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by a current of electricity and gives out a current of electricity, the
form of the store of energy which it contains is not that of electrical
stress or strain, but that of chemical separation — a form of potential
energy which can be caused, under certain circumstances, to become
kinetic energy in the form of heat. However, the term has now be-
come established, and, being convenient, will probably survive. But
it is to be hoped that the real state of things will be thoroughly and
publicly explained by our leaders of science, so that the use of this
form of words may not cause a confusion in scientific ideas.



" THE ELECTRIC STORAGE OF ENERGY:' 547

From the ease with which secondary batteries can be constructed
of very low resistance, so that they will give for a short time what
practical electricians call a quantity current, they have been for some
time in use for certain special purposes, principally for heating the
wire of the galvanic ecraseur in surgical practice. By a secondary
battery is meant a galvanic battery which, as at first put together, has
no tendency to give a current at all ; but, if a current of electricity be
passed through it of sufficient tension to decompose the fluids which it
contains, will give a cuiTent in the ojjposite direction, due to the recom-
bination of the separated parts of the decomposed fluid. The older
forms consisted of two plates of platinum, preferably coated with
spongy platinum immersed in a weak mixture of sulphuric acid and
water, the action in this case being that the charging current decom-
poses the water (either directly or as the result of a chemical action
set up by decomposing the acid first) into oxygen and hydrogen, which
gases are absorbed by the platinum plates, the oxygen by one and the
hydrogen by the other. When the charging battery is removed, the
secondary battery will give a powerful current until all the oxygen
and hydrogen absorbed by the plates are recombined in the form of
water. It was afterward found that satisfactory results could be got
from plates of lead treated in the same way. Their employment, of
course, reduced the first cost of the apparatus. M. Plante then pro-
duced his secondary battery, in which he obtained great surface, and
consequently low internal resistance, and large current, by rolling into
a spiral form two lead plates separated by pieces of insulating material
placed between them at intervals. He further succeeded in greatly
increasing the time for which the battery would yield a given current,
or its capacity, by adopting an elaborate process for the " formation "
of the plates, which consisted in charging the battery and discharging
it, varying the direction of the exciting current, and leaving the bat-
tery undisturbed between the charging and discharging for gradually
increasing intervals of time. This process added enormously to the
expense of the apparatus, which was also too bulky and heavy.

M. Faure, however, has succeeded in increasing the capacity of the
battery, and getting rid of the long and delicate process of formation.
His battery, like M. Plant^'s, consists of two plates of lead rolled
together into a spiral, but he coats each plate with a thin layer of red-
lead (one of the oxides of that metal), kept in its place by a piece of
absorbent felt, which also keeps the two plates from touching. This
felt is saturated with the weak acid. The effect of the exciting cur-
rent in this case is to deposit spongy lead on one plate and to convert
the red oxide on the other into puce-colored oxide which contains more
oxygen than the red form ; no doubt, also, the spongy lead at a late
period of the charging becomes saturated with hydrogen. ^Vhen the
battery is now set in action, the spongy lead becomes reoxidized to red-
lead and the puce-colored oxide reduced to the same salt.



548 THE POPULAR SCIEXCE MONTHLY.

Sir "William Thomson eai-ly in this month wrote to the "Times,"
pointing out the great advance which this invention had made in the
practical and economical storage of energy. His letter was answered
by Professor Osborne Reynolds, who, with the intention of preventing
the public from being astonished at the storing of so much energy as
one million foot-pounds in apparatus occupying a cubic foot of space
and weighing about seventy-two pounds, proceeded — somewhat irrele-
vantly as we think — to discuss the energy contained in a pound of coal,
and also to complicate the now inevitable controversy by referring to
a totally different problem, the transmission of energy by electrical
means. The controversy thus started has gone on. Sir William Thom-
son, Professor Osborne Reynolds, Professor Ayrton, and Professor
Tyndall, taking part in it.

The question, as far as the public are concerned, is a purely com-
mercial one. As yet, of course, the data of the cost of the battery and
its durability are not yet ascertained ; but, in any future discussion on
the subject, the question of convenience, as well as that of absolute
expense, will have to be taken into consideration. At present we
know that, at some expense, probably not too great, we can utilize a
source of energy of feeble power for many purposes by allowing it to
act for a long time, collecting its energy, and using it quickly, and
that the loss in the process will be but small ; and that, further, if it
be desired to use the electric light temporarily, it can be produced
conveniently, if not economically, by the use of M. Faure's invention.
Sir William Thomson in his first letter points out many practical uses
for the new invention ; we may supplement them by pointing out how
the new secondary battery may be applied conveniently for many pur-
poses. Three ordinary Daniell's cells will charge an element of the
new battery easily, so that, if there be plenty of time for preparation,
we can, by the aid of Faure's batteries, use this cleanly apparatus,
which gives off no noxious fumes and needs but little attention, for all
the purposes for which, up to the present time, we were obliged to em-
ploy the costly and troublesome Grove's or Bunsen's batteries, which
contain violent caustic poisons, and give off irritating and unwhole-
some fumes.

The whole discussion about the mechanical value of coal seems to
us mistaken ; neither Sir William Thomson nor any other physicist
proposes to use the new battery universally, and, at present, our
cheapest way of charging it is by the use of a dynamo-electric ma-
chine, driven by a steam- or gas-engine — i. e., by making use of the
mechanical power of coal and the oxygen of the air ; setting aside, of
course, the exceptional cases where water-power is to be obtained.
Sir William Thomson himself gave, we think, the coup de grace to any
attempt at comparing the relative values of transmitting electric cur-
rents through conductors from the source of energy to a distant sta-
tion where energy is wanted, and conveying energy by exciting Faure's



THE ELECTRIC STORAGE OF ENERGY.



549



batteries at the one place and conveying them to another, when he
wrote in one of his letters of " Professor Reynolds's disappointment
with M. Faure's practical realization of electric storage, because it does
not provide a method of porterage superior to conduction through a
wire." This is " like being disappointed with an invention of improve-
ments in water-cans and water-reservoirs because the best that can be
done in the way of movable water-<?ans and fixed water-reservoirs
will never let the watei'-carrier supersede water-pipes wherever water-
pipes can be laid." If we may venture to extend the great electrician's
metaphor, it is like finding fault with the Great Eastern Railway
Company's service of sea-water brought to London in cans, on the
ground that it is just possible to obtain sea-water by a large main laid
down to the coast, and that such a scheme is now under consideration.
Another valuable property of the new battery is pointed out by Sir
William Thomson. If it were to be used either at a fixed station to
work an electric railway, such as the firm of Siemens have already
brought into practical use, or to be carried on an ordinary carriage to
drive it, the energy developed by the vehicle in running down-hill
would be stored up ready to be used for its propulsion when it again
reached a level or an ascending incline.

In the course of the corresi)ondence Professor Ayrton has again
mentioned the experiments which he and Professor Perry are carrying
out with the view of using coal or coal-gas instead of zinc in a primary
battery. Should he succeed in doing so, we should obtain a source of
energy about ten times cheaper in working than the best-known steam-
engine, and M. Faure's invention may very likely be the means of
making it a commercial success ; for, should Messrs. Ayrton and Perry,
or any other physicist, succeed in making a coal or coal-gas battery
giving a good proportion of the theoretical energy of the coal or gas,
should it have a high internal resistance, it would be difficult to use it
in practice ; but, by the aid of Faure's batteries, in cases where work
was only wanted to be done for a few hours a day, as in the case of
electric lighting, the comparatively feeble current of the primary bat-
tery might be collected and stored for fifteen or sixteen hours, and
then allowed to run out again in the eight or nine hours for which the
source of energy is practically wanted.

The subject of this new secondary battery is one of great scientific
importance. As the writer of a leader in the " Times " points out, it is
by no means unlikely that a similar piece of apparatus may be made of
some metal, and its appropriate salt, which shall be cheaper and lighter
than one of M. Faure's form of similar powers ; at all events, the in-
vention and its results are pretty sure to turn the attention of invent-
ors and investigators toward batteries both secondary and primary —
a branch of inquiry which has for so many years been quite thrown
aside in favor of endeavors to improve the dynamo-machine. Now, a
primary battery is theoretically the most economical artificial source



550 THE POPULAR SCIENCE MONTHLY.

of energy, and it is only the comparatively high cost of the fuel gen-
erally used in these — zinc — which prevents them from being practically
useful. A galvanic battery gives out very nearly the whole energy
due to the chemical combinations which take place in it ; so that it is
hardly too much to say that, were a battery to be employed to drive
an electro-motor, under suitable conditions, we could obtain at least
sixty per cent, of the chemical energy, while the best-known steam-
engine will only give about ten per cent, of the chemical energy of
the coal and air consumed in its furnace. There is thus a large margin
for the first cost of the substance to be consumed in the battery. —
Saturday Review.



SKETCH OF EGBERT WILHELM BUNSEN.

IT has been given to few scientific investigators to be more closely
identified through their discoveries with the practical progress of
the world, to see the fruits of their researches taken up and applied,
made appreciable and beneficial in a greater diversity of lines, than to
Robert Wilhelv Bunsex.

Professor Bunsen was born in Gottingen, March 31, 1811. His fa-
ther was Professor of Theology, and of the Oriental Languages and Lit-
erature, in the University of Gottingen. Having passed through the
course of the gymnasium, he entered the university, devoted himself to
the study of chemistry and physics, and was graduated as a Doctor of
Philosophy in 1830, publishing as his inaugural dissertation, "Enu-
meratio ac Hescriptio Hygrometorum," or, "Enumeration and De-
scription of Hygrometers." He afterward studied in London, Paris,
and Vienna, and became, in 1833, tutor at the University of Gottin-
gen ; in 1836 he was appointed Professor of Chemistry at the Poly-
technic school in Cassel ; took the corresponding chair at the Univer-
sity of Marburg in 1838, and remained there thirteen years ; then
went, in 1851, to Breslau, where he planned a famous working labora-
tory ; and in the next year went to Heidelberg, where he has for
thirty years added to the fame of the great university.

His works in his chosen field have been numerous ; their value,
whether they are measured in relation to the advance of theoretical
science, or as factors in the perfection of the operations of practical
art, has been very great.

In 1834, in conjunction with Berthold, he published a research
upon hydrated peroxide of iron as an antidote to arsenical poison, in-
troducing a remedy which, having become universally known and uni-
versally accessible, may be regarded as a positive addition to the secu-
rity of human life against a certain class of dangers.

He next, in 1835, described some singular compounds which the



SKETCH OF ROBERT WILHELM -BUN SEN. 551

double cya7iides form with ammonia, and the crystals of many of the
double cyanides. In 1837 he began a series of investigations of the
liquid called Cadet's fuming arsenical liquid — the product of heating
a mixture of acetate of potash and white arsenic, discovered in 17G0 —
and brought out the radicle oacodyl, the first of a series of organo-
metallic compounds which exhibit striking analogies with the metals.
These bodies are unpleasant in every way, extremely poisonous, dan-
gerously explosive, highly inflammable, and often, like cacodyl, insuf-
ferably offensive in odor. " It is difficult enough nowadays," says Pro-
fessor Roscoe, in " Nature," " for a chemist to work with such sub-
stances, armed as he is with a knowledge of the danger which he has
to encounter, as also with improved appliances of every kind to assist
him in overcoming his difficulties. But Bunsen, forty years ago, was
a traveler in an unknown and treacherous land, without sign-posts to
guide him, or more assistance on his journey than was furnished by
his own scientific acumen and his unfaltering determination. Nor did
he escape scot-free from such a labor, for, in analyzing the cyanide of
cacodyl, the combustion-tube exploded, Bunsen lost the sight of an
eye, and for weeks lay between life and death, owing to the com-
bined effects of the explosion and the poisonous nature of the vapor.
' This substance,' he writes, ' is extraordinarily poisonous, ^nd for this
reason its preparation and purification can only be carried on in the
open air ; indeed, under these circumstances, it is necessary for the
operator to breathe through a long open tube so as to insure the inspi-
ration of air free from impregnation with any trace of the vapor of
this very volatile compound. If only a few grains of this substance
be allowed to evaporate in a room at the ordinary temperature, the
effect upon any one inspiring the air is that of sudden giddiness and
insensibility, amounting to complete unconsciousness.' "

His next research, published in 1838, was into the chemical changes
which occur in the blast-furnace. In it he showed that at least forty-
two per cent, of the heat evolved from the fuel employed in the fur-
nace was lost, and pointed out that a great economy might be effected
by collecting the combustible gases which escaped, and saving them
for subsequent use. The investigation led to the introduction of im-
proved methods by which the waste gases were utilized, and the cost
of the manufacture of iron was cheapened. The experiments made in
this research were the first in which an accurate method of gas-analysis
was employed, and entitle Bunsen to the credit of having introduced
new and valuable processes in that line to chemistry.

In 1841 he invented the Bunsen battery, an apparatus which has
come into general use as a scientific instrument, and in telegraphy.
Its chief peculiarity is the substitution of carbon for copper or plati-
num as the negative pole.

He visited Iceland in 1846-'4:T, and devoted special attention to the
study of the volcanic phenomena of the island, particularly of the



SS'



THE POPULAR SCIENCE MONTHLY.



geysers. The memoirs which he published on the subjects of these
studies contain the analyses of the volcanic rocks occurring in the
island, which led him to the theory that all the erujitive rocks that
reach the surface consist either of an acid or a basic silicate, or a
mixture of the two, that has been formed and crystallized within the
interior of the earth. Other papers relate to the formation of various
crystalline minerals by the joint action of heat, acid gases, and moist-
ure, on the rocks, and the theory of the geysers.

With the aid of his battery, Bunsen performed the electrolysis of
some of the rarer metals. He began with magnesium, which he pre-
vented from taking fire as soon as it came to the surface by the ingen-
ious device of catching the metal as it rose in a cup, which he formed
in his carbon pole for the purpose, while it was still under the salt.
He then proceeded to the reduction, in conjunction with the late Dr.
Matthiessen, of the alkaline-earth metals, and, with Hillebrand and
Norton, of the metals of the cerium group. Applying metallic mag-
nesium in photo-chemical researches and in comparison of the light of
its flame with that of the sun, he gave the impulse which induced the
undertaking of the commercial preparation of the metal.

Other researches, with which his name is connected, are those of
Kolbe on the electrolysis of the fatty acids, of Kolbe and Frankland
on the isolation of the organic radicals, the explanation of a new
method of determining vapor densities, the investigation and correc-
tion of Dalton and Henry's law of absorption of gases in water, experi-
ments on laws of gaseous diffusion, on applications of gaseous diffusion
in gasometric analysis, on the phenomena of the combustion of gases,
and on the temperature of ignition of gases ; all of which were per-
formed by himself or his pupils, or both.

In analytical chemistry Bunsen has contributed something valuable
to the solution of nearly every important problem, and the best meth-
ods in complicated laboratory processes like those of the analysis of
silicates and mineral waters, methods for the estimation of nitrogen
and sulphur, and a method of volumetric analysis, which, though re-
quiring considerable time for its completion, leaves little to be desired
in point of accuracy and simplicity of manipulation. He introduced a
general method for the separation of the rare earths, by which he for
the first time prepared pure yttria and erbia, and by which .several
new metals have been discovered by other chemists.

In connection with his investigations on the measurements of the
chemical action of light. Professor Roscoe, who was associated with
him, speaks admiringly of his untiring energy and wonderful manipu-
lative power, and says that, in all the difiiculties and perplexities by
which the experimental investigation of such a subject is beset, he
never knew Bunsen discouraged, or at a loss for an expedient by which
an obstacle could be overcome. " Cheerful and self-reliant under the
most depressing circumstances, he never gave up hope, and thus it was



■wr-



SKETCH OF ROBERT WILIIELM BUN SEN. 553

that these somewhat intricate and difficult investigations were brought
to a successful close."

Perhaps none of his labors are more distinguished than the experi-
ments with which he and KirchhoflF laid the foundation of the new
science of spectrum analysis. Among his own most important trans-
actions in this work was the discovery, by means of the spectrum
lines, of the metals caesium and rubidium. He first saw the ca?sium
lines, says Professor Roscoe, in a few milligrammes of the alkaline resi-
due obtained in an analysis of the Durkheim mineral waters, and the
discovery of a second new metal (rubidium) soon followed that of the
first. " So certain was he of the truth of his spectroscopic test, that he
at once set to work to evaporate forty tons of the water, and with 16"5
grammes of the mixed chlorides of the two new metals which he thus
obtained he separated the one metal from the other (no easy task) and
worked out completely their chemical relationship and analogies ; so
much so, that the labors of subsequent experimenters have done little
more than confirm and extend his observations." Another research in
this direction was that on the spark spectra of the metals contained in
cerite and other rare minerals, which he carefully mapped in such a
manner as to make the separation and identification possible.

Bunsen's name is identified with two instruments which he has
devised, which have come into general use in science and the arts ; the
Bunsen gas-burner, which is almost indispensable in laboratories and in
many processes of manufacturing, and is used in many households ;
and the Bunsen pump for accelerating filtration, which those who em-
ploy it could likewise hardly do without.

His published writings are many. Most of them arc special papers
relating to the subjects of investigation that have been already men-
tioned ; others embody more general results of his studies. His visit to
Iceland gave rise to several papers on the various physical, geological,
and volcanic phenomena of the island ; his studies in metals to a num-
ber of monographs ; his spectroscopic studies to " Chemical Analy-
sis based on Observations of the Spectrum," published by him and
Kirchhoff. Besides these, we may mention "Researches on Chemical
Affinity " ; " On a New Volumetric Method " ; and " A Treatise on Gas
Analysis."

Concluding his notice in " Nature," from which we have drawn
liberally in the preparation of this article, Professor Roscoe says :
" The many hundreds of pupils who, during the last half-century, have
been benefited by personal contact with Bunsen will all agree that as
a teacher he is without an equal. Those who enjoy his private friend-
ship regard him with still warmer feelings of affectionate reverence.
All feel that to have known Bunsen is to have known one of the truest
and noblest-hearted of men."



;54



THE POPULAR SCIENCE MONTHLY.



CORRESPONDENCE



THE PHENOMENA OP SPOUTING
SPRINGS.
Messrs. Editors.

DEAR SIRS : On papes 28 and 29 of
the May number of the " Monthly "
there is given an explanation of the fact
that some of the Saratoga springs spout
intermittently, which seems to be entirely
inadequate.

The author says : " As the water flows
into the pocket from the surrounding in-
lets it gradually rises above the outlet,
which results in the compression of the gas
between the roof of the cavity and the sur-
face of the accumulating water ; when the
force of compression reaches its maximum,
it drives the water from the chamber up
through the tube, from which it escapes in
some instances to a distance of thirty feet
in a vertical direction. After the pent-up
water and gas have escaped, the spouting
ceases," etc. There is nothing in the ex-
planation or the diagram referred to in
connection with it that would warrant the
conclusion that gas thus pent up would re-
lieve itself of pressure with a suddenness
sufficient to produce the spouting. On the
contrary, the flow of the spring, under the
conditions stated, ought to be very uniform
instead of intermittent. If the inflowing
water " gradually rises above the outlet,"
the gas in the upper portion of the pocket
would be as gradually compressed, and its
reaction upon the water would tend, pre-
cisely like that of the air in the air-cham-
ber of the common force-pump, to steady
the outflowing stream and to prevent spout-
ing. Very respectfully,

G. H. COLTON.

IIiRAM. Ohio, May 9, 1881.



CONTROL OF PAIN BY MECHANICAL
VIBRATIONS.
Messrs. Editors.

As the article entitled " Mechanical Vi-
bration as a Remedy in Neuralgia," in the
Miscellany Department of the June number
of " The Popular Science Monthly," is likely
to elicit further inquiry, on account of the
wellnigh universal interest in the conclu-
sions set forth, I may be pardoned for of-
fering a few facts pertinent to the same
subject.

The control of neuralgia, and indeed of
pain in almost any chronic form, by mechani-
cal vibration, as asserted by M. Boudet de
Paris and Dr. Granville, has been so thor-



oughly demonstrated as no longer to admit
of question, and should be considered as
well settled as any princi[)le in medicine.
Nor is the control of this agent over the
nerves limited to pathological conditions.
It is an anaesthetic as powerful as simple.
Under its influence I have repeatedly wit-
nessed such injury to the skin and flesh as



Online LibraryD. S. (David Samuel) MargoliouthThe Popular science monthly (Volume 19) → online text (page 68 of 110)