Various - Scientific American Supplement, No. 312, December 24, 1881

V >> Various >> Scientific American Supplement, No. 312, December 24, 1881

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Having thus endeavored to explain what electricity is, and the laws
which govern the occlusion of static caloric, and the development of
dynamic caloric (electricity), in conclusion I call the attention of
the inventors of the age to the great need of a process for oxidizing
coal or oil at a low degree, within an insulated vessel. With such an
invention electricity would be obtained at such a low cost that it
would be used exclusively to light and heat our houses, to smelt,
refine, and manipulate our metals, to propel our cars, wagons,
carriages, and ships, cook our food, and drive all machinery requiring
motive power.

* * * * *

ELECTRIC LIGHT APPARATUS FOR PHOTOGRAPHIC PURPOSES.

By A.J. JARMAN.

For some time past it has been the desire of many photographers to
have at hand a ready means of producing a powerful and highly actinic
artificial light, suitable for the production of negatives, and easily
controllable. Several forms of apparatus have been designed, and I
believe have been, to a certain extent, employed successfully in
portraiture. But it has been well known for many years that the
electric light was just the light that would answer the photographer's
requirements, owing to its possessing great actinic power; but the
cost of its production was too great for general adoption; indeed,
such might be said of it now as far as dynamo-electric machines and
steam or gas motors are concerned, for the majority of photographers.
It is true that several influential photographers have already adopted
the use of the electric light for portraiture, but the primary cost of
the apparatus employed by these firms is far beyond the reach of most
portraitists. The apparatus about to be described is one that has been
carefully worked out to meet the wants of the photographer in almost
every particular; in fact, with this apparatus, portraits can, and
have been, produced in an ordinary sitting room, as good and as
perfect as if taken in a well-lighted studio.

[Illustration: FIG. 1.]

The generator of the electric current consists of a series of voltaic
elements of zinc and carbon--forty-eight in number--these elements
being made up of ninety-six zinc plates and forty-eight carbon plates;
thus the generator consists of forty-eight voltaic elements arranged
in rows of twelve; they are all carefully screwed upon suitable bars
of wood, and these bars are joined by other cross bars, which bind the
whole in a compact form; the battery being suitably connected so as to
produce a current of very high electro-motive force, and so arranged
over their exciting trough that the plates can be raised or lowered at
will, as seen in Fig. 1, which will explain itself almost at first
sight.

The troughs are made of mahogany, put together with brass screws, and
well saturated with an insulating compound which also makes them acid
proof; the cells are charged with a saturated solution of bichromate
of potash, to which has been added twenty fluid ounces of sulphuric
acid to each gallon.

[Illustration: FIG. 2.]

To produce the electric current, all that is needed is to lower these
suspended elements down into the trough, having previously connected
the wires as shown in Fig. 1, to the electric lamp, Fig 2. At once a
light starts up, between the carbon pencils, of a thousand-candle
power or more. With a light of this power, a large head on cabinet or
carte size plate may be produced in three or four seconds.

The generator occupies a floor space of three feet six inches by two
feet, and stands two feet six inches high. The cells will cost 5s. to
charge, and will produce upward of sixty negatives before being
exhausted. All that is necessary, in recharging, is to lift the
elements up out of the way, take out the troughs by their handles and
empty them, charging them again by means of a toilet jug. When
replaced, the whole apparatus is fit for use again; the whole of the
above operation occupies but a quarter of an hour, and as there are no
earthenware cells employed, there is no fear of breakage.

The small amount of labor and cost of working the above apparatus will
compare favorably with the production of the electric light from a
dynamo-electric machine for the photographer, and when we consider
that the cost of the whole of the above apparatus, consisting of a
generator automatic lamp, reflector, and all the necessary
appendages, is less then one-tenth of the dynamo machine, motor,
shafting, etc., to produce the same result, it would seem to have a
greater claim for its adoption with those who wish to employ the
electric light, whether for work at night, use in the sitting room, or
to assist daylight on the dark and foggy days of winter.

Fig. 2 shows the arrangement of the electric lamp. A is the automatic
regulator; B, the reflector; C, top extension of the reflector; D,
small tissue paper screen to prevent the intense arc-rays from coming
in contact with the sitter; E, stand with sliding rod. This appendage
can be wheeled about with ease, as it is arranged to run upon four
casters.

When the generator is in use it may be placed within easy reach of the
operator, so that the exposure may be made by lowering the elements in
their troughs just for the requisite time, and withdrawing immediately
the exposure is made; there is no need to fear any inconvenience from
deleterious fumes as none are given off, so it may be used in any
studio or sitting-room without any inconvenience from this source, and
as far as many trials have gone, it seems to meet every requirement
demanded by the photographer for the production of portraits by means
of the electric light.--_Photo. News._

* * * * *

DESRUELLES'S ELECTRIC LIGHTER

[Illustration: ELECTRIC LIGHTER.]

The little apparatus shown in the accompanying cut will certainly find
favor with smokers, as well as with persons generally who often have
need of a fire or light. It forms one of the most direct applications
of dry piles of all the systems on the Desruelles plan. Instead of
filling piles with a liquid, this plan contemplates the introduction
into them of a sort of asbestos sponge saturated with an acid or any
suitable solution. In this way there is obtained the advantage of
having a pile which is in some sort _dry_, that may be moved, shaken,
or upset without any outflow of liquid, and which will prove of
special value when applied to movable apparatus, such as portable
lighters, alarms on ships, railroads, etc. It is hardly necessary to
say that while the introduction of this inert substance diminishes the
volume of the liquid, the electro-motive force of the pile is thereby
in nowise affected, but its internal resistance is increased. This,
however, is of no consequence in the application under consideration.
The lighter consists of a small, round, wooden box containing the
pile, and surmounted by a spirit lamp. A platinum spiral opposite the
wick serves for producing the light. The pile is a bichromate of
potash element, in which there is substituted for the liquid a
solution of bichromate identical with that used in bottle piles. The
zinc is suspended from a small lever, in which it is only necessary to
press slightly to bring the former in contact with the asbestos paste,
when, the zinc being attached, a current is set up which traverses the
spiral, heats it to redness, and lights the spirit. The pile, when
once charged, may be used for several hundred lightings. When the
spiral no longer becomes red hot, it is only necessary to replace the
paste--an operation of extreme simplicity. When the pressure is
removed from the little lever, the zinc, being raised, is no longer
acted upon by the liquid with which the asbestos is saturated. Mr
Desruelles is constructing upon the same principle a gas lighter, the
pile of which is fixed at the extremity of a handle whose length
varies with the height of the gas burners to be reached. These little
domestic apparatus are being exhibited at the Paris Electrical
Exhibition.

* * * * *

SOLENOID UNDERGROUND WIRES IN PHILADELPHIA.

The _Evening Bulletin_ of the 29th October has the following:

This afternoon a series of experiments were conducted at the Public
Buildings which will be of great interest to electricians all over the
country, and upon which the success of a number of underground
telegraph projects in different parts of the United States depends. In
all projects of this kind the problem which has given most trouble to
inventors has been to overcome the induction. In other words, electric
currents will leave their original conductors and pass to other
conductors which may be near at hand. This interchange of currents may
take place without seriously hindering ordinary telegraphy, as the
indicators are not delicate enough to detect the induction. When
telephones came into use, however, the induction became a great source
of trouble to electricians, it often being the case that the sounds
and influences from without were sufficient to drown out sounds in a
telephone. To-day's experiment was conducted by Mr. J.F. Shorey, a
well-known electrician, who exhibited Dr. Orazio Lugo's cables for
electric light, telephone, and telegraphic purposes.

A large number of prominent electricians were present, including the
following: General J.H. Wilson, President of the N.Y. and N.E.
Railroad, of Boston; Messrs. Frank L Pope, S.L.M Barlow, George B.
Post, Charles G. Francklyn, Col. J.F. Casey, W.H. Bradford, and Selim
R. Grant, of New York; James Gamble, General Manager of the Mutual
Union Telegraph Co.; T.E. Cornich and W.D. Sargent, of the Bell
Telegraph Co.; S.S. Garwood and J.E. Zeublen, of the Western Union,
and others.

The principal tests were made through the conduits on Market Street,
laid by the National Underground Electric Company as far as Ninth
Street. A cable of five conductors was laid through the conduit. Two
of these conductors consisted of simple "circuit wires," while the
other three were what is known as "solenoids." A solenoid wire is a
single straight wire, connected at each end with and wound closely
around by another insulated wire, this forming a complete system, the
electric currents returning into themselves. Electricians claim that
the solenoid effectually overcomes all induction, and this afternoon
experiments were made for the purpose of proving that assertion. In
the telephones, connected by the ordinary wires, a constant burr and
click could be heard, that sound being the induction from the wires on
the poles on Market Street, sixty feet overhead. With the solenoid the
only sound in the telephones was the voices of the persons speaking.
The faintest whispers could be heard distinctly, and the ease and
comfort of conversation was in marked contrast to the other telephone
on the ground wires. A set of telegraph indicators was also attached
to the wires in use in the cable. The sounds were transferred from one
"ground wire" to the other, while the solenoids seemed to resist every
influence but that directed upon them by the operators. Another
interesting test was made. The electric current for a Hauckhousen lamp
was passed through a long coil of solenoid wire. Separated from this
coil by a single newspaper, lay a coil of wire attached to telephones,
yet not a sound could be heard in the telephones but the voices of the
persons using them. The current of electricity created by a
dynamo-electric machine is of necessity a violent one, and in the use
of ordinary wires the induction would be so great that no other sounds
could possibly be heard in the telephones.

* * * * *

DR. HERZ'S TELEPHONIC SYSTEMS.

In an article by Count du Moncel, published in SCIENTIFIC AMERICAN
SUPPLEMENT, No 274, page 4364, the author, after describing Dr.
Herz's telephonic systems, deferred to another occasion the
description of a still newer system of the same inventor, because at
that time it had not been protected by patent. In the current number
of _La Lumiere Electrique_, Count Moncel returns to the subject to
explain the principles of these new apparatus of Dr. Herz, and says:

I will first recall the fact that Dr. Herz's first system was based
upon the ingenious use (then new) of derivations. The microphone
transmitter was placed on a derivation from the current going to the
earth, taken in on leaving the pile, and the different contacts of the
microphone were themselves connected directly and individually with
the different elements of the pile. The telephone receiver was located
at the other end of the line, and when this receiver was a condenser
its armatures were, as a consequence of this arrangement, continuously
and preventively polarized, thus making it capable of reproducing
conversation.

[Illustration: DR. HERZ'S TELEPHONIC SYSTEMS.]

This arrangement evidently presented its advantages; but it likewise
possessed its inconveniences, one of the most important of these being
the necessity of employing rather strong piles and consequently of
exposing the line to those effects of charge which react in so
troublesome a manner in electrical transmissions when they occur on
somewhat lengthy lines. Now the fact should be recalled that Dr.
Herz's principal object was the application of the telephone to long
lines, and he has been applying himself to this problem ever since. He
at first thought of employing reversed currents, as in telegraphy; but
how was such a result to be attained with systems based upon the use
of sonorously-vibrating transmitters? He might have been able to solve
the problem with the secondary currents of an induction bobbin, as
Messrs. Gray, Edison, and others had done; but then he would no longer
have been benefited by those amplifications which are furnished by the
variations of pressure-derivations in microphones, and this led him to
endeavor to increase the effects of the induced currents themselves by
prolonging their duration, or rather by combining them in such a way
that they should succeed each other, two by two, in the same
direction; and this is the way he solved the problem in the beginning.

The fact should also be recalled that Dr. Herz had, from his first
experiments, recognized the efficiency of those microphonic contacts
that are obtained by the superposition of carbon disks or other
semi-conducting substances. He has employed these under different
arrangements and with very diverse groupings, but, as a general thing,
it has been the horizontal arrangement which has given him the best
effects.

Let us suppose, then, that four systems of contacts of this nature are
arranged at the four corners of an ebonite plate, C C (Figs. 1 and 2),
at A, A¹, B, B¹, and that they are connected with each other, as shown
in the cuts--that is to say, the upper disks, _e_, _f_, _g_, _h_,
parallel with the sides of the plate, and the lower disks, A, A¹, B,
B¹, diagonally. Let us admit, further, that the plate pivots about an
axis, R; that the disks are traversed by small pins fixed in the
plate; and that small leaden disks rest upon the upper disks. Finally,
let us imagine that the plate is connected at one end, through a rod
T, with a telephone diaphragm. Now it will be readily understood that
the vibrations produced by the diaphragm will cause the oscillation of
the plate, C C, and that there will result therefrom, on the part of
the disks, two effects that will succeed one another. The first will
be, for the ascending vibrations, an increase of pressure effected
between the disks of the left side, by reason of their force of
inertia being increased by that of the lead disks; and the second will
be, for the disks to the right, and, for the same reason, a reduction
of pressure which will take place through resilience, at the moment of
change in direction of the vibrating motions.

If the current from a pile, P, traverses all these disks, through the
connections that we have just mentioned, and passes through the
primary helix (through the wire, I) of an induction coil H H' (Fig.
2), located beneath the apparatus, and if the secondary current from
this bobbin corresponds, through the wire I, with a telephone line in
which there is interposed a telephone or a speaking condenser, there
will be set up an inverse induced current, which, being reversed as a
consequence of the crosswise connections of the disks, will continue
the action of the first or increase its duration, and, consequently,
its force, through the telephone receiver.

The results of this system are very good; but Dr. Herz has endeavored
to simplify it still further, and with this object in view has
experimented on several arrangements. For example, to obtain inversion
a contact was simply placed on each side of the vibrating plate.
Although the movements of this latter are not, as we know, of the
nature of ordinary sonorous vibrations, it was thought that they might
prove to be in opposite directions on the two sides of the plate, and
that one of the contacts might be compressed while the other was free.
So notwithstanding the advantages of this arrangement, it was thought
necessary to place the plate vertically in order to give the same
regulation to the two contacts which it is essential should be
identical. But it became difficult to regulate by weight; and even to
succeed in regulating at all, it became necessary to employ two
parallel diaphragms, vibrating in unison, and each carrying its
contact, but in opposite directions. Afterwards, the horizontal
arrangement was again adopted; but, by a clever combination, the two
principles applied by Dr. Herz--derivation and inversion--were united.
The current is then led to a double contact, where it divides. This
contact is arranged under the plate in such a way that its two points
of variable resistance act in opposite directions to each other, or,
in some apparatus, so that one of the points has no variation, while
the other is in action. The result that occurs may be easily imagined.
The system has been experimented with under different forms; in one
case the derivation is simple, that is, a single one of the currents
being sent into the line, while in another case it is double, each of
the branches being provided with a bobbin and communicating with the
receiver. In the latter case the result is remarkably good, but the
apparatus is not free from a certain amount of complication, and
demands, moreover, particular care in its construction, experience
having shown that the induction coils must not be equal, but that they
must present resistances combined according to the circuit doing duty.
It should be added that researches have been continued as to the
bodies proper to be employed as microphonic contact, with the result
of bringing out the important fact that the number of substances that
can be put to this use is almost unlimited. The contacts of the Herz
apparatus are now being made of conducting bodies (metals for example)
reduced to powder and conglomerated by chemical means with a sort of
non-conductive cement. The proportion of the elements depends upon the
conductivity of the materials employed, and it alone determines the
microphonic value of the compound, the nature of the elements
apparently having scarcely any influence.

Nor has the speaking condenser been neglected. As regards this,
efforts have seemingly been made toward finding a convenient
arrangement and a regular mode of construction, the good working of
these apparatus being absolutely dependent upon the care with which
they are set up.

In Dr. Herz's opinion, the telephone is not to remain a single
apparatus, varied only as to form, but, on the contrary, must be
actually modified according to the purposes for which it is designed.
He thinks that a telephone operating at great distances must differ
from a city apparatus, and that an instrument for transmitting song
can not be absolutely the same as one for conversational purposes. So
he has endeavored to create types that shall prove appropriate for
these different applications.

* * * * *

DECISION OF THE CONGRESS OF ELECTRICIANS ON THE UNITIES OF
ELECTRIC MEASURES.

For these measures there are adopted the fundamental
unities--centimeter, gramme, second, and this system is briefly
designated by the letters C., G., S. The practical units, the _ohm_ and
the _volt_, will retain their present definitions; the ohm is a
resistance equal to 10^{9} absolute unities (C., G., S.), and the volt
is an electromotive force equal to 10^{8} absolute unities (C., G., S.).
The practical unit of resistance (ohm) will be represented by a column
of mercury of 1 square mm. in section at the temperature of 0 deg.C. An
international commission will be charged with ascertaining for
practice, by means of new experiments, the height of this column of
mercury representing the ohm. The name _ampere_ will be given to the
current produced by the electromotor force of 1 volt in a circuit
whose resistance is 1 ohm. _Coulomb_ is the quantity of electricity
defined by the condition that in the current of an ampere the section
of the conductor is traversed by a coulomb per second. _Farad_ is the
capacity defined by the condition that a coulomb in a condenser, whose
capacity is a farad, establishes a difference of potential of a volt
between the armatures.

* * * * *

SECONDARY BATTERIES.

By J. ROUSSE.

In order to accumulate electricity for the production of light or
motive power, the author has arranged secondary batteries, which
differ from those of M.G. Plante. At the negative pole he uses a sheet
of palladium, which, during the electrolysis, absorbs more than 900
times its volume of hydrogen. At the positive pole he uses a sheet of
lead. The electrolyzed liquid is sulphuric acid at one tenth. This
element is very powerful, even when of small dimensions. Another
secondary element which has also given good results, is formed at the
negative pole of a slender plate of sheet-iron. This plate absorbs
more than 200 times its volume of hydrogen when electrolyzed in a
solution of ammonium sulphate. The positive pole is formed of a plate
of lead, pure or covered with a stratum of litharge, or pure oxide, or
all these substances mixed. These metallic plates are immersed in a
solution containing 50 per cent. of ammonium sulphate. Another
arrangement is at the negative pole, sheet-iron; at the positive pole
a cylinder of ferro-manganese. The electrolyzed liquid contains 40 per
cent. ammonium sulphate.

* * * * *

THE TREATMENT OF QUICKSILVER ORES IN SPAIN.

Though known from remote times, the date of the first opening of the
famous mines of quicksilver of Almaden has not been precisely
determined. Almost all the writers on the subject agree that cinnabar,
from Spain, was already known in the times of Theophrastus, three
hundred years before the Christian era, although there is evidence in
the writings of Vitruvius that they were worked at a still earlier
date, Spanish ore being sent to Rome for the manufacture of vermilion.
Such ore constituted a part of the tribute which Spain paid to Rome
emperors, and there are records of its receipt until the first century
after Christ. The history of Almaden during the reign of the Moors is
so much involved in doubt that some writers deny altogether that the
Arabs worked the deposit; still the very name it now bears, which
means "the mine," and many of the technical terms still in use, give
evidence that they knew and worked that famous deposit. As for their
Christian conquerors, there are stray indications that they extracted
mercury during the twelfth and thirteen centuries. In 1417, Almaden
was given the privileges of a city, and from 1525 to 1645 the working
of mines was contracted for by the wealthy family of Fugger, of
Augsburg, Germany. Since then, the mine has been worked by the state,
though the Rothschilds have controlled the sale of the product.

According to Vitruvius, the works for manufacturing vermilion from
Spanish ore in Rome were situated between the temple of Flora and
Quirino. The ore was dried and treated in furnaces, to remove the
native mercury it contained, and was then ground in iron mortars and
washed. In addition, small quantities of quicksilver and vermilion
were made at Almaden. The ancients describe other methods, among which
Theophrastus speaks of using vinegar, which, however, appears from
modern investigations to have been an erroneous account. Nothing
definite is known concerning the methods of the Moors; we possess only
as a proof that they produced mercury, an account of a quicksilver
fountain in the marvelous palace of Abderrahman III., at
Medina-Zahara, and the works of Rasis, an Arab. The Moors probably
extracted mercury at Almaden, from the eighth to the twelfth century,
by the use of furnaces called "xabecas," which latter, in the
fourteenth century, were still employed by the Christians, who
continued them till the seventeenth century, when German workmen
replaced them by "reverberatory" furnaces, which in turn were
superseded in 1646 by aludel or Bustamente furnaces. There is an
anonymous description of the working with xabecas as practiced at
Almaden in 1543, and later accounts in 1557 and 1565. The ore was put
into egg-shaped vessels with a lid, the mineral being covered over
with ashes. The vessels were packed in a furnace heated with wood,
about 60 pounds being used per pound of quicksilver made. This system
was also applied at the Guancavelica mines, discovered in Peru in
1566, where the xabecas were abandoned in 1633, being replaced by the
furnaces invented by Lope Saavedra Barba, which there were called
"busconiles," while in Spain they were named Bustamente furnaces, and
elsewhere aludel furnaces. They were introduced at Almaden thirteen
years after their first use in Peru by Juan Alfonso de Bustamente,
Barba and his son having been lost at sea on their way to the
Peninsula. In 1876, there were at Almaden, at the works at Buitrones,
twenty such aludel furnaces and two Idria furnaces. D. Luis de la
Escosura y Morrogh, from whose work we take the above notes, has
followed the historical details of the growth of Almaden closely, and
from his account of the method of working in 1878 we take some data:

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