between crossed Nicols it behaves as if an amorphous body, save in
the very center where a speck of flashing color reveals the remains of
molecular symmetry. Bubbles have formed in the surrounding glass.

Orthoclase becomes a clear glass filled with bubbles: at a lower
temperature beryl behaves in the same way.

Topaz whitens to a milky glass--apparently decomposing, throwing out
filmy threads of clear glass and bubbles of glass which break,
liberating a gas (fluorine?) which, attacking the white-hot platinum,
causes rings of color to appear round the specimen. I have now been
using the apparatus for nearly a month, and in its earliest days it led
me right in the diagnosis of a microscopical mineral, iolite, not before
found in our Irish granite, I think. The unlooked-for characters of the
mineral, coupled with the extreme minuteness of the crystals, led me
previously astray, until my meldometer fixed its fusibility for me as
far above the suspected bodies.

Carbon slips were at first used, as I was unaware of the capabilities of
platinum.

A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to
fit into the lantern for projection on the screen has been made for me
by Yeates. In this form the heated conductor passes both below and above
the specimen, which is regarded from a horizontal direction.

J. JOLY.

Physical Laboratory, Trinity College, Dublin.

       *       *       *       *       *

[AMERICAN ANNALS OF THE DEAF AND DUMB.]




TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES.


Progress in electrical science is daily causing the world to open its
eyes in wonder and the scientist to enlarge his hopes for yet greater
achievements. The practical uses to which this subtile fluid,
electricity, is being put are causing changes to be made in time-tested
methods of doing things in domestic, scientific, and business circles,
and the time has passed when startling propositions to accomplish this
or that by the assistance of electricity are dismissed with incredulous
smiles. This being the case, no surprise need follow the announcement of
a device to facilitate the imparting of instruction to deaf children
which calls into requisition some service from electricity.

The sense of touch is the direct medium contemplated, and it is intended
to convey, with accuracy and rapidity, messages from the operator (the
teacher) to the whole class simultaneously by electrical
transmission.[1]

[Footnote 1: By the same means two deaf-mutes, miles apart, might
converse with each other, and the greatest difficulty in the way of a
deaf-mute becoming a telegraph operator, that of receiving messages,
would be removed. The latter possibilities are incidentally mentioned
merely as of scientific interest, and not because of their immediate
practical value. The first mentioned use to which the device may be
applied is the one considered by the writer as possibly of practical
value, the consideration of which suggested the appliance to him.]

An alphabet is formed upon the palm of the left hand and the inner side
of the fingers, as shown by the accompanying cut, which, to those
becoming familiar with it, requires but a touch upon a certain point of
the hand to indicate a certain letter of the alphabet.

A rapid succession of touches upon various points of the hand is all
that is necessary in spelling a sentence. The left hand is the one upon
which the imaginary alphabet is formed, merely to leave the right hand
free to operate without change of position when two persons only are
conversing face to face.

The formation of the alphabet here figured is on the same principle as
one invented by George Dalgarno, a Scottish schoolmaster, in the year
1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_,
accompanying the reprint of a work entitled "_Didascalocophus_."
Dalgarno's idea could only have been an alphabet to be used in
conversation between two persons _tete a tete_, and--except to a limited
extent in the Horace Mann School and in Professor Bell's teaching--has
not come into service in the instruction of deaf-mutes or as a means of
conversation. There seems to have been no special design or system in
the arrangement of the alphabet into groups of letters oftenest
appearing together, and in several instances the proximity would
seriously interfere with distinct spelling; for instance, the group "u,"
"y," "g," is formed upon the extreme joint of the little finger. The
slight discoverable system that seems to attach to his arrangement of
the letters is the placing of the vowels in order upon the points of the
fingers successively, beginning with the thumb, intended, as we suppose,
to be of mnemonic assistance to the learner. Such assistance is hardly
necessary, as a pupil will learn one arrangement about as rapidly as
another. If any arrangement has advantage over another, we consider it
the one which has so grouped the letters as to admit of an increased
rapidity of manipulation. The arrangement of the above alphabet, it is
believed, does admit of this. Yet it is not claimed that it is as
perfect as the test of actual use may yet make it. Improvements in the
arrangement will, doubtless, suggest themselves, when the alterations
can be made with little need of affecting the principle.

In order to transmit a message by this alphabet, the following described
appliance is suggested: A matrix of cast iron, or made of any suitable
material, into which the person receiving the message (the pupil) places
his left hand, palm down, is fixed to the table or desk. The matrix,
fitting the hand, has twenty-six holes in it, corresponding in position
to the points upon the hand assigned to the different letters of the
alphabet. In these holes are small styles, or sharp points, which are so
placed as but slightly to touch the hand. Connected with each style is a
short line of wire, the other end of which is connected with a principal
wire leading to the desk of the operator (the teacher), and there so
arranged as to admit of opening and closing the circuit of an electric
current at will by the simple touch of a button, and thereby producing
along the line of that particular wire simultaneous electric impulses,
intended to act mechanically upon all the styles connected with it. By
these impulses, produced by the will of the sender, the styles are
driven upward with a quick motion, but with only sufficient force to be
felt and located upon the hand by the recipient. Twenty-six of these
principal or primary wires are run from the teacher's desk (there
connected with as many buttons) under the floor along the line of
pupils' desks. From each matrix upon the desk run twenty-six secondary
wires down to and severally connecting with the twenty-six primary wires
under the floor. The whole system of wires is incased so as to be out of
sight and possibility of contact with foreign substances. The keys or
buttons upon the desk of the teacher are systematically arranged,
somewhat after the order of those of the type writer, which allows the
use of either one or both hands of the operator, and of the greatest
attainable speed in manipulation. The buttons are labeled "a," "b," "c,"
etc., to "z," and an electric current over the primary wire running from
a certain button (say the one labeled "a") affects only those secondary
wires connected with the styles that, when excited, produce upon the
particular spot of the hands of the receivers the tactile impression to
be interpreted as "a." And so, whenever the sender touches any of the
buttons on his desk, immediately each member of the class feels upon the
palm of his hand the impression meant to be conveyed. The contrivance
will admit of being operated with as great rapidity as it is probable
human dexterity could achieve, i.e., as the strokes of an electric bell.
It was first thought of conveying the impressions directly by slight
electric shocks, without the intervention of further mechanical
apparatus, but owing to a doubt as to the physical effect that might be
produced upon the persons receiving, and as to whether the nerves might
not in time become partly paralyzed or so inured to the effect as to
require a stronger and stronger current, that idea was abandoned, and
the one described adopted. A diagram of the apparatus was submitted to a
skillful electrical engineer and machinist of Hartford, who gave as his
opinion that the scheme was entirely feasible, and that a simple and
comparatively inexpensive mechanism would produce the desired result.

[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.]

The matter now to consider, and the one of greater interest to the
teacher of deaf children, is, Of what utility can the device be in the
instruction of deaf-mutes? What advantage is there, not found in the
prevailing methods of communication with the deaf, i.e., by gestures,
dactylology, speech and speech-reading, and writing?

I. The language of gestures, first systematized and applied to the
conveying of ideas to the deaf by the Abbe de l'Epee during the latter
part of the last century, has been, in America, so developed and
improved upon by Gallaudet, Peet, and their successors, as to leave but
little else to be desired for the purpose for which it was intended. The
rapidity and ease with which ideas can be expressed and understood by
this "language" will never cease to be interesting and wonderful, and
its value to the deaf can never fail of being appreciated by those
familiar with it. But the genius of the language of signs is such as to
be in itself of very little, if any, direct assistance in the
acquisition of syntactical language, owing to the diversity in the order
of construction existing between the English language and the language
of signs. Sundry attempts have been made to enforce upon the
sign-language conformity to the English order, but they have, in all
cases known to the writer, been attended with failure. The sign-language
is as immovable as the English order, and in this instance certainly
Mahomet and the mountain will never know what it is to be in each
other's embrace. School exercises in language composition are given with
great success upon the basis of the sign-language. But in all such
exercises there must be a translation from one language to the other.
The desideratum still exists of an increased percentage of pupils
leaving our schools for the deaf, possessing a facility of expression in
English vernacular. This want has been long felt, and endeavoring to
find a reason for the confessedly low percentage, the sign-language has
been too often unjustly accused. It is only when the sign-language is
abused that its merit as a means of instruction degenerates. The most
ardent admirers of a proper use of signs are free to admit that any
excessive use by the pupils, which takes away all opportunities to
express themselves in English, is detrimental to rapid progress in
English expression.

II. To the general public, dactylology or finger spelling is the
sign-language, or the basis of that language, but to the profession
there is no relation between the two methods of communication.
Dactylology has the advantage of putting language before the eye in
conformity with English syntax, and it has always held its place as one
of the elements of the American or eclectic method. This advantage,
however, is not of so great importance as to outweigh the disadvantages
when, as has honestly been attempted, it asserts its independence of
other methods. Very few persons indeed, even after long practice, become
sufficiently skillful in spelling on the fingers to approximate the
rapidity of speech. But were it possible for all to become rapid
spellers, another very important requisite is necessary before the
system could be a perfect one, that is, the ability to _read_ rapid
spelling. The number of persons capable of reading the fingers beyond a
moderate degree of rapidity is still less than the number able to spell
rapidly. While it is physically possible to follow rapid spelling for
twenty or thirty minutes, it can scarcely be followed longer than that.
So long as this is true, dactylology can hardly claim to be more than
one of the _elements_ of a system of instruction for the deaf.

III. Articulate speech is another of the elements of the eclectic
method, employed with success inversely commensurate with the degree of
deficiency arising from deafness. Where the English order is already
fixed in his mind, and he has at an early period of life habitually used
it, there is comparatively little difficulty in instructing the deaf
child by speech, especially if he have a quick eye and bright intellect.
But the number so favored is a small percentage of the great body of
deaf-mutes whom we are called upon to educate. When it is used as a
_sole_ means of educating the deaf as a class its inability to stand
alone is as painfully evident as that of any of the other component
parts of the system. It would seem even less practicable than a sole
reliance upon dactylology would be, for there can be no doubt as to what
a word is if spelled slowly enough, and if its meaning has been learned.
This cannot be said of speech. Between many words there is not, when
uttered, the slightest visible distinction. Between a greater number of
others the distinction is so slight as to cause an exceedingly nervous
hesitation before a guess can be given. Too great an imposition is put
upon the eye to expect it to follow unaided the extremely circumscribed
gestures of the organs of speech visible in ordinary speaking. The ear
is perfection as an interpreter of speech to the brain. It cannot
correctly be said that it is _more_ than perfection. It is known that
the ear, in the interpretation of vocal sounds, is capable of
distinguishing as many as thirty-five sounds per second (and oftentimes
more), and to follow a speaker speaking at the rate of more than two
hundred words per minute. If this be perfection, can we expect the _eye_
of ordinary mortal to reach it? Is there wonder that the task is a
discouraging one for the deaf child?

But it has been asserted that while a large percentage (practically all)
of the deaf _can_, by a great amount of painstaking and practice, become
speech readers in some small degree, a relative degree of facility in
articulation is not nearly so attainable. As to the accuracy of this
view, the writer cannot venture an opinion. Judging from the average
congenital deaf-mute who has had special instruction in speech, it can
safely be asserted that their speech is laborious, and far, very far,
from being accurate enough for practical use beyond a limited number of
common expressions. This being the case, it is not surprising that as an
unaided means of instruction it cannot be a success, for English neither
understood when spoken, nor spoken by the pupil, cannot but remain a
foreign language, requiring to pass through some other form of
translation before it becomes intelligible.

There are the same obstacles in the use of the written or printed word
as have been mentioned in connection with dactylology, namely, lack of
rapidity in conveying impressions through the medium of the English
sentence.

I have thus hastily reviewed the several means which teachers generally
are employing to impart the use of English to deaf pupils, for the
purpose of showing a common difficulty. The many virtues of each have
been left unnoticed, as of no pertinence to this article.

The device suggested at the beginning of this paper, claiming to be
nothing more than a school room appliance intended to supplement the
existing means for giving a knowledge and practice of English to the
deaf, employs as its interpreter a different sense from the one
universally used. The sense of sight is the sole dependence of the deaf
child. Signs, dactylology, speech reading, and the written and printed
word are all dependent upon the eye for their value as educational
instruments. It is evident that of the two senses, sight and touch, if
but one could be employed, the choice of sight as the one best adapted
for the greatest number of purposes is an intelligent one; but, as the
choice is not limited, the question arises whether, in recognizing the
superior adaptability to our purpose of the one, we do not lose sight of
a possibly important, though secondary, function in the other. If sight
were all-sufficient, there would be no need of a combination. But it
cannot be maintained that such is the case. The plan by which we acquire
our vernacular is of divine, and not of human, origin, and the senses
designed for special purposes are not interchangeable without loss. The
theory that the loss of a certain sense is nearly, if not quite,
compensated for by increased acuteness of the remaining ones has been
exploded. Such a theory accuses, in substance, the Maker of creating
something needless, and is repugnant to the conceptions we have of the
Supreme Being. When one sense is absent, the remaining senses, in order
to equalize the loss, have imposed upon them an unusual amount of
activity, from which arises skill and dexterity, and by which the loss
of the other sense is in some measure alleviated, but not supplied. No
_additional_ power is given to the eye after the loss of the sense of
hearing other than it might have acquired with the same amount of
practice while both faculties were active. The fact, however, that the
senses, in performing their proper functions, are not overtaxed, and are
therefore, in cases of emergency, capable of being extended so as to
perform, in various degrees, additional service, is one of the wise
providences of God, and to this fact is due the possibility of whatever
of success is attained in the work of educating the deaf, as well as the
blind.

In the case of the blind, the sense of touch is called into increased
activity by the absence of the lost sense; while in the case of the
deaf, sight is asked to do this additional service. A blind person's
education is received principally through the _two_ senses of hearing
and touch. Neither of these faculties is so sensible to fatigue by
excessive use as is the sense of sight, and yet the eye has, in every
system of instruction applied to the deaf, been the sole medium. In no
case known to the writer, excepting in the celebrated case of Laura
Bridgman and a few others laboring under the double affliction of
deafness and blindness, has the sense of touch been employed as a means
of instruction.[1]

[Footnote 1: This article was written before Professor Bell had made his
interesting experiments with his "parents' class" of a touch alphabet,
to be used upon the pupil's shoulder in connection with the oral
teaching.--E.A.F.]

Not taking into account the large percentage of myopes among the deaf,
we believe there are other cogent reasons why, if found practicable, the
use of the sense of touch may become an important element in our
eclectic system of teaching. We should reckon it of considerable
importance if it were ascertained that a portion of the same work now
performed by the eye could be accomplished equally as well through
feeling, thereby relieving the eye of some of its onerous duties.

We see no good reason why such accomplishment may not be wrought. If,
perchance, it were discovered that a certain portion could be performed
in a more efficient manner, its value would thus be further enhanced.

In theory and practice, the teacher of language to the deaf, by whatever
method, endeavors to present to the eye of the child as many completed
sentences as are nominally addressed to the ear--having them "caught" by
the eye and reproduced with as frequent recurrence as is ordinarily done
by the child of normal faculties.

In our hasty review of the methods now in use we noted the inability to
approximate this desirable process as a common difficulty. The facility
now ordinarily attained in the manipulation of the type writer, and the
speed said to have been reached by Professor Bell and a private pupil of
his by the Dalgarno touch alphabet, when we consider the possibility of
a less complex mechanism in the one case and a more systematic grouping
of the alphabet in the other, would lead us to expect a more rapid means
of communication than is ordinarily acquired by dactylology, speech (by
the deaf), or writing. Then the ability to receive the communication
rapidly by the sense of feeling will be far greater. No part of the body
except the point of the tongue is as sensible to touch as the tips of
the fingers and the palm of the hand. Tactile discrimination is so acute
as to be able to interpret to the brain significant impressions produced
in very rapid succession. Added to this advantage is the greater one of
the absence of any more serious attendant physical or nervous strain
than is present when the utterances of speech fall upon the tympanum of
the ear. To sum up, then, the advantages of the device we find--

First. A more rapid means of communication with the deaf by syntactic
language, admitting of a greater amount of practice similar to that
received through the ear by normal children.

Second. Ability to receive this rapid communication for a longer
duration and without ocular strain.

Third. Perfect freedom of the eye to watch the expression on the
countenance of the sender.

Fourth. In articulation and speech-reading instruction, the power to
assist a class without distracting the attention of the eye from the
vocal organs of the teacher.

Fifth. Freedom of the right hand of the pupil to make instantaneous
reproduction in writing of the matter being received through the sense
of feeling, thereby opening the way for a valuable class exercise.

Sixth. The possible mental stimulus that accompanies the mastery of a
new language, and the consequent ability to receive known ideas through
a new medium.

Seventh. A fresh variety of class exercises made possible.

The writer firmly believes in the good that exists in all methods that
are, or are to be; in the interdependence rather than the independence
of all methods; and in all school-room appliances tending to supplement
or expedite the labors of the teacher, whether they are made of
materials delved from the earth or snatched from the clouds.

S. TEFFT WALKER,

_Superintendent of the Kansas Institution, Olathe, Kans_.

       *       *       *       *       *




WATER GAS.

THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS.

By B.H. THWAITE.


In order to approximately ascertain the relative reducing action of
water gas, carbon monoxide, and superheated steam on iron ore, the
author decided to have carried out the following experiments, which were
conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the
analyses. The ore used was from Bilbao, and known as the Ruby Mine, and
was a good average hematite. The carbonaceous material was the Trimsaran
South Wales anthracite, and contained about 90 per cent. of carbon.

A small experimental furnace was constructed of the form shown by
illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base,
and gradually swelling to 2 ft. 9 in. at the top, built entirely of
fireclay bricks. Two refractory tubes, 2 in. square internally, and the
height of the furnace, were used for the double purpose of producing the
gas and reducing the ore.

The end of the lower tube rested on a fireclay ladle nozzle, and was
properly jointed with fireclay; through this nozzle the steam or air was
supplied to the inside of the refractory tubes. In each experiment the
ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg.
Fahr." by means of an external fire of anthracite. Great care was taken
to prevent the contact of the solid carbonaceous fuel with the ore. In
each experiment in which steam was used, the latter was supplied at a
temperature equivalent to 35 lb. to the square inch.

The air for producing the carbon monoxide (CO) gas was used at the
temperature of the atmosphere. As near as possible, the same conditions
were obtained in each experiment, and the equivalent weight of air was
sent through the carbon to generate the same weight of CO as that
generated when steam was used for the production of water gas.

[Illustration]

_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled
with ore broken to the size of nuts. The tube, A, was heated to about
2,000 deg. Fahr., the upper one to about 1,500 deg.

NOTE.--In this experiment, part of the steam was dissociated in passing
through the turned-up end of the steam supply pipe, which became very
hot, and the steam would form with the iron the magnetic oxide
(Fe_{3}O_{4}). The reduction would doubtless be due to this
dissociation. The pieces of ore found on lowest end of the tube, A, were
dark  and semi-fused; part of one of these pieces was crushed
fine, and tested; see column I. The remainder of these black pieces was
mixed with the rest of the ore contained in tube, A, and ground and
tested; see column II. The ore in upper tube was all broken up together
and tested; see column III. When finely crushed, the color of No. I. was
bluish black; No. II., a shade darker red; No. III., a little darker
than the natural color of the ore. The analyses gave:

-----------------------------+---------+---------+---------
                             |    I.   |   II.   |  III.
                             +---------+---------+---------
                             |per cent.|per cent.|per cent.
Ferric oxide (Fe_{2}O_{3}).  |  68.55  |  76.47  |  84.81
Ferrous oxide (FeO).         |  16.20  |   9.50  |   1.50
                             +---------+---------+---------
        Total.               |  84.75  |  85.97  |  86.31
                             +---------+---------+---------
Calculated:                  |         |         |
Ferric oxide (Fe_{2}O_{3}).  |  32.55  |  55.36  |  81.47
Magnetic oxide (Fe_{3}O_{4}).|  52.20  |  30.61  |   4.84
Ferrous oxide (FeO).         |         |         |
                             +---------+---------+---------
Total.                       |  84.75  |  85.97  |  86.31
                             +---------+---------+---------
Percentage of total
        oxygen reduced.      |   6.93  |   4.02  |   1.07
Metallic iron.               |  60.59  |  60.92  |  60.54
-----------------------------+---------+---------+---------

_Second Experiment, Water Gas_.--The tube, A, was filled with small
pieces of anthracite, and heated until all the volatile matter had been
expelled. The tube, B, was then placed in tube, A, the joint being made
with fireclay, and to prevent the steam from carrying small particles of
solid carbon into ore in the upper tube, the anthracite was divided from
the ore by means of a piece of fine wire gauze. The steam at a pressure
of about 35 lb. to the square inch was passed through the anthracite.
The tube, A, was heated to white heat, the tube, B, at its lower end to
bright red, the top to cherry red.

------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Experiment.       |      1st.       |          2d.          |       3d.       |
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Number.           |  I. | II. | III.|  I. | II. | III.| IV. |  I. | II. | III.|
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Total Iron.       |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54|
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Iron occurring as
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  FeO.            |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12
  Fe_{2}O_{3}     |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Per cent. of Oxides.                                                          |
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  FeO.            |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44
  Fe_{2}O_{3}.    |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74
  Total.          |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Oxygen in Ore.
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80
After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64
  Difference.     | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Per cent. of oxygen reduced.
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Degree of Oxidation of the Ore after the Experiment.
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
FeO.              | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... |
Fe_{3}O_{4}.      |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64|
Fe_{2}O_{3}.      |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54|
Total.            |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|
------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

------------------+-----------------+-----------------------+-----------------+
The ore having    |                 |                       |                 |
been exposed to   |     Steam.      |     Water gas.        | Carbon monoxide.|
------------------+-----------------+-----------------------+-----------------+

_Four Samples were Tested_.--I. The bottom layer, 11/4 in. thick; the
color of ore quite black, with small particles of reduced spongy
metallic iron. II. Layer above I., 41/4 in. thick; the color was also
black, but showed a little purple tint. III. Layer above II., 5 in.
thick; purple red color. IV. Layer above III., ore a red color. The
analyses gave:

-----------------------------+---------+---------+---------+---------
                             |    I.   |   II.   |  III.   |   IV.
                             +---------+---------+---------+---------
                             |per cent.|per cent.|per cent.|per cent.
Ferric oxide (Fe_{2}O_{3}).  |  26.08  |  61.60  |  82.71  |  80.55
Ferrous oxide (FeO).         |  60.40  |  23.90  |   5.18  |   1.08
                             +---------+---------+---------+---------
        Total.               |  86.48  |  85.50  |  87.89  |  81.63
                             +---------+---------+---------+---------
Calculated:                  |         |         |         |
Ferric oxide (Fe_{2}O_{3}).  |   ...   |   8.49  |  59.77  |  77.75
Magnetic oxide (Fe_{3}O_{4}).|  37.82  |  77.01  |  28.12  |   3.88
Ferrous oxide (FeO).         |  48.66  |         |         |
                             +---------+---------+---------+---------
Total.                       |  86.48  |  85.41  |  87.89  |  81.63
                             +---------+---------+---------+---------
Percentage of total
        oxygen reduced.      |  24.03  |  10.02  |   2.26  |   0.49
Metallic iron.               |  65.24  |  61.71  |  61.93  |  57.23
-----------------------------+---------+---------+---------+---------

NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic
carbonate was expelled.

_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with
anthracite in the manner described for the second experiment, and heated
to drive off the volatile matter, before the ore was placed in the upper
tube, B, and the anthracite was divided from the ore by means of a piece
of fine wire gauze. The lower tube, A, was heated to the temperature of
white heat, the upper one, B, to a temperature of bright red. I. Layer,
1 in. thick from the bottom; ore dark brownish . II. Layer 4 in.
thick above I.; ore reddish brown. III. Layer 11 in. thick above II.;
ore red color. The analyses gave:

-----------------------------+---------+---------+---------
                             |    I.   |   II.   |  III.
                             +---------+---------+---------
                             |per cent.|per cent.|per cent.
Ferric oxide (Fe_{2}O_{3}).  |  43.26  |  78.91  |  77.74
Ferrous oxide (FeO).         |  37.86  |   3.46  |   1.44
                             +---------+---------+---------
        Total.               |  81.12  |  82.37  |  79.18
                             +---------+---------+---------
Calculated:                  |         |         |
Ferric oxide (Fe_{2}O_{3}).  |   ...   |  71.23  |  74.54
Magnetic oxide (Fe_{3}O_{4}).|  62.72  |  11.14  |   4.64
Ferrous oxide (FeO).         |  18.40  |         |
                             +---------+---------+---------
Total.                       |  81.12  |  82.37  |  79.18
                             +---------+---------+---------
Percentage of total
        oxygen reduced.      |  16.44  |   1.49  |   0.42
Metallic iron.               |  59.73  |  57.93  |  55.54
-----------------------------+---------+---------+---------

NOTE.--The carbon monoxide (CO) had failed to remove from the ore the
carbon dioxide existing as calcic carbonate. The summary of experiments
in the following table appears to show that the water gas is a more
powerful reducing agent than CO in proportion to the ratio of as

                 4.21 x 100
4.21 : 6.72, or ------------ = 52 per cent.
                      72

Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now
constructing large experimental plant in which water gas will be used as
the reducing agent. This plant would have been at work before this but
for some defects in the valvular arrangements, which will be entirely
removed in the new modifications of the plant.

       *       *       *       *       *




ANTISEPTIC MOUTH WASH.


Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use
of perchloride of mercury in the following form: One grain of the
perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz.
of eau de Cologne or tincture of lemons, and a teaspoonful of the
solution to be mixed with two-thirds of a wineglassful of water, making
a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and
Druggist_.

       *       *       *       *       *




ANNATTO.

[Footnote: Read at an evening meeting of the North British Branch of the
Pharmaceutical Society, January 21.]

By WILLIAM LAWSON.


The subject which I have the honor to bring shortly before your notice
this evening is one that formed the basis of some instructive remarks by
Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read
before the Society in London in January, 1856, which latter gave rise to
an animated discussion. The work detailed below was well in hand when
Mr. MacEwan drew my attention to these and kindly supplied me with the
volume containing reports of them. Unfortunately, they deal principally
with the adulterations, while I was more particularly desirous to learn
the composition in a general way, and especially the percentage of
coloring resin, the important constituent in commercial annatto. Within
the last few years it was one of the articles in considerable demand in
this part of the country; now it is seldom inquired for. This,
certainly, is not because butter coloring has ceased to be employed, and
hence the reason for regretting that the percentage of resin was not
dealt with in the articles referred to, so that a comparison could have
been made between the commercial annatto of that period and that which
exists now. In case some may not be in possession of literature bearing
on it--which, by the way, is very meager--it may not be out of place to
quote some short details as to its source, the processes for obtaining
it, the composition of the raw material, and then the method followed in
the present inquiry will be given, together with the results of the
examination of ten samples; and though the subject doubtless has more
interest for the country than for the town druggist, still, I trust it
will have points of interest for both.

Annatto is the coloring matter derived from the seeds of an evergreen
plant, _Bixa Orellana_, which grows in the East and West Indian Islands
and South America, in the latter of which it is principally prepared.
Two kinds are imported, Spanish annatto, made in Brazil, and flag or
French, made mostly in Cayenne. These differ considerably in characters
and properties, the latter having a disagreeable putrescent odor, while
the Spanish is rather agreeable when fresh and good. It is, however,
inferior to the flag as a coloring or dyeing agent. The seeds from which
the substance is obtained are red on the outside, and two methods are
followed in order to obtain it. One is to rub or wash off the coloring
matter with water, allow it to subside, and to expose it to spontaneous
evaporation till it acquires a pasty consistence. The other is to bruise
the seeds, mix them with water, and allow fermentation to set in, during
which the coloring matter collects at the bottom, from which it is
subsequently removed and brought to the proper consistence by
spontaneous evaporation. These particulars, culled from Dr. Redwood's
remarks, may suffice to show its source and the methods for obtaining
it.

Dr. John gives the following as the composition of the pulp surrounding
the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5;
ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of
spicy and acid matter.

It must be understood, however, that commercial annatto, having
undergone processes necessary to fit it for its various uses, as well as
to preserve it, differs considerably from this; and though it may not be
true, as some hint, that manufacturing in this industry is simply a term
synonymous with adulterating, yet results will afterward be given
tending to show that there are articles in the market which have little
real claim to the title. I tried, but failed, to procure a sample of raw
material on which to work, with a view to learn something of its
characters and properties in this state, and thus be able to contrast it
with the manufactured or commercial article. The best thing to do in the
circumstances, I thought, was to operate on the highest priced sample at
disposal, and this was done in all the different ways that suggested
themselves. The extraction of the resin by means of alcohol--the usual
way, I believe--was a more troublesome operation than it appeared to be,
as the following experiment will show: One hundred grains of No. 8 were
taken, dried thoroughly, reduced to fine powder, and introduced into a
flask containing 4 ounces of alcohol in the form of methylated spirit,
boiled for an hour--the flask during the operation being attached to an
inverted condenser--filtered off, and the residue treated with a smaller
amount of the spirit and boiled for ten minutes. This was repeated with
diminishing quantities until in all 14 ounces had been used before the
alcoholic solution ceased to turn blue on the addition to it of strong
sulphuric acid, or failed to give a brownish precipitate with stannous
chloride. As the sample contained a considerable quantity of potassium
carbonate, in which the resin is soluble, it was thought that by
neutralizing this it might render the resin more easy of extraction.
This was found to be so, but it was accompanied by such a mass of
extractive as made it in the long run more troublesome, and hence it was
abandoned. Thinking the spirit employed might be too weak, an experiment
with commercial absolute alcohol was carried out as follows: One hundred
grains of a red sample, No. 4, were thoroughly dried, powdered finely,
and boiled in 2 ounces of the alcohol, filtered, and the residue treated
with half an ounce more. This required to be repeated with fresh half
ounces of the alcohol until in all 71/2 were used; the time occupied from
first to last being almost three hours. This was considered
unsatisfactory, besides being very expensive, and so it, also, was set
aside, and a series of experiments with methylated spirit alone was set
in hand. The results showed that the easiest and most satisfactory way
was to take 100 grains (this amount being preferred, as it reduces error
to the minimum), dry thoroughly, powder finely, and macerate with
frequent agitation for twenty-four hours in a few ounces of spirit, then
to boil in this spirit for a short time, filter, and repeat the boiling
with a fresh ounce or so; this, as a rule, sufficing to completely
exhaust it of its resin. Wynter Blyth says that the red resin, or bixin,
is soluble in 25 parts of hot alcohol. It appears from these experiments
that much more is required to dissolve it out of commercial annatto.

The full process followed consisted in determining the moisture by
drying 100 grains at 212 deg. F. till constant, and taking this dried
portion for estimation of the resin in the way just stated. The
alcoholic extract was evaporated to dryness over a water-bath, the
residue dissolved in solution of sodium carbonate, and the resin
precipitated by dilute sulphuric acid (these reagents being chosen as
the best after numerous trials with others), added in the slightest
possible excess. The resin was collected on a tared double filter paper,
washed with distilled water until the washings were entirely colorless,
dried and weighed.

The ash was found in the usual way, and the extractive by the
difference. In the ash the amount soluble was determined, and
qualitatively examined, as was the insoluble portion in most of them.

The results are as follows:

         |  1.  |  2.  |  3.  |  4.  |  5.  |  6.  |  7.  |  8.  |  9.  |  10.
Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50
Resin    |  3.00|  2.90|  1.00|  8.80|  3.00|  1.80|  5.40| 12.00|  5.90|  9.20
Extrac-
tive     | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50
Ash      | 17.96| 16.17| 13.61|  2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80
-------------------------------------------------------------------------------
         |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00
-------------------------------------------------------------------------------
Ashes:   |      |      |      |Almost|      |      |      |      |      |
Soluble  | 13.20| 12.57|  7.50|wholly|  10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8
Insoluble|  4.76|  3.60|  6.11| NaCl.|  10.6|  2.50| 33.5 |  9.0 | 36.0 | 26.0

The first six are the ordinary red rolls, with the exception of No. 4,
which is a red mass, the only one of this class direct from the
manufacturers. The remainder are brown cakes, all except No. 7 being
from the manufacturers direct. The ash of the first two was largely
common salt; that of No. 3 contained, besides this, iron in some
quantity. No. 4 is unique in many respects. It was of a bright red
color, and possessed a not disagreeable odor. It contained the largest
percentage of moisture and the lowest of ash; had, comparatively, a
large amount of coloring matter; was one of the cheapest, and in the
course of some dairy trials, carried out by an intelligent farmer, was
pronounced to be the best suited for coloring butter. So far as my
experience goes, it was a sample of the best commercial excellence,
though I fear the mass of water present and the absence of preserving
substances will assist in its speedy decay. Were such an article easily
procured in the usual way of business, there would not be much to
complain of, but it must not be forgotten that it was got direct from
the manufacturers--a somewhat suggestive fact when the composition of
some other samples is taken into account. No. 5 emitted a disagreeable
odor during ignition. The soluble portion of the ash was mostly common
salt, and the insoluble contained three of sand--the highest amount
found, although most of the reds contained some. No. 6 was a
vile-looking thing, and when associated in one's mind with butter gave
rise to disagreeable reflections. It was wrapped in a paper saturated
with a strongly smelling linseed oil. When it was boiled in water and
broken up, hairs, among other things, were observed floating about. It
contained some iron. The first cake, No. 7, gave off during ignition an
agreeable odor resembling some of the finer tobaccos, and this is
characteristic more or less of all the cakes. The ash weighed 52 per
cent., the soluble part of which, 18.5, was mostly potassium carbonate,
with some chlorides and sulphates; the insoluble, mostly chalk with iron
and alumina. No. 8--highest priced of all--had in the mass an odor which
I can compare to nothing else than a well rotted farmyard manure. Twenty
parts of the ash were soluble and largely potassium carbonate, the
insoluble being iron for the most part. The mineral portions of Nos. 9
and 10 closely resemble No. 7.

On looking over the results, it is found that the red rolls contained
starchy matters in abundance (in No. 4 the starch was to a large extent
replaced by water), and an ash, mostly sodium chloride, introduced no
doubt to assist in its preservation as well as to increase the color of
the resin--a well known action of salt on vegetable reds. The cakes,
which are mostly used for cheese coloring, I believe, all appeared to
contain turmeric, for they gave a more or less distinct reaction with
the boric acid test, and all except No. 8 contained large quantities of
chalk. These results in reference to extractive, etc., reveal nothing
that has not been known before. Wynter Blyth, who gives the only
analyses of annatto I have been able to find, states that the
composition of a fair commercial sample (which I take to mean the raw
article) examined by him was as follows: water, 24.2; resin, 28.8; ash,
22.5; and extractive, 24.5; and that of an adulterated (which I take to
mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron,
silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If
this be correct, it appears that the articles at present in the market,
or at least those which have come in my way, have been wretched
imitations of the genuine thing, and should, instead of being called
adulterated annatto, be called something else adulterated, but not
seriously, with annatto. I have it on the authority of the farmer
previously referred to, that 1/4 of an ounce of No. 4 is amply sufficient
to impart the desired cowslip tint to no less than 60 lb. of butter.
When so little is actually required, it does not seem of very serious
importance whether the adulterant or preservative be flour, chalk, or
water, but it is exasperating in a very high degree to have such
compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1,
2, and 5 have been rejected by dairymen as useless for the purpose. In
conclusion, I may be permitted to express the hope that others may be
induced to examine the annatto taken into stock more closely than I was
taught to do, and had been in the habit of doing, namely, to see if it
had a good consistence and an odor resembling black sugar, for if so,
the quality was above suspicion.

       *       *       *       *       *




JAPANESE RICE WINE AND SOJA SAUCE.


Professor P. Cohn has recently described the mode in which he has
manufactured the Japanese sake or rice wine in the laboratory. The
material used was "Tane Kosi," i.e., grains of rice coated with the
mycelium, conidiophores, and greenish yellow chains of conidia of
_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this
fungus before the development of the fructification. The rice is first
exposed to moist air so as to change the starch into paste, and then
mixed with grains of the "Tane Kosi." The whole mass of rice becomes in
a short time permeated by the soft white shining mycelium, which imparts
to it the odor of apple or pine-apple. To prevent the production of the
fructification, freshly moistened rice is constantly added for two or
three days, and then subjected to alcoholic fermentation from the
_Saccharomyces_, which is always present in the rice, but which has
nothing to do with the _Aspergillus_. The fermentation is completed in
two or three weeks, and the golden yellow, sherry-like sake is poured
off. The sample manufactured contained 13.9 per cent. of alcohol.
Chemical investigation showed that the _Aspergillus_ mycelium transforms
the starch into glucose, and thus plays the part of a diastase.

Another substance produced from the _Aspergillus_ rice is the soja
sauce. The soja leaves, which contain little starch, but a great deal of
oil and casein, are boiled, mixed with roasted barley, and then with the
greenish yellow conidia powder of the _Aspergillus_. After the mycelium
has fructified, the mass is treated with a solution of sodium chloride,
which kills the _Aspergillus_, another fungus, of the nature of a
_Chalaza_, and similar to that produced in the fermentation of
"sauerkraut," appearing in its place. The dark-brown soja sauce then
separates.

       *       *       *       *       *




ALUMINUM.

[Footnote: Annual address delivered by President J.A. Price before the
meeting of the Scranton Board of Trade, Monday, January 18, 1886.]

By J.A. PRICE.


Iron is the basis of our civilization. Its supremacy and power it is
impossible to overestimate; it enters every avenue of development, and
it may be set down as the prime factor in the world's progress. Its
utility and its universality are hand in hand, whether in the
magnificent iron steamship of the ocean, the network of iron rail upon
land, the electric gossamer of the air, or in the most insignificant
articles of building, of clothing, and of convenience. Without it, we
should have miserably failed to reach our present exalted station, and
the earth would scarcely maintain its present population; it is indeed
the substance of substances. It is the Archimedean lever by which the
great human world has been raised. Should it for a moment forget its
cunning and lose its power, earthquake shocks or the wreck of matter
could not be more disastrous. However axiomatic may be everything that
can be said of this wonderful metal, it is undoubtedly certain that it
must give way to a metal that has still greater proportions and vaster
possibilities. Strange and startling as may seem the assertion, yet I
believe it nevertheless to be true that we are approaching the period,
if not already standing upon the threshold of the day, when this magical
element will be radically supplanted, and when this valuable mineral
will be as completely superseded as the stone of the aborigines. With
all its apparent potency, it has its evident weaknesses; moisture is
everywhere at war with it, gases and temperature destroy its fiber and
its life, continued blows or motion crystallize and rob it of its
strength, and acids will devour it in a night. If it be possible to
eliminate all, or even one or more, of these qualities of weakness in
any metal, still preserving both quantity and quality, that metal will
be the metal of the future.

The coming metal, then, to which our reference is made is aluminum, the
most abundant metal in the earth's crust. Of all substances, oxygen is
the most abundant, constituting about one-half; after oxygen comes
silicon, constituting about one-fourth, with aluminum third in all the
list of substances of the composition. Leaving out of consideration the
constituents of the earth's center, whether they be molten or gaseous,
more or less dense as the case may be, as we approach it, and confining
ourselves to the only practical phase of the subject, the crust, we find
that aluminum is beyond question the most abundant and the most useful
of all metallic substances.

It is the metallic base of mica, feldspar, slate, and clay. Professor
Dana says: "Nearly all the rocks except limestones and many sandstones
are literally ore-beds of the metal aluminum." It appears in the gem,
assuming a blue in the sapphire, green in the emerald, yellow in the
topaz, red in the ruby, brown in the emery, and so on to the white,
gray, blue, and black of the slates and clays. It has been dubbed "clay
metal" and "silver made from clay;" also when mixed with any
considerable quantity of carbon becoming a grayish or bluish black "alum
slate."

This metal in color is white and next in luster to silver. It has never
been found in a pure state, but is known to exist in combination with
nearly two hundred different minerals. Corundum and pure emery are ores
that are very rich in aluminum, containing about fifty-four per cent.
The specific gravity is but two and one-half times that of water; it is
lighter than glass or as light as chalk, being only one-third the weight
of iron and one-fourth the weight of silver; it is as malleable as gold,
tenacious as iron, and harder than steel, being next the diamond. Thus
it is capable of the widest variety of uses, being soft when ductility,
fibrous when tenacity, and crystalline when hardness is required. Its
variety of transformations is something wonderful. Meeting iron, or even
iron at its best in the form of steel, in the same field, it easily
vanquishes it at every point. It melts at 1,300 degrees F., or at least
600 degrees below the melting point of iron, and it neither oxidizes in
the atmosphere nor tarnishes in contact with gases. The enumeration of
the properties of aluminum is as enchanting as the scenes of a fairy
tale.

Before proceeding further with this new wonder of science, which is
already knocking at our doors, a brief sketch of its birth and
development may be fittingly introduced. The celebrated French chemist
Lavoisier, a very magician in the science, groping in the dark of the
last century, evolved the chemical theory of combustion--the existence
of a "highly respirable gas," oxygen, and the presence of metallic bases
in earths and alkalies. With the latter subject we have only to do at
the present moment. The metallic base was predicted, yet not identified.
The French Revolution swept this genius from the earth in 1794, and
darkness closed in upon the scene, until the light of Sir Humphry Davy's
lamp in the early years of the present century again struck upon the
metallic base of certain earths, but the reflection was so feeble that
the great secret was never revealed. Then a little later the Swedish
Berzelius and the Danish Oersted, confident in the prediction of
Lavoisier and of Davy, went in search of the mysterious stranger with
the aggressive electric current, but as yet to no purpose. It was
reserved to the distinguished German Wohler, in 1827, to complete the
work of the past fifty years of struggle and finally produce the minute
white globule of the pure metal from a mixture of the chloride of
aluminum and sodium, and at last the secret is revealed--the first step
was taken. It took twenty years of labor to revolve the mere discovery
into the production of the aluminum bead in 1846, and yet with this
first step, this new wonder remained a foetus undeveloped in the womb of
the laboratory for years to come.

Returning again to France some time during the years between 1854 and
1858, and under the patronage of the Emperor Napoleon III., we behold
Deville at last forcing Nature to yield and give up this precious
quality as a manufactured product. Rose, of Berlin, and Gerhard, in
England, pressing hard upon the heels of the Frenchman, make permanent
the new product in the market at thirty-two dollars per pound. The
despair of three-quarters of a century of toilsome pursuit has been
broken, and the future of the metal has been established.

The art of obtaining the metal since the period under consideration has
progressed steadily by one process after another, constantly increasing
in powers of productivity and reducing the cost. These arts are
intensely interesting to the student, but must be denied more than a
reference at this time. The price of the metal may be said to have come
within the reach of the manufacturing arts already.

A present glance at the uses and possibilities of this wonderful metal,
its application and its varying quality, may not be out of place. Its
alloys are very numerous and always satisfactory; with iron, producing a
comparative rust proof; with copper, the beautiful golden bronze, and so
on, embracing the entire list of articles of usefulness as well as works
of art, jewelry, and scientific instruments.

Its capacity to resist oxidation or rust fits it most eminently for all
household and cooking utensils, while its color transforms the dark
visaged, disagreeable array of pots, pans, and kitchen implements into
things of comparative beauty. As a metal it surpasses copper, brass, and
tin in being tasteless and odorless, besides being stronger than either.

It has, as we have seen, bulk without weight, and consequently may be
available in construction of furniture and house fittings, as well in
the multitudinous requirements of architecture. The building art will
experience a rapid and radical change when this material enters as a
component material, for there will be possibilities such as are now
undreamed of in the erection of homes, public buildings, memorial
structures, etc. etc., for in this metal we have the strength,
durability, and the color to give all the variety that genius may
dictate.

And when we take a still further survey of the vast field that is
opening before us, we find in the strength without size a most desirable
assistant in all the avenues of locomotion. It is the ideal metal for
railway traffic, for carriages and wagons. The steamships of the ocean
of equal size will double their cargo and increase the speed of the
present greyhounds of the sea, making six days from shore to shore seem
indeed an old time calculation and accomplishment. A thinner as well as
a lighter plate; a smaller as well as a stronger engine; a larger as
well as a less hazardous propeller; and a natural condition of
resistance to the action of the elements; will make travel by water a
forcible rival to the speed attained upon land, and bring all the
distant countries in contact with our civilization, to the profit of
all. This metal is destined to annihilate space even beyond the dream of
philosopher or poet.

The tensile strength of this material is something equally wonderful,
when wire drawn reaches as high as 128,000 pounds, and under other
conditions reaches nearly if not quite 100,000 pounds to the square
inch. The requirements of the British and German governments in the best
wrought steel guns reach only a standard of 70,000 pounds to the square
inch. Bridges may be constructed that shall be lighter than wooden ones
and of greater strength than wrought steel and entirely free from
corrosion. The time is not distant when the modern wonder of the
Brooklyn span will seem a toy.

It may also be noted that this metal affords wide development in
plumbing material, in piping, and will render possible the almost
indefinite extension of the coming feature of communication and
exchange--the pneumatic tube.

The resistance to corrosion evidently fits this metal for railway
sleepers to take the place of the decaying wooden ties. In this metal
the sleeper may be made as soft and yielding as lead, while the rail may
be harder and tougher than steel, thus at once forming the necessary
cushion and the avoidance of jar and noise, at the same time
contributing to additional security in virtue of a stronger rail.

In conductivity this metal is only exceeded by copper, having many times
that of iron. Thus in telegraphy there are renewed prospects in the
supplanting of the galvanized iron wire--lightness, strength, and
durability. When applied to the generation of steam, this material will
enable us to carry higher pressure at a reduced cost and increased
safety, as this will be accomplished by the thinner plate, the greater
conductivity of heat, and the better fiber.

It is said that some of its alloys are without a rival as an
anti-friction metal, and having hardness and toughness, fits it
remarkably for bearings and journals. Herein a vast possibility in the
mechanic art lies dormant--the size of the machine may be reduced, the
speed and the power increased, realizing the conception of two things
better done than one before. It is one of man's creative acts.

From other of its alloys, knives, axes, swords, and all cutting
implements may receive and hold an edge not surpassed by the best
tempered steel. Hulot, director in the postage stamp department, Paris,
asserts that 120,000 blows will exhaust the usefulness of the cushion of
the stamp machine, and this number of blows is given in a day; and that
when a cushion of aluminum bronze was substituted, it was unaffected
after months of use.

If we have found a metal that possesses both tensile strength and
resistance to compression; malleability and ductility--the quality of
hardening, softening, and toughening by tempering; adaptability to
casting, rolling, or forging; susceptibility to luster and finish; of
complete homogeneous character and unusually resistant to destructive
agents--mankind will certainly leave the present accomplishments as
belonging to an effete past, and, as it were, start anew in a career of
greater prospects.

This important material is to be found largely in nearly all the rocks,
or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal."
It is in every clay bank. It is particularly abundant in the coal
measures and is incidental to the shales or slates and clays that
underlie the coal. This under clay of the coal stratum was in all
probability the soil out of which grew the vegetation of the coal
deposits. It is a compound of aluminum and other matter, and, when mixed
with carbon and transformed by the processes of geologic action, it
becomes the shale rock which we know and which we discard as worthless
slate. And it is barely possible that we have been and are still carting
to the refuse pile an article more valuable than the so greatly lauded
coal waste or the merchantable coal itself. We have seen that the best
alumina ore contains only fifty-four per cent. of metal.

The following prepared table has been furnished by the courtesy and
kindness of Mr. Alex. H. Sherred, of Scranton.

               ALUMINA.

Blue-black shale, Pine Brook drift                            27.36
Slate from Briggs' Shaft coal                                 15.93
Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53
First cut on railroad, black clay above Rolling Mill          32.60
G vein black clay, Hyde Park mines                            28.67

It will be seen that the black clay, shale, or slate, has a constituent
of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the
highest. Under every stratum of coal, and frequently mixed with it, are
these under deposits that are rich in the metal. When exposed to the
atmosphere, these shales yield a small deposit of alum. In the
manufacture of alum near Glasgow the shale and slate clay from the old
coal pits constitute the material used, and in France alum is
manufactured directly from the clay.

Sufficient has been advanced to warrant the additional assertion that we
are here everywhere surrounded by this incomparable mineral, that it is
brought to the surface from its deposits deep in the earth by the
natural process in mining, and is only exceeded in quantity by the coal
itself. Taking a columnar section of our coal field, and computing the
thickness of each shale stratum, we have from twenty-five to sixty feet
in thickness of this metal-bearing substance, which averages over
twenty-five per cent. of the whole in quantity in metal.

It is readily apparent that the only task now before us is the reduction
of the ore and the extraction of the metal. Can this be done? We answer,
it has been done. The egg has stood on end--the new world has been
sighted. All that now remains is to repeat the operation and extend the
process. Cheap aluminum will revolutionize industry, travel, comfort,
and indulgence, transforming the present into an even greater
civilization. Let us see.

We have seen the discovery of the mere chemical existence of the metal,
we have stood by the birth of the first white globule or bead by Wohler,
in 1846, and witnesssed its introduction as a manufactured product in
1855, since which time, by the alteration and cheapening of one process
after another, it has fallen in price from thirty-two dollars per pound
in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent
labor at smelting have increased the quantity over a thousandfold and
reduced the cost upward of fifty per cent.

All these processes involve the application of heat--a mere question of
the appliances. The electric currents of Berzelius and Oersted, the
crucible of Wohler, the closed furnaces and the hydrogen gas of the
French manufacturers and the Bessemer converter apparatus of Thompson,
all indicate one direction. This metal can be made to abandon its bed in
the earth and the rock at the will of man. During the past year, the
Messrs. Cowles, of Cleveland, by their electric smelting process, claim
to have made it possible to reduce the price of the metal to below four
dollars per pound; and there is now erecting at Lockport, New York, a
plant involving one million of capital for the purpose.

Turning from the employment of the expensive reducing agents to the
simple and sole application of heat, we are unwilling to believe that we
do not here possess in eminence both the mineral and the medium of its
reduction. Whether the electric or the reverberatory or the converter
furnace system be employed, it is surely possible to produce the result.

To enter into consideration of the details of these constructions would
involve more time than is permitted us on this occasion. They are very
interesting. We come again naturally to the limitless consideration of
powdered fuel, concerning which certain conclusions have been reached.
In the dissociation of water into its hydrogen and oxygen, with the
mingled carbon in a powdered state, we undoubtedly possess the elements
of combustion that are unexcelled on earth, a heat-producing combination
that in both activity and power leaves little to be desired this side of
the production of the electric force and heat directly from the carbon
without the intermediary of boilers, engines, dynamos, and furnaces.

In the hope of stimulating thought to this infinite question of proper
fuel combustion, with its attendant possibilities for man's
gratification and ambition, this advanced step is presented. The
discussion of processes will require an amount of time which I hope this
Board will not grudgingly devote to the subject, but which is impossible
at present. Do not forget that there is no single spot on the face of
the globe where nature has lavished more freely her choicest gifts. Let
us be active in the pursuit of the treasure and grateful for the
distinguished consideration.

       *       *       *       *       *




THE ORIGIN OF METEORITES.


On January 9, Professor Dewar delivered the sixth and last of his series
of lectures at the Royal Institution on "The Story of a Meteorite." [For
the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that
cosmic dust is found on Arctic snows and upon the bottom of the ocean;
all over the world, in fact, at some time or other, there has been a
large deposit of this meteoric dust, containing little round nodules
found also in meteorites. In Greenland some time ago numbers of what
were supposed to be meteoric stones were found; they contained iron, and
this iron, on being analyzed at Copenhagen, was found to be rich in
nickel. The Esquimaux once made knives from iron containing nickel; and
as any such alloy they must have found and not manufactured, it was
supposed to be of meteoric origin. Some young physicists visited the
basaltic coast in Greenland from which some of the supposed meteoric
stones had been brought, and in the middle of the rock large nodules
were found composed of iron and nickel; it, therefore, became evident
that the earth might produce masses not unlike such as come to us as
meteorites. The lecturer here exhibited a section of the Greenland rock
containing the iron, and nickel alloy, mixed with stony crystals, and
its resemblance to a section of a meteorite was obvious. It was 21/2 times
denser than water, yet the whole earth is 51/2 times denser than water, so
that if we could go deep enough, it is not improbable that our own globe
might be found to contain something like meteoric iron. He then called
attention to the following tables:

  _Elementary Substances found in Meteorites_.

  Hydrogen.       Chromium.       Arsenic.
  Lithium.        Manganese.      Vanadium?
  Sodium.         Iron.           Phosphorus.
  Potassium.      Nickel.         Sulphur.
  Magnesium.      Cobalt.         Oxygen.
  Calcium.        Copper.         Silicon.
  Aluminum.       Tin.            Carbon.
  Titanium.       Antimony.       Chlorine.

_Density of Meteorites_.

  Carbonaceous (Orgueil, etc.)     1.9 to 3
  Aluminous (Java)                 3.0  " 3.2
  Peridotes (Chassigny, etc.)      3.5  " --
  Ordinary type (Saint Mes)        3.1  " 3.8
  Rich in iron (Sierra de Chuco)   6.5  " 7.0
  Iron with stone (Krasnoyarsk)    7.1  " 7.8
  True irons (Caille)              7.0  " 8.0

_Interior of the Earth_

  Parts
  of the
  radius.    Density.
   0.0        11.0
   0.1        10.3
   0.2         9.6
   0.3         8.9
   0.4         8.3
   0.5         7.8
   0.6         7.4
   0.7         7.1
   0.8         6.2
   0.9         5.0
   1.0         2.6

[Illustration]

Twice a year, said Professor Dewar, what are called "falling stars"
maybe plentifully seen; the times of their appearance are in August and
November. Although thousands upon thousands of such small meteors have
passed through our atmosphere, there is no distinct record of one having
ever fallen to the earth during these annual displays. One was said to
have fallen recently at Naples, but on investigation it turned out to be
a myth. These annual meteors in the upper air are supposed to be only
small ones, and to be dissipated into dust and vapor at the time of
their sudden heating; so numerous are they that 40,000 have been counted
in one evening, and an exceptionally great display comes about once in
331/4 years. The inference from their periodicity is, that they are small
bodies moving round the sun in orbits of their own, and that whenever
the earth crosses their orbits, thereby getting into their path, a
splendid display of meteors results. A second display, a year later,
usually follows the exceptionally great display just mentioned,
consequently the train of meteors is of great length. Some of these
meteors just enter the atmosphere of the earth, then pass out again
forever, with their direction of motion altered by the influence of the
attraction of the earth. He here called attention to the accompanying
diagram of the orbits of meteors.

The lecturer next invited attention to a hollow globe of linen or some
light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and
contained hidden within it the great electro-magnet, weighing 2 cwt., so
often used by Faraday in his experiments. He also exhibited a ball made
partly of thin iron; the globe represented the earth, for the purposes
of the experiment, and the ball a meteorite of somewhat large relative
size. The ball was then discharged at the globe from a little catapult;
sometimes the globe attracted the ball to its surface, and held it
there, sometimes it missed it, but altered its curve of motion through
the air. So was it, said the lecturer, with meteorites when they neared
the earth. Photographs from drawings, by Professor A. Herschel, of the
paths of meteors as seen by night were projected on the screen; they all
seemed to emanate from one radiant point, which, said the lecturer, is a
proof that their motions are parallel to each other; the parallel lines
seem to draw to a point at the greatest distance, for the same reason
that the rails of a straight line of railway seem to come from a distant
central point. The most interesting thing about the path of a company of
meteors is, that a comet is known to move in the same orbit; the comet
heads the procession, the meteors follow, and they are therefore, in all
probability, parts of comets, although everything about these difficult
matters cannot as yet be entirely explained; enough, however, is known
to give foundation for the assumption that meteorites and comets are not
very dissimilar.

The light of a meteorite is not seen until it enters the atmosphere of
the earth, but falling meteorites can be vaporized by electricity, and
the light emitted by their constituents be then examined with the
spectroscope. The light of comets can be directly examined, and it
reveals the presence in those bodies of sodium, carbon, and a few other
well-known substances. He would put a piece of meteorite in the electric
arc to see what light it would give; he had never tried the experiment
before. The lights of the theater were then turned down, and the
discourse was continued in darkness; among the most prominent lines
visible in the spectrum of the meteorite, Professor Dewar specified
magnesium, sodium, and lithium. "Where do meteorites come from?" said
the lecturer. It might be, he continued, that they were portions of
exploded planets, or had been ejected from planets. In this relation, he
should like to explain the modern idea of the possible method of
construction of our own earth. He then set forth the nebular hypothesis
that at some long past time our sun and all his planets existed but as a
volume of gas, which in contracting and cooling formed a hot volume of
rotating liquid, and that as this further contracted and cooled, the
planets, and moons, and planetary rings fell off from it and gradually
solidified, the sun being left as the solitary comparatively uncooled
portion of the original nebula. In partial illustration of this, he
caused a little globe of oil, suspended in an aqueous liquid of nearly
its own specific gravity, to rotate, and as it rotated it was seen, by
means of its magnified image upon the screen, to throw off from its
outer circumference rings and little globes.

       *       *       *       *       *




CANDELABRA CACTUS AND CALIFORNIA WOODPECKER.

By C.F. HOLDER.


One of the most picturesque objects that meet the eye of the traveler
over the great plains of the southern portion of California and New
Mexico is the candelabra cactus. Systematically it belongs to the Cereus
family, in which the notable Night-blooming Cereus also is naturally
included. In tropical or semi-tropical countries these plants thrive,
and grow to enormous size. For example, the Cereus that bears those
great flowers, and blooms at night, exhaling powerful perfume, as we see
them in hothouses in our cold climate, are even in the semi-tropical
region of Key West, on the Florida Reef, seen to grow enormously in
length.

[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.]

We cultivated several species of the more interesting forms during a
residence on the reef. Our brick house, two stories in height, was
entirely covered on a broad gable end, the branches more than gaining
the top. There is a regular monthly growth, and this is indicated by a
joint between each two lengths. Should the stalk be allowed to grow
without support, it will continue growing without division, and exhibit
stalks five or six feet in length, when they droop, and fall upon the
ground.

Where there is a convenient resting place on which it can spread out and
attach itself, the stalk throws out feelers and rootlets, which fasten
securely to the wall or brickwork; then, this being a normal growth,
there is a separation at intervals of about a foot. That is, the stalk
grows in one month about twelve inches, and if it has support, the
middle woody stalk continues to grow about an inch further, but has no
green, succulent portion, in fact, looks like a stem; then the other
monthly growth takes place, and ends with a stem, and so on
indefinitely. Our house was entirely covered by the stems of such a
plant, and the flowers were gorgeous in the extreme. The perfume,
however, was so potent that it became a nuisance. Such is the
Night-blooming Cereus in the warm climates, and similarly the Candelabra
Cereus grows in stalks, but architecturally erect, fluted like columns.
The flowers are large, and resemble those of the night-blooming variety.
Some columns remain single, and are amazingly artificial appearing;
others throw off shoots, as seen in the picture. There are some smaller
varieties that have even more of a candelabra look, there being clusters
of side shoots, the latter putting out from the trunk regularly, and
standing up parallel to each other. The enormous size these attain is
well shown in the picture.

Whenever the great stalks of these cacti die, the succulent portion is
dried, and nothing is left but the woody fiber. They are hollow in
places, and easily penetrated. A species of woodpecker, _Melanerpes
formicivorus_, is found to have adopted the use of these dry stalks for
storing the winter's stock of provisions. There are several round
apertures seen on the stems in the pictures, which were pecked by this
bird. This species of woodpecker is about the size of our common robin
or migratory thrush, and has a bill stout and sharp. The holes are
pecked for the purpose of storing away acorns or other nuts; they are
just large enough to admit the fruit, while the cup or larger end
remains outside. The nuts are forced in, so that it requires
considerable wrenching to dislodge them. In many instances the nuts are
so numerous, the stalk has the appearance of being studded with bullets.
This appearance is more pronounced in cases where the dead trunk of an
oak is used. There are some specimens of the latter now owned by the
American Museum of Natural History, which were originally sent to the
Centennial Exhibition at Philadelphia. They were placed in the
department contributed by the Pacific Railroad Company, and at that time
were regarded as some of the wonders of that newly explored region
through which the railroad was then penetrating. Some portions of the
surface of these logs are nearly entirely occupied by the holes with
acorns in them. The acorns are driven in very tightly in these examples;
much more so than in the cactus plants, as the oak is nearly round, and
the holes were pecked in solid though dead wood. One of the most
remarkable circumstances connected with this habit of the woodpecker is
the length of flight required and accomplished. At Mount Pizarro, where
such storehouses are found, the nearest oak trees are in the
Cordilleras, thirty miles distant; thus the birds are obliged to make a
journey of sixty miles to accomplish the storing of one acorn. At first
it seemed strange that a bird should spend so much labor to place those
bits of food, and so far away. De Saussure, a Swiss naturalist,
published in the _Bibliotheque Universelle_, of Geneva, entertaining
accounts of the Mexican Colaptes, a variety of the familiar "high hold,"
or golden winged woodpecker. They were seen to store acorns in the dead
stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied
him to Central America, records the same facts. These travelers saw
great numbers of the woodpeckers in a region on the <DW72> of a range of
volcanic mountains. There was little else of vegetation than the
_Agave_, whose barren, dead stems were studded with acorns placed there
by the woodpeckers.

The maguey throws up a stalk about fifteen feet in height yearly, which,
after flowering, grows stalky and brittle, and remains an unsightly
thing. The interior is pithy, but after the death of the stalk the pith
contracts, and leaves the greater portion of the interior hollow, as we
have seen in the case of the cactus branches. How the birds found that
these stalks were hollow is a problem not yet solved, but, nevertheless,
they take the trouble to peck away at the hard bark, and once
penetrated, they commence to fill the interior; when one space is full,
the bird pecks a little higher up, and so continues.

Dr. Heerman, of California, describes the California _Melanerpes_ as one
of the most abundant of the woodpeckers; and remarks that it catches
insects on the wing like a flycatcher. It is well determined that it
also eats the acorns that it takes so much pains to transport.

[Illustration: FLOWER OF CEREUS GIGANTEUS.]

It seems that these birds also store the pine trees, as well as the
oaks. It is not quite apparent why these birds exhibit such variation in
habits; they at times select the more solid trees, where the storing
cannot go on without each nut is separately set in a hole of its own.
There seems an instinct prompting them to do this work, though there may
not be any of the nuts touched again by the birds. Curiously enough,
there are many instances of the birds placing pebbles instead of nuts in
holes they have purposely pecked for them. Serious trouble has been
experienced by these pebbles suddenly coming in contact with the saw of
the mill through which the tree is running. The stone having been placed
in a living tree, as is often the case, its exterior had been lost to
sight during growth.

Some doubt has been entertained about the purpose of the bird in storing
the nuts in this manner. De Saussure tells us he has witnessed the birds
eating the acorns after they had been placed in holes in trees, and
expresses his conviction that the insignificant grub which is only seen
in a small proportion of nuts is not the food they are in search of.

C.W. Plass, Esq., of Napa City, California, had an interesting example
of the habits of the California _Melanerpes_ displayed in his own house.
The birds had deposited numbers of acorns in the gable end. A
considerable number of shells were found dropped underneath the eaves,
while some were found in place under the gable, and these were perfect,
having no grubs in them.

The picture shows a very common scene in New Mexico. The columns,
straight and angular, are often sixty feet in height. It is called torch
cactus in some places. There are many varieties, and as many different
shapes. Some lie on the ground; others, attached to trunks of trees as
parasites, hang from branches like great serpents; but none is so
majestic as the species called systematically _Cereus giganteus_, most
appropriately. The species growing pretty abundantly on the island of
Key West is called candle cactus. It reaches some ten or twelve feet,
and is about three inches in diameter. The angles are not so prominent,
which gives the cylinders a roundish appearance. They form a pretty,
rather picturesque feature in the otherwise barren undergrowth of
shrubbery and small trees. Accompanied by a few flowering cocoa palms,
the view is not unpleasing. The fiber of these plants is utilized in
some coarse manufactures. The maguey, or Agave, is used in the
manufacture of fine roping. Manila hemp is made from a species. The
species whose dried stalks are used by the woodpeckers for their winter
storage was cultivated at Key West, Florida, during several years before
1858. Extensive fields of the Agave stood unappropriated at that period.
Considerable funds were dissipated on this venture. Extensive works were
established, and much confidence was entertained that the scheme would
prove a paying one, but the "hemp" rope which this was intended to rival
could be made cheaper than this. The great Agave plants, with their long
stalks, stand now, increasing every year, until a portion of the island
is overrun with them.


CEREUS GIGANTEUS.

This wonderful cactus, its colossal proportions, and weird, yet grand,
appearance in the rocky regions of Mexico and California, where it is
found in abundance, have been made known to us only through books of
travel, no large plants of it having as yet appeared in cultivation in
this country. It is questionable if ever the natural desire to see such
a vegetable curiosity represented by a large specimen in gardens like
Kew can be realized, owing to the difficulty of importing large stems in
a living condition; and even if successfully brought here, they survive
only a very short time. To grow young plants to a large size seems
equally beyond our power, as plants 6 inches high and carefully managed
are quite ten years old. When young, the stem is globose, afterward
becoming club-shaped or cylindrical. It flowers at the height of 12
feet, but grows up to four or five times that height, when it develops
lateral branches, which curve upward and present the appearance of an
immense candelabrum, the base of the stem being as thick as a man's
body. The flower, of which a figure is given here, is about 5 inches
long and wide, the petals cream , the sepals greenish white.
Large clusters of flowers are developed together near the top of the
stem. A richly  edible fruit like a large fig succeeds each
flower, and this is gathered by the natives and used as food under the
name of saguarro. A specimen of this cactus 3 feet high may be seen in
the succulent house at Kew.--_B., The Garden_.

       *       *       *       *       *




HOW PLANTS ARE REPRODUCED.

[Footnote: Read at a meeting of the Chemists' Assistants' Association.
December 16, 1885.]

By C.E. STUART, B.Sc.


In two previous papers read before this Association I have tried to
condense into as small a space as I could the processes of the nutrition
and of the growth of plants; in the present paper I want to set before
you the broad lines of the methods by which plants are reproduced.

Although in the great trees of the conifers and the dicotyledons we have
apparently provision for growth for any number of years, or even
centuries, yet accident or decay, or one of the many ills that plants
are heirs to, will sooner or later put an end to the life of every
individual plant.

Hence the most important act of a plant--not for itself perhaps, but for
its race--is the act by which it, as we say, "reproduces itself," that
is, the act which results in the giving of life to a second individual
of the same form, structure, and nature as the original plant.

The methods by which it is secured that the second generation of the
plant shall be as well or even better fitted for the struggle of life
than the parent generation are so numerous and complicated that I cannot
in this paper do more than allude to them; they are most completely seen
in cross fertilization, and the adaptation of plant structures to that
end.

What I want to point out at present are the principles and not so much
the details of reproduction, and I wish you to notice, as I proceed,
what is true not only of reproduction in plants but also of all
processes in nature, namely, the paucity of typical methods of attaining
the given end, and the multiplicity of special variation from those
typical methods. When we see the wonderfully varied forms of plant life,
and yet learn that, so to speak, each edifice is built with the same
kind of brick, called a cell, modified in form and function; when we see
the smallest and simplest equally with the largest and most complicated
plant increasing in size subject to the laws of growth by
intussusception and cell division, which are universal in the organic
world; we should not be surprised if all the methods by which plants are
reproduced can be reduced to a very small number of types.

The first great generalization is into--

1. The vegetative type of reproduction, in which one or more ordinary
cells separate from the parent plant and become an independent plant;
and--

2. The special-cell type of reproduction, in which either one special
cell reproduces the plant, or two special cells by their union form the
origin of the new plant; these two modifications of the process are
known respectively as asexual and sexual.

The third modification is a combination of the two others, namely, the
asexual special cell does not directly reproduce its parent form, but
gives rise to a structure in which sexual special cells are developed,
from whose coalescence springs again the likeness of the original plant.
This is termed alternation of generations.

The sexual special cell is termed the _spore_.

The sexual special cells are of one kind or of two kinds.

Those which are of one kind may be termed, from their habit of yoking
themselves together, _zygoblasts_, or conjugating cells.

Those which are of two kinds are, first, a generally aggressive and
motile fertilizing or so-called "male cell," called in its typical form
an _antherozoid_; and, second, a passive and motionless receptive or
so-called "female cell," called an _oosphere_.

The product of the union of two zygoblasts is termed a _zygospore_.

The product of the union of an antherozoid and an oosphere is termed an
_oospore_.

In many cases the differentiation of the sexual cells does not proceed
so far as the formation of antherozoids or of distinct oospheres; these
cases I shall investigate with the others in detail presently.

First, then, I will point out some of the modes of vegetative
reproduction.

The commonest of these is cell division, as seen in unicellular plants,
such as protococcus, where the one cell which composes the plant simply
divides into two, and each newly formed cell is then a complete plant.

The particular kind of cell division termed "budding" here deserves
mention. It is well seen in the yeast-plant, where the cell bulges at
one side, and this bulge becomes larger until it is nipped off from the
parent by contraction at the point of junction, and is then an
independent plant.

Next, there is the process by which one plant becomes two by the dying
off of some connecting portion between two growing parts.

Take, for instance, the case of the liverworts. In these there is a
thallus which starts from a central point and continually divides in a
forked or dichotomous manner. Now, if the central portion dies away, it
is obvious that there will be as many plants as there were forkings, and
the further the dying of the old end proceeds, the more young plants
will there be.

Take again, among higher plants, the cases of suckers, runners, stolons,
offsets, etc. Here, by a process of growth but little removed from the
normal, portions of stems develop adventitious roots, and by the dying
away of the connecting links may become independent plants.

Still another vegetative method of reproduction is that by bulbils or
gemmae.

A bulbil is a bud which becomes an independent plant before it commences
to elongate; it is generally fleshy, somewhat after the manner of a
bulb, hence its name. Examples occur in the axillary buds of _Lilium
bulbiferum_, in some _Alliums_, etc.

The gemma is found most frequently in the liverworts and mosses, and is
highly characteristic of these plants, in which indeed vegetative
reproduction maybe said to reach its fullest and most varied extent.

Gemmae are here formed in a sort of flat cup, by division of superficial
cells of the thallus or of the stem, and they consist when mature of
flattened masses of cells, which lie loose in the cup, so that wind or
wet will carry them away on to soil or rock, when, either by direct
growth from apical cells, as with those of the liverworts, or with
previous emission of thread-like cells forming a "protonema," in the
case of the mosses, the young plant is produced from them.

The lichens have a very peculiar method of gemmation. The lichen-thallus
is composed of chains or groups of round chlorophyl-containing cells,
called "gonidia," and masses of interwoven rows of elongated cells which
constitute the hyphae. Under certain conditions single cells of the
gonidia become surrounded with a dense felt of hyphae, these accumulate
in numbers below the surface of the thallus, until at last they break
out, are blown or washed away, and start germination by ordinary cell
division, and thus at once reproduce a fresh lichen-thallus. These
masses of cells are called soredia.

Artificial budding and grafting do not enter into the scope of this
paper.

As in the general growth and the vegetative reproduction of plants
cell-division is the chief method of cell formation, so in the
reproduction of plants by special cells the great feature is the part
played by cells which are produced not by the ordinary method of cell
division, but by one or the other processes of cell formation, namely,
free-cell formation or rejuvenescence.

If we broaden somewhat the definition of rejuvenescence and free-cell
formation, and do not call the mother-cells of spores of mosses, higher
cryptogams, and also the mother-cells of pollen-grains, reproductive
cells, which strictly speaking they are not, but only producers of the
spores or pollen-grains, then we may say that _cell-division is confined
to vegetative processes, rejuvenescence and free-cell formation are
confined to reproductive processes_.

Rejuvenescence may be defined as the rearrangement of the whole of the
protoplasm of a cell into a new cell, which becomes free from the
mother-cell, and may or may not secrete a cell-wall around it.

If instead of the whole protoplasm of the cell arranging itself into one
mass, it divides into several, or if portions only of the protoplasm
become marked out into new cells, in each case accompanied by rounding
off and contraction, the new cells remaining free from one another, and
usually each secreting a cell wall, then this process, whose relation to
rejuvenescence is apparent, is called free-cell formation.

The only case of purely vegetative cell-formation which takes place by
either of these processes is that of the formation of endosperm in
Selaginella and phanerogams, which is a process of free-cell formation.

On the other hand, the universal contraction and rounding off of the
protoplasm, and the formation by either rejuvenescence or free-cell
formation, distinctly mark out the special or true reproductive cell.

Examples of reproductive cells formed by rejuvenescence are:

1. The swarm spores of many algae, as Stigeoclonium (figured in Sachs'
"Botany"). Here the contents of the cell contract, rearrange themselves,
and burst the side of the containing wall, becoming free as a
reproductive cell.

2. The zygoblasts of conjugating algae, as in Spirogyra. Here the
contents of a cell contract and rearrange themselves only after contact
of the cell with one of another filament of the plant. This zygoblast
only becomes free after the process of conjugation, as described below.

3. The oosphere of characeae, mosses and liverworts, and vascular
cryptogams, where in special structures produced by cell-divisions there
arise single primordial cells, which divide into two portions, of which
the upper portion dissolves or becomes mucilaginous, while the lower
contracts and rearranges itself to form the oosphere.

4. Spores of mosses and liverworts, of vascular cryptogams, and pollen
cells of phanerogams, which are the analogue of the spores.

The type in all these cases is this: A mother-cell produces by
cell-division four daughter-cells. This is so far vegetative. Each
daughter-cell contracts and becomes more or less rounded, secretes a
wall of its own, and by the bursting or absorption of the wall of its
mother-cell becomes free. This is evidently a rejuvenescence.

Examples of reproductive cells formed by free-cell formation are:

1. The ascospores of fungi and algae.

2. The zoospores or mobile spores of many algae and fungi.

3. The germinal vesicles of phanerogams.

The next portion of my subject is the study of the methods by which
these special cells reproduce the plant.

1st. Asexual methods.

1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of
the protoplasm of a cell contracts, becomes rounded and rearranged, and
escapes into the water, in which the plant floats as a mass of
protoplasm, clear at one end and provided with cilia by which it is
enabled to move, until after a time it comes to rest, and after
secreting a wall forms a new plant by ordinary cell-division. Example:
Oedogonium.

2. Free-cell formation forms swarm-spores which behave as above.
Example: Achlya.

3. Free-cell formation forms the typical motionless spore of algae and
fungi. For instance, in the asci of lichens there are formed from a
portion of the protoplasm four or more small ascospores, which secrete a
cell-wall and lie loose in the ascus. Occasionally these spores may
consist of two or more cells. They are set free by the rupture of the
ascus, and germinate by putting out through their walls one or more
filaments which branch and form the thallus of a new individual. Various
other spores formed in the same way are known as _tetraspores_, etc.

4. Cell-division with rejuvenescence forms the spores of mosses and
higher cryptogams.

To take the example of moss spores:

Certain cells in the sporogonium of a moss are called mother-cells. The
protoplasm of each one of these becomes divided into four parts. Each of
these parts then secretes a cell-wall and becomes free as a spore by the
rupture or absorption of the wall of the mother-cell. The germination of
the spores I shall describe later.

5. A process of budding which in the yeast plant and in mosses is merely
vegetatively reproductive, in fungi becomes truly reproductive, namely,
the buds are special cells arising from other special cells of the
hyphae.

For example, the so-called "gills" of the common mushroom have their
surface composed of the ends of the threads of cells constituting the
hyphae. Some of these terminal cells push out a little finger of
protoplasm, which swells, thickens its wall, and becomes detached from
the mother-cell as a spore, here called specially a _basidiospore_.

Also in the common gray mould of infusions and preserves, Penicillium,
by a process which is perhaps intermediate between budding and
cell-division, a cell at the end of a hypha constricts itself in several
places, and the constricted portions become separate as _conidiospores_.

_Teleutospores, uredospores_, etc., are other names for spores similarly
formed.

These conidiospores sometimes at once develop hyphae, and sometimes, as
in the case of the potato fungus, they turn out their contents as a
swarm-spore, which actively moves about and penetrates the potato leaves
through the stomata before they come to rest and elongate into the
hyphal form.

So far for asexual methods of reproduction.

I shall now consider the sexual methods.

The distinctive character of these methods is that the cell from which
the new individual is derived is incapable of producing by division or
otherwise that new individual without the aid of the protoplasm of
another cell.

Why this should be we do not know; all that we can do is to guess that
there is some physical or chemical want which is only supplied through
the union of the two protoplasmic masses. The process is of benefit to
the species to which the individuals belong, since it gives it a greater
vigor and adaptability to varying conditions, for the separate
peculiarities of two individuals due to climatic or other conditions are
in the new generation combined in one individual.

The simplest of the sexual processes is conjugation. Here the two
combining cells are apparently of precisely similar nature and
structure. I say apparently, because if they are really alike it is
difficult to see what is gained by the union.

Conjugation occurs in algae and fungi. A typical case is that of
Spirogyra. This is an alga with its cells in long filaments. Two
contiguous cells of two parallel filaments push each a little projection
from its cell-wall toward the other. When these meet, the protoplasm of
each of the two cells contracts, and assumes an elliptical form--it
undergoes rejuvenescence. Next an opening forms where the two cells are
in contact, and the contents of one cell pass over into the other, where
the two protoplasmic bodies coalesce, contract, and develop a cell-wall.
The zygospore thus formed germinates after a long period and forms a new
filament of cells.

Another example of conjugation is that of Pandorina, an alga allied to
the well-known volvox. Here the conjugating cells swim free in water;
they have no cell-wall, and move actively by cilia. Two out of a number
approach, coalesce, contract, and secrete a cell-wall. After a long
period of rest, this zygospore allows the whole of its contents to
escape as a swarm-spore, which after a time secretes a gelatinous wall,
and by division reproduces the sixteen-celled family.

We now come to fertilization, where the uniting cells are of two kinds.

The simplest case is that of Vaucheria, an alga. Here the vegetative
filament puts out two protuberances, which become shut off from the body
of the filament by partitions. The protoplasm in one of these
protuberances arranges itself into a round mass--the oosphere or female
cell. The protoplasm of the other protuberance divides into many small
masses, furnished with cilia, the spermatozoids or male cells. Each
protuberance bursts, and some of the spermatozoids come in contact with
and are absorbed by the oosphere, which then secretes a cell-wall, and
after a time germinates.

The most advanced type of fertilization is that of angiosperms.

In them there are these differences from the above process: the contents
of the male cell, represented by the pollen, are not differentiated into
spermatozoids, and there is no actual contact between the contents of
the pollen tube and the germinal vesicle, but according to Strashurger,
there is a transference of the substance of the nucleus of the pollen
cell to that of the germinal vesicle by osmose. The coalescence of the
two nuclei within the substance of the germinal vesicle causes the
latter to secrete a wall, and to form a new plant by division, being
nourished the while by the mother plant, from whose tissues the young
embryo plant contained in the seed only becomes free when it is in an
advanced stage of differentiation.

Perhaps the most remarkable cases of fertilization occur in the Florideae
or red seaweeds, to which class the well-known Irish moss belongs.

Here, instead of the cell which is fertilized by the rounded
spermatozoid producing a new plant through the medium of spores, some
other cell which is quite distinct from the primarily fertilized cell
carries on the reproductive process.

If the allied group of the Coleochaeteae is considered together with the
Florideae, we find a transition between the ordinary case of Coleochaete
and that of Dudresnaya. In Coleochaete, the male cell is a round
spermatozoid, and the female cell an oosphere contained in the base of a
cell which is elongated into an open and hair-like tube called the
trichogyne. The spermatozoid coalesces with the oosphere, which secretes
a wall, becomes surrounded with a covering of cells called a cystocarp,
which springs from cells below the trichogyne, and after the whole
structure falls from the parent plant, spores are developed from the
oospore, and from them arises a new generation.

In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with
the trichogyne, but this does not develop further. From below the
trichogyne, however, spring several branches, which run to the ends of
adjacent branches, with the apical cells of which they conjugate, and
the result of this conjugation is the development of a cystocarp similar
to that of Coleochaete. The remarkable point here is the way in which the
effect of the fertilizing process is carried from one cell to another
entirely distinct from it.

Thus I have endeavored to sum up the processes of asexual and of sexual
reproduction. But it is a peculiar characteristic of most classes of
plants that the cycle of their existence is not complete until both
methods of reproduction have been called into play, and that the
structure produced by one method is entirely different from that
produced by the other method.

Indeed, it is only in some algae and fungi that the reproductive cells of
one generation produce a generation similar to the parent; in all other
plants a generation A produces are unlike generation B, which may either
go on to produce another generation, C, and then back to A, or it may go
on producing B's until one of these reproduces A, or again it may
directly reproduce; A. Thus we have the three types:

  1. A-B-C.--A-B-C.--A..................... etc.
  2. A-B-B.--B-B...................B--A ... etc.
  3. A B A B A............................. etc.

The first case is not common, the usual number of generations being two
only; but a typical example of the occurrence of three generations is in
such fungi as _Puccinia Graminis_. Here the first generation grows on
barberry leaves, and produces a kind of spore called an _aecidium spore_.
These aecidium spores germinate only on a grass stem or leaf, and a
distinct generation is produced, having a particular kind of spore
called an _uredospore_. The uredospore forms fresh generations of the
same kind until the close of the summer, when the third generation with
another kind of spore, called a _teleutospore_, is produced.

The teleutospores only germinate on barberry leaves, and there reproduce
the original aecidium generation.

Thus we have the series A.B.B.B ... BCA

In this instance all the generations are asexual, but the most common
case is for the sexual and the asexual generations to alternate. I will
describe as examples the reproduction of a moss, a fern, and a
dicotyledon.

In such a typical moss as Funaria, we have the following cycle of
developments: The sexual generation is a dioecious leafy structure,
having a central elongated axis, with leaves arranged regularly around
and along it. At the top of the axis in the male plant rise the
antheridia, surrounded by an envelope of modified leaves called the
perigonium. The antheridia are stalked sacs, with a single wall of
cells, and the spiral antherozoids arise by free-cell formation from the
cells of the interior. They are discharged by the bursting of the
antheridium, together with a mucilage formed of the degraded walls of
their mother cells.

In the female plant there arise at the apex of the stem, surrounded by
an envelope of ordinary leaves, several archegonia. These are of the
ordinary type of those organs, namely, a broad lower portion, containing
a naked oosphere and a long narrow neck with a central canal leading to
the oosphere. Down this canal pass one or more antherozoids, which
become absorbed into the oosphere, and this then secretes a wall, and
from it grows the second or asexual generation. The peculiarity of this
asexual or spore-bearing plant is that it is parasitic on the sexual
plant; the two generations, although not organically connected, yet
remain in close contact, and the spore-bearing generation is at all
events for a time nourished by the leafy sexual generation.

The spore-bearing generation consists of a long stalk, closely held
below by the cells of the base of the archegonium; this supports a
broadened portion which contains the spores, and the top is covered with
the remains of the neck of the archegonium forming the calyptra.

The spores arise from special or mother-cells by a process of division,
or it may be even termed free-cell formation, the protoplasm of each
mother-cell dividing into four parts, each of which contracts, secretes
a wall, and thus by rejuvenescence becomes a spore, and by the
absorption of the mother-cells the spores lie loose in the spore sac.
The spores are set free by the bursting of their chamber, and each
germinates, putting out a branched thread of cells called a protonema,
which may perhaps properly be termed a third generation in the cycle of
the plant; for it is only from buds developed on this protonema that the
leafy sexual plant arises.

The characteristics, then, of the mosses are, that the sexual generation
is leafy, the one or two asexual generations are thalloid, and that the
spore-bearing generation is in parasitic connection with the sexual
generation.

In the case of the fern, these conditions are very different.

The sexual generation is a small green thalloid structure called a
prothallium, which bears antheridia and archegonia, each archegonium
having a neck-canal and oosphere, which is fertilized just as in the
moss.

But the asexual generation derived from the oospore only for a short
while remains in connection with the prothallium, which, of course,
answers to the leafy portion of the moss. What is generally known as the
fern is this asexual generation, a great contrast to the small leafless
moss fruit or sporogonium as it is called, to which it is
morphologically equivalent. On the leaves of this generation arise the
sporangia which contain the spores. The spores are formed in a manner
very similar to those of the mosses, and are set free by rupture of the
sporangium.

The spore produces the small green prothallium by cell-division in the
usual way, and this completes the cycle of fern life.

The alternation of generations, which is perhaps most clear and typical
in the case of the fern, becomes less distinctly marked in the plants of
higher organization and type.

Thus in the Rhizocarpae there are two kinds of spores, _microspores_ and
_macrospores_, producing prothallia which bear respectively antheridia
and archegonia; in the Lycopodiaceae, the two kinds of spores produce
very rudimentary prothallia; in the cycads and conifers, the microspore
or pollen grain only divides once or twice, just indicating a
prothallium, and no antheridia or antherozoids are formed. The
macrospore or embryo-sac produces a prothallium called the endosperm, in
which archegonia or corpuscula are formed; and lastly, in typical
dicotyledons it is only lately that any trace of a prothallium from the
microspore or pollen cell has been discovered, while the macrospore or
embryo-sac produces only two or three prothallium cells, known as
antipodal cells, and two or three oospheres, known as germinal vesicles.

This description of the analogies of the pollen and embryo-sac of
dicotyledons assumes that the general vegetative structure of this class
of plants is equivalent to the asexual generation of the higher
cryptogams. In describing their cycle of reproduction I will endeavor to
show grounds for this assumption.

We start with the embryo as contained in the seed. This embryo is the
product of fertilization of a germinal vesicle by a pollen tube. Hence,
by analogy with the product of fertilization of rhizocarp's, ferns, and
mosses, it should develop into a spore bearing plant. It does develop
into a plant in which on certain modified leaves are produced masses of
tissue in which two kinds of special reproductive cells are formed. This
is precisely analogous to the case of gymnosperms, lycopods, etc., where
on leaf structures are formed macro and micro sporangia.

To deal first with the microsporangium or pollen-sac. The pollen cells
are formed from mother cells by a process of cell division and
subsequent setting free of the daughter cells or pollen cells by
rejuvenescence, which is distinctly comparable with that of the
formation of the microspores of Lycopodiaceae, etc. The subsequent
behavior of the pollen cell, its division and its fertilization of the
germinal vesicle or oosphere, leave no doubt as to its analogy with the
microspore of vascular cryptogams.

Secondly, the nucleus of the ovule corresponds with the macrosporangium
of Selaginella, through the connecting link of the conifers, where the
ovule is of similar origin and position to the macrosporangium of the
Lycopodiaceae. But the formation of the macrospore or embryo-sac is
simpler than the corresponding process in cryptogams. It arises by a
simple enlargement of one cell of the nucleus instead of by the division
of one cell into four, each thus becoming a macrospore. At the top of
this macrospore or embryo-sac two or three germinal vesicles are formed
by free cell formation, and also two or three cells called antipodal
cells, since they travel to the other end of the embryo-sac; these
latter represent a rudimentary prothallium. This formation of germinal
vesicles and prothallium seems very different from the formation of
archegonia and prothallium in Selaginella, for instance; but the link
which connects the two is in the gymnosperms, where distinct archegonia
in a prothallium are formed.

Thus we see that the flowering plant is essentially the equivalent of
the asexual fern, and of the sporogonium of the moss, and the pollen
cell and the embryo-sac represent the two spores of the higher
cryptogams, and the pollen tube and the germinal vesicles and antipodal
cells are all that remain of the sexual generation, seen in the moss as
a leafy plant, and in the fern as a prothallium. Indeed, when a plant
has monoecious or dioecious flowers, the distinction between the asexual
and the sexual generation has practically been lost, and the
spore-bearing generation has become identified with the sexual
generation.

Having now described the formation of the pollen and the germinal
vesicles, it only remains to show how they form the embryo. The pollen
cell forms two or three divisions, which are either permanent or soon
absorbed; this, as before stated, is the rudimentary male prothallium.
Then when it lies on the stigma it develops a long tube, which passes
down the style and through the micropyle of the ovule to the germinal
vesicles, one of which is fertilized by what is probably an osmotic
transference of nuclear matter. The germinal vesicle now secretes a
wall, divides into two parts, and while the rest of the embyro-sac fills
with endosperm cells, it produces by cell division from the upper half a
short row of cells termed a suspensor, and from the lower half a mass of
cells constituting the embryo. Thus while in the moss the asexual
generation or sporogonium is nourished by the sexual generation or leafy
plant, and while in the fern each generation is an independent
structure, here in the dicotyledon, on the other hand, the asexual
generation or embryo is again for a time nourished in the interior of
the embryo-sac representing the sexual generation, and this again
derives its nourishment from the previous asexual generation, so that as
in the moss, there is again a partial parasitism of one generation on
the other.

To sum up the methods of plant reproduction: They resolve themselves
into two classes.

1st. Purely vegetative.

2d. Truly reproductive by special cells.

In the second class, if we count conjugation as a simple form of
fertilization, there are only two types of reproductive methods.

1st. Reproduction from an asexual spore.

2d. Reproduction from an oospore formed by the combination of two sexual
cells.

In the vast majority of plant species these two types are used by the
individuals alternately.

The extraordinary similarity of the reproductive process, as shown in
the examples I have given, Achlya, Spirogyra, and Vaucheria among algae,
the moss, the fern, and the flowering plant, a similarity which becomes
the more marked the more the details of each case and of the cases of
plants which form links between these great classes are studied, points
to a community of origin of all plants in some few or one primeval
ancestor. And to this inference the study of plant structure and
morphology, together with the evidence of palaeobotany among other
circumstances, lends confirmatory evidence, and all modern discoveries,
as for instance that of the rudimentary prothallium formed by the pollen
of angiosperms, tend to the smoothing of the path by which the descent
of the higher plants from simpler types will, as I think, be eventually
shown.

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End of the Project Gutenberg EBook of Scientific American Supplement, Vol.
XXI., No. 531, March 6, 1886, by Various

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