Scientific American Supplement, No. 520, December 19, 1885
by
Various
Part 2 out of 2
torpedo, especially during the night or in a fog; and hence torpedoes are
often made automatic by what is called a circuit closer. This is a device
which automatically bridges over the distance between two points which
were separated, thus allowing the current to pass between them. In
submarine torpedoes it is usual to employ a small weight, which, when the
torpedo is struck, is thrown by the force of the blow across two contact
points, one of which points is in connection with the fuse and the other
in connection with the battery, so that the current immediately runs over
the bridge thus offered, and through the fuse. In practice, these two
contact points are connected by a wire, even when the torpedo is not in
the state of being struck; but the wire is of such great resistance that
the current is too weak to heat the wire in the fuse. Yet when the weight
above mentioned is thrown across the two contact points, the current runs
across the bridge, instead of through the resistance wire, and is then
strong enough to heat the wire in the fuse and explode the torpedo. The
advantage of having a wire of high resistance between the contact points,
instead of having no wire between them, is that the current which then
passes through the fuse, though too weak to fire it, shows by its very
existence to the men on shore that the circuit through the torpedo is all
right.
But instead of having the increased current caused by striking the
torpedo to fire the torpedo directly, a better way is to have it simply
make a signal on shore. Then, when friendly vessels are to pass, the
firing battery can be disconnected; and when the friendly ship bumps the
torpedo, the working of the signal shows not only that the circuit
through the fuse is all right, but also that the circuit closer is all
right, so that, had the friendly ship been a hostile ship, she would
certainly have been destroyed.
While the management of the torpedo is thus simple, the defense of a
harbor becomes a complex problem, on account of the time and expense
required to perfect it, and the training of a corps of men to operate the
torpedoes.
In order to detect the presence of torpedoes in an enemy's harbor, an
instrument has been invented by Capt. McEvoy, called the "torpedo
detecter," in which the action is somewhat similar to that of the
induction balance, the iron of a torpedo case having the effect of
increasing the number of lines of force embraced by one of two opposing
coils, so that the current induced in it overpowers that induced in the
other, and a distinct sound is heard in a telephone receiver in circuit
with them. As yet, this instrument has met with little practical success,
but, its principle being correct, we can say with considerable confidence
that the reason of its non-success probably is that the coils and current
used are both too small.
Lieut. Fiske described the spar torpedo and the various classes of
movable torpedoes, including the Lay. His conclusion is that the most
successful of the movable torpedoes is the Simms, with which very
promising experiments have been conducted under the superintendence of
Gen. Abbot.
Recent experiments in England have shown that the Whitehead torpedo, over
which control ceases after it is fired, is not so formidable a weapon
when fired at a ship _under way_ as many supposed, for the simple reason
that it can be dodged. But an electrical torpedo, over which control is
exercised while it is in motion through the water, cannot be dodged,
provided it receives sufficient speed. For effective work against ships
capable of steaming fifteen knots per hour, the torpedo should have a
speed of twenty knots. There is no theoretical difficulty in the way of
producing this, for a speed of eleven knots has already been recorded,
though an electric torpedo, to get this speed, would have to be larger
than a Whitehead having the same speed. It may be conceived that a
torpedo carrying 50 lb. of gun-cotton, capable of going 20 knots per
hour, so that it would pass over a distance of 500 yards in about 45
sec., and yet be absolutely under control all the time, so that it can be
constantly kept pointed at its target, would be a very unpleasant thing
for an enemy to meet.
Military telegraphy is a second use of electricity in warfare. Lieut.
Fiske traces its origin to our own civil war. Foreign nations took the
hint from us, and during the invasion of France the telegraph played a
most important part. In military telegraph trains, miles of wire are
carried on reels in specially constructed wagons, which hold also
batteries and instruments. Some of the wire is insulated, so that it can
rest on the ground, and thus be laid out with great speed, while other
wire is bare, and is intended to be put on poles, trees, etc. For
mountain service the wires and implements are carried by pack animals.
Regularly trained men are employed, and are drilled in quickly running
lines, setting up temporary stations, etc. In the recent English
operations in Egypt, the advance guard always kept in telegraphic
communication with headquarters and with England, and after the battle of
Tel-el-Kebir news of the victory was telegraphed to the Queen and her
answer received in forty-five minutes.
The telephone is also used with success in warfare, and in fact sometimes
assists the telegraph in cases where, by reason of the haste with which a
line has been run, the current leaks off. A telephone may then be used to
receive the message--and for a transmitter a simple buzzer or automatic
circuit breaker, controlled by an ordinary key. In the case of vessels
there is much difficulty in using the telegraph and the telephone, as the
wire may be fouled and broken when the ship swings by a long chain. In
England in the case of a lightship this difficulty has been surmounted,
or rather avoided, by making hollow the cable by which the ship rides,
and running an insulated wire along the long tube thus formed inside. But
the problem is much simplified when temporary communication only is
desired between ships at anchor, between a ship and the shore, or even
between a ship and a boat which has been sent off on some special
service, such as reconnoitering, sounding, etc. In this case portable
telephones are used, in which the wire is so placed on a reel in circuit
with the telephone that communication is preserved, even while the wire
is running off the reel.
The telegraph and telephone are both coming largely into use in artillery
experiments, for example, in tracking a vessel as she comes up a channel
so that her exact position at each instant may be known, and in
determining the spot of fall of a projectile. In getting the time of
flight of projectiles electricity is of value; by breaking a wire in
circuit with a chronograph, the precise instant of start to within a
thousandth of a second being automatically registered. Velocimeters are a
familiar application of electricity somewhat analogous. In these, wires
are cut by the projectile at different points in its flight, and the
breaking of the electric current causes the appearance of marks on a
surface moving along at a known speed. The velocity of the projectile in
going from one wire to another can then be found.
Electricity is also used for firing great guns, both in ships and forts.
In the former, it eliminates the factor of change produced by the rolling
of the ship during the movement of the arm to fire the gun. The touch of
a button accomplishes the same thing almost instantaneously. Moreover, an
absolutely simultaneous broadside can be delivered by electricity. The
officer discharges the guns from a fighting tower, whither the wires
lead, and the men can at once lie down out of the enemy's machine guns,
as soon as their own guns are ready for discharge. The electric motor
will certainly be used very generally for handling ordnance on board
ships not very heavily plated with armor, since a small wire is a much
more convenient mode of conveying energy to a motor of any kind, and is
much less liable to injury, than a comparatively large pipe for conveying
steam, compressed air, or water under pressure. Besides, the electric
motor is the ideal engine for work on shipboard, by reason of its smooth
and silent motion, its freedom from dirt and grease, the readiness with
which it can be started, stopped, and reversed, and its high efficiency.
Indeed, in future we may look to a protected apparatus for all such uses
in every fort and every powerful ship.
In photographing the bores of great guns, electric lights are used, and
they make known if the gun is accurately rifled and how it is standing
the erosion of the powder gases.
In the case of a fort, electricity can be employed in connection with the
instruments used for determining at each instant the position of an
approaching vessel or army. Whitehead torpedoes are now so arranged that
they can be ejected by pressing an electric button.
Electric lights for vessels are now of recognized importance. At first
they were objected to on the ground that if the wire carrying the current
should be shot away in action, the whole ship would be plunged in
darkness; and so it would be in an accident befalling the dynamo that
generates the current. The criticism is sensible, but the answer is that
different circuits must be arranged for different parts of the ship, and
the wires carrying the current must be arranged in duplicate. It is also
easy to repair a break in a copper wire if shot away. As to the dynamo
and engines, they must be placed below the water line, under a protective
deck, and this should be provided for in building the vessel. There
should be several dynamos and engines. All the dynamos should, of course,
be of the same electromotive force, and feed into the same mains, from
which all lamps draw their supply, and which are fed by feeders from the
dynamo at different points, so that accident to the mains in one part of
the ship will affect that part only. But it is the arc light, used as
what is called a search light, that is most valuable in warfare. Lieut.
Fiske thinks its first use was by the French in the siege of Paris, to
discover the operations of the besiegers. It can be carried by an army in
the field, and used for examining unknown ground at night, searching for
wounded on the battle field, and so on. On fighting vessels the search
light is useful in disclosing the attack of torpedo boats or of hostile
ships, in bringing out clearly the target for guns, and in puzzling an
enemy by involving him successively in dazzling light and total darkness.
Lieut. Fiske suggests that this use would be equally effective in
embarrassing troops groping to the attack of a fort at night by sudden
alternations of blinding light and paralyzing darkness. There should be
four search lights on each side of a ship.
As to the power and beauty of the search light, Lieut. Fiske refers to
the magnificent one with which he lighted up Philadelphia last autumn,
during the electric exhibition in that city. One night he went to the
tower of the Pennsylvania railroad station and watched the light
stationed at the Exhibition building on 32d street. The ray of light when
turned at right angles to his direction looked like a silver arrow going
through the sky; and when turned on him, he could read the fine print of
a railroad time table at arm's length. Flashes from his search light were
seen at a distance of thirty miles.
In using incandescent lamps for night signaling, the simplest way is to
arrange a keyboard with keys marked with certain numbers, indicating the
number of lamps arranged in a prominent position, which will burn while
that key is being pressed. For example, suppose the number 5348 means
"Prepare to receive a torpedo attack." Press keys 5, 3, 4, 8, and the
lights of lamps 5, 3, 4, 8, successively blaze out.
Electrical launches have been used to some extent, their storage
batteries being first charged ashore or on board the ship to which the
launch belongs. They have carried hundreds of people, and have made eight
knots an hour. The improvement of storage batteries, steadily going on,
will eventually cause the electrical launch to replace the steam launch.
One of its advantages is in having no noise from an exhaust and no flame
flaring above a smoke pipe to betray its presence. In warfare two sets of
storage batteries should be provided for launches, one being recharged
while the other is in use.
Mr. Gastine Trouse has recently invented "an electric sight," a filament
of fine wire in a glass tube covered with metal on all sides save at the
back. The battery is said to be no larger than a man's finger, and to be
attached to the barrel near the muzzle by simple rubber bands, so
arranged that the act of attaching the battery to the barrel
automatically makes connection with the sight; and so arranged also that
the liquid of the battery is out of action except when the musket is
brought into a horizontal position for firing.
To throw a good light upon the target the same inventor has devised a
small electric lamp and projector, which is placed on the barrel near the
muzzle by rubber bands, the battery being held at the belt of the
marksman, with such connections that the act of pressing the butt of the
musket against the shoulder completes the circuit, and causes the bright
cylinder of light to fall on the target, thus enabling him to get as good
a shot as in the day time.
Search lights and incandescent lights are advantageously used with
balloons. In submarine boats electricity will one day be very useful.
Submarine diving will play a part in future wars, and the diver's lamp
will be electrical.
Progress has been made also in constructing "electrical guns," in which
the cartridge contains a fuse which is ignited by pressing an electric
button on the gun. A better aim can be had with it, when perfected, than
with one fired by a trigger. At present, according to Lieut. Fiske, this
invention has not reached the practical stage, and the necessity for a
battery to fire a cartridge is decidedly an objection. But the battery is
very small, needs little care, and will last a long time. The hard pull
of the ordinary trigger causes a movement of the barrel except in the
hands of the most highly skilled marksmen, and this hard pull is a
necessity, because the hammer or bolt must have considerable mass in
order to strike the primer with sufficient force to explode it. Having
the mass, it must have considerable inertia; hence it needs a deep notch
to hold it firm when jarred at full cock, and this deep notch
necessitates a strong pull on the trigger. But with an electric gun the
circuit-closing parts are very small and light, and can be put into a
recess in the butt of the gun, out of the way of chance blows. Thus a
light pressure of the finger is alone needed to fire it, while from the
small inertia of the parts a sudden shock will not cause accidental
closing of the circuit and firing of the gun.
* * * * *
MEUCCI'S CLAIMS TO THE TELEPHONE.
Our readers have already been informed through these columns that,
notwithstanding the refusal of the Attorney-General, Mr. Garland, to
institute suit for the nullification of the Bell patent, application has
again been made by the Globe Telephone Co., of this city, the Washington
Telephone Co., of Baltimore, and the Panelectric Co. These applications
have been referred to the Interior Department and Patent Office for
examination, and upon their report the institution of the suit depends.
The evidence which the companies above mentioned have presented includes
not only the statement of Prof. Gray and the circumstances connected with
his caveat, but brings out fully, for the first time, the claims of
Antonio Meucci.
[Illustration: MEUCCI'S CAVEAT, 1871.]
The latter evidence is intended to show that Meucci invented the
speaking telephone not only before Bell, but that he antedated Reis by
several years. In a recent interview with Meucci we obtained a brief
history of his life and of his invention, which will, no doubt, interest
our readers. Meucci, a native of Italy, was educated in the schools of
Florence, devoting his time as a student to mechanical engineering. In
1844 he gave considerable attention to the subject of electricity, and
had a contract with the government of the island of Cuba to galvanize
materials used in the army. While experimenting with electricity he read
the works of Becquerel, Mesmer, and others who treated largely of the
virtues of electricity in the cure of disease. Meucci made experiments in
this direction, and at one time thought that he heard the sound of a sick
person's voice more distinctly than usual, when he had the spatula
connected with the wire and battery in his mouth.
[Illustration: FIGS. 1 AND 2.--1849.]
The apparatus he used for this purpose is shown in Fig. 1. It consists of
an oval disk or spatula of copper attached to a wire which was coiled and
supported in an insulating handle of cork. To ascertain that he was able
to hear the sound, he covered the device with a funnel of pasteboard,
shown in the adjoining figure, and held it to his ear, and thought that
he heard the sound more distinctly.
These instruments were constructed in 1849 in Havana, where Meucci was
mechanical director of a theater. In May, 1851, he came to this country,
and settled in Staten Island, where he has lived ever since. It was not
until a year later that he again took up his telephonic studies, and then
he tried an arrangement somewhat different from the first. He used a tin
tube, Figs. 3 and 4, and covered it with wire, the ends of which were
soldered to the tongue of copper. With this instrument, he states, he
frequently conversed with his wife from the basement of his house to the
third floor, where she was confined as an invalid.
[Illustration: FIGS. 3 AND 4.--1852.]
Continuing his experiments, he conceived the idea of using a bobbin of
wire with a metallic core, and the first instrument he constructed on
this idea is shown in Fig. 5. It consisted of a wooden tube and
pasteboard mouth piece, and supported within the tube was a bundle of
steel wires, surrounded at their upper end by a bobbin of insulated wire.
The diaphragm in this instrument, was an animal membrane, and it was slit
in a semicircle so as to make a flap or valve which responded to the air
vibrations. This was the first instrument in which he used a bobbin, but
the articulation naturally left much to be desired, on account of the use
of the animal membrane. Meucci fixes the dates from the fact that
Garibaldi lived with him during the years 1851-54, and he remembers
explaining the principles of his invention to the Italian patriot.
After constructing the instrument just described, Meucci devised another
during 1853-54. This consisted of a wooden block with a hole in the
center which was filled with magnetic iron ore, and through the center of
which a steel wire passed. The magnetic iron ore was surrounded by a coil
of insulated copper wire. But an important improvement was introduced
here in the shape of an iron diaphragm. With this apparatus greatly
improved effects were obtained.
[Illustration: FIG. 5.--1853.]
In 1856 Meucci first tried, he says, a horseshoe magnet, as shown in Fig.
6, but he went a step backward in using an animal membrane. He states
that this form did not talk so well as some which he had made before, as
might be expected.
During the years 1858-60 Meucci constructed the instrument shown in Fig.
7. He here employed a core of tempered steel magnetized, and surrounded
it with a large coil. He used an iron diaphragm, and obtained such good
results that he determined to bring his invention before the public. His
national pride prompted him to have the invention first brought out in
Italy, and he intrusted the matter to a Mr. Bendalari, an Italian
merchant, who was about to start for that country. Bendalari, however,
neglected the matter, and nothing was heard of it from that quarter. At
the same time Meucci described his invention in _L'Eco d'Italia_, an
Italian paper published in this city, and awaited the return of
Bendalari.
Meucci, however, kept at his experiments with the object of improving his
telephone, and several changes of form were the result. Fig. 8 shows one
of these instruments constructed during 1864-65. It consisted of a ring
of iron wound spirally with copper wire, and from two opposite sides iron
wires attached to the core supported an iron button. This was placed
opposite an iron diaphragm, which closed a cavity ending in a mouthpiece.
He also constructed the instrument which is shown in Fig. 9, and which,
he says, was the best instrument he had ever constructed. The bobbin was
a large one, and was placed in a soapbox of boxwood, with magnet core and
iron diaphragm. Still seeking greater perfection, Meucci, in 1865, tried
the bent horseshoe form, shown in Fig. 10, but found it no improvement;
and, although he experimented up to the year 1871, he was not able to
obtain any better results than the best of his previous instruments had
given.
[Illustration: FIG. 6.--1856.]
When Meucci arrived in this country, he had property valued at $20,000,
and he entered into the brewing business and into candle making, but he
gradually lost his money, until in 1868 he found himself reduced to
little or nothing. To add to his misery, he had the misfortune of being
on the Staten Island ferryboat Westfield when the latter's boiler
exploded with such terrible effect in 1871. He was badly scalded, and for
a time his life was despaired of. After he recovered he found that his
wife, in their poverty, had sold all his instruments to John Fleming, a
dealer in second-hand articles, and from whom parts of the instruments
have recently been recovered.
[Illustration: FIG. 7.--1858-60.]
With the view of introducing his invention, Meucci now determined to
protect it by a patent; and having lost his instrument, he had a drawing
made according to his sketches by an artist, Mr. Nestori. This drawing he
showed to several friends, and took them to Mr. A. Bertolino, who went
with him to a patent attorney, Mr. T.D. Stetson, in this city. Mr.
Stetson advised Meucci to apply for a patent, but Meucci, without funds,
had to content himself with a caveat. To obtain money for the latter he
formed a partnership with A.Z. Grandi, S.G.P. Buguglio, and Ango
Tremeschin. The articles of agreement between them, made Dec. 12, 1871,
credit Meucci as the inventor of a speaking telegraph, and the parties
agree to furnish him with means to procure patents in this and other
countries, and to organize companies, etc. The name of the company was
"Teletrofono." They gave him $20 with which to procure his caveat, and
that was all the money he ever received from this source.
The caveat which Meucci filed contained the drawing made by Nestori, and
as shown in the cut, which is a facsimile, represents two persons with
telephones connected by wires and batteries in circuit. The caveat,
however, does not describe the invention very clearly; it describes the
two persons as being insulated, but Meucci claims that he never made any
mention of insulating persons, but only of insulating the wires. To
explain this seeming incongruity, it must be stated that Meucci
communicated with his attorney through an interpreter, as he was not
master of the English language; and even at the present time he
understands and speaks the language very poorly, so much so that we found
it necessary to communicate with him in French during the conversation in
which these facts were elicited.
[Illustration: FIG. 8.--1864-65.]
In the summer of 1872, after obtaining his caveat, Meucci, accompanied by
Mr. Bertolino, went to see Mr. Grant, at that time the Vice President of
the New York District Telegraph Company, and he told the latter that he
had an invention of sound telegraphs. He explained his inventions and
submitted drawings and plans to Mr. Grant, and requested the privilege of
making a test on the wires of the company, which test if successful would
enable him to raise money. Mr. Grant promised to let him know when he
could make the test, but after nearly two years of waiting and
disappointment, Mr. Grant said that he had lost the drawings; and
although Meucci then made an instrument like the one shown in Fig. 9 for
the purpose of a test, Mr. Grant never tried it. Meucci claims that he
made no secret of his invention, and as instance cites the fact that in
1873 a diver by the name of William Carroll, having heard of it, came to
him and asked him if he could not construct a telephone so that
communication could be maintained between a diver and the ship above.
Meucci set about to construct a marine telephone, and he showed us the
sketch of the instrument in his memorandum book, which dates from that
time and contains a number of other inventions and experiments made by
him.
[Illustration: FIG. 9.--1864-65.]
[Illustration: FIG. 10.--1865.]
When Professor Bell exhibited his inventions at the Centennial, Meucci
heard of it, but his poverty, he claims, prevented him from making his
protestations of priority effective, and it was not until comparatively
recently that they have been brought out with any prominence.--_The
Electrical World._
* * * * *
AN ELECTRICAL CENTRIFUGAL MACHINE FOR LABORATORIES.
[Footnote: Paper read before Section B, British Association, Aberdeen
meeting.]
By ALEXANDER WATT, F.I.C., F.C.S.
The late Dr. Mohr[1] of Bonn, advocated the use of a centrifugal machine
as a means of rapidly drying crystals and crystalline precipitates; but
although they are admirably adapted for that purpose, centrifugal
machines are seldom seen in our chemical laboratories.
[Footnote 1: "Lehrb. d. Chem. Analyt. Titrirmethode," 3d ed., 1870, p.
684.]
The neglect of this valuable addition to our laboratory apparatus is
probably owing to the inconvenience involved in driving the machine at a
high speed by means of the ordinary hand driving gear, especially when
the rotation has to be maintained for a considerable length of time. It
occurred to me, therefore, that by attaching the drum or basket of the
machine (or the rotating table of Mohr's apparatus) directly to the
spindle of an electro-motor, the difficulty of driving might be got over,
and at the same time a combination of great efficiency would result, as
the electro-motor, like the centrifugal machine, is most efficient when
run at a high speed. The apparatus shown in the sketch consists
essentially of a perforated basket, A, which is slipped on to a cone
attached to the spindle, S, of an electro-motor, and held in position by
the nut, D. The casing, B, with its removable cover, C, serves to receive
the liquid driven out of the substance being dried. A flat form of the
ordinary Siemens H armature, E, revolves between the poles, P, of the
electro-magnets, M, which are connected by means of the base plate, I.
The brass cross-bar, G, carries the top bearing of the spindle, S, and
prevents the magnet poles from being drawn together.
[Illustration]
From four to six cells of a bichromate battery or Faure secondary battery
furnish sufficient power to run the machine at a high speed. An apparatus
with a copper basket four inches in diameter has been found extremely
useful in the laboratory for drying such substances as granulated
sulphate of copper and sulphate of iron and ammonia, but more especially
for drying sugar, which when crystallized in very small crystals cannot
be readily separated from the sirupy mother-liquor by any of the usual
laboratory appliances. For drying substances which act on copper the
basket may be made of platinum or ebonite; in the latter case, owing to
the increased size of the perforations, it may be necessary to line the
basket with platinum wire gauze or perforated parchment paper.
* * * * *
TRANSMISSION OF POWER BY ELECTRICITY.
The experiments of M. Marcel Deprez have entered on a decisive phase. The
dynamos are completed, and were put in place on the 20th October, when M.
Deprez carried out some preliminary tests in the presence of a commission
consisting of MM. Collignon, Inspector-General des Ponts et Chaussees;
Delebecque, Ingenieur en Chef du Materiel et de la Traction of the
Northern Railway of France; Contanini, engineer in the same company; and
Sartaux. The generating dynamos made by MM. Breguet, and the receiving
dynamos constructed by MM. Mignon and Rouart, were during a preliminary
trial placed side by side, one portion of the circuit being very short,
and the other twice the distance between La Chapelle and Creil, or
seventy miles. In future experiments the two dynamos will be placed in
their normal positions at each end of the line. The generating machine is
driven by a locomotive engine; the resistance of its field magnets is
5.68 ohms, and of the two armatures 33 ohms. The resistance of the two
armatures of the receiving machine is 36.8 ohms, and the resistance of
the line is 97 ohms; the generator and receiver field magnets are excited
each by a separate machine. Five different trials were made at varying
speeds of the driving shaft; the initial work on this shaft was measured
by a dynamometer, and the available energy of the shaft of the receiving
machine was ascertained by a Prony brake; the other results of the
experiments were deduced from the constants of the machines and from
galvanometric measurements. For the first trials the different elements
were as follows:
1. _Generating dynamos:_
Velocity of shaft 123 revolutions.
Electromotive force at terminals, 3370.25 volts.
" " total 3624.7 "
Available work at driving shaft. 43 h. p.
Electrical work of generator 37.38 "
Difference absorbed 5.62 "
2. _Line:_
Work absorbed by the line. 7.59 h. p.
3. _Receiving dynamos:_
Velocity of shaft 154 revolutions.
Electromotive force at terminals, 2616.25 volts.
" " total 2336.94 "
Electrical work of receiver 24.10 h. p.
Available work on shaft 22.10 "
Difference absorbed 2 "
The duty obtained would thus be 22.10/43 = 51.3 per cent., if the work
absorbed by the exciting machines be not considered. Taking this into
account, it would be reduced to 40 per cent.
In subsequent experiments the speed of the generator was increased
gradually. In the last trial the following were the elements:
1. _Generating dynamos:_
Speed of shaft 190 revolutions.
Electromotive force at terminals 5231.25 volts.
" " total 5469.75 "
Available work on driving shaft, 62 h. p.
Electrical work on generator 53.59 "
Difference absorbed 8.51 "
Work absorbed by armature 2.33 "
2. _Line:_
Work absorbed by conductors 7.21 h. p.
3. _Receiving dynamos_:
Speed of shaft 248 revolutions.
Electromotive force at terminals 4508 volts.
Electromotive force total 4242.67 "
Electrical work of receiver 41.44 h. p.
Work measured on receiver shaft 35.8 "
Difference absorbed 5.64 "
Duty obtained, not including exciting machine 57 per cent.
Duty obtained, including exciting machine 48 "
During the various experiments the current traversing the line varied
from 7.59 amperes to 7.21 amperes. No heating of any kind was observed.
M.J. Bertrand, who communicated a paper to the Academy of Sciences on the
subject, commented on the relatively low speeds. It corresponds to a
linear displacement of the surface armatures, in no case exceeding the
speed of a locomotive wheel. The tension reached 5,500 volts., under very
satisfactory mechanical conditions, and with a current that in no way
endangered the line. This first experiment is certainly encouraging, and
it will be followed by others of a more complete and exhaustive
character. MM. De Rothschild are now embodying a powerful commission of
French and foreign scientists who will follow the subject carefully, and
report upon it. It may be safely predicted that one result of this action
will be the development of a new series of observations of the highest
technical interest and value.--_Engineering._
* * * * *
THE LOCKED AND CORDED BOX TRICK.
The trick with the locked and corded box, I believe, is an old one,
though perhaps not in its present form. In late years it has been revived
with improvements, and popularized by those clever illusionists, Messrs.
Maskelyne & Cook and Dr. Lynn, at the Egyptian Hall. There are several
ways of working the trick or, rather, of arranging the special bit of
mechanism wherein the peculiar features of the box consist. The one I am
about to describe is, I think, the best of those I am acquainted with, or
at liberty to divulge. Indeed, I don't know that any method is better,
and this one has the advantage over most others of allowing the performer
to get into as well as out of the box, without leaving a trace of his
means of ingress. It will be seen the box is paneled, and all the panels
look equally firm and fixed. As a matter of fact, one of the panels is
movable, though the closest scrutiny would fail to discover this if the
box and fittings are carefully made and adjusted. Fig. 1 shows the
general appearance of the box, of which the back is the same as the
front. In the box I describe, the end marked + has a movable panel. The
size of the box should be regulated by the size of the performer; but one
measuring 3 feet 6 inches long by 2 feet back to front, and 21 inches
high, exclusive of the lid, which may be 3 inches, will be of general
use. In making the box it is most important that all sides and panels
look alike, and that nothing special in the appearance of the end with
the loose panel should attract notice. Fig. 2 shows this end with
fittings drawn half of full size, and it will he seen from this that the
framing, A, is 3 inches wide by 11/4 inches thick, and the panel, B, 1/2 inch
thick.
[Illustration: FIG. 1.]
It will be noticed that the top and bottom rails of the frame are
rabbeted to receive the panel, but the sides are grooved, the groove in
front rail being double the depth of the one in the back rail.
[Illustration: THE LOCKED AND CORDED BOX TRICK. By DAVID B. ADAMSON.]
The dotted line, B, shows the size of the panel; the dotted line, C,
shows the depth of groove in the front rail. From this it will be clear
that the panel is only held in place at the back and front, and that on
sliding it toward the front it will be free out of the groove in the back
rail. Three sides of it are thus free, and a little manipulation will
allow of its being taken out altogether, leaving plenty of space for the
performer to get out, presuming him to have been locked inside the box.
If the panel were to be finished in this way, without further fittings,
the secret would soon be discovered; and I now proceed to show how the
panel is held in place and firm while under examination.
Determine the size of screws that are to be used in fixing the brass
corner clamps. Let us say No. 7 is decided on; and if brass screws are
used, then get a piece of brass, Fig. 4, the exact diameter of the
screw-head, and a little longer than the thickness of the framing. If
iron screws are to be used, then this piece must be iron. Now bore a hole
into which this bolt will fit closely, right through the framing at D,
Fig. 2. It is most important that the hole should be made close up to the
edge of the panel, B, so that when the bolt is in it firmly holds the
panel, and prevents it moving from back to front in the grooving. Now get
a piece of sheet brass, 1/8 inch thick, and cut it to the shape shown by
E, Fig. 2. The width of this piece should not be less than 3/8 inch, and
it must be of such length that the end reaches to the middle of the top
framing, as shown at L, Fig. 2. This piece of brass is sunk in the top
and front framing, as shown by the dotted lines, G, in Figs. 2 and 3, and
also in section in the latter.
When the box is open, the lower or short arm of this lever, which is
shaped as shown full size, at E, Fig. 8, is kept pressed down on the
bolt, D, as shown by the dotted lines, E, E, E, Fig. 2, and E, Fig. 7, by
of the spring, J, Fig. 2.
On the box being closed, a pin on the under edge of lid goes into the
hole, L, Fig. 3, and presses the end of the lever down in such a way as
to raise the claw end of it from D. The thick dotted lines, F, F, F, Fig.
2, show position of lever when box is closed.
It will be noted that the bolt, D, Fig. 4, has a groove cut in it all
around, into which the claw fits. This prevents the bolt being pushed
backward or forward when the box is open.
The lever must be hung as shown, K, Fig. 2. The exact position of this
is immaterial, but it is as well to have the fulcrum as near the end as
may be, in order that the claw may be raised sufficiently with only a
small movement of the short arm of the lever. Of course, the shorter the
arm is, the more accurately the lid and pin must be made to close.
If the pin, pressing short arm down, be too short, the pressure will not
be enough to release the claw, and consequently the performer might find
himself really unable to get out of the box after it is locked.
The end of the lever should be finished with a wood block, as Fig. 6,
larger than the pin on the lid, as represented by L and M, Fig. 3.
The block may be of other material, but should be colored the same as the
wood the box is made of, so that, if any one were to look down on it, no
suspicion would be aroused, as might be were plain brass used.
[Illustration: FIG 4.]
[Illustration: FIG 5.]
In Fig. 5, I show an easy way of hanging the lever. It is simply a piece
of wire sharpened and notched, so as to form several small barbs,
preventing withdrawal. The mode of fixing will be easily understood by
reference to B and C, Fig. 5. Some considerable amount of care will have
to be bestowed on fitting and adjusting this part of the work, on which
the successful performance of the trick consists, and before finally
fixing up, it should be ascertained that all the movements work
harmoniously. It will be best to cut the groove in which the lever works
from below, and, after the lever is fixed, to fill up the space not
required by the lever with strips of wood, H, H. If preferred, the space
can be shaped out from the back, i.e., the inside of the framing, and
then filled where not required, but as this, however neatly done, would
show a joint which might be detected by sharp eyes, it is better to cut
from below, though more troublesome.
The end containing the movable panel being arranged, make up the rest of
the box to it, taking care to make the rebates of the top and bottom
frames to correspond with those of the end.
The other panels should not, however, depend on the grooves on two sides
only, but at tops and bottoms as well.
[Illustration: FIG. 6.]
[Illustration: FIG. 7. & FIG. 8.]
[Illustration: FIG. 9.]
The rebates are to be cut only to have all the framing inside look alike;
and as the panel, B, is made to fit quite close into the rebate, it will
not be surmised that it is not fitted in the usual way.
After the box is made and fitted together, the clamping must be done. The
only necessity for this is in order that the bolt, D, which we have seen
is made on the outside end exactly to match the screws used to fasten the
clamps, should not be conspicuous, as it would be were it alone. As it
is, it will not be specially observable, being apparently only one of the
screws to fasten the clamps.
The clamps may be of thin brass or iron, shaped as shown at Fig. 9. One
of the corner holes must be arranged to cover D exactly, and the others
regulated to it. Let us suppose that A, Fig. 9, is the one through which
the bolt goes; the other corner screw holes must be equally distant from
the edges of the clamps. Twelve of these clamps will be needed. After
they have been screwed on, put the bolt through, and let the claw of the
lever hold it in place. Then mark and cut the bolt flush with the clamp,
making a hollow on the end of it to imitate the screws, as D, Fig. 4. The
other end of the bolt should either be made flush with the inside of
frame and colored to match it, or, better, cut short and faced flush with
a piece of wood to match the framing.
If a piece of wood with a knot be chosen for this side of the frame, so
much the better. Immediately over the hole, L, a wooden pin should be
fixed in the lid, and of such length that it will press the short arm of
lever down sufficiently. It should fit the hole pretty closely.
At the other end, a corresponding pin and hole should be made, and, say,
two along the front. These will then look as if they were intended merely
as fittings to hold the lid in position. The lid at the other end of the
box from the movable panel should have a stop of some sort; the ordinary
brass joint stop will do as well as any, and should be strong. The reason
for placing it at what I may call "the other end" is that, when the box
is being examined, it will attract notice, and draw attention from the
movable panel end.
We may now finally adjust the loose panel, which must fit tight at top
and bottom, and be slightly beveled, as shown on section. Two holes must
also be cut through it, at such a distance from each other that a finger
and thumb can be put through them, so as to allow of the panel being
moved. In the deep grooving in front also put a couple of springs, say
pieces of clock springs, as shown, I, I, Fig, 2. These serve to assist
the bolt, D, by pushing the panel into position.
Holes to match those in end panel must also be cut in the other panels,
and when a lock, preferably a padlock, has been fitted, the box is
complete.
I don't know whether it is necessary to say that the lid should be hinged
at the back, and of course it will add to the appearance of the box if it
be polished or oiled.
Now, for those who may not have seen the locked and corded box trick
performed, a few words of caution may not be out of place. Don't forget
to have something in a pocket easily got at that will serve to push the
bolt out, before going into the box. A piece of stout wire, a small
pencil case, or anything of that sort will do. Be careful when getting
into the box to lie with your head toward the loose panel end, and face
toward the front--as there will be no space to turn round; the right hand
will then be uppermost and free to push the bolt out. Having done this,
grasp the panel with the finger and thumb by means of the two holes, push
it to the front of the box, when the back edge will be clear of the
groove. It can now easily be pulled into the box, and the performer can
creep out. When out, refix panel and bolt so that everything looks as it
was. Any cording that may be over the end of the box will give
sufficiently to allow of exit.
I have, I think, made it quite clear that padlock and ropes have nothing
to do with the real performance of the trick, but they serve to mystify
spectators, who may be allowed to knot the rope and seal the knots in any
way they choose.
There must always be a screen or curtain to hide the box from the
spectators while the performer is getting in or out.--_D.B. Adamson, in
Amateur Work._
* * * * *
PRICES OF METALS.
The _Metallarbeiter_ remarks that metals have in most cases experienced a
reduction in value of late years, this depreciation being attributed in
some measure to the cheaper methods of obtaining metals as well as to the
discovery of new sources of mineral wealth.
The following comparative table shows the approximate prices of various
metals in December, 1874, and December, 1884:
Dec., 1874. Dec., 1884.
Per lb. Per lb.
L s d. L s. d.
Osmium 71 10 0 62 0 0
Iridium 70 0 0 45 0 0
Gold 62 15 0 63 0 0
Platinum 25 7 6 21 7 6
Thallium 23 17 6 4 15 0
Magnesium 10 5 0 1 15 0
Potassium 5 0 0 4 0 0
Silver 3 17 6 (in Hamburg) 3 7 6
Aluminum 1 16 0 1 16 0
Cobalt 1 14 0 1 2 0
Sodium 0 14 2 0 8 8
Nickel 0 11 0 0 3 1
Bismuth 0 8 1 0 8 1
Cadmium 0 7 1 0 4 0
Quicksilver 0 2 0 (in London) 0 1 9
Tin 0 1 1 (in Berlin) 0 0 9
Copper 0 0 10 (" " ) 0 0 7
Arsenic 0 0 8 0 0 4-1/2
Antimony 0 0 6-1/4 (" " ) 0 0 5
Lead 0 0 2-3/4 (" " ) 0 0 1-3/8
Zinc 0 0 2-1/2 (" " ) 0 0 1-3/4
Steel 0 0 1-3/8 ( in 0 0 0-3/4
Bar iron 0 0 1-1/8 Upper 0 0 0-5/8
Pig iron 0 0 0-7/16 Silesia ) 0 0 0-1/4
Gold now ranks highest in value of all metals, the competition of osmium
and iridium having been over come. It is only by reason of improved
methods of preparation that the latter have become cheaper, while their
use has at the same time increased. Iridium is mixed with platinum in
order to increase its strength and durability. The normal standards of
the metrical system are made of platinum-iridium on account of its known
immutabilty. In 1882, platinum stood 15 per cent. below its present
value; but its increased employment for industrial purposes led to the
subsequent improvement in price. Thallium has experienced a severe
depreciation on account of the economical process by which it is
extracted from the residue of the lead chambers used in the manufacture
of sulphuric acid. The use of this metal is mainly confined to
experimental purposes. The fall in silver has arisen from increased
production and diminished use for coinage.
Magnesium was scarcely of any industrial value prior to the fall in price
now recorded. Improved processes for its treatment have successfully
engaged the attention of scientific men, and it is now capable of being
used as an alloy with other metals. The Salindres factory regulates the
price to a certain extent, and its system of working is regarded as a
guide in the various processes connected with this branch of industry.
The manufacture of potassium and sodium will, it is expected, be more
fully elucidated than hitherto, by means of researches made at Schering's
Charlottenburg factory. The course of nickel prices illustrates the
stimulus to economical production afforded by an increased consumption.
This latter fact is principally due to the employment of nickel for
coinage, as alloy for alfenide, etc. The use of cadmium is materially
restricted by its relatively limited supply. Hitherto, its only source
was in the incidental products of zinc distillation, but of late it has
been attempted to bring it into solution from its oxide combinations. An
increased employment of cadmium for industrial purposes is expected to
follow.
Production in excess of the demand has caused the depreciation recorded
in tin, and various other metals not commented upon, this remark applying
even to the scarce metals, arsenic and antimony. Even the better marks of
Cornwall tin and Mansfield refined copper have had to follow the downward
course of the market.
* * * * *
A PERPETUAL CALENDAR.
The annexed figure represents a perpetual calendar, which any one can
construct for himself, and which permits of finding the day that
corresponds to a given date, and conversely.
The apparatus consists of a certain number of circles and arcs of circles
divided by radii. The ring formed by the two last internal circles is
divided into 28 equal parts, which bear the names of the week, the first
seven letters of the alphabet in reversed order, and two signs X. The
circle formed by the external circumference of the ring constitutes the
movable part of the apparatus, and revolves around its center. Two
circular sectors, which are diametrically opposite, are each divided into
seven parts and constitute the fixed portions. In the divisions of the
upper sector are distributed the months, according to the order of the
monthly numbers. In the other sector the days of the month are regularly
distributed. In order to render the affair complete, a table is arranged
upon the movable disk for giving the annual numbers, or rather, in this
case, the annual letters. The calendar is used as follows: Say, for
example, we wish to find what days correspond to the different dates of
August, 1885; we look in the table for the letter (D) that corresponds to
this year; then we bring this letter under the given month (August) and
the days marked upon the movable disk corresponding to the dates sought,
and it only remains to make a simple reading.
[Illustration: PERPETUAL CALENDAR.]
It will be seen that the leap-years correspond to two letters. We here
employ the first to Feb. 29 inclusive, and the second for the balance of
the year. The calendar may be made of cardboard, and be fixed to
wood.--_La Nature._
* * * * *
AN ACCOMPLISHED PARROT.
Around the door of a Sixth Ave. bird store near Twenty-third St. was
gathered the other day a crowd so large that it was a work of several
minutes to gain entrance to the interior. From within there proceeded a
hoarse voice dashed with a suspicion of whisky, which bellowed in
Irish-American brogue the enlivening strains of "Peek-a-boo." With each
reiteration of "Peek-a-boo" the crowd hallooed with delight, and one
small boy, in the exuberance of his joy, tied himself into a sort of knot
and rolled on the pavement. Suddenly the inebriated Irishman came to a
dead stop, and another voice, pleasanter in quality, sang the inspiring
national ode of "Yankee Doodle," followed by the stentorian query and
answer all in one, "How are the Psi-Upsilon boys? Oh, they're all right!"
A passer-by, puzzled at the scene, made his way into the store and soon
solved the mystery. In a large cage in the center was an enormous green
and yellow parrot, which was hanging by one foot to a swinging perch, and
trolling forth in different voices with the ease of an accomplished
ventriloquist. He resumed a normal position as he was approached, and
flapping his wings bellowed out, "Hurrah for Elaine and Logan!" Then,
cocking his head on one side, he dropped into a more conversational tone,
and with a regular "Alice in Wonderland" air remarked: "It's never too
late to mend a bird in the hand;" and again, after a pause, "It's a long
lane that never won fair lady." His visitor affably remarked:
"You're quite an accomplished bird, Polly," and quick as a flash the
creature replied:
"I can spell, I can. C-a-t, cat. D-o-g, fox," with an affectation of
juvenility which was grewsome. He resented an ill-advised attempt at
familiarity by snapping at the finger which tried to scratch his poll,
and barked out:
"Take care! I'm a bad bird, I am. You betcher life!"
"He's one of the cleverest parrots I have had for some time," said his
owner, Mr. Holden. "In fact, he is almost as good as Ben Butler, whom I
sold to Patti. His stock of proverbs seems inexhaustible, and he makes
them quite funny by the ingenious way in which he mixes them up. I could
not begin to tell you all the things he says, but his greatest
accomplishment is his singing. He is a double yellowhead--the only
species of parrot which does sing. The African grays are better talkers,
but they do not sing. They only whistle. What do I ask for him? Oh, I
think $200 is cheap for such a paragon, don't you?"--_N.Y. Tribune._
* * * * *
THE ROSCOFF ZOOLOGICAL LABORATORY.
The celebrated Roscoff zoological station was founded in 1872, and has
therefore been in existence for thirteen years; but it may be said that
it has changed appearance thirteen times. Those who, for the last six or
seven years, have gone thither to work with diligence find at every
recurring season some improvement or new progress.
A rented house, a small shed in a yard, little or no apparatus, and four
work rooms--such was the debut of the station; and modest it was, as may
be seen. Later on, the introduction of a temporary aquarium, which,
without being ornamental, was not lacking in convenience, sufficed for
making some fine discoveries regarding numerous animals.
A small boat served for supplying necessaries to the few workers who were
then visiting Roscoff; but as the number of these kept gradually
increasing, it became necessary to think of enlarging the station, and
the purchase of a piece of property was decided upon. Since then, Mr.
Lacaze Duthiers has done nothing but develop and transform this first
acquisition. A large house, which was fitted up in 1879, formed the new
laboratory. This was built in a large garden situated nearly at the edge
of the sea. We say _nearly_, as the garden in fact was separated from the
sea by a small road. The plan in Fig. 1 shows that this road makes an
angle; but formerly it was straight, and passed over the terrace which
now borders upon the fish pond. How many measures, voyages, and endless
discussions, and how much paper and ink, it has taken to get this road
ceded to the laboratory! Finally, after months of contest, victory
rewarded Mr. Duthiers's tenacity, and he was then able to begin the
construction of a pond and aquarium. All this was not done at once.
[Illustration: FIG. 1.--PLAN OF THE ROSCOFF LABORATORY.]
Another capital improvement was made in 1882. The public school adjoining
the establishment was ceded to it, the separating walls fell, the school
became a laboratory, the class rooms were replaced by halls for research,
and now no trace of the former separation can be seen--so uniform a whole
does the laboratory form. No one knows what patience it required to form,
piecemeal as it were, so vast an establishment, and one whose every part
so completely harmonizes.
During the same year a park, one acre in area, was laid out on the beach
opposite the laboratory. This is daily covered by the sea, and forms a
preserve in which animals multiply, and which, during the inclement
season, when distant excursions are impossible, permits of satisfying the
demands that come from every quarter. All, however, is not finished. Last
year a small piece of land was purchased for the installation of
hydraulic apparatus for filling the aquarium. This acquisition was
likewise indispensable, in order to prevent buildings from being erected
upon the land and shutting off the light from the work rooms opposite.
Alas, here we find our enemy again--the little road! Negotiations have
been going on for eighteen months with the common council, and, what is
worse, with the army engineers, concerning the cession of this wretched
footpath.
The reader now knows the principal phases of the increases and
improvements through which the Roscoff station has passed. If, with the
plan before his eyes, he will follow us, we will together visit the
various parts of the laboratory. The principal entrance is situated upon
the city square, one of the sides of which is formed by the buildings of
the station. We first enter a large and beautiful garden ornamented with
large trees and magnificent flowers which the mild and damp climate of
Roscoff makes bloom in profusion. We next enter a work room which is
designed for those pupils who, doing no special work, come to Roscoff in
order to study from nature what has been taught them theoretically in the
lecture courses of schools, etc. There is room here for nine pupils, to
each of whom the laboratory offers two tables, with tanks, bowls,
reagents, microscopes, and instruments of all kinds for cabinet study, as
well as for researches upon animals on the beach. Here the pupils are in
presence of each other, and so the explanations given by the laboratory
assistants are taken advantage of by all. At the end of this room, on
turning to the left, we find two large apartments--the library and
museum. Here have been gradually collected together the principal works
concerning the fauna of Roscoff and the English Channel, maps and plans
useful for consultation, numerous memoirs, and a small literary library.
The scientific collection contains the greater portion of the animals
that inhabit the vicinity of Roscoff. To every specimen is affixed a
label giving a host of data concerning the habits, method of capture, and
the various biological conditions special to it. In a few years, when the
data thus accumulated every season by naturalists have been brought
together, we shall have a most valuable collection of facts concerning
the fauna of the coast of France. Two store rooms at the end of these
apartments occupy the center of the laboratory, and are thus more easy of
access from the work rooms, and the objects that each one desires can be
quickly got for him.
[Illustration: FIG. 2.--INTERIOR OF ONE OF THE STALLS FOR STUDY.]
After the store rooms comes what was formerly the class room for boys,
and which has space for three workers, and then the former girls' class
room, which has space for eight more. Let us stop for a moment in this
large room, which is divided up into eight stalls, each of which is put
at the disposal of some naturalist who is making original researches.
Fig. 2 represents one of these, and all the rest are like it. Three
tables are provided, the space between which is occupied by the worker.
Of these, one is reserved for the tanks that contain the animals,
another, placed opposite a window giving a good light, supports the
optical apparatus, and the last is occupied by delicate objects,
drawings, notes, etc., and is, after a manner, the worker's desk. Some
shelving, some pegs, and a small cupboard complete the stall. It is
unnecessary to say that the laboratory furnishes gratuitously to those
who are making researches everything that can be of service to them.
Four of these stalls are situated to the north, with a view of the sea,
and the other four overlook the garden. They are separated from each
other by a simple partition, and all open on a wide central corridor that
leads to the aquarium. Before reaching the latter we find two offices
that face each other, one of them for the lecturer and the other for the
preparator. These rooms, as far as their arrangement is concerned, are
identical with the stalls of the workers. The laboratory, then, is
capable of receiving twenty-three workers at a time, and of offering them
every facility for researches.
[Illustration: FIG. 3.--GENERAL VIEW OF THE ROSCOFF LABORATORY.]
The aquarium is an immense room, 98 ft. in length by 33 in width, glazed
at the two sides. It is at present occupied only by temporary tanks that
are to be replaced before long by twenty large ones of 130 gallons
capacity, and two oval basins of from 650 to 875 gallons capacity,
constructed after the model of the one that is giving so good results at
Banyuls. At the extremity of the aquarium there is a store room
containing trawls, nets of all kinds, and mops, for the capture of
animals. Here too is kept the rigging of the two laboratory boats, the
Dentale and Laura. Above the store room is located the director's work
room.
A wide terrace separates the aquarium from the pond. This latter is 38
yards long by 35 wide. Thanks to a system of sluice valves, it is filled
during high tide, and the water is shut in at low tide, thus permitting
of having a supply of living animals in boxes and baskets until the
resources of the laboratory permit of a more improved arrangement. This
basin is shown in Fig. 3. It is at the north side of the laboratory as
seen from the beach. Here too we see the aquarium, the garden, and a
portion of the shore that serves as a post for the station boats.
We must not, in passing, fail to mention the extreme convenience that the
proximity of the aquarium work room to the pond and sea offers to the
student.
This entire collection of halls, constituting the scientific portion of
the laboratory, occupies the ground floor. The first and second stories
are occupied by sleeping apartments, fourteen in number. These, without
being luxurious, are sufficiently comfortable, and offer the great
advantage that they are very near the work rooms, thus permitting of
observing, at leisure, and at any hour of the day or night, the animals
under study.
Everything is absolutely free at the laboratory. The work rooms,
instruments, reagents, boats, dwelling apartments, etc., are put at the
disposal of all with an equal liberality; and this absence of distinction
between rich or poor, Frenchmen or foreigners, is the source of a
charming cordiality and good will among the workers.
Shall we speak, too, of the richness of the Roscoff fauna? This has
become proverbial among zoologists, as can be attested by the 265 of them
who have worked at the laboratory. The very numerous and remarkable
memoirs that have been prepared here are to be found recorded in the
fourteen volumes of the _Archives de Zoologie Experimentale_ founded by
Mr. Lacaze Duthiers.
It only remains to express our hope that the aquarium may be soon
finished; but before this is done it will be necessary to get possession
of that unfortunate little road. After this final victory, Mr. Duthiers
in his turn will be able, amid his pupils, to enjoy all those advantages
of his work which he has until now offered to others, but from which he
himself has gained no benefit.--_La Nature._
* * * * *
THE MURAENAE AT THE BERLIN AQUARIUM.
Of all fish, eels are probably the most interesting, as the least is
known of them. Electricians are now examining the animal source of
electricity in the electric eel (Gymnotus electricus); zoologists are
still searching for the solution of the problem of the generation of
eels, of which no more is known than that the young eels are not born
alive; and numerous fishing societies are now studying the important
question of raising eels in ponds, lakes, etc., that are not connected
with the sea.
[Illustration: THE MURAENAE AT THE BERLIN AQUARIUM.]
The annexed cut, taken from the _Illustrirte Zeitung_, is a copy of a
drawing by Muetzel, and represents a group of Mediterranean Muraenae
(Muraena Helena). This fish attains a length of from 5 ft. to 6 ft., and
has a smooth, scaleless body of a dark color, on which large light-yellow
spots appear, which give the fish a very peculiar appearance. The
pectoral fin is missing, but it has the dorsal and anal fins, which it
uses with great ability. Its head is pointed, and its jaws are provided
with extraordinarily sharp teeth, which are inclined toward the rear; and
at each side of the head it is provided with a gill. The nostrils are on
the upper side of the snout, and a second, tubular, pair of nostrils is
located near the eyes. The bright eyes have a fierce expression, which
makes the fish appear very much like a snake. These fish are ravenous,
and devour crabs, snails, worms, and fishes, and if they have no other
food, bite off the tails of their brethren. They are caught in eel
baskets or cages, and by means of hooks; but they are rather dangerous to
handle, as they attack the fishermen and injure them severely.
Since the times of the ancients, Muraenae have been prized very highly on
account of their savory flesh. The Romans were great experts at feeding
these fish, Vidius Pollio being the master of them all, as he made a
practice of feeding his Muraenae with the flesh of slaves sentenced to
death. Pliny states that at Caesar's triumphal entry Hirius furnished six
thousand Muraenae. Slaves were frequently driven into the ponds, and were
immediately attacked by the voracious fishes, and killed in a very short
time.
* * * * *
METAMORPHOSES OF ARCTIC INSECTS.
In the chapter entitled "Das insektenleben in arktischen laendern," which
Dr. Christopher Aurivillius contributes to the account of A.E.
Nordenskioeld's Arctic investigations, published this year in Leipzig,[2]
the author says: "The question of the mode of life of insects and of its
relation to their environment in the extreme north is one of especial
interest. Knowing, as we do, that any insect in the extreme north has at
the most not more than from four to six weeks in each year for its
development, we wonder how certain species can pass through their
metamorphosis in so short a period. R. McLachlan adverts, in his work
upon the insects of Grinnell Land, to the difficulties which the
shortness of the summer appears to put in the way of the development of
the insects, and expresses the belief that the metamorphosis which we are
accustomed here to see passed through in one summer there requires
several summers. The correctness of this supposition has been completely
shown by the interesting observations which G. Sandberg has made upon
species of lepidoptera in South Varanger, at 69 deg. 40' north latitude.
Sandberg succeeded in following the development from the egg onward of
some species of the extreme north. _Oeneis bore_, Schn., a purely Arctic
butterfly, may be taken as an example. This species has never been found
outside of Arctic regions, and even there occurs only in places of purely
Arctic stamp. It flies from the middle of June onward, and lays its eggs
on different species of grass. The eggs hatch the same summer; the larva
hibernates under ground, continues eating and growing the next summer,
and does not even then reach its full development, but winters a second
time and pupates the following spring. The pupa, which in closely related
forms, in regions further to the south, is suspended free in the air upon
a blade of grass or like object, is in this case made in the ground,
which must be a very advantageous habit is so raw a climate. The imago
leaves the pupa after from five or six weeks, an uncommonly long period
for a butterfly. In more southern regions the butterfly pupa rests not
more than fourteen days in summer. The entire development, then, takes
place much more slowly than it does in regions further south. Sandberg
has shown, then, by this and other observations, that the Arctic summer,
even at 70 deg. N., is not sufficient for the development of many
butterflies, but that they make use of two or more summers for it. If
then more than one summer is requisite for the metamorphosis of the
butterflies, it appears to me still more likely that the humble-bees need
more than one summer for their metamorphosis. With us only the developed
female lives over from one year to the next; in spring she builds the new
nest, lays eggs, and rears the larvae which develop into the workers, who
immediately begin to help in the support of the family; finally, toward
autumn, males and females are developed. It seems scarcely credible that
all this can take place each summer in the same way in Grinnell Land, at
82 deg. N., especially as the access to food must be more limited than it is
with us. The development of the humble-bee colony must surely be quite
different there. If it is not surely proved that the humble-bees occur at
so high latitudes, one would not, with a knowledge of their mode of life,
be inclined to believe that they could live under such conditions. They
seem, however, to have one advantage over their relatives in the south.
In the Arctic regions none of those parasites are found which in other
regions lessen their numbers, such as the _conopidae_ among the flies, the
mutillas among the hymenoptera, and others."--_Psyche._
[Footnote 2: Nordenskioeld, A.E., Studien und forschungen veranlasst durch
meine reisen im hohen norden. Autorisirte ausgabe. Leipzig, Brockhaus,
1885, 9 + 581 pp., 8 pl., maps, O. il.]
* * * * *
A YEAR'S SCIENTIFIC PROGRESS IN NERVOUS AND MENTAL DISEASES.
[Footnote: Volunteer report presented to Nebraska State Medical
Society, May, 1885, at Grand Island, Neb.]
By L.A. MERRIAM, M.D., Omaha, Neb.,
Professor of the Principles and Practice of Medicine in the
University of Nebraska College of Medicine, Lincoln, Neb.
The records of the Nebraska State Medical Society show that the only
report of progress on nervous and mental diseases ever made in the
history of the society (sixteen years) was made by the writer last year;
and expecting that those appointed to make a report this year would,
judging by the history of the past, fail to prepare such a report, I have
seen fit to prepare a brief volunteer report of such items of progress as
have come to my notice during the last twelve months. I have not been
able to learn that any original work has been done in our State during
the past year, nor that those having charge of the insane hospital have
utilized the material at their command to add to the sum of our knowledge
of mental diseases.
Last year I said: "There is a growing sentiment that many diseases not
heretofore regarded as nervous (and perhaps all diseases) are of nervous
origin." This truth, that all pathologico-histological changes in the
tissues of the body are degenerative in character, and, whether caused by
a parasite, a poison, or some unknown influence, are first brought about
by or through a changed innervation, is one that is being accepted very
largely by the best men in the profession, and the accumulation of facts
is increasing rapidly, and the acceptance of this great truth will prove
to be little short of revolutionary in its influence on the treatment of
the disease. This is the outgrowth of the study of disease from the
standpoint of the evolution hypothesis. Derangements of function precede
abnormalities of structure; hence the innervation must be at fault before
the organ fails. Hence the art of healing should aim at grappling with
the neuroses first, for the local trophic changes, perverted secretions,
and structural abnormalities are the effects or symptoms, not the causes
of the disease. Dr. J.L. Thudicum has studied the chemical constitution
of the brain, and he holds that, "When the normal composition of the
brain shall be known to the uttermost item, then pathology can begin its
search for abnormal compounds or derangements of quantities." The great
diseases of the brain and spine, such as general paralysis, acute and
chronic mania, and others, the author believes will all be shown to be
connected with special chemical changes in neuroplasm, and that a
knowledge of the composition and properties of this tissue and of its
constituents will materially aid in devising modes of radical treatment
in cases in which, at present, only tentative symptomatic measures are
taken.
The whole drift of recent brain inquiry sets toward the notion that the
brain always acts as a whole, and that no part of it can be discharging
without altering the tensions of all the other parts; for an identical
feeling cannot recur, for it would have to recur in an unmodified brain,
which is an impossibility, since the structure of the brain itself is
continually growing different under the pressure of experience.
Insanity is a disease of the most highly differentiated parts of the
nervous system, in which the psychical functions, as thought, feeling,
and volition, are seriously impaired, revealing itself in a series of
mental phenomena. Institutions for the insane were at first founded for
public relief, and not to benefit the insane; but this idea has changed
in the past, and there is a growing feeling that a natural and domestic
abode, adapted to the varying severity of the different degrees of
insanity, should be the place for the insane, with some reference to
their wants and necessities, and that many patients (not all) could be
better treated in a domestic or segregate asylum than in the prison-like
structures that so often exist, and that the asylum should be as much
house-like and home-like in character as the nature of the insanity would
permit; while exercise and feeding are accounted as among the best
remedies in some cases of insanity, particularly in acute mania.
The new disease called morbus Thomsenii, of which I wrote in my report
last year, has been carefully studied by several men of eminence, and the
following conclusions have been reached as to its pathology: The weight
of the evidence seems to prove that it is of a neuropathic rather than a
myopathic nature, and that it depends on an exaggerated activity of the
nervous apparatus which produces muscular tone, and that it has much
analogy to the muscular phenomena of hysterical hypnosis, the genesis of
which is precisely explained by a functional hyperactivity of the nervous
centers of muscular activity. Until quite recently it was supposed that
the rhythmical action of the heart was entirely due to the periodical and
orderly discharge of motor nerve force in the nerve ganglia which are
scattered through the organ; but recent physiological observations, more
especially the brilliant researches of Graskell, seem to show that the
influence of the cardiac ganglia is not indispensable, and that the
muscular fiber itself, in some of the lower animals, at all events
possesses the power of rhythmical contraction.
Several valuable additions to our knowledge of the anatomy of the nervous
system have been made by Huschke, Exner, Fuchs, and Tuczek.
Tuczek and Fuchs have confirmed the discoveries of Exner, that there are
no medullated nerve fibers in the convolutions of the infant, and
Flechzig has developed this law, that "medullated nerve fibers appear
first in the region of the pyramidal tracts and corona radiata, and
extend from them to the convolutions and periphery of the brain," being
practically completed about the eighth year. This fact is of practical
importance in nervous and mental diseases, since it is becoming an
admitted truth that the histological changes in disease follow in an
inverse order the developmental processes taking place in the embryo.
Hence the recent physiological division of the nervous system by Dr.
Hughlings Jackson into highest, middle, and lowest centers, and the
evolution of the cerebro-spinal functions from the most automatic to the
least automatic, from the most simple to the most complex, from the most
organized to the least organized. In the recognition of this division we
have the promise of a steadier and more scientific advance, both in the
physiology and in the pathology of the nervous system.
Mr. Victor Horsley has recently demonstrated the existence of true
sensory nerves supplying the nerve trunks of nervi-nervorum.
Prof. Hamilton, of Aberdeen, claims that the corpus callosum is not a
commissure, but the decussation of cortical fibers on their way down to
enter the internal and external capsules of the opposite side.
Profs. Burt G. Wilder, of Ithaca, and T. Jefrie Parker, of New Zealand
Institute, have proposed a new nomenclature for macroscopic encephalic
anatomy, which, while seemingly imperfect in many respects, has, at
least, the merit of stimulating thought, and has given an impulse to a
reform which will not cease until something has been actually
accomplished in this direction. The object being to substitute for many
of the polynomial terms, technical and vernacular, now in use, technical
names which are brief and consist of a single word. This has already been
adopted by several neurologists, of whom we may mention Spitzka, Ramsey,
Wright, and H.T. Osborn.
Luys holds that the brain, as a whole, changes its position in the
cranial cavity according to different attitudes of the body, the free
spaces on the upper side being occupied by cerebro-spinal fluid, which,
obeying the laws of gravity, is displaced by the heavier brain substance
in different positions of the body.
Luys claims that momentary vertigo, often produced by changing from a
horizontal to a vertical position, seasickness, pain in movement in cases
of meningitis, epileptic attacks at night, etc., may be by this
explained. These views of Luys are accepted as true, but to a less extent
than taught by Luys. The prevalent idea that a lesion of one hemisphere
produces a paralysis upon the opposite side of the body alone is no
longer tenable, for each hemisphere is connected with both sides of the
body by motor tracts, the larger of the motor tracts decussating and the
smaller not decussating in the medulla. Hence a lesion of one hemisphere
produces paralysis upon the opposite side of the body. It has recently
been established that a lesion of one hemisphere in the visual area
produces, not blindness in the opposite eye, as was formerly supposed,
but a certain degree of blindness in both eyes, that in the opposite eye
being greater in extent than that in the eye of the same side. Analogy
would indicate that other sensations follow the same law, hence the
probability is that all the sensations from one side of the body do not
pass to the parietal cortex of the opposite side, but that, while the
majority so pass, a portion go up to the cortex of the same side from
which they come.
Dr. Hammond says that the chief feature of the new Siberian disease
called miryachit is, that the victims are obliged to mimic and execute
movements that they see in others, and which motions they are ordered to
execute.
Dr. Beard, in June, 1880, observed the same condition when traveling
among the Maine hunters, near Moosehead Lake. These men are called
jumpers, or jumping Frenchmen. Those subject to it start when any sudden
noise reaches the ears. It appears to be due to the fact that motor
impulse is excited by perceptions without the necessary concurrence of
the volition of the individual to cause the discharge, and are analogous
to epileptiform paroxysms due to reflex action.
The term spiritualism has come to signify more than has usually been
ascribed to it, for some recent authors are now using the term to denote
a neurosis or nervous affection peculiar to that class of people who
claim to be able to commune with the spirits of the dead.
Evidence obtained from clinical observations has tended of late to locate
the pathological lesions of chorea in the cerebral cortex.
Dr. Godlee's operation of removing a tumor from the brain marks an
important step in cerebral localization, and cerebral surgery bids fair
to take a prominent place in the treatment of mental diseases.
Wernicke has observed that the size of the occipital lobes is in
proportion to the size of the optic tracts, and that the occipital lobes
are the centers of vision.
Hughlings Jackson has observed that limited and general convulsions were
often produced by disease in the cortex of the so-called motor
convolutions. The sense of smell has been localized by Munk in the gyri
hippocampi, while the center of hearing has been demonstrated to be in
the temporal lobes. The center for the muscles of the face and tongue is
in the inferior part of the central convolution; that for the arm, in the
central part; that for the leg, in the superior part of the same
convolution; the center for the muscles and for general sensibility, in
the angular gyrus; and the center for the muscles of the trunk, in the
frontal lobes. In pure motor aphasia the lesion is in the posterior part
of the left third frontal convolution; in cases of pure sensory aphasia,
the lesion is in the left first temporal convolution.
The relation of the cerebrum to cutaneous diseases has been studied much
of late, and it is now held that the cutaneous eruptions are mainly due
to the degree of inhibiting effect exerted upon the vaso-motor center.
The relation of the spinal cord to skin eruptions has been more
thoroughly investigated and more abundant evidence supplied to
demonstrate the influence degeneration of the spinal cord has in causing
skin diseases, notably zoster, urticaria, and eczema.
This rheumatism, pneumonia, diabetes, and some kidney diseases and liver
affections are often the result of persistent nervous disturbance is now
held. That a high temperature (the highest recorded) has resulted from
injuries of the spinal cord, and where the influence of microzymes is
excluded, is not a matter of question. In one instance, the temperature
reached 122 deg. F., and remained for seven weeks between 108 deg. and 118 deg. F.
The patient was a lady; the result was recovery. Hence it cannot be fever
which kills or produces rapid softening of the heart and other organs in
fatal cases of typhoid. Fever, so far as it consists in elevation of
temperature, can be a simple neurosis.
Many other items of progress might be presented did time permit,
particularly in the treatment of nervous affections, but this I leave for
another occasion.
* * * * *
SCARING THE BABY OUT.
Dr. Grangier, surgeon in the French army, writes from Algeria: "A few
days after the occupation of Brizerte, when the military authorities had
forbidden, under the severest penalties, the discharge of firearms within
the town, the whole garrison was awakened at three o'clock one morning by
the tremendous explosion of a heavily loaded gun in the neighborhood of
the ramparts; a guard of soldiers rushed into the house from whence the
sound had come, and found a woman lying on the floor with a newly born
babe between her thighs. The father of the child stood over his wife with
the smoking musket still in his hand, but his intentions in firing the
gun had been wholly medical, and not hostile to the French troops. The
husband discovered that his wife had been in labor for thirty-six hours.
Labor was slow and the contractions weak and far apart. He had thought it
advisable to provoke speedy contraction, and, following the Algerian
custom to _scare the baby_ out, he had fired the musket near his wife's
ear; instantanously the accouchement was terminated. After being
imprisoned twenty-four hours, the Arab was released."--_Cincinnati
Lancet._
* * * * *
"ELASTIC LIMIT" IN METAL.
The _Engineering and Mining Journal_ raises the question whether steel,
which is becoming so popular a substitute for wrought iron, will, when it
is subjected to continuous strain in suspension bridges and other similar
structures, do as well as iron has proved that it can. Recent tests of
sections from the cables at Fairmount Park, Philadelphia, and at Niagara
Falls show that long use has not materially changed the structure. The
_Journal_ says: "It is a serious question, and one which time only can
completely answer, whether steel structures will prove as uniformly and
permanently reliable as wrought iron has proved itself to be. In other
words, whether the fibrous texture of wrought iron can be equaled in this
respect by the granulated texture of steel or ingot iron. In this
connection it is interesting to note that the fibrous texture referred to
is imparted to wrought iron by the presence in it of a small proportion
of slag from the puddling furnace, and that this can be secured in the
Bessemer converter also if desired. The so-called _Klein-Bessemerei,_
carried on at Avesta in Sweden for several years past, produces an
exclusively soft, fibrous iron by the simple device of pouring slag and
iron together into the ingot mould. This requires however a very small
charge (usually not more than half a ton), and a direct pouring from the
converter, without the intervention of a ladle, which would chill the
slag."
The effect of the introduction of slag would seem to be to retrace the
steps usually taken in producing steel, viz., to separate the iron from
its impurities, and then to add definite quantities of carbon and such
other ingredients as are found to neutralize the effects of certain
impurities not fully removed.
The most intelligent engineers, after ascertaining by exhaustive physical
tests what they need, present their "requirements" to the iron and steel
makers, whose practical experience and science guide them in the
protracted metallurgical experiments necessary to find the exact process
required. The engineer verifies the product by further tests, and by
practical use may find that his "requirement" needs further
modifications. As a result of all this care, some degree of certainty is
secured as to what the material may be expected to do.
No doubt the chemical composition of the slag used at Avesta was known
and met some equally well known want in the iron, and thus the result
arrived at was one which had been definitely and intelligently sought.
An important factor in selecting material for the cables of suspension
bridges is its _true elastic limit_. By this term we mean the percentage
of the total strength of the material which it can exert continuously
without losing its resilience, i.e., its power to resume its former shape
and position when stress is removed. Now, in the case particularly of
steel wire as commonly furnished in spiral coils, the curve put into the
wire in the process of manufacture seriously diminishes this available
sustaining power.
For it is evident that it would be unsafe to subject these cables at any
time to a stress beyond their elastic limit. If, e.g., a snowstorm or a
great crowd of people should load a bridge beyond this limit, when the
extra weight was removed the cables could not bring the bridge back to
its normal place, and the result would be a permanent flattening and
weakening of the arch.
By a process invented and patented by Col. Paine, the wire in the New
York and Brooklyn bridge was furnished _straight_ instead of curved. Now,
if a short piece of common steel wire is taken from the coil, and pulled
toward a straight position, and then released, it springs back into its
former curve; but if a short piece of the straight-furnished wire that
was put into this bridge is bent, and then released, it springs back
toward its straight position.
It is easy to see that if a curved wire is pulled straight, there must
occur a distention of the particles on the inside of the curve and a
compression of those on the outside. The inside is in fact strained past
its elastic limit before _any_ stress comes upon the outside. Hence,
after the wire has been pulled straight, the elastic limit of only a
portion of it can be taken into the account in calculating the load that
can safely be put upon it. In the case of curved steel wire pulled
straight, its ultimate strength was found to be only about 90 per cent.
that of similar wire furnished straight by this process. The superior
ductility of iron wire in some measure compensates for the distention of
the particles on the inside of the curve, and that is a reason why it has
heretofore been used for suspension bridges. But with straight steel wire
there is no such distention, and its _entire elastic limit_ is available.
This elastic limit is 66 per cent. of the ultimate strength, and,
besides, that ultimate strength is 10 per cent. greater than that of
similar curved wire. Thus if we have a curved steel wire large enough to
sustain 1,000 lb. without breaking, a similar straight wire, such as
those in this bridge, will hold up 1,100 lb., and 66 per cent. of this
1,100 lb = 720 lb.
The elastic limit of curved wire has never been determined, since any
stress that will cause it to reach a straight line is beyond the elastic
limit of the inside of its sectional area. That of curved iron wire has
been estimated at 40 per cent. of its ultimate strength, which is about
half the ultimate strength of curved steel wire; that is, it would be
unsafe to put more than 40 per cent. of 500 lb.--or 200 lb.--upon a
curved iron wire when a _straight_ steel one can sustain 720 lb. without
injury. In the New York and Brooklyn bridge the cost of a sufficient
amount of such iron wire as is used in all other suspension bridges would
have been some $200,000 greater than that of the straight steel wire
which was used. At five per cent., this effects an annual saving in
interest of $10,000.
There must, too, be a considerable saving in the current expense for
painting and care, to say nothing of the more neat and elegant appearance
of the less bulky steel. And as the whole area of the section of these
wires is subjected to an even strain that is always far within the
elastic limit, there is no danger of a change of structure under that
stress.
It is highly probable--although Col. Paine has been too busy to work up
the matter--that piano wire made in this straight method could be drawn
up to and kept at pitch, without approaching very near the elastic limit.
In that case not only would they seldom if ever require tuning, but
probably all along the tone would be more satisfactory. And there would
not be those exasperating periods when the pitch is not quite perfect,
but yet is not far enough out to make it seem worth while to send for a
tuner.
* * * * *
A catalogue, containing brief notices of many important scientific papers
heretofore published in the SUPPLEMENT, may be had gratis at this office.
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