-
FIRST 'GLIMPSB OF THE ELECTRIC LIGHT.
THE
AGE OF ELECTRICITY
From Amber-Soul to Telephone
BY
PARK BENJAMIN, PH.D.
Ariel and all his quality."
The Tempest.
NEW YORK
CHARLES SCRIBNER'S SONS
1889
COPYRIGHT, 1886, BY
CHARLES SCRIBNER'S SONS.
PRESS OF BERWICK & SMITH,
BOSTON, MASS.
PREFACE.
THIS little work is not a technical treatise, nor is it
addressed in any wise to the professional electrician. It
is simply an effort to present the leading principles of
electrical science, their more important applications, and
of these last the stories, in a plain and, it is hoped, a
readable way. There are no formulas in the book.
Only such technical terms as have now made their way
into every-day use are employed ; and the more strictly
scientific branches of the subject, such as measurement,
testing, etc., are omitted altogether.
It is a singular fact, that probably not an electrical
invention of major importance has ever been made, but
that the honor of its origin has been claimed by more
than one person. There was a dispute over the Leyden-
jar, and a long and acrimonious, controversy about the
galvanic battery. Franklin's discovery of the identity
of lightning and electricity is still claimed for French
philosophers; the title of u the father of the telegraph'*
is given to Wheatstone in England, and to Morse in the
United States, although to neither of these inventors, but
to Joseph Henry, the lasting gratitude of the world be-
iii
136
iv PEE FACE.
longs ; Dal Negro, McGawley, Page, and Henry have all
been named each as the first and only original inventor
of the electro-motor ; Davidson, Davenport, Lillie, Jacobi,
Page, and Hall are each credited with the invention of
the electric railway ; Page and Ruhmkorff dispute the
invention of the induction coil ; Jordan and Spenser, and
others beside, waged a bitter war over their respective
claims to the discovery of the electro-deposition of
metals. Plaute, as the inventor of the secondary bat-
tery, becomes deposed by the prior work of Ritter ;
Gramme finds his ring armature in the dynamo antici-
pated by Pacinotti. Professor Hughes had no sooner
announced his microphone than Mr. Edison claimed it.
Hjorth, Varley, Siemens, and Wheatstone share the
honor of originating the self-exciting dynamo. Contests
are still in existence over the incandescent electric lamp,
with Edison and Swan and Sawyer in the front. And as
for the present telephone war, the greatest conflict of
all, this is fast becoming not merely a question of
whether Reis or Drawbaugh or Gray or Bell or Dolbear,
or any other of the numerous claimants, was or was not
the inventor of the electrical transmission of speech, but
a national issue involving the rights of the people against
corporate monopoly, and perhaps also in some degree the
integrity of our patent system.
Where it has been necessary to deal with these disputed
matters, the author has endeavored to present the facts
without partisan bias. The reader will, no doubt, notice
that the names of many electrical inventors now celebrated
PREFACE. V
are not mentioned, or but briefly referred to. This is
because their inventions when theirs are but improve-
ments in details remarkable rather for quantity than
quality ; or else require descriptions too technical for
these pages.
For the most part, all historical data have been gath-
ered from publications contemporary with the date of first
production of the several discoveries and inventions, and
in many cases from the original writings of the inventors
and discoverers themselves. As for sources of informa-
tion in general, the author can only say that there lie
before him, at this writing, the first book on electricity
ever written in the English language, Robert Boyle's
modest little pamphlet of 1675, and the latest numbers
of the electrical journals, fresh from the press ; and that
he has ranged throughout the whole field of electrical
literature anywhere and everywhere, in the most arbitrary
manner, between these limits.
In a few instances, however, it would be ungracious
to deny special credit : and therefore acknowledgment is
made for aid from Prof. S. P. Thomson's excellent " Ele-
mentary Lessons in Electricity and Magnetism," Mr. J.
H.Gordon's ''Treatise on Electric Lighting," Messrs.
Preece & Sivewright's "Telegraphy," and Prof. J. T.
Sprague's latest and best treatise on " Electricity," among
modern works ; and from Dr. Priestley's grand "History
of Electricity," among those of the last century. Free
use has been made of the files of "The Scientific Amer-
ican," of " The Journal of the Franklin Institute," and
vi PREFACE.
the special electrical journals of this country; and of
those of " Engineering " and "The Mechanics' Maga-
zine," and electrical periodicals abroad. In the prepara-
tion of the chapter on Telegraphy, Mr. Alfred M. A.
Beale has rendered valuable assistance ; and several of
the engravings in the chapter on Galvanic Batteries have
been kindly supplied by Messrs. John Wiley & Sons, from
Niaudet's work on that subject.
NEW YORK, May 15, 1886.
CONTENTS.
CHAPTER PAGE
I. THE MYTH OF THE AMBER SOUL .... 1
II. THE DISCOVERIES OF THE EARLY EXPERI-
MENTERS 7
III. THE CAGING OF THE LIGHTNING .... 15
IV. ELECTRICITY IN HARNESS 28
V. THE GALVANIC BATTERY, AND THE CONVERSION
OF CHEMICAL ENERGY INTO ELECTRICAL
ENERGY 35
VI. THE ELECTRO-MAGNET, AND THE CONVERSION OF
ELECTRICITY INTO MAGNETISM .... 68
VII. THE DYNAMO-ELECTRIC MACHINE, AND THE CON-
VERSION OF MAGNETISM AND MECHANICAL
MOTION INTO ELECTRICITY 88
VIII. THE ELECTRIC LIGHT. THE CONVERSION OF
ELECTRICAL ENERGY INTO HEAT AND LIGHT . 118
IX. ELECTRO-MOTORS, AND THE CONVERSION OF ELEC-
TRICAL ENERGY INTO MECHANICAL ENERGY . 152
X. ELECTROLYSIS. ELECTRO-METALLURGY AND THE
STORAGE-BATTERY 182
vU
Vlll CONTENTS.
CHAPTEK PAGE
XI. THE ELECTRIC TELEGRAPH 208
XII. THE SPEAKING TELEPHONE 272
XIII. THE INDUCTION COIL, AND POWERFUL ELECTRIC
DISCHARGES 325
XIV. THE APPLICATIONS OF ELECTRICITY TO MEDICINE,
WAR, RAILWAYS, TIME, Music, ETC. . , 333
THE AGE OF ELECTRICITY.
THE AGE OF ELECTRICITY.
CHAPTER I.
THE MYTH OF THE AMBER SOUL.
SOME years ago, there was found in a tomb in Egypt an
alabaster vase, the sole contents of which were a few dry,
hard, and blackened seeds. These the discoverer brought
to England, and planted them in the rich loam of his
garden, more from curiosity than from any belief that
they actually would germinate. To his surprise, in due
time fresh young sprouts appeared which grew and flour-
ished ; and finally, in the harvest season, ears of wheat,
as many as fifteen or twenty from a single stalk, were
gathered. So it was proved that despite their having
been sealed in the ancient tomb for nearly three thousand
years, the seeds, to all appearances as lifeless as the huge
stones which surrounded them, had retained all their vi-
tality ; and we might imagine, that if, during these many
centuries, wheat had disappeared from among the earth's
products, it would have been possible in time from these
few grains to cause all the lands again to teem with golden
harvest.
A suggestive parallel exists between the history of the
wheat kernel shut up in the Egyptian tomb, and that
1
2 THE AGE OF ELECTRICITY.
of a mere atom of human knowledge which for nearly
as long a period remained as unfruitful and buried in
the minds of men. Indeed, among all the wonders of
that strangest manifestation of the energy which pervades
all nature, and which we call electricity, there is nothing
more remarkable and more impressive than the growth of
the single, simple, and uncoordinated fact, namely, that
amber, when rubbed, behaves in a curious way, into the
great science which underlies the telegraph, the electric
light, and the telephone.
How rapid this growth has been, is within the remem-
brance of most of us. Of the vastness of its extent, we
have on all sides ocular proof. What farther progress
may be made, no one can predict. Conjecture too often
outstrips reason : impossibilities and impracticabilities be-
come confounded ; and each new advance only reveals a
new horizon, beyond which who knows what fields may
lie?
There is a familiar old Greek legend, which tells how
Phaethon, son of the Sun, once rashly undertook to drive
his father's chariot through the heavens. As the story
goes, the horses despised their driver, and refused to be
guided by him, so that the blazing chariot approached too
near the earth, and living things thereon were burned.
Then Jupiter, very wroth, hurled his thunderbolt, and
killed the charioteer. When his body, which fell to the
earth, was found by his sisters, the Heliades, they mourned
long and bitterly, until at last the Father of Gods, pitying
them, changed them into ever-sighing poplars, and their
tears into translucent amber.
And so, perhaps because of this legend, the Greeks
looked upon amber with superstitious reverence, and even
thought that it had a soul. For when it was rubbed, it
seemed to live, and to exercise an attraction upon other
THE MYTH OF THE AMBEE SOUL. 3
things distant from it. They likened it to the magnet ; and
yet knew it to be different from the loadstone, for in the
latter the property of drawing other things to itself was
inherent, whereas amber could only be brought into life and
activity. It was easier to conceive how a natural body
might have its own peculiar properties, however incom-
prehensible, just as a tree might grow, than to ima-
gine how this strange substance, at one time inert, could be
brought to life by the same process which would restore
vitality to a limb benumbed by cold. Thus they specu-
lated upon an amber life, and an amber soul as its
essence.
In the light of our modern knowledge we might perhaps
trace farther the chain of ancient speculation. Jupiter's
thunderbolt was but another name for the lightning-stroke,
and the sequence of events following the tragedy resulted
in amber. From amber we can reproduce the lightning in
miniature ; so that by some stretch of the imagination
we might suppose that the Greeks had a crude concep-
tion of electrical storage, and traced the manifestations
derived from amber to imprisoned lightning. It is quite
certain, however, that those who were initiated in the
mystic rites of the ancients clearly understood many of
the principles of electricity and magnetism which have been
re-discovered within recent years. Professor Schweigger
considers that the Vestal fire was electrical, and points
out that the "twin fires from the electrical spark are
sketched in a very natural manner in the representations
of Castor and Pollux on ancient coins." So also it is
believed that the ancients knew of the therapeutic effects
of electrical currents, and the polarity of electricity and
magnetism.
Although these mysteries were jealously guarded from
public comprehension, and hence all knowledge of them
4 THE AGE OF ELECTRICITY.
died with its possessors, Ennemoser in his History of
Magic says that "it was not forbidden to make known
every thing : some things were explained to the uniniti-
ated. For instance, the uninitiated were made acquainted
with amber, and with its property when rubbed." We
can conjecture that the uninitiated were thus favored be-
cause in any event they would be reasonably certain to
find out the phenomenon for themselves. Amber was
constantly worn as an amulet and in jewellery ; and the
friction of garments would produce sufficient excitation
to cause it to attract lint or other fine particles which
would dim its lustre, and so draw the wearer's atten-
tion. And of course, inasmuch as explanations natur-
ally would be sought, it perhaps suited the policy of the
magi to attribute the fact to the supernatural qualities of
the substance. It is remarkable, however, to note that
the knowledge of the electrical properties of amber sur-
vived for centuries, doubtless, because the whole world had
it, while the great mass of facts which the priests and magi
collected fell into utter oblivion ; and that this is exactly
the reverse of the conditions under which the great bulk of
learning which was handed down from antiquity through
the dark ages maintained its existence. The mediaeval
monks and scholars treasured their knowledge of natural
science while dwelling amid rude and barbarous peoples,
in order that it might be handed down to posterity. The
Greek and Egyptian priests, on the other hand, in the
midst of the most cultivated peoples that had ever lived,
surrounded their discoveries with every sort of misleading
myth, until finally they faded into oblivion.
As the world grew older, here and there in the writings
of the philosophers reference to this strange property of
amber appears. Thales (600 B.C.) mentions it, and,
being the earliest writer who has been found to do so, is
THE MYTH OF THE AMBER SOUL. 5
too often credited with the discovery. Some three hun-
dred years later Theophrastus notes that another body,
called lyncurium, supposed to be either tourmaline, or
the hyacinth, which looks like amber, acts in like man-
ner ; and Pliny (B.C. 70) refers to the same.
Then there is a great gap of sixteen centuries, with
hardly a published word to show that all had not been for-
gotten. Beckmann quotes from an edition of John Sera-
piou, " Lib. de simplicibus medicinis," published in 1531,
a reference to a red stone, " Hager Albuzedi." found in
the East, " which when strongly rubbed against the hair of
the head attracts chaff as the magnet does iron ; " and per-
haps other references exist. The fact however, remained,
and was supposed to be peculiar to amber. No one
attempted to explain it. The superstition of the amber
soul faded and was forgotten. The phenomena which
Pliny called the "awful mysteries of nature" puzzled
men's souls ; yet to inquire into them suggested only
impiety. " A star," says Seneca, "settled on the lance
of Gylippus as he was sailing to Syracuse ; and spears
have seemed to be on fire in the Roman camp." "About
that time," Caesar records, " there was a very extraordinary
appearance in the army of Caesar. In the mouth of Feb-
ruary, about the second watch of the night, there suddenly
arose a thick cloud, followed by a shower of stones ; and
the same night, the points of the spears belonging to the
fifth legion seemed to take fire." Aristotle, Pliny, Oppian,
and Claudius were fully acquainted with the shocks pro-
duced by the torpedo. Eustathius, who lived in the fourth
century of the Christian era, says that a freedman of Tibe-
rius was cured of the gout by a shock from this fish ; the
first-known instance of the application of electricity to
medical purposes, and if authentic much more successful
than its application in modern times. The same authority
6 THE AGE OF ELECTRICITY.
asserts that Wolimer, king of the Goths, was able to emit
sparks from his body. But all these were wonders beyond
human ken and control. The whole science lay in the
knowledge of the single fact, that excited amber attracted
certain light bodies.
DISCOVERIES OF EAELY EXPERIMENTERS.
CHAPTER II.
THE DISCOVERIES OF THE EARLY EXPERIMENTERS.
IN the year 1GOO Dr. William Gilbert of London, a
surgeon to Queen Elizabeth, published his famous work
" De Magnete," and then made known that the attractive
property of amber, when rubbed, was not inherent to that
substance, but existed in some twenty other bodies, such as
the precious stones, glass, sealing-wax, sulphur, and resin.
Inasmuch as these all acted like amber, Gilbert called
them electrics; and he described the peculiar phenomenon
itself as electricity, deriving the term from the Greek
word for amber, elektron. It has recently been pointed
out, that the Elektra of the Homeric legends possesses
certain qualities that would tend to suggest that she is
the personification of lightning, and that the resemblance
between the names Elektra and elektron cannot be ac-
cidental. Whether, however, Gilbert was thus antici-
pated or not, is immaterial. The publication of his work
marks the true beginning of the progress of the science ;
and its immediate effect was to incite philosophers every-
where to efforts to extend his list of electrics.
Singularly enough, this remarkable treatise was severely
condemned by Bacon in the " Novum Organum." Not
content with singling it out for citation as a peculiarly
striking instance of inconclusive reasoning, and of truth
distorted by " preconceived fancies/' he elsewhere alludes
8 THE AGE OF ELECTRICITY.
to the " electric energy concerning which Gilbert has told
so many fables." A century and a half later, as we shall
see, these " fables " assumed the form of realities. The
sweeping censure of so high an authority seems to have
produced its natural effect, and may have had much to do
in materially retarding the development of the infant
science.
To Gilbert's category, Cabaeus, an Italian Jesuit, added
the gums, white wax, and gypsum. Then Robert Boyle
got the first glimpse (it was no more) of the electric light,
by noting that a diamond when rubbed became luminous
in the dark. Then Otto von Guericke, burgomaster of
Magdeburg, and inventor of the air-pump, discovered that
electricity was manifested by repulsion as well as by at-
traction, and that a globe of sulphur after attracting a
feather repelled the same until the feather had again been
placed in contact with some other substance.
Guericke contrived an apparatus for rotating his sulphur
globe, and succeeded in obtaining sparks therefrom ; and
that was the real genesis of the electric light. By this
time the attention of the scientific world was aroused,
and other philosophers joined in the investigation of the
curious phenomena. Boyle, then contemporary with von
Guericke, proved that a suspended piece of rubbed am-
ber, which attracted other bodies to itself, was in turn
attracted by a body brought near it ; and he even went
so far as to maintain that an electrified body threw out
an invisible glutinous substance which laid hold of light
bodies, and, returning to the source from which it ema-
nated, carried them along with it. Sir Isaac Newton, by
rubbing a flat glass, caused light bodies to jump between
it and the table, and noticed that electric attraction was
thus transmitted through the glass. A sea-captain named
Grofton excited the dismay of mariners by asserting that
DISCOVERIES OF EARLY EXPERIMENTERS. 9
a violent thunder-storm had reversed the polarity of the
compass-needles aboard his vessel. Dr. Wall, in 1708,
made experiments with large pieces of amber rubbed by
wool, and found that " a prodigious number of little crack-
lings " was produced, each accompanied by a flash of light.
" This light and crackling," says Dr. Wall, " seem in
some degree to represent thunder and lightning."
Probably every one has observed the peculiar crackling
which follows combing of the hair during dry, cold weather,
and the tendency of the " knotted and combined locks to
part" under the electrical excitement following the rub-
bing of the comb.
Robert Boyle appears to have discovered this ; and he
wrote in 1G75 this amusing description intended to be
perfectly serious and scientific of his original experi-
ment on "Locks (false) worn by two very Fair Ladies
that you know:" "For at some times I observed that
they could not keep their Locks from flying to their Cheeks
and (though neither of them made any use or had any
need of Painting) from sticking there. When one of these
Beauties first shew'd me this Experiment, I turn'd it into
a Complemental Raillery, as suspecting there might be
some trick in it, though I after saw the same thing happen
to others Locks too. But as she is no ordinary Virtuoso.,
she very ingeniously remov'd my suspicions and (as I re-
quested) gave me leave to satisfie myself further by desir-
ing her to hold her warm hand at a convenient distance
from one of these Locks taken off and held in the air. For
as soon as she did this, the lower end of the Lock which
was free applied itself presently to her hand : which seemed
the most strange because so great a multitude of Hair
would not have been easily attracted by an ordinary
Electrical Body."
In this way, for more than a hundred and twenty years
10 THE AGE OF ELECTRICITY.
after the publication of Gilbert's work, and at long inter-
vals, isolated phenomena were observed, and a fact here
and there gathered. A variety of curious theories had
been formulated. Cabseus, in the quaint language of
Robert Boyle, "thinks the drawing of light bodies by
Jet, Amber, etc., may be accounted for by supposing that
the steams that issue, or if I may so speak, sally, out of
Amber when heated by rubbing, discuss and expell the
neighbouring air ; " and that these " Electrical Steams . . .
shrinking back swiftly enough to the Amber do in their
returns bring along with them such light bodies as they
meet with in their way." Then there was the hypothesis
"proposed by that Ingenious Gentleman Sir Kenelm Digby,
and embraced by the very Learned Dr. Browne," that
" Rayes or Files of unctuous steams " were emitted, which
became cooled and condensed, and so "shrinking" back,
carried light bodies with them. Newton supposed that
the excited body emitted an elastic fluid which penetrated
glass ; and Gravesande and other writers maintained that
electricity was fire, which, being inherent to all bodies,
became manifest by friction.
In 1720 Stephen Gray, a Charterhouse pensioner, that
"most meritorious philosopher" as Tyndall calls him,
began a series of investigations which terminated only
when he died sixteen years later.
In 1729 Gray experimented with a glass tube stopped
by a cork. When the tube was rubbed, the cork attracted
light bodies. Gray states that he was "much surprised "
at this, and he "concluded that there was certainly an
attractive virtue communicated to the cork." " This,"
says Professor Tyndall, " was the starting-point of our
knowledge of electric conduction ; ' ' and the same author-
ity gives the following account of Gray's most remarkable
experiment :
DISCOVERIES OF EARLY EXPERIMENTERS. 11
"He suspended a long hempen line horizontally by
loops of pack-thread, but failed to transmit through it the
electric power. He then suspended it by loops of silk,
and succeeded in sending the ' attractive virtue ' through
seven hundred and sixty-five feet of thread. He at first
thought that the silk was effectual because it was thin ;
but on replacing a broken silk loop by a still thinner wire,
he obtained no action. Finally he came to the conclusion
that his loops were effectual, not because they were thin,
but because they were silk. This was the starting-point
of our knowledge of insulation."
Gray died in the midst of his work ; and the report of
his last experiments was dictated by him from his death-
bed, to the secretary of the Royal Society.
In 1733 Dufay, a French physicist, while experimenting
with an electrically excited body, found that a piece of
gold-leaf floating in the air was repelled if the excited
substance was glass, and attracted if the excited sub-
stance was resin. And hence he recognized two kinds of
electricity, which were for a long time known respectively
as vitreous and resinous. There is no such real distinc-
tion, because by changing the rubbing material the elec-
tricity of resin can be obtained upon glass, and vice versa.
But what we now know as plus or positive electricity is
that produced by rubbing glass with silk ; and negative
or minus electricity, that due to the rubbing of resin with
flannel.
The electrical apparatus of 1730 was, as may readily be
imagined, very crude. We reproduce from Dr. Grave-
sande's treatise of that date, the accompanying represen-
tation of an electrical machine of the period. It consists
simply of a glass globe G, supported on tubes which are
revolved by a belt from the - large pulley R, which is
rotated by the handle M. One of the tubes has an
12
THE AGE OF ELECTRICITY.
open end, and is provided with a stop-cock E. Through
this tube the air can be exhausted from the interior of
Fig. 1. Electrical Machine of 1730.
the globe. Over the globe is an arch of brass wire from
which are suspended threads. The hand is used as a
DISCOVERIES OF EARLY EXPERIMENTERS. 13
rubber, and the machine as shown is intended to demon-
strate the following experiment :
" Whirl the globe, and apply the hand, and immediately
the threads will be moved irregularly by the agitation of
the air ; but when the glass is heated by the attrition, all
the threads are directed toward the centre of the globe,
as may be seen in the figure ; and, if the hand be applied
a little on one side, or nearer the pole of the globe,
the threads will be directed toward that point of the axis
which is tinder the hand. If the air be drawn out of the
globe, this whole effect ceases."
This machine had a very disagreeable habit of explod-
ing by reason of the expansion of the air within the glass
globe, caused by the heating of the latter by friction.
We have already stated that Otto von Guericke made
his electrical machine from a globe of sulphur. For the
sulphur globe, Hawksbee and Winkler substituted the
glass globe represented in the engraving. The prime
conductor, at first a tin tube supported by resin or sus-
pended by silk, and nearly equal in importance to the
glass insulator which is to be excited, was not invented
until ten years after by Boze of Wittenberg (1741) ; and
Winkler of Leipsic suggested a fixed cushion instead of
the human hand as a rubber. Still later Gordon of Erfurt
substituted a glass cylinder for the globe; and in 1760
Planta introduced the circular plate of glass still used.
In the year 1745 a discovery was made, which in point
'of importance overshadowed every thing that had been
previously accomplished. And it seems as if the time
had come for some great advance. The electrical machine
had reached a form in which, with little variation, it has
since remained. Large pieces of electrical material had
been used to produce manifestations sufficiently potent to
suggest thunder and lightning ; and certain properties of
14 THE AGE OF ELECTRICITY.
the electric fluid, or aura, or whatever it might be, had been
more or less perfectly recognized. Yet, after all, what
practical advantage to mankind had been gained ? Curious
things had been developed, as wonderful as any thing the
conjurers could do ; but beyond gratifying the natural
taste for the marvellous, and furnishing food for the
speculations and material for the lecture-room experi-
ments of a few philosophers, all that had been done had
added nothing, so far as then appeared, to. that knowledge
which directly contributes to human welfare.
THE CAGING OF THE LIGHTNING. 15
CHAPTER III.
THE CAGING OF THE LIGHTNING.
ON Oct. 11, 1745, Dean von Kleist of the cathedral of
Camin, in Germany, made an experiment which on the
following 4th of November he describes in a letter to Dr.
Lieberkuhn of Berlin, in the following terms :
" When a nail or a piece of brass wire is put into a
small apothecaries' phial and electrified, remarkable effects
follow ; but the phial must be very dry and warm. I com-
monly rub it over beforehand with a finger on which I put
some powdered chalk. If a little mercury or a few drops
of spirits of wine be put into it, the experiment succeeds
the better. As soon as this phial and nail are removed
from the electrifying glass, or the prime conductor to
which it hath been exposed is taken away, it throws out
a pencil of flame so long that with this burning machine
in my hand I have taken about sixty steps in walking
about my room ; when it is electrified strongly I can take
it into another room, and then fire spirits of wine with it.
If while it is electrifying I put my finger or a piece of gold
which I hold in my hand to the nail, I receive a shock
which stuns my arms and shoulders."
This was the first announcement of the possibility of
accumulating electricity.
In the following year Cunseus of Leyden made substan-
tially the same discovery. It caused great wonder and
16 THE AGE OF ELECTRICITY.
dread, which arose chiefly from the excited imagination.
Musscheubroek felt the shock, and declared in a letter to
a friend, that he would not take a second one for the crown
of France. Bleeding at the nose, ardent fever, a heavi-
ness of head which endured for days, were all ascribed to
the shock. Boze, on the other hand, seems to have coveted
electrical martyrdom ; for he is said to have expressed a
wish to die by the electric shock, " so that an account of
his death might furnish an article for the Memoirs of the
French Academy of Sciences."
Winkler, his coadjutor in the improvement of the elec-
trical machine, " suffered great convulsions through his
body," which " put his blood into agitation ; " and his wife,
who took the shock twice, was rendered so weak by it that
she could hardly walk. Nothing daunted, this adventur-
ous lady (who shall say whether from scientific interest or
feminine curiosity?) persisted in being shocked for the
third time ; and then her previous ailments were augmented
by the nosebleed.
After the philosophers had got through administering
shocks to themselves and to their immediate relatives, and
had recovered in some measure their mental as well as per-
sonal equilibrium, and it might equally well be added,
their moral balance, for as a matter of fact their reports
as to the force of the shock and its attendant disastrous
effects were all more or less grossly exaggerated, they
sot about seeing what this extraordinary discovery really
amounted to. What Von Kleist actually did was simply
to insert a nail through a cork into a phial into which he
poured a little mercury, spirits, or water. Why this sim-
ple contrivance should produce the observed effects, Von
Kleist did not know ; but Cunseus and the other Leyden
philosophers solved the problem, and in this way Von
Kleist's apparatus came to be known as the Leydeu-jar,
THE CAGING OF THE LIGHTNING. 17
Subsequently the jar was constructed by Dr. Bevis in the
form shown in Fig. 2, which is that which it has ever since
had. In charging the jar, the outer coating, usually of tin-
foil, is connected with the earth ;
and the inner coating of the same
material, by means of the central
wire and knob, receives the sparks
from an electric machine. The
positive electricity from a glass
electrical machine, passing to the
inner coating, acts inductively
across the glass upon the outer Fig . 2 .
coating, and is supposed to at-
tract only its negative electricity, while the positive elec-
tricity there resident is repelled into the earth, with which
the outer coating is connected. In this way two opposite
and mutually attracting electricities are separated by the
glass. But if a path be provided by which these two
electricities can flow to one another, they will do so, and
the jar will be discharged. If the outer coating be grasped
with one hand, and the knuckle of the other hand be pre-
sented to the knob of the jar, the body will then form a
conducting path over which this flow can take place ; a
bright spark will pass between the knob and the knuckle,
with a sharp report ; and at the same moment a convulsive
"shock" will be communicated to the muscles of the
wrists, elbows, and shoulders.
In Von Kleist's apparatus, the water or mercury formed
the inner conducting coating, and his hand, grasping the
bottle, the outer coating which was thus connected to earth
through his body. When he touched the nail with his dis-
engaged hand, he completed the path between the inner
and outer coatings through his body, and thus received the
shock.
18 THE AGE OF ELECTEIC1TY.
Scientists everywhere now began to investigate this
phenomenon. Graham caused a number of persons to lay
hold of the same metal plate, which was connected with
the outer coating of a charged Leyden-jar, and also to
grasp a rod by which the jar was discharged. The shock
divided itself equally among them. Abbe" Nollet procured
a detail of one hundred and eighty soldiers, stood them up
in a line, and sent shocks through the whole battalion, a
significant commentary on the strength of military disci-
pline, which could make ignorant men face manifestations
which disconcerted and agitated the philosophers them-
selves. But the monks outdid the soldiers : seven hundred
and fifty Carthusians formed a line 5,400 feet long, an iron
wire extending between each two persons ; when the abb6
caused the discharge, the entire company of ecclesiastics
"gave a sudden spring, and sustained the shock at the
same instant." Apparatus was constructed so that large
quantities of electricity could be accumulated, and results
hitherto unexpected were obtained. Dr. Watson made
experiments to discover through how great a distance the
electric shock could be propagated, and in 1747 conveyed
it across the River Thames at Westminster Bridge, and
finally concluded that " the velocity of the electric matter
in passing through a wire 12,276 feet in length is instan-
taneous." Other investigators killed small animals and
birds with powerful discharges from the Leyden-jar.
In 1745 Mr. Peter Collinson of the Royal Society sent
a jar to the Library Society of Philadelphia, with instruc-
tions how to use it. This fell into the hands of Benjamin
Franklin, who at once began a series of electrical ex-
periments. On March 28, 1747, Franklin began his
famous letters to Collinson, regarding which Priestley
says, " Nothing was ever written upon the subject of
electricity which was more generally read and admired in
THE CAGING OF THE LIGHTNING. 19
all parts of Europe. It is not easy to say whether we
are most pleased with the simplicity and perspicuity with
which they are written, the modesty with which the author
proposes every hypothesis of his own, or the noble frank-
ness with which he relates his mistakes when they are
corrected by subsequent experiments." In these letters
he propounded the single-fluid theory of electricity, and
referred all electric phenomena to its accumulation in
bodies in quantities more than their natural share, or to
its being withdrawn from them so as to leave them minus
their proper portion. A body having more than its natural
quantity, he regarded as electrified positively, or plus; and
one having less, as electrified negatively or minus. On
this theory he explained the action of the Leyden-jar as
it has already been explained above ; and he conceived
the idea of connecting together a number of Leyden-jars,
the outer coating of each being connected to the outer
coating of the next succeeding one, and thus produced
his famous "cascade battery," in which the strength
of the shock was enormously increased. He also dis-
covered that the connecting coatings of the Le} 7 den-jar
"served only, like the armature of the loadstone, to unite
the forces of the several parts, and bring them at once to
any point desired ; ' ' and that the electricity in fact existed
only upon the glass. One of Franklin's letters to Collin-
son is celebrated for his quaintly humorous proposition
of an ; ' electric feast " to be held on the banks of the
Schuylkill. Whether this ever occurred, is questionable ;
but Franklin's description of it is well worth quoting.
" The hot weather coming on," he says, " when electrical
experiments are not so agreeable, it is proposed to put
an end to them for this season, somewhat humorously,
in a party of pleasure on the banks of the Schuylkill.
Spirits, at the same time, are to be fired by a spark sent
20 THE AGE OF ELECTEICITY.
from side to side through the river without any other con-
ductor than the water ; an experiment which we some time
since performed to the amazement of many. A turkey
is to be killed for our dinner by the electric shock, and
roasted by the electric jack before a fire kindled by the
electric bottle; when the healths of all the famous elec-
tricians of .England. Holland, France, and Germany are
to be drunk in electrified bumpers, under a discharge of
guns from the electrical battery." If Franklin's proposal
bordered on the absurd or grotesque, it proves how near
the ridiculous in thought may be to the sublime ; for at
that same period he was formulating the speculations
which ultimately culminated in one of the most audacious
yet most brilliantly successful experiments ever made by
man. More than forty years before, Wall had compared
the crackling from his rubbed amber to thunder and light-
ning ; Nollet in France had not long before quaintly
said, " If any one should take upon him to prove from a
well-connected comparison of phenomena, that thunder is
in the hands of Nature what electricity is in ours, and
that the wonders which we now exhibit at our pleasure
are little imitations of these great effects which frighten
us ; I avow that this idea, if it was well supported, would
give me a great deal of pleasure." Meanwhile the facts
derived from experiment were rapidly multiplying, which
showed the similarity between the powerful sparks of the
Leyden battery and the lightning flash. The exag-
gerated accounts of Musschenbroek and others who had
received the shocks went to prove that increase in force
or strength would cause death. Experiments upon birds
and small animals did produce death as sudden as that
due to the lightning stroke. Franklin himself was twice
struck senseless by shocks ; and he afterwards sent the
discharge of two large jars through six robust men, who
THE CAGING OF THE LIGHTNING. 21
fell to the ground, and got up again without knowing
what had happened, neither feeling nor hearing the dis-
charge.
While all these facts convinced Franklin of the identity
of lightning and electricity, they demonstrated at the
same time to him the imminent danger which must attend
any experiment which would serve as proof. One scarcely
knows which to admire most, the lucid reasoning wherein
he states his convictions to Collinson, or the cool courage
with which he faced not only possible death, but the
ridicule of the world, which would be heaped upon his
memory in event of failure. The result would brand him
as a madman and a suicide, or raise him to the topmost
pinnacle of human fame. The account given by Dr.
Stuber of Philadelphia, an intimate personal friend of
Franklin, and published in one of the earliest editions of
the works of the great philosopher, is as follows :
"The plan which he had originally proposed was to
erect on some high tower, or other elevated place, a sen-
try-box, from which should rise a pointed iron rod, insu-
lated by being fixed in a cake of resin. Electrified clouds
passing over this would, he conceived, impart to it a
portion of their electricity, which would be rendered evi-
dent to the senses by sparks being emitted when a key,
a knuckle, or other conductor was presented to it. Phila-
delphia at this time offered no opportunity of trying an
experiment of this kind. Whilst Franklin was waiting
for the erection of a spire, it occurred to him that he
might have more ready access to the region of clouds by
means of a common kite. He prepared one by attaching
two cross-sticks to a silk handkerchief, which would not
suffer so much from the rain as paper. To his upright
stick was fixed an iron point. The string was, as usual,
of hemp, except the lower end which was silk. Where
22 THE AGE OF ELECTEICITY.
the hempen string terminated, a key was fastened. With
this apparatus, on the appearance of a thunder-gust ap-
proaching, he went into the common, accompanied by his
son, to whom alone he communicated his intentions, well
knowing the ridicule which, too generally for the interest
of science, awaits unsuccessful experiments in philosophy.
He placed himself under a shed to avoid the rain. His
kite was raised. A thunder-cloud passed over it. No
signs of electricity appeared. He almost despaired of
success, when suddenly he observed the loose fibres of his
string move toward an erect position. He now pressed
his knuckle to the key, and received a strong spark. How
exquisite must his sensations have been at this moment !
On his experiment depended the fate of his theory.
Doubt and despair had begun to prevail, when the fact
was ascertained in so clear a manner, that even the most
incredulous could no longer withhold their assent. Re-
peated sparks were drawn from the key, a phial was
charged, a shock given, and all the experiments made
which are usually performed with electricity." And thus
the identity of lightning and electricity was proved.
Meanwhile, Franklin, in his letters to Collinson, had
already outlined his proposed experiments. Collinson
offered the letters to the Royal Society for publication,
but encountered a contemptuous refusal. The suggestion
that pointed rods would "probably draw the electrical
fire silently out of a cloud before it came nigh enough to
strike, and thereby secure us from that most sudden and
terrible mischief," was received with open derision. But
some years later the Royal Society elected Franklin an
honorary member, and decreed him their highest honor,
the Copley medal. Franklin's letters were, however, pub-
lished by Dr. Fothergitl. They went through five editions
in London, and attracted the attention of all Europe.
THE CAGING OF THE LIGHTNING. 23
An incorrect French translation falling into the hands of
Buffon, that celebrated philosopher repeated the experi-
ments successfully, and commended them to his friend M.
d'Alibard. A report of the wonderful results reached
Louis XV., then King of France; and at his request
further experiments were undertaken. The notice of the
king now acted as a stimulus to the French scientists ; and
three of them, Buffon, De Lor, and D'Alibard, erected ap-
paratus for attracting the lightning at different localities.
It is a curious fact, that despite the eagerness of these
philosophers, each to outstrip the other in being the first
to obtain actual results, disappointment awaited them all.
D'Alibard employed an old soldier, named Coiffier, to
help build his apparatus, and subsequently to watch it. It
so happened that the long-expected thunder-storm came
along during D'Alibard's absence ; and Coiffier, who had
no idea of the danger of receiving the spark, determined
to experiment on his own account. Accordingly, he
mounted the insulated stool which had been prepared,
and presented a wire to D'Alibard's rod, obtaining a fine
spark, and then another. He at once called all his
neighbors, and some one ran in search of the parish
priest. The latter was seen making his way to the ap-
paratus in such undignified haste, that it was immediately
surmised that the daring Coiffier had fallen a victim to
his bold experiment ; and accordingly the good father
found himself the leader of a miscellaneous mob of vil-
lagers. Regardless of the pouring rain and hail, the
crowd surrounded the machine, and there in open-mouthed
wonder watched the priest himself draw sparks from the
rod. Both the clergyman and the soldier managed to get
lightly struck, so lightly, that, in their absorbed atten-
tion to the sparks, they scarcely noticed the occurrence
until afterwards, when each, feeling stinging pains in his
24 THE AGE OF ELECTRICITY.
fore-arm, searched for the cause, and found bright red
stripes on the flesh just as if a few sound lashes had
been administered. It is very likely that the villagers
saw no good in these supernatural manifestations ; and
when they all perceived about the persons of the priest
and his companion the marked odor of the ozone gener-
ated, somewhat sulphurous in character, they were con-
firmed in their idea that the powers of the nether world
had been invoked. To Coiffier, however, remained the
honor of being the first to receive the spark. This was
on May 10, 1752, about a month before Franklin's fa-
mous experiment ; and, in many French works, priority as
the original discoverer is for this reason patriotically
claimed for D'Alibard. There is no doubt, however, that
D'Alibard obtained his instructions from Franklin's let-
ters, as he himself afterwards frankly admitted that he
merely followed the tiack which Franklin had pointed
out.
The European philosophers now remitted experiments
to find out how strong the shock of the Leyden-jar was,
and turned with increased enthusiasm to measuring the
power of the lightning stroke. And then the caged light-
ning found its first victim. In the engraving of the old
electrical machine, Fig. 1, there are shown a number of
threads which hang from a curved support over the glass
globe, and which are attracted by the globe when excited
so as to assume an inclined position. Professor Richmann
of St. Petersburg had constructed an " electrical gnomon "
on this same principle ; his idea being, to measure the
strength of the lightning discharge by observing the angle
of inclination assumed by a suspended thread electrified
thereby. He arranged on the roof of his house an iron
rod which he insulated from the adjacent part of the build-
ing ; and to this rod he fastened a chain which led down
THE CAGING OF THE LIGHTNING. 25
into his laboratory, and was connected to an insulated
support from which hung his thread, the end of which
extended over a dial. Richmaim had invited an engraver
named Solokow to witness the working of the apparatus ;
and as a thunder-storm gathered, the two men eagerly
watched the movement of the thread. Suddenly a peal of
thunder of terrific loudness was heard. Richmaim bent
forward to observe his thread more closely ; and ' ' as he
stood in that posture, a great white and bluish fire ap-
peared between the rod of the electrometer and his head.
At the same time a sort of steam or vapor arose, which
entirely benumbed the engraver, and made him sink to the
ground." The apparatus was torn to pieces, the doors of
the room thrown down, and the house violently shaken.
Richmaim's wife, running into the room, found her hus-
band sitting on a chest which happened to be immediately
behind him. He was stone dead, bearing no mark beyond
a red spot on his forehead. His shoe was ripped open
and his waistcoat singed, showing that the deadly current
had passed through his body. Solokow was removed
insensible, but subsequently recovered. The luckless ex-
perimenter had forgotten to provide an earth connection
whereby the charge might have passed harmlessly to the
ground. In the absence of this, the enormous electro-
motive force of the current was sufficient to enable it to
leap over the interval of air between the electrometer and
Richmann's head, and so to be led through his body.
Of course there were not wanting emotional people to
draw all sorts of warnings from Richmann's fate. Frank-
lin's proposition to erect lightning-rods which would
convey the lightning to the ground, and so protect the
buildings to which they were attached, found abundant
opponents, who agreed with Abbe Nollet, that it was " as
impious to ward off Heaven's lightnings as for a child to
26 THE AGE OF ELECTRICITY.
ward off the chastening rod of its father." Others, whose
religious scruples did not carry them quite so far, went to
the opposite extreme, and concluded that if there was any
impiety^ about lightning-rods, it lay in the fact that they
invited the u chastening rod/' and that it was madness
to u tempt Providence " in any such way. Nevertheless,
public opinion became settled, that whether lightning-rods
were impious because they opposed the decree of Provi-
dence, or suicidal because they induced Providence to
make decrees, the fact remained that they did .protect
buildings ; and as long as they did that, the theological
questions raised might be left to time for settlement.
Then the philosophers raised a new controversy as to
whether the conductors should be blunt or pointed ; Frank-
lin, Cavendish, and Watson advocating points, and Wilson
blunt ends. That wise monarch whose scientific acumen
stood nonplussed before the problem of how apples are
got into dumplings, graciously considered the question, be-
cause it affected his own royal abode, Buckingham Palace,
and, after much balancing of the pros and cons, reached
the sage conclusion that the pointed conductors ' ' were a
republican device calculated to injure his Majesty,"
whereupon he ordered them removed from the palace, and
ball conductors substituted. The same public opinion
which ran counter to him when he tried rather fruitlessly
to repress, some years later, numerous other republican de-
vices calculated to injure his Majesty on the opposite side
of the Atlantic, asserted itself here. "The king's chan-
ging his pointed conductors for blunt ones," said Franklin,
" is a small matter to me. If I had a wish about them,
it would be that he would reject them altogether as in-
effectual. For it is only since he thought himself and
his family safe from the thunder of heaven, that he has
dared to use his own thunder in destroying his innocent
THE CAGING OF THE LIGHTNING. 27
subjects." The logic of experiment, however, showed
the advantage of pointed conductors ; and people persisted
then in preferring them, as they have clone ever since.
We have now traced, though very briefly, the progress
of knowledge of electricity, from the germ of the science
which lay hidden for thousands of years in amber, like
the insects so often found in that substance, and yet
unlike them, for it possessed immortality, up to the first
practical application of that knowledge to human use and
benefit. The lightning had been caged. The mighty
force, which since the creation of mankind had aroused
but feelings of awe and terror, could now be confined and
examined, or diverted at will from its path of destruction.
The wise men of the eighteenth century had captured the
electrical Pegasus : it remained for the wiser men of
the nineteenth to yoke him to the plough.
28 THE AGE OF ELECTRICITY.
CHAPTER IV.
ELECTRICITY IN HARNESS.
THE death of Richmann, and the potent effects of even
small discharges of electricity upon the human body,
caused, as may be well imagined, much speculation as to
the part which an electric discharge could be made to
take in curing the ills that flesh is heir to. The electric
machine was of course the only available means of artifi-
cially producing the current ; and the modern practitioner
can easily figure to himself the unhappy experiences of
patients who were subjected to its unregulated and power-
ful discharges.
Between those who sought to use electricity as a nos-
trum for the cure of all ailments, and those who investi-
gated its action physiologically, there was a wide difference.
Through the latter class of investigators many discoveries
of great value were made, and, finally, one of the utmost
importance. Beccaria and others meanwhile observed the
effects of the electric discharge upon the muscles, and had
noted that those of the leg of a cock were strongly con-
tracted when a shock passed through them.
In 1786 Luigi Galvani, medical lecturer at the Univer-
sity of Bologna, while engaged upon investigations similar
to those of Beccaria, prepared some frogs' legs, with the
object of observing whether any effect would be produced
upon them by the electricity of the atmosphere. To this
ELECTRICITY IN HARNESS. 29
end, after carefully skinning the legs, he hung them upon
a hook which protruded from the railing of his balcony.
lie stood watching them for some time, but no results
showed themselves. Finally, disappointed, he lifted them
from the hook ; and then, while in the act of so doing,
he noticed to his astonishment that the very effects, the
peculiar muscular contractions, which he expected the
atmospheric electricity would cause, were taking place.
As it was evident that the surrounding atmosphere had
no part in the phenomenon, he at once sought for the
concealed cause ; and finally he found that the limbs con-
tracted whenever the iron railing touched their moist sur-
face, their contact meanwhile with the hook, which was of
copper, being still maintained. Conjecturing that the hook
and railing, of course,, as such, had nothing to do with the
matter, he made a metallic arc, formed of two pieces of
iron and copper ; and with this he soon found that it was
necessary simply to bring one metal into contact with a
nerve or with the end of the spine, and the other into
contact with a muscle of the leg, to produce immediately
muscular contractions.
Galvani came to the conclusion that the electricity of
which he had observed the effects resided in the muscles,
which received their supply from the nerves and blood ;
and in 1791 he published his celebrated work on the sub-
ject. If people believed that electricity was a valuable
remedy before this, they now began enthusiastically to
accept the shock as a universal panacea. Du Bois Rey-
mond says, that wherever frogs were to be found, and
where two different kinds of metal could be procured,
everybody was anxious to see the mangled limbs of frogs
brought to life in this wonderful way. The physiologists
believed that at length they -could realize their visions of
a vital power. The physicians whom Galvani had some-
30 THE AGE OF ELECTRICITY.
what thoughtlessly led on with attempts to explain all
kinds of nervous diseases, as sciatica, tetanus, and epi-
lepsy, began to believe that no cure was impossible.
It is a curious circumstance in matters of invention,
that discoveries of the most important nature have been
frequently made by people, who, being unable to realize
their importance, have passed them by, leaving them to be
made over again by others. The electrical effects of dis-
similar metals upon animal substance had been observed
by Sulzer, a German investigator, some twenty-three years
before Galvani made his experiments. Sulzer applied the
two metals, one above and the other below the tongue,
and then on bringing them into contact perceived the
peculiar sour taste. He ascribed this sensation to some
vibratory motion, excited by the contact of the metals,
and communicated to the nerves of the tongue ; and then,
content with this loose and fanciful explanation, he an-
nounced the fact in 17G7, in a work entitled "The General
Theory of Pleasures," where it remained wholly unnoticed
until long after Galvani's discovery had aroused the atten-
tion of the world. Galvani's discovery was also to some
extent anticipated by Cotugno, a Neapolitan professor of
anatomy, who in 1786 published the curious statement
that one of his pupils, feeling a sharp pain in the lower
part of his leg, clapped his hand upon the spot, and 'cap-
tured a mouse which had bit him. The little animal, after
being killed, was made a subject for dissection. During
this proceeding the pupil " accidentally touched the dia-
phragmatic nerve with his scalpel, and then received a
shock strong enough to make him snatch away his hand."
Cotugno's report attracted considerable attention through-
out Italy, and, it is said, caused further investigations to
be made by Vassalli, who formulated the odd theory that
nature accumulates electricity in certain parts of animals,
ELECTRICITY IN HARNESS. 31
and that they can draw upon this supply at will. It is
quite certain, however, that the work of both Cotugno and
Sulzer had been forgotten when Galvani's discovery was
made ; and the meagre suggestions published by them
detract nothing from the honor due the Bolognese philoso-
pher. But Galvani reaped neither profit nor glory in his
lifetime. The Cisalpine Republic ordered him to take a
certain oath entirely contrary to his political and religious
convictions, and, on his refusal, stripped him of his posi-
tions and titles. Thus reduced to poverty, he retired to
his brother's house, and, it is said, fell into a state of
lethargy, whence the tardy retraction by the Government
of its unjust decree failed to arouse him, and in which he
died. Only six years ago, Bologna erected a statue to his
memory, in one of her principal squares, and so made that
usual reparation of the public to unappreciated genius.
Some two years after Galvani's results and theories had
been published, Alessandro Volta, a professor in the Uni-
versity of Pavia, strongly opposed his deductions.
Volta was then one of the foremost electricians of the
day. He had invented the electrophorus and the electri-
cal condenser by which small charges of electricity were
accumulated. Volta maintained that Galvani's pretended
animal electricity was developed simply by
the contact of two different metals ; and
thus began a controversy which lasted long
after Galvani's death in 1798. Its outcome
was the invention of the voltaic pile, which
was contrived by Volta as a means of prov-
ing his theory. He soldered together two Fig. 3. Voita's
disks, one of copper (c) and one of zinc (z) .
Between these he placed circular pieces of woollen cloth
(/i), moistened with a solution of common salt or diluted
sulphuric acid. Several sets of disks thus arranged were
32 THE AGE OF ELECTRICITY.
placed one above the other ; each pair of disks in the pile
was separated from the next pair by a moist conductor.
A pile composed of a number of such pairs of disks will
produce electricity enough to give quite a perceptible
shock, if the top and bottom disk, or wires connected
with them, be touched simultaneously with the moist
fingers.
Volta's next step was the invention of the cup form of
battery. He arranged a number of cups, filled either with
brine or dilute acid, into which dipped a number of com-
pound strips, half zinc and half copper ; the zinc portion
of one strip dipping into one cup, while the copper portion
dipped into the other. In each cup, therefore, there was
a copper plate and a zinc plate, separated by a conducting
fluid ; and this is in substance the voltaic cell of to-day.
In discussing the sources of electricity, we shall advert
to the theory and operation of this great invention which
marks the beginning of a new era in the progress of elec-
trical science. Even as Von Kleist and Franklin may be
said to have caged the lightning, so Volta tamed it. He
made electricity manageable. He reduced the infinite ra-
pidity of the lightning stroke to the comparatively slow
but enormously powerful current, which in the future was
destined to carry men's words from one end of the world
to the other, and to produce the dazzling light inferior
only to the solar ray ; and the recognition accorded him
might well have satisfied his highest ambition. In marked
contrast to the fate of the broken-hearted Galvani, it was
Volta's fortune to be called to Paris by Napoleon, then
nearing the zenith of his glory, in order to explain his
discoveries before the assembled philosophers of France.
The First Consul himself presided ; and when Volta's
demonstration was completed, it was Napoleon who pro-
posed that the rules of the Academy should be suspended,
ELECTRICITY IN HARNESS, 33
and that the gold medal of the Institute immediately
should be awarded Volta in testimony of the gratitude of
the French nation. On the same day two thousand crowns
were sent to Volta from the national treasury ; and, as a
final and lasting honor, Napoleon founded the award of
an annual medal of the value of three thousand francs
for the best experiment in electricity, and a prize of sixty
thousand francs to him who should give electricity or
magnetism, by his researches, an impulse comparable to
that which it received from the discoveries of Franklin
and Volta.
And yet, singularly enough, we speak almost instinc-
tively of the galvanic, seldom of the voltaic, cell, as
if posterity had been guided by sympathy for the unfor-
tunate, rather than by a sense of justice to the favored,
discoverer. Such words as " galvanize" and "galvanic,"
possessing even a figurative meaning, are in every-day
speech. Volta's name is embalmed only in the techni-
calities of the science.
Among those who had studied deepest into the phenom-
ena of galvanic electricity was Hans Christian Oersted, a
Danish physicist, and professor of physics in the University
of Copenhagen. Oersted's researches led him to suspect
the identity of magnetism and electricity, but for a long-
time no means of experimentally proving the fact revealed
itself. The expedient had been tried of placing the two
poles of a battery, as highly charged as possible, in a
parallel line with the poles of a magnetic needle, without
results. In one of the reports of the Smithsonian Insti-
tute, the story of his discovery is thus graphically told :
"Fortune, it might be said, ceased to be blind at the
moment when to Oersted was allotted the privilege of first
divining that it was not electricity in repose accumulated
at the two poles of a charged battery, but electricity in
34 THE AGE OF ELECTRICITY.
movement along the conductor by which one of the poles
is discharged into the other, which would exert an action
on the magnetic needle. While thinking of this (it was
during the animation of a lecture before the assembled
pupils), Oersted announces to them what he is about to
try : he takes a magnetic needle, places it near the electric
battery, waits till the needle has arrived at a state of rest ;
then seizing the conjunctive wire traversed by the current
of the battery, he places it above the magnetic needle,
carefully avoiding any manner of collision. The needle
everyone plainly sees it the needle is at once in motion.
The question is resolved. Oersted has crowned, by a
great discovery, the labors of his whole precious life."
On July 21, 1820, the discovery was announced, that a
galvanic current passing through a wire placed horizontally
above and parallel to an ordinary compass-needle, will
cause that needle to sway on its axis to the east or west,
according to the direction of the current through the wire.
Oersted's discovery may be said to have pointed the way
to the great applications of electricity to human use ; for
it showed that energy in the form of electricity could be
converted into energy in the form of mechanical motion.
The discovery of the electro-magnet lay but a step be-
yond, a short step, and it was quickly taken. And
then opened the era of electricity at work, the era when
the discoverer too frequently finds his sole reward in the
applause of his compeers, and when the world lavishes its
honors and wealth upon the fortunate inventor. This is
the era in which we live.
THE GALVANIC BATTERY. 35
CHAPTER V.
THE GALVANIC BATTERY, AND THE CONVERSION OP
CHEMICAL ENERGY INTO ELECTRICAL ENERGY.
WHAT is electricity? No one knows. It seems to be
one manifestation of the energy which fills the universe,
and which appears in a variety of other forms, such as
heat, light, magnetism, chemical affinity, mechanical
motion, etc. For the purposes of convenient thinking, it
is well to consider the electrical current as a fluid, because
it apparently follows certain laws of fluids.
In its usual form, the galvanic cell consists of any two
dissimilar conducting substances subjected to the action
of a third substance capable of chemically attacking but
one of them, or of attacking one. in less degree than the
other. There is a containing vessel, in which is placed a
liquid called the electrolyte ; and in this liquid are plunged
the two conducting substances, usually in solid form, which
are called the elements, one of which is attackable by the
liquid, and the other non-attackable or less attackable.
When the two conducting bodies are connected by a wire
of conducting material, then an electrical current will cir-
culate, and will proceed from the body that is attacked
to the body that is not attacked, by way of the liquid,
and thence back to the attacked body by the wire. The
path thus traversed by the Current is its circuit. If the
circuit is anywhere interrupted, the current stops.
36
THE AGE OF ELECTRICITY.
Fig. 4.
The diagram (Fig. 4) will make this quite clear. Here
the wires are attached to the two bodies, immersed in a
liquid which will chemically attack one of them. The
current then circulates in the direction
of the arrow, from A the attacked body
to B the non-attacked body, and thence
back through the connecting wire.
Almost every branch of science now-
adays has its own language, made up
of its technical terms, which in time
become absorbed into general speech.
This is fast becoming the case with the
language of electricity. Amperes and
volts and ohms are no longer possessed
of meaning only to the initiated, but are taking their place
among such every-day standards as pounds and gallons
and inches. Although this little work makes no pretence
to be a treatise, it is believed that a plain statement of
some significations will be of service to the reader as a
help to a clearer comprehension of the applications of
electricity hereafter described.
If we run or walk, or saw wood or pump water, we are
conscious after a time of having exerted ourselves. We
have apparently expended certain of our bodily energy
in accomplishing something against an opposing force.
That is to say, we have done work. Before beginning
the task, we were conscious of an ability to undertake it.
At the end of the task, comes a sense of fatigue which
may be sufficiently strong to demonstrate our inability to
repeat the same labor until a period of rest and recupera-
tion intervenes. At the outset, therefore, we possess a
power, ability, or potential, to exert so much energy.
After the exertion, we have not this power, because we
have expended the energy in the form of bodily motions,
THE GALVANIC BATTERY. 37
against the opposing forces of friction or gravity. As
we have already stated, electricity is simply one form of
energy, and when it is exerted against opposition it does
work. But, like ourselves, in order to do work, it must
acquire a certain condition.
If an athlete is about to enter into an exhausting con-
test, he trains himself to that end ; and by dint of exercise,
judicious fare, etc., he brings his muscles and other
organs into a condition competent to the great exertion
before him. His potential, his capacity to do the work, is
thus enhanced. And so in general, any sort of education,
whether mental or physical, simply has for its object the
raising of the potential of the brain or the muscles, to
accomplish certain ends. We have constantly before us
examples of natural forces under varying potential. A
hot iron must acquire a high temperature before it will burn
inflammable bodies, a still higher one that it may be welded,
and still higher that it may melt. Water must be carried
to a high elevation before, by its fall, it can turn a wheel.
The steam in a boiler must reach a certain pressure before
it can move the engine piston. And so also electricity,
before it can do work, must reach a certain condition,
analogous in some degree to temperature and pressure.
Suppose we had a tank of water at A (Fig. 5), elevated
above the ground. If we connect a pipe B to ife, the
water will run down. What determines the flow? Simply
the elevation of the water. Again, take two tanks, one
not as high as the other, but both higher than the ground.
The water of course flows from the highest one J., to the
lower one B, and so to the earth. The water flows from
A to B simply because of their difference in height ;
and this difference determines the flow of water from
one tank to the other, or from either tank to the
ground. Therefore we say of water, that its ability to
38
THE AGE OF ELECTRICITY.
do work by exerting pressure (its potential) depends on
its elevation.
So of electricity. A body may be electrified up to a cer-
tain potential. For convenience the earth is considered as
of zero or no potential. Then, if by any material capable
of conducting electricity we connect the electrified body to
the earth, the conditions will be the same as in the case of
Fig. 5.
the tank of water (Fig. 5) : the electricity will flow from
the electrified body to the earth. Again, if a body electri-
fied to a high potential communicate with one electrified
to a low potential, then the electricity (as in the case of
the water between the tanks A and B in Fig. 5) will flow
from the body at high potential to the body at low potential.
There is a force which moves the electricity from one
THE GALVANIC BATTERY. 39
point to another, analogous to the force of gravity which
makes water run down hill. That force is commonly
called electro-motive force, or, as it is sometimes termed,
electrical pressure.
We have said that work is energy exerted against an
opposing force, or, in other words, against a resistance.
This resistance, in the case of water, may be due to fric-
tion against the sides of a pipe, or to the opposition to
the flow offered by an interposed water-wheel which drives
machinery. Electricity in motion in the same way does
work, and that which opposes its motion is technically
called the resistance.
Certain bodies, as glass and India rubber, offer very
great resistance to the electric flow : these are known as
insulators. Others offer very little resistance, and these
are termed conductors.
In order to maintain a constant flow or current of elec-
tricity, there must, as we have seen, be a difference of
potential between two points between which a conductor
extends ; and this difference of potential must be kept up,
otherwise the current would simply equalize itself at both
points, just as water will rise to its own level and then
cease flowing. The current is urged along the conductor
by its electro-motive force, and it is opposed by whatever
resistance lies in its path. The greater the electro-motive
force in proportion to the resistance, the greater will be
the strength of the current ; or, to use the water analogy
again, the more gallons of water (for example) will flow
through the pipe in a given time. Conversely, the greater
the resistance, the more opposition the current will meet,
and hence the weaker it will be.
This simple relation of electro-motive force and resist-
ance is the fundamental law of electricity in motion, discov-
ered by Professor Ohm, a distinguished German physicist.
40 THE AGE OF ELECTRICITY.
Consequently there ar,e three things about any electrical
current to be known : namely, its electro-motive force, or
pressure ; the resistance which it encounters ; and the
strength of the current, which depends upon these.
We measure steam or water pressure in pounds per
square inch, heat by thermometric degrees, distances by
feet and inches, and so on. Electro-motive force is meas-
ured in volts. A volt is very nearly the pressure yielded
by a certain standard galvanic cell, usually the Daniell
hereafter described. The term has also a very accurate
mathematical signification, which need not be discussed
here.
Resistance is measured in ohms. A column of mercury
one millimetre in cross section, and 106.2 centimetres in
length, has a resistance of one ohm ; but, for convenience,
it may be remembered that ordinary iron telegraph-wire
has a resistance of about 13 ohms to a mile.
An electrical current having an electro-motive force of
one volt, traversing a resistance of one ohm, is said to
have a strength of one ampere.
Here we diverge a little from the water analogy. If
we referred to water, we should say that water under so
many pounds pressure per inch, going through a pipe of
a certain diameter, is delivered at the rate of so many
gallons (for example) per minute. If we had some one
word which meant "gallons per minute," that would cor-
respond to ampere. When a current of one ampere
strength flows for one second, the quantity of electricity
delivered is called one coulomb. A current of the strength
of one-tenth ampere will not yield a quantity of electricity
equal to a coulomb until it has flowed ten seconds.
To recapitulate in briefer terms : Electro-motive force
means electrical pressure. Resistance has its obvious
meaning. Electro-motive force is not measured in pounds
THE GALVANIC BATTERY. 41
per square inch like steam or water pressure, but in volts ;
and a volt is the pressure given by one standard cell.
Resistance is measured in ohms, and an ohm answers to
the resistance offered by four hundred and sixty feet of
ordinary telegraph-wire, approximately. Strength of cur-
rent is measured in amperes. Speaking of a water-wheel,
we say we need a current flowing at the rate of so many
gallons per minute to drive it. Speaking of an electric
lamp, we say we need a current of from one to fifty am-
peres to keep it glowing. The term "coulomb" is far
less employed in practice ; but it may be in the end most
familiar of all, for when the electric light comes into use
in dwellings, we shall pay for our electrical supply at so
much per thousand coulombs, for example, as we now pay
for gas at so much per thousand cubic feet.
To return now to the galvanic battery : It is not neces-
sary here to review the various theories suggested to
account for its behavior. These are all in the regular
treatises ; and whether the current be due to contact of
dissimilar substances, or to chemical action in the cell,
was a subject warmly discussed by the grandfathers of the
present generation. It is better for present purposes to
take the facts as we find them, and look upon the cell in
the light of what we see happening in it ; and, of these
happenings, the principal ones necessarily attend the de-
velopment of the current, and essential thereto is the
chemical action on one of the bodies, or so-called ele-
ments, therein. In fact, any chemical re-action which
occurs between conducting substances may be utilized to
generate electric currents. The chemical affinity both sup-
plies and measures exactly the electro-motive force.
There are some very curious but important facts now to
be noted about galvanic cells and their currents. The size
of the cell has nothing to do with the electrical pressure
42 THE AGE OF ELECTRICITY.
yielded, the electro-motive force. A cell the size of
a percussion-cap will give just as high an electro-motive
force as a cell as big as the distributing reservoir in New-
York City. Electro-motive force, as we have stated, de-
pends on difference of potential ; difference of potential
exists in all dissimilar electrified bodies. Whether they
are large bodies or small ones, is beside the question ; just
as the fact that the pressure of water, due to its flow from
a reservoir to a plain beneath, is not influenced at all by
the area of the reservoir, but by the height of the water-
level above the plain. Water-pressure is the same per
foot of vertical height, no matter whether the column is at
its base a square inch or a square mile in area. The two
connecting bodies in the cell, when one is attackable and
attacked by the liquid, are at different potential : that of
the attacked body is the highest. The current then flows
to the non-attacked body through the conducting liquid,
and then back by the wire to the attacked body. The
constant chemical attack keeps the current flowing. A
current of water will flow from a high place to a low place
by gravity, but it will not flow up hill again unless work
is done to force it up. So, in a cell, the current will flow
from high potential to low potential, but not back again.
Work is required to send it back, and this the chemical
action supplies.
When we warm our houses, or drive a steam-engine, we
know that the amount of heat v;e get in the first case, or
power in the second, depends upon how much coal we
burn, other things being equal. The burning of coal is
simply the chemical action between the carbon of the fuel
and tne oxygen of the air. So, in a galvanic cell, we burn
the attacked element. As we convert coal into ashes of
no further use in the furnace, to produce heat, we convert
the zinc of the cell into another substance of no further
THE GALVANIC BATTERY. 43
use in the cell to produce electricity. Through the steam
boiler and engine we can convert chemical action into
mechanical work, which we can apply to drive locomotives
or steamships or machinery.
The galvanic cell converts chemical action into elec-
tricity. The amount of work realized in one case, and
of electricity in the other, depends on the amount of fuel,
whether coal or zinc, consumed. If, then, in the galvanic
cell we burn twice as much zinc in a given time, we
shall have a current twice as strong. We can do this
by making the attacked body in the cell larger, so as to
expose double the area to the attack.
Hence it appears, that, while the size of the bodies in
the cell has no bearing on the pressure of the current,
it has a very material bearing on the strength of it. It
is, as we have said, so far as the pressure is concerned,
immaterial whether two water columns of the same height
press on bases of a square inch or a square mile in
area ; but the strength of the two currents, the gallons
flowing down per minute, will be enormously different.
Consequently, when we want high-pressure electricity,
we put into the cell bodies which are, or will be, of widely
different potential ; we look to the nature of the bodies.
When we want great strength of current, we look to their
dimensions.
In practice, however, we do not make huge cells, chiefly
because of their cumbrousness and difficulty to handle.
We can increase either the electro-motive force, or the
strength of the current, by using several cells of con-
venient size, and connecting them together differently.
Thus, in Fig. 6, each cell is supposed to give an electro-
motive force of one volt. If we connect the wire of the
attacked element in one cell to the unattacked element in
the next, and so on, we shall add together the several
44
THE AGE OF ELECTRICITY.
electro-motive forces of each, and obtain an aggregate
pressure of four volts, while the strength of the current
Fig. 6.
will remain the same as that of one cell. If, however, we
connect all the attacked elements together by one wire,
Fig. 7.
and all the non-attacked elements together by another, as
in Fig. 7, then we shall really have quadrupled the size
of the elements ; and we shall have a
current four times as strong, while its
pressure will remain at one volt.
Take the water analogy again. Sup-
pose we start with a tank of water at the
level marked 1 in Fig. 8. Then the water
will flow out with a certain pressure, de-
pending on the elevation of the tank. So
in a given cell the current will flow out
with a given electro-motive force, depend-
ent on the materials of the cell. Let us
now elevate the tank to position 2, then
we have doubled the water pressure ; if
Fig. 8.
we carry it to the position 3, still higher, we may make
the pressure three times, and if to position 4, four times,
THE GALVANIC BATTERY.
45
as great. We do the same thing electrically by adding
cells as shown in Fig. 6. The quantity of water or of
electricity yielded remains the same, but its pressure in-
creases. Suppose, however, that we start again with
our tank of water, which, however, contains say but ten
gallons, which it will discharge completely in a minute.
If we place beside it three other tanks of equal capacity,
and at the same elevation, each one will discharge ten
gallons a minute, or all together forty gallons a minute.
This is the parallel case to that of connecting the cells
as in Fig. 9. The pressure of water or electricity re-
Fig. 9.
mains the same ; but more water or electricity is dis-
charged in a given time.
Or, to put this in a more practical form, suppose we
have a pipe plenty large enough to carry all the water we
need, in a given time, to the top of a house, but find
the water will not come up. We increase the water press-
ure, and the water rises to the desired height. That is
the first case. Suppose, again, that we have a water-
wheel to turn, but only a little stream delivered, say, from
a small pipe, with great force. We increase the size of
the pipe, and get more water. That is the second case.
This makes the foregoing facts easy to remember.
When the current in a cell travels from the attacked
element to the non-attacked element, through the liquid in
the cell, it meets with resistance ; and so, also, when the
current travels around from the non-attacked element to
46*
THE AGE OF ELECTRICITY.
Fig. 10.
the attacked element, by the wire outside the cell, it meets
with still further resistance.
Here, then, are two places where the current will meet
obstacles ; one inside the cell, and the
other outside of it. The resistance offered
by the liquid inside the cell is called the
internal resistance ; and that of the cir-
cuit outside the cell, the external resist-
ance, as illustrated in Fig. 10.
The external resistance we control.
It may be due to many miles of tele-
graph-wire, or to the coils of an electric
motor, or the filament of an electric lamp,
or to any other path which we provide for
the current, in traversing which it does the work we desire.
The internal resistance, however, is peculiar to the cell
itself ; and whatever work the current has to do to get
through this may be taken as wasted energy. Conse-
quently it is necessary to make the internal resistance of
the cell as small as possible ; and to do this there are
several ways.
It requires much less work to swim ten feet than twenty :
so in like manner, if we shorten the path of the current
through the liquid, it will have less liquid to go through,
and hence meet less resistance. Therefore we bring the
two solid bodies, or elements, in the cell, as near together
as possible without touching.
If, however, for any reason we find it impracticable or
undesirable thus to bring the plates close together, we can
leave the thickness of the intervening liquid as it is, but
increase the size (surface area) of the plates. Then more
of the attackable body will be attacked in a given time ;
and, as we have already seen, we shall have a stronger
current, which will more easily overcome the resistance.
THE GALVANIC BATTERY. 47
In the first case, therefore, we actually diminish the
resistance by diminishing the thickness of the liquid, the
strength of the current remaining the same. In the second
& O
case, we neither increase nor diminish the resistance ; but
we augment the current strength, so that the obstacle is
more easily overcome.
It is very like journeying by railway from one place to
another. We can take a slow train by a short road, or a
fast train over a long road.
There is one more very important fact about the gal-
vanic cell, which is yet to be noticed. If we make a
simple cell, say of a plate of copper (the unattacked ele-
ment) , a plate of zinc (the attacked element) , and water,
we shall find, that after a very short time the electro-
motive force of the cell runs down, and that the current
very perceptibly weakens, or stops altogether. When this
happens, if we examine the copper plate carefully we shall
find it covered with minute bubbles of gas. This gas is
hydrogen, which in all cells, although generated at the
surface of contact of the attacking liquid and the attacked
element, nevertheless appears on the surface of the non-
attacked element.
This hydrogen is responsible for the weakening of our
cell : first, because it is a very bad conductor, and thus
opposes a high resistance to the current ; and, second,
because it may be itself attacked more readily than the
attackable element, so that a reverse current is set up,
flowing in the opposite direction to the one originally gen-
erated. When a cell thus becomes weakened, or rendered
inoperative, it is said to be polarized. It is therefore of
great importance to prevent this polarization ; because, no
matter how high the electro-motive force of the current at
the start, if the current is not- constant the battery is of
little value.
-IS
777 /: AGE '>/'' i:Li:i r
We can now reeo<'iii/.e the 68ft6Htill] ('diidil ions of M o;oou
<r:ilv:inic cell ; :IIK| these MIT,
i. it should ha\e high electromotive force.
"2. It should have l>\\ internal resistance, so tint no
PIUTiiY should he wasted within I lie cell.
3. It should ejve a constant eiirrenl, :n:d Ilierefnre
pol:iri/:ilioii should he prevented in it.
Beyond these, MIT the further rci|uircmenls, that there
should heuoadion in the cell \vhcn the circuit is open;
lliMl it should emit n< di ^.\>< i -eeMhlc fumes; MIK|. liiiMlly, it
should he nuide of ehenp ;ind l.-istinu, iiiMtcriMls. No one
f.>iiu of cell fulfils :ill these conditions; hut, MS there MIT
verv IIIMIIV \Mrieties, it is possihle to select ccrhiin cells
MS especially :idMptcd to pnrliciilMr purposes.
<ol\:inic cells MTC usually dassilied with rc;v:m! to their
const I'licl ion. Mild lo Ihe dcpolMri/ino- Mjj,Tiit employed.
Thus (here MIT (I) ouc-lluid cells with no depolari/,ei\
(J) one lluid cells with solitl dcpi.lai'i/ei' or li<|iii<l dcpolar-
i/cr, and ('.\ ) 1 \\ o lluid cells.
The simple cell of Volta, with ils
xinc :nd copper plates plunged in Mcid-
ulated water, is MII example of NIC lirsl
class. One of Ihe hcsi forms is I hat
kno\\n as Smce's hattcry, in which
the copper is repLaced hy platinum or
plaliui/.ed silver. The rou>li suri'Mce
of the platinum o'ives up Ihe hydro-ren
bubbles j :md so diminishes polari/.a-
tion. The ordinary arrangement of
Smee's cell is shown in l'ij. I I. The
plate of platinum or platini/.ed silver
is suspended from a wooden har whicn
sujtports two plates of amalgamated /.inc. Siue,le-lluid
lotteries of the al>o\e l\| v are siihjccl to three defects:
n. \ /T/-: /,)".
49
(lirst) their electro-motive force is weakened by polariza-
tion, and they have (second) neither a constant current,
nor (third) a constant
To the second class of cells
above enumerated, belong the
well-known (In-net (liquid
depolarizer) and Lcclanche
(solid depolarizer) forms.
The Crenet cell (Fig. 12),
or. as it is sometimes called,
the bottle battery," con-
tains a plate of zinc sus-
pended between two plates
of carbon. The /ine is usu-
ally alllxed to a rod, so that
it can be conveniently raised
out of the solution when the
cell is not in use. The liquid
here contains bichromate of
potash, sulphuric acid, and water. This solution chemi-
cally acts upon the hydrogen bubbles, t,, destroy them
while they are in a nascent state. This cell has a
electro-motive force at the lu^inninir, and yield* a
fill current.
The Leclanche' cell, which is very much used on
telephone lines, and which is represented in Fiu;. 1;;,
contains a carbon plate, against which are fastened
by rubber bands blocks of solid auulomerate. composed
of black oxide of manganese, carbon, bisulphate of
potassium, and .mini lac. These agglomerate blocks act
as depolarizers. The zinc clement is in the form of a
rod.
Complete depolarization is obtained only in two-lluid
cells, which constitute the third class of battery above
Fig. 12.
50 THE AGE OF ELECTRICITY.
noted. Of these the most prominent examples are the
Daniell and the Bnnsen.
The Daniell cell (Fig. 14) consists of a containiug-
vessel in which is placed a porous earthenware jar or cup.
Within the porous jar is a plate of amalgamated zinc, and
a dilute sulphuric acid. In the outer vessel is a plate of
Fig. 13.
copper ; the entire vessel is often itself made of that metal,
and the liquid here is a saturated solution of sulphate of
copper. When the circuit is closed, the zinc is attacked,
forming sulphate of zinc, and liberating hydrogen. Hut
this gas, in this cell, cannot as in other cells appear on the
copper plate ; because, in meeting the sulphate of copper,
THE GALVANIC BATTERY.
51
the hydrogen combines with the sulphur to form sulphuric
acid, while the copper is deposited in the metallic state
on the copper plate. There is consequently no polariza-
Fig. 14.
tion, and the cell is constant ; but it has a high internal
resistance, and hence does not give a powerful current.
The gravity cell, based on the Daniell, is very widely used
Fig. 15.
for telegraphic purposes. Fig. 15 represents the Callaud
form, in which the zinc, in the form of a cylinder, is sus-
pended by hooks from the rim of the jar. The copper
THE AGE OF ELECTRICITY.
Fig. 16.
element, a thin strip of rolled metal, rests on the bottom.
The solution of sulphate of copper is at the bottom of the
jar, and remains there because it is heavier than the sul-
phate of zinc solution which floats upon it.
Bunsen's battery is repre-
sented in Fig. 1G, and consists
of a glass vase V, in which is
placed a cylinder Z of amal-
gamated zinc, immersed in a
mixture of water and sulphuric
acid. Within the zinc cylinder
is a porous jar D of earthen-
ware, which contains a rod or
plate of carbon C immersed in
bichromate solution such as is
employed in the Grenet single-
fluid cell above described.
Of the different forms of batteries above enumerated,
the Daniell, for its constancy, is usually taken as the
standard. Taking its electro-motive force as unity, or
one volt, the electro-motive forces of the other cells men-
tioned are approximately as follows :
Smee, about .47 volt.
Leclanche, 1.48 volt.
Grenet, 2 volts.
Bun sen, 1.9 volt.
These forms are mentioned here merely as typical.
The actual number of different galvanic cells known to
electricians reaches into the hundreds. Experiment with
the hope of finding a cell which will be more constant,
of higher electro-motive force, or which will consume a
cheaper material than zinc, is constantly going forward.
As compared with the steam boiler, plus the engine and
the dynamo-electric machine, as a means of generating
THE GALVANIC BATTERY. 53
electricity, the battery is most attractive. It costs but a
trifle to construct ; it needs no lire, and no attendance :
these are its advantages. On the other hand, zinc costs
twenty times as much as coal, and, other things being
equal, generates one-seventh the energy.
Yet we know that the consumption of zinc in the cell is
combustion, differing not essentially from the burning of
coal in the furnace. Why, we ask ourselves, from the
combustion of the expensive substance can we get a direct
current of electricit}', and not from the combustion of the
cheaper material? Wherever there is oxidation, there, in
some degree, an electric current is generated. But oxida-
tion in air is oxidation in the most perfect of electrical
insulators. The current will not travel from the attacked
body to a convenient conductor via the air, as it will via
water ; and so, up to the present time, we have found no
way of collecting the electricity which may be developed
in our grates and furnaces.
Why, then, if we can consume one oxidizable material
in the battery, cannot we consume another? If zinc, why
not carbon? In the Bunsen cell, and in a great many
others, carbon already enters into use as the non-attacked
element. Is it not possible to use with it some other sub-
stance, which the attacking material will not re-act upon
so readily as it will upon carbon ? Attempts in this direc-
tion have not been wanting. M. Jablochkoff has made a
cell in which one element is of coke, and the other of cast
iron. His liquid is melted nitrate of potash or nitrate of
soda. Here the coke, the carbon, is burned at the ex-
pense of the oxygen of the nitrate, while the cast iron
remains unattacked. Immense volumes of carbonic acid
are produced. The current yielded is powerful. But the
cell has no practical utility, save as a mile-post on a road
toward perhaps the most important electrical invention
54 THE AGE OF ELECTRICITY.
that can be made ; namely, the consumption of carbon
directly in the battery, at low temperatures.
A curious improvement upon Jablochkoff's battery has
been contrived by M. Brard of La Rochelle, France,
which he calls an electro-generative combustible. It is,
in fact, a fuel which produces electricity ; or, rather, a
piece of prepared carbon, which when thrown into the lire
produces electricity by its combustion. Each so-called
slab is about six inches long by two inches wide and an
inch thick. It is composed of a prism of carbon, a prism
of nitrate of potash, and between these a plate of asbestos
which acts like the porous partition in ordinary cells.
The nitrate of potash is mixed with ashes to prevent too
rapid combustion and melting, and in this part of the slab
is embedded a sheet of copper which serves as one pole.
In the carbon are embedded several strips of brass or
copper which are connected to a single sheet, which forms
the other pole. It is necessary simply to throw the brick
into the fire, previously attaching wires to the poles, to
obtain a continuous current for an hour or two. The cur-
rent of a single slab will actuate an ordinary electric bell.
The galvanic battery, we have defined as an apparatus
for converting the energy of chemical affinity into electri-
cal energy. In most cases the force of chemical affinity
exerts itself as soon as the ingredients of the cell are put
together ; in others, as in the instance of the Jablochkoff
carbon nitrate-of-potash battery, the constituents of the
cell must be heated before the chemical re-actions can
occur. Of course, in the latter case, the resulting elec-
trical energy should represent not merely the energy of
chemical affinity, but also the heat energy employed in
setting free the latter. In fact, however, the energy pro-
duced is in no wise commensurate with the energy ex-
pended ; and all thermo-galvauic cells, so far as now
THE GALVANIC BATTERY.
55
known, are exceedingly wasteful. The therm o-galvanic
cell should not be confounded with the thermo-electric cell
or thermo-pile. There is a broad distinction between them,
in that the thermo-galvanic cell converts heat energy into
electrical energy, through the medium of the energy of
chemical affinity ; while there is no perceptible chemical
re-action in the thermo-pile, and the heat applied is directly
converted into electricity.
The thermo-electric bat-
tery was discovered by
Professor Seebeck in 1821.
He soldered together
a piece of bismuth and a
piece of antimony, con-
nected their free ends to
a galva nometer which
would show when a cur-
rent passed, and then
heated a joint between the
metals. He found that
when the temperature of
the joint was greater than that of the remainder of the
circuit, a current traversed the circuit, apparently moving
from the bismuth to the antimony as shown in Fig. 17;
whereas, if the joint was cooler than the rest of the circuit,
then the current would move the other way. The electro-
motive force thus set up maintains a constant current so
long as the excess of temperature of the heated point is
kept up, heat being all the while absorbed in order to
maintain the energy of the current.
Curiously enough, just as the heating or the cooling of
the joint will produce a current in one or the other direc-
tion, so the passage of a current through the joint will
either heat or cool it. Thus, if a current be conducted
Fig. 17.
56 THE AGE OF ELECTRICITY.
from bismuth to antimony, the joint is cooled ; if it be led
in the other direction, the joint is heated. This peculiar
phenomenon was discovered by Peltier in 1834, and is
known as the Peltier effect. Another remarkable effect
was discovered by Sir William Thompson. If a copper
wire be heated at one point, and cooled at another, a cur-
rent passing through the wire from the hot place to the
cool place will heat the wire. If the current goes the
other way, the wire will be cooled ; but if the wire be of
iron, then a current from the hot portion to the cold
portion causes cooling.
In constructing a thermo-electric pile, it is usual to join
a number of pairs of metal, as bismuth and antimony, in
series so bent that the alternate junctions can be heated
as shown in Fig. 17, at A A A, whilst the other set B B B
are kept cool. The various electro-motive forces then act
all in the same direction, and the current is increased in
proportion to the number of pairs of junctions.
Numerous experiments have been made on thermo-elec-
tric batteries, chiefly in France ; and with an apparatus of
six thousand elements, consuming some twenty-two pounds
of coke per hour, two arc lights, equal to between four
hundred and fifty and seven hundred and fifty candles,
have been maintained. The trouble with the thermo-pile
is its great waste ; the amount of energy utilized being
only between two and five per cent of that of the heat sup-
plied. Its best application is that made by Melloni, who
constructed many small pairs of antimony and bismuth in
a compact form for use as a thermometer. It is employed
with a sensitive galvanometer, and produces currents pro-
portional to the difference of temperature between the hot-
ter set of junctions on one face of the thermo-pile, and the
cooler set on the other face. If the hand, for instance,
be brought near on the one side, a current indicates its
THE GALVANIC BATTERY. 57
radiant power ; or, if a piece of ice be brought near, a
current is also indicated, but moving in the opposite direc-
tion. In Professor Tyndall's admirable series of lectures
on " Heat as a Mode of Motion," this instrument is con-
stantly experimentally employed to show minute differ-
ences of temperature. It has been proposed to utilize the
waste heat of furnace-flues by surrounding them with
thermo-electric elements ; and the reverse process has also
been suggested, of making stoves the casing of which
generates electricity, while radiators diffuse the uncon-
verted heat for purposes of warmth.
In the preceding chapters we have seen that the dis-
charge of an electric machine or of a Leyden-jar is a min-
iature lightning flash. The discharge of a galvanic cell,
on the other hand, is continuous, and may flow over a
long period of time. The so-called static discharge may
be compared to the sudden explosion of dynamite ; the
so-called dynamic discharge or current, to the gradual
flow of steam or water. Both are electrical discharges,
and there is no inherent difference in the electricity mani-
fested ; although even to suppose such a difference in-
volves the conception of electricity as a corporeal thing,
like water, which is not proved. So-called static electri-
city is simply electricity of little strength, but of enormous
pressure. Dynamic or galvanic electricity has immense
strength, but little pressure. To borrow Professor Tyn-
dall's illustration : a cubic inch of air, if compressed with
sufficient power, may be able to rupture a very rigid en-
velope ; while a cubic yard of air, if not so compressed,
may exert but a feeble pressure upon the surface which
bounds it. Static or frictional electricity is in a con-
dition analogous to compressed air: its pressure, its
electro-motive force, is great. Galvanic or dynamic
electricity resembles the uncompressed air : there is a
58 THE AGE OF ELECTRICITY.
great deal more of it, but its pressure is comparatively
minute.
The immense strength of current of the galvanic cell,
and consequent quantity of electricity yielded thereby, as
compared with the infinitesimal quantity and enormous
pressure of the static discharge, was illustrated in a
remarkable manner by Professor Faraday. As will be
explained hereafter, an electrical current when conducted
into water will decompose the same, tearing asunder the
hydrogen and oxygen molecules, and of course exerting
energy to effect this separation. The quantity-of current
necessary to decompose a grain of water is very small.
It measures 3.13 amperes ; and some idea of what it can
do will be obtained from the fact that it should keep a
platinum wire T J T of an inch in diameter red hot for three
and three-quarters minutes. In order to effect this same
decomposition by static electricity, there would be required
eight hundred thousand charges of fifteen large Leyden-
jars : each charge would be fully capable of killing a rat,
and if all of the charges could be accumulated into one,
the result would be a great flash of lightning. Faraday
estimated the electricity due to the chemical action of a
single grain of water on four grains of zinc to be equal
in quantity to that of a powerful thunder-storm.
By linking cells together, as has already been described,
we can increase the pressure of the galvanic current, and
make it more nearly approach that of the fractional or static
current. Professor Tyndall, however, states that it requires
a battery of more than a thousand cells to make the gal-
vanic current jump over an interval of air one-thousandth
of an inch in length. An electric machine of moderate
power, and furnished with a suitable conductor, is com-
petent to urge its current across an interval ten thousand
times as great as this. The magnetic needle will respond
THE GALVANIC BATTERY. 59
to, and show by its deflection, the passage of an almost
infinitesimally small galvanic current ; but it is only by
the aid of arrangements for multiplying the effect that the
discharge of a large static electrical machine is enabled to
produce any deflection. With 11,000 cells, the aggregate
electro-motive force of which was 11,330 volts, Mr. War-
ren de la Rue succeeded in obtaining a spark but 0.62 inch
in length. On this basis, the electro-motive force of a
lightning flash a mile long should be over three and one-
half million volts.
We have already noted the fact, that wherever a chemi-
cal re-action exists between conducting substances, an
electric current is produced. This re-action in a great
many instances results from oxidation, the combining of
the oxygen of the liquid, usually with the substance of the
attacked element.
A very ingenious form of gas battery, invented by Sir
W. Grove, contains platinum elements in contact respec-
tively with hydrogen and oxygen gases. These elements
enter water ; and if they are joined by a wire, a current
apparently flows from the hydrogen, through the water
in which the ends of the elements enter, to the oxygen.
The hydrogen plays the part of a zinc plate, being
oxidized by the water ; and the hydrogen set free ap-
pears at the positive element (oxygen), and combines
with it.
Various cells have been devised with the object of
utilizing the oxygen of the air for depolarizing purposes.
Thus currents of air are sometimes pumped into the cell,
and against the plate on which the hydrogen is formed ;
and various cells have been devised, in which the polarized
plate is in the form of an endless belt, a wheel, or a series
of radial spokes. The wheel or- belt is revolved so as to
be partly in and partly out of the cell ; so that a portion
60 THE AGE OF ELECTRICITY.
of it is always active while the remainder is in the air, the
hydrogen then escaping.
Jablochkoff's auto-accumulator is a cell remarkable for
its small size, light weight, low cost, and freedom from
deleterious fumes. It consists of a shallow vessel of hard
carbon, in which are placed scraps of metal, such us iron,
zinc, or sodium amalgam. Above the metal is a thickness
of sawdust, or a piece of coarse cloth, impregnated with
chloride of calcium. Upon the cloth are laid hollow sticks
of porous carbon. The whole forms a cell four inches
square and one inch high. The metal scraps and the
carbon vessel form a couple, the carbon being polarized
or charged with hydrogen. This carbon is in electrical
circuit with the upper porous carbons, which absorb oxy-
gen from the air. Thus we have two surfaces of carbon,
one charged with hydrogen and the other with oxygen ;
and these constitute the elements of the cell. As the cur-
rent flows, the oxygen and hydrogen generally combine ;
and the action continues until the supply of one or the
other of them is practically exhausted. Then, if the cir-
cuit be broken, a recuperative process immediately com-
mences : the hydrogen is evolved from the metal, and
attaches itself to the one carbon plate ; while the other
electrode fills its interstices again with oxygen, which will
be drawn out when the current commences to circulate.
And so the process goes on, action following rest, and
rest following action, as long as the supply of metal is not
exhausted, and there remains a small quantity of moisture
required for its oxidation. Five of these cells in series
will operate a five-candle-power lamp for an hour, the fila-
ment being still bright red at the end of that time. This
cell is believed to be of great promise as a means of sup-
plying current for domestic electric lighting.
Another curious atmospheric battery, devised by M.
THE GALVANIC BATTERY. 61
Jablochkoff, consists simply of a small rod of sodium,
squeezed into contact with an amalgamated copper wire,
and flattened. This is wrapped in paper, and secured to
a plate of porous carbon. No liquid is used, the moisture
of the air settling on the oxidized surface of the sodium
being sufficient.
A battery which appears to be a decided step in the
direction of producing electricity from the oxidation of
coal, without the intervention of the steam-engine, was de-
vised in 1885 by Mr. J. A. Kendall, an English electrician.
Its operation is based upon the well-known phenomenon of
hydrogen passing through platinum at a red heat ; two
platinum plates being used as the poles, one exposed to
hydrogen, and the other to oxygen. These plates are
arranged in concentric tubes, closed at one end, and are
separated by a fluid medium of fused glass. Hydrogen
gas is continuously supplied to the inner platinum tube,
while the entire apparatus is maintained at a high tem-
perature by means of a furnace. The absorption of
hydrogen by the platinum is accompanied by electric gen-
eration, and the current is led away by wires connected to
the platinum tubes. The inventor has estimated that a
ton of coke used in heating the battery, including the
hydrogen-producer, will give at least three times the elec-
trical energy that would be produced by the same quantity
of coke used in working a steam-engine and dynamo.
There are a great many other forms of galvanic cell,
and new ones are constantly appearing. Most of them
are mere modifications of certain general types : others,
and especially those which involve novel modes of pre-
venting polarization, or which amount to real advances
in the direction of consuming carbon, or utilizing the oxy-
gen of the atmosphere, are of great scientific interest.
The subject is a most inviting one to inventors.
62 THE AGE OF ELECTRICITY.
The battery of the future and it will be the greatest
of electrical wonders, when it is invented will simply
reproduce the Conditions existing in every household grate ;
that is, it will burn coal, by the aid of the air, to produce
electricity. At the present time, however, there are sev-
eral forms of battery which are worth noting as electrical
curiosities. One inventor boldly grasps the ocean, and
utilizes it as his conducting liquid. Of " earth batteries,"
the globe we live on forms a part. These have been used
for driving clocks, and many people have supposed that
in some way electricity is drawn directly out of the ground.
Earth batteries, however, simply consist of plates of dif-
ferent metals, usually zinc and copper, which are buried
at a little distance apart in moist soil, the latter acting
like the liquid in an ordinary cell. They have a high
resistance, and low electro-motive force. The best place
for the zinc plate is under a stable, where saline liquids
permeate the ground. One inventor thought he had made
a tremendous discovery in recognizing that the lead water-
pipes and the iron gas-mains buried under city streets
constitute a huge earth battery, from which unlimited
electricity might be drawn to light the city. The fact that
a battery is there is true enough : but, unfortunately, the
attackable substance of the couple is the iron gas-main,
which would be surely consumed ; and, as the plan did
not contemplate any remuneration to gas-companies for
gas lost by leakage, it failed to come into practical use.
M. Duchemin has proposed to use the ocean as the
liquid in his battery, and submerge in the sea plates of
zinc and carbon attached to a floating body. The main
object of this battery was the preservation of the iron
hulls of vessels, or the iron buoys, from oxidation. Some
experiments were made on a small scale, which apparently
demonstrated that it was possible in this way to preserve
THE GALVANIC BATTERY. 63
a surface of iron eighteen times larger than that of the
zinc electrode used. The investigations were interrupted
by the outbreak of the Franco-German war, and have not
been resumed. A somewhat similar idea was proposed
many years earlier, by Sir Humphry Davy, who suggested
the protection of the copper sheathing of vessels, by means
of a communicating sheet of zinc immersed in the sea. It
was found that an extent of zinc surface, one hundred
and fifty times less than that of the copper, was suffi-
cient to protect the latter ; but the plan was abandoned
for the reason that certain salts contained in the sea-water
were decomposed, and the resulting earthy oxides depos-
ited themselves on the copper, roughening the surface,
and rendering the same particularly inviting to barnacles,
which attached themselves in great numbers, and so ma-
terially impeded the speed of the vessel.
It may be mentioned here, that efforts have been made
of late years to remove barnacles from ships' bottoms by
powerful currents led to the copper from dynamo-electric
machines, thence passing to the water. The current
seriously incommoded the barnacles, which made such
efforts as lie within the limited capacity of the clam, to
get out of their shells ; but, Nature not having provided
them with suitable means for this purpose, they remained,
and submitted to the disturbance with their usual equa-
nimity, possibly cheered by the knowledge that on the
whole the experiment was a failure.
Probably the largest galvanic battery ever made is that
used in the Royal Institution in London. It consists of
14,400 cells of chloride of silver and zinc elements. It is
estimated that a lightning flash a mile long could be pro-
duced by 243 such batteries.
The battery which will last- the longest is the dry pile
devised by Zamboni. This consists of a number of paper
64 THE AGE OF ELECTRICITY.
disks, coated with zinc foil on one side and with an oxide
of manganese on the other, piled upon one another, to the
number of many thousands, in a glass tube. The electro-
motive force is great, and a good pile will yield sparks.
The current is very weak, but it lasts an extraordinary
length of time. In the Clarendon Library at Oxford,
there is a pile, the poles of which are two metal bells ;
between them is hung a small brass ball, which, by oscil-
lating to and fro, slowly discharges the electricity. It
has been continuously ringing the bells for over forty
years.
One of the most curious alleged discoveries concerning
the galvanic battery was that of Mr. Arnold Crosse, who
in the early part of the present century announced the
extraordinary fact that living insects were generated in
the cell. He stated, that while endeavoring to deposit
crystals of silica on a lump of stone, by the agency of the
current, he noticed, after the experiment had continued
for a fortnight, whitish specks on the stone, which at the
end of the twenty-eighth day assumed the appearance of
insects, standing erect on the bristles which formed their
tails, and distinctly moving their legs. The experimenter
was greatly astonished. Instead of a mineral, for which
be had looked as the result of his experiment, he had
found an animal, alive and kicking. It was plain these
were no mere appearances ; for in a few days they de-
tached themselves from the stone, and began to move
about. They were, to be sure, not creatures of a very
inviting and attractive character ; for they belonged ap-
parently to the genus acarus, which includes some of the
most disagreeable parasites of the animal body. But they
continued to increase, and in the course of a few weeks
hundreds made their appearance. Crosse himself hesi-
tated to believe that spontaneous generation could attend
THE GALVANIC BATTERY. 65
any action of electricity, and conjectured that bis cell was
simply a favorable place for tbe hatching of the ova of
the insects existing in the atmosphere. He and others at
the time made many experiments intended to preclude the
possibility of these ova being present, but the insects
continued to appear. The phenomenon made a great
sensation. Despite the fact of Crosse's own hesitancy
in asserting that he could produce life, others flatly main-
tained the possibility. At the opposite extreme, were
those who attacked Crosse for impiety. If he began by
creating animals by electrical power, no matter of how
inferior sort, who could tell where he might stop? He
was called a " disturber of the peace of families," and a
" reviler of religion."
The French Academy of Sciences, however, on receipt
of a phial of the mysterious insects, treated the whole
matter as unworthy of serious consideration ; and one
member individually pointed out that the means employed
by Crosse simply excited and favored the germination of
the ova which must have been present. Many years later
(1859), Professor Schulze in Germany repeated Crosse's
experiments, aided by more modern knowledge of minute
organisms, and modes of sterilization, and showed con-
clusively that none were generated. The controversy had
then continued for nearly half a century.
Among other remarkable ideas concerning the galvanic
battery, it has been suggested, that, wherever two flavors
are habitually formed in cooking and eating, the reason
why they mutually improve each other is because a certain
amount of electric action is set up between the sub-
stances employed to produce them. Mr. Edwin Smith,
M.A., has conducted quite an extended series of experi-
ments based on this theory ; and has used as elements in
a galvanic cell, pairs of eatables which generally go to-
66 THE AGE OF ELECTRICITY.
gether, such as pepper and salt, coffee and sugar, almonds
and raisins. He states that he found a voltaic current,
more or less strong, excited in every instance, and that
bitters and sweets, pungents and salts, or bitters and
acids, generally appear to furnish true voltaic couples,
doubtless in consequence of the mutual action of some
alkaloid salt, and an acid or its equivalent. Mr. Smith
gives quite a long list of substances tested. Among his
couples are tea and sugar, raw potato and lemon- juice,
nutmeg and sugar, horse-radish and table salt, onion and
beet-root, vanilla and sugar, starch and iodine, and
tobacco and tartaric acid. The substance firs't named in
each couple takes the place of the zinc, or attacked
element, in the cell.
Mr. Smith suggests that the rationale of the right
blending of flavors " might be found partly, no doubt,
in chemistry, but partly also in galvanism."
One of the most curious batteries is that devised by
Sauer, which appears to act only in the sunlight. It
consists of a glass vessel containing a solution of table
salt and sulphate of copper in water ; within is a porous
cell containing mercury. One element is of platinum,
and is immersed in the mercury : the other is sulphide of
silver, and is placed in the salt solution. Both elements
are connected to a galvanometer. When the battery is
placed in the sunlight, the needle is deflected to a certain
point, and the sulphide of silver is found to be the negative
pole. The action of the battery depends on the effect of
the chloride of copper upon the mercury. Sub-chloride
is formed, and reduces the sulphide of silver ; but this
can take place only by the aid of sunlight.
For the heavy work of electric lighting, or the driving
of electro- motors, batteries are superseded by dynamo-
electric machines, for economical reasons already pointed
THE GALVANIC BATTERY. 67
out; but where large expenditure of energy is not re-
quired, as in the telegraph and telephone, batteries find
a wide utilization. Ultimately they will displace the
dynamo, and in time the steam-boiler. To make them do
this, is the great electrical problem of the century.
68 THE AGE OF ELECTRICITY.
CHAPTER VI.
THE ELECTRO-MAGNET, AND THE CONVERSION OF ELEC-
TRICITY INTO MAGNETISM.
THE tide of a great river moving to the sea is the
embodiment of mighty volume. The mountain stream,
albeit a mere thread of water leaping down from rock to
rock, conve} r s to us the idea of intense energy. The
volume of the river, the force of the torrent, unite in the
great cataract. All of these conditions find their parallels
in the electrical current. From the galvanic battery flows
the slow and steady river ; from the electric machine,
the swift but slender torrent ; and from the dynamo, the
Niagara.
And, as we have seen, the electrical current moving in
its path is governed by laws similar to those which control
water flowing in its channel. We can contract the area
of the conduit to diminish, or enlarge it to increase, the
flow. We can augment or decrease the pressure of either
water or electricity, and so send more or less through the
appointed path in a given time.
A step farther, and the analogy fails. Water acts
directly only upon objects in it or on it. It may float a
vessel, or turn a wheel, or break down barriers ; but the
mightiest flood cannot influence a grain of iron to move
one way or the other, if a few feet of air intervene. Sup-
pose a current of water did have all the properties of an
THE ELECTRO-MAGNET. 69
electrical current : what might happen ? Perhaps, around
and above every stream, there would be a viewless atmos-
phere which we could not penetrate ; an atmosphere in
which the laws of gravity affecting iron and steel would
be set at naught, in which every iron bar would be a mag-
net placing itself across the flood, a most strange and
mysterious medium, in which things of iron and steel
would arrange themselves in curious cuives, whorls and
whirlpools and vortices of iron ; a field of strains and
stresses in something not the air yet in and with the air,
of lines of forces without breadth and unending.
This sounds fantastic when spoken of water. But it is
true of two natural phenomena, a conductor through
which an electrical current is passing, and the magnet.
Around the wire through which electricity is passing, and
in front of the poles of a magnet, exists this strange
aura ; not in imagination, but in fact, for we can make it
visible.
First, however, let us recall something about magnets
in general.
Ages ago, in Magnesia in Asia Minor, were found cer-
tain hard black stones which possessed the remarkable
property of attracting to themselves bits of iron and steel.
These the ancients called magnets, from the name of the
locality in which they were found. And as their behavior
was altogether incomprehensible, the ancients, in accord-
ance with their usual way of dealing with things which
they did not understand, disposed of the problem very
easily by ascribing the phenomenon to the supernatural
powers. It is a little odd, by the way, that pretty much
every thing which the ancients used to attribute to genii
and spirits because unintelligible is unhesitatingly as-
cribed by a large section of their posterity to "electri-
city ; " the mere mention of the word being quite sufficient
70 THE AGE OF ELECTRICITY.
to account for any thing out of the common run. from
rheumatism to red sunsets.
The knowledge of the ancients about the magnet seems
to have stopped with the fact of its attractive power. The
Orientals, with characteristic largeness of imagination,
were not slow to conceive of the tremendous things which
huge magnets might do. Who does not remember the
story of the third calendar in the "Arabian Nights,"
wherein the story-teller recounts the remarkable fate which
befell his ship ?
" A sailor from the mast-head gave notice that he saw
something which had the appearance of land, but looked
uncommonly black. The pilot, on this report, expressed
the utmost consternation. ' We are lost ! ' said he : ' the
tempest has driven us within the influence of the black
mountain, which is a rock of adamant, and at this lime
its attraction draws us toward it : to-morrow we shall
approach so near that the iron and nails will be drawn out
of the ship, which of course must fall to pieces ; and as
the mountain is entirely inaccessible, we must all perish/
This account was too true. The next day, as we drew
near the mountain, the iron all flew out of the ship : it fell
to pieces, and the whole crew perished in my sight."
For a great many centuries, the world knew simply that
magnets would attract iron. Then somebody tradition
says the Chinese (which is convenient, because every-
body knows they were civilized ages ago, and if they did
not have modern improvements then, no one can dispute
to the contrary) hung up a magnet by a thread, and
discovered that it pointed north and south. After that it
was called the loadstone (leading stone), and the mari-
ner's compass came into existence. Now we know the
magnet as an ore of iron, miueralogically termed magnet-
ite, and chemically Fe 8 O 4 .
THE ELECTEO-MAGNET. 71
This knowledge, however, useful as it is, has not pre-
vented people from trying to press the magnet into service
as a means of solving that long- vexed problem, of lifting
one's self over a fence by one's own boot-straps. Where-
fore they have invented or rather failed to invent
magnetic motors, not electro-magnetic motors, which
are quite another thing, but motors depending on the
constant attraction of permanent magnets. Every once
in a while, some one announces the accomplishment of
this feat, which primarily depends on cutting off the at-
traction of the magnet by causing the latter to move some-
thing in the way of a screen between its own pole and
the thing attracted. Unfortunately, magnetic attraction
refuses to be cut off in any such way. It is as stubborn in
this respect as the attraction of gravity, which it very
much resembles.
In that same famous work which began the modern
science of electricity in 1600, Dr. Gilbert's " De Mag-
nete," it was announced that the attractive power of
a magnet, when in elongated form, resides at the ends.
These, Gilbert called the poles ; and he also pointed out
that the intermediate region attracted iron-filings less
strongly, while midway between the poles there was no
attraction at all. Every magnet, large or small, has these
poles : they are inseparable. We may grind a magnet
into powder : every grain will be an independent magnet,
having its opposite poles. Furthermore, just as there ap-
pear to be two kinds of electricity, high potential and
low potential, or positive and negative, so these two poles
appear to have opposite characters ; one tending to move to
the north, the other to the south. Hence the poles are com-
monly called, respectively, the north and the south poles.
When the poles of two magnets are brought together, like
poles always repel, while unlike poles attract each other.
72 THE AGE OF ELECTRICITY.
To Gilbert is due the distinction between magnets and
magnetic bodies. A magnetic body is a body capable of
being magnetized, such as a piece of iron. Either pole
of a magnet will attract a magnetic body ; but two mag-
nets will attract or repel each other, according as unlike
or like poles are presented. Gilbert also made the ex-
traordinary discovery that the earth is a huge magnet ;
that its poles coincide, nearly, with the geographical North
and South Poles ; and that therefore it causes the freely
suspended magnet which forms the compass needle to
place itself in a north-and-south position.
And now we reach a fact about magnets which is be-
wildering, because it tends to upset all our notions about
time. If we present a magnet to a bit of iron, we see the
iron attracted apparently instantly. We should be ready
to assert, by all the evidences of our senses, that abso-
lutely nothing could happen between the instant the mag-
net is presented and the instant the iron is attracted. Yet
something does happen. Before that magnet can attract
the iron, while the iron is yet distant from it, it must
alter the whole magnetic state of the iron mass. The
magnet must induce, on the end of the iron nearest it, a
pole of opposite name to the pole presented ; and at the
farther end of the iron, a pole of the same name. In
other words, it must convert the magnetic body into a
magnet. Having done that, it repels one end, and at-
tracts the other. But this is done before the attraction
begins ; but in what period of time we do not know, nor
could we form the faintest conception of its duration if
we did.
Why does a magnet act in this way? What is the mys-
terious atmosphere surrounding it, which makes it repel
or attract bodies, or convert other bodies into magnets?
There is a theory, a very learned one, which is al-
THE ELECTRO-NAG NET. 73
together too deep for these pages, so it is left out ; but,
without going into that, we can see for ourselves the
effects of this atmosphere, in a very satisfactory way.
If we take an ordinary bar magnet, and place a piece
of paper or, better, glass over one of its poles, and
sprinkle finely sifted iron-filings on the glass, we shall see
these filings arrange themselves in curious curves, appar-
Fig. 19.
ently radiating from the pole, as in Fig. 18. If we sub-
stitute for the bar magnet a horse-shoe magnet, and place
the glass over both poles, we shall find that the lines
74
THE AGE OF ELECTRICITY.
diverge nearly radially from each pole, and curve around
to meet the opposite pole, as in Fig. 19. If we take two
horse-shoe magnets, and place like poles facing each other,
then the filings curve away as if repelling each other, as in
Fig. 20 : on the other hand, if we bring opposite poles of
the magnets into proximity, then the filings curve around
from one pole to the other. The actual appearance of the
Fig. 21.
iron-filings
iron-filings is here shown, in Fig. 21. The
represented were dusted over glass plates supported on
the poles of the magnets ; and when they had assumed
THE ELECTEO-MAGNET. 75
the positions clue to the magnetic influence, they were
fixed in place by an adhesive substance, and the plates
were used as photographic negatives, whence the engrav-
ings were produced.
Now, what does all this mean? Simply, that the mag-
net is telling its own story, writing it, in fact, for us to
read. We know perfectly well that iron-filings will no
more arrange themselves in rows or curves, of their own
volition, than books will place themselves in rows on
shelves ; and that there must be some force which tends
to place the filings in these lines. We notice also that the
curves are closer together near the poles, and, in fact, the
filings resemble a crowd of people massed around some
common object of interest : the crowd is thickest around
the object, and more scattering as the distance therefrom
increases.
It appears, therefore, that around the pole of a magnet
exists this strange atmosphere to which we have already
referred, a so-called "field of force," in which exist
strains and pulls and pushes as if a host of infinitesimal
beings were at work seizing upon the filings, and arran-
ging them to make them accommodate themselves to this
new condition of affairs. And the result of it all is, that
we recognize seeming lines of force radiating from the
pole. It is a wonderful atmosphere, that magnetic field.
We have only to move a piece of iron in it, in a peculiar
way, to make speech heard miles distant, or to produce
the light which is weaker only than the sun in power ;
and what still stranger things may yet be done, no one
knows. Meanwhile these lines of force, which we see
mapped for us by the iron-filings, have some singular
properties of their own. They never have a free end.
The finding of a free end to a magnetic line, and of the
place whence the rainbow rises, and the invention of a
76
THE AGE OF ELECTRICITY.
magnetic motor, are all will-o'-the-wisps together. Every
magnetic line that starts gets somewhere. If apparently
curving from a north pole, it will end in a south pole,
perhaps the south pole of the same magnet, perhaps the
south pole of some other magnet, and perhaps in a south
pole induced by itself in a magnetic body.
There must be,
however, a magnet or
magnetic body ; and
Gilbert, the reader
will remember, not
tSih-er C/tit/vv ^~ Gilbert who wrote
"De Magnete," but
a later Gilbert who
wrote "Pinafore"
and ' ; Patience,"
has very clearly de-
monstrated this in a
pathetic ballad about
a magnet which vainly attempted to attract a silver churn.
That magnet sent out no lines of force toward the silver
churn ; and perhaps it may be well to illustrate this sad
condition of affairs, just to fix the idea in our minds. No
lines of force in Fig. 22 go to the silver churn ; but if
the churn had been of iron, the result, as we see, would
have been very different, and then
" This magnetic
Peripatetic
Lover who lived to learn,
By no endeavor
Can magnet ever
Attract a silver churn,"
Iron C/iur/v
Fig. 22.
might not have wasted his rejected fascinations.
THE ELECTRO-MAGNET.
77
And this also, by the way, indicates the reason why the
officers of Atlantic steamers show so much uneasiness
when young ladies persist in bringing their sewing appara-
tus into the neighborhood of the compasses. The lines
of force from the north pole of a very sedate and responsi-
ble compass-needle may find easily a south pole in the
frivolous knitting or crochet needle, and, turning in the
direction of the latter, may lead the ship miles from her
course.
It has been said that a magnet, when it attracts a body
of magnetic material, first induces magnetism in the latter.
Thus by simply placing a piece of iron in a magnetic field,
and taking it out again, we can render that iron magnetic
or non-magnetic, as it is termed, by induction. If, how-
ever, we wish to render the metal permanently magnetic,
we can do so by rubbing it with a permanent magnet in a
peculiar way.
We have stated that in two instances in nature this
strange surrounding atmosphere is produced. We have
seen it proved by the behav-
ior of the iron-filings in the
neighborhood of the pole of
a magnet. It remains to de-
tect it around the conductor
of an electric current. This
is easily done. Take a piece
of card, or, better, a sheet of
glass, through which a hole
has been drilled, and pass the
wire through which the current
is moving, through the hole.
Then sprinkle iron-filings around the wire. The filings
will arrange themselves in a series of concentric circles,
just as if they were controlled by a whirlwind, around the
Fig. 23.
78
THE AGE OF ELECTRICITY.
wire. This is beautifully represented in Fig. 23, which has
been prepared from a photograph. If the wire is carried
parallel to and across the glass plate as in Fig. 24, the
filings will arrange them-
selves in straight lines per-
pendicular to the direction
of the wire and at equal
distances from one another ;
and may be regarded as a
number of repetitions of
Fig. 23, strung upon a wire,
and looked at edgeways.
This is different from
F '9' 24 - what happens with the
magnet. Compare Figs. 18 and 23.
If we suppose the lines of force indicated by the iron-
filings to represent a wind
blowing, then a flag placed
near a magnet would stand
as in Fig. 25; whereas, ;,'^
if the flag were placed near
the wire, it would stand as in Fig.
Fig. 25.
26. A suspended
magnetized needle would place it-
self in the same positions with ref-
erence to wire or magnet, under the
influence of the lines of force.
A wire conducting a current,
therefore, is surrounded by lines of
force like those surrounding the
natural magnet, but differently dis-
posed. Such a wire is, in fact, a
magnet. It will attract iron-filings ;
and they will cling to it as long as the current continues,
but drop off as soon as the current stops.
THE ELECTRO-MAGNET.
79
Now, suppose we wind our conducting wire into a helix
or coil, as in Fig. 27. If the entire length of the wire is
surrounded by the whorl of lines of force, clearly a great
many of these lines will /.
converge in the space in-
side the coil, and we shall
have there a very strong or
concentrated field of force.
Into this field we can easily
insert an iron bar, which will then become very strongly
magnetized. That is, just as it would become a magnet
if placed in the field of another magnet, so now it
becomes a magnet when placed in the field of force of
the wire.
This is very perfectly illustrated in Fig. 28. Here the
wire is represented with a turn in it, and the lines are thus
Fig. 27.
Fig. 28.
Fig. 29.
perpendicular to the plane of the loop. The filings now
form themselves (as far as the plate will allow them) into
lines perpendicular to the plane of the paper, and there-
fore, as seen from above, appear simply as isolated dots
or points. Fig. 29 illustrates the lines of force brought
into play in the manner above described in the induction
80 THE AGE OF ELECTRICITY.
of magnetism in an iron bar when an electric current is
sent through a wire coiled around it. It represents a
small electro-magnet, showing four turns of its coil. In
the actual experiment, the bar was a strip of ferrotype
iron, and the wire carrying the current was threaded
through the eight holes, four being on one side of the bar,
and four on the other.
The iron bar or core of an electro-magnet, as we have
said, temporarily behaves like a permanent magnet. It
has a magnetic field of its own, with endless lines of force,
and, in fact, is a permanent magnet as long as the
electrical current flows in the coil surrounding it. And
it is worth while to
repeat this very im-
portant distinction.
A permanent magnet
is always a magnet :
an electro-magnet is
not a magnet except
Fjg 30 when the electrical
current is passing
through its coil. It i3 a difficult thing, comparatively
speaking, either to convert a piece of iron into a per-
manent magnet, or to render a permanent magnet free
from magnetism. On the other hand, an electro-magnet
is energized or de-energized witli infinite rapidity, by
simply establishing or stopping the current in the coil.
The poles of a permanent magnet are fixed : those of an
electro-magnet depend upon the direction of the current,
Thus, in Fig. 3-0, supposing the inner shaded circle to rep-
resent the bar, or "core" of the magnet, if the current
moves in the coil represented by the outer circle in the
direction of the arrow in 1, that is, in the same direction
as the hands of a watch, the end of the core facing us is
THE ELECTRO-MAGNET.
81
JElecti'o Miufiiet
Core
a south pole. If the current travelled the other way> as in
2, the same end of the bar would be a north pole. So
that we can not only make and unmake an electro-magnet,
b}^ establishing or breaking the current ; but we can
reverse the polarity of the magnet at will, by simply
reversing the direction of the current in the coil.
In Fig. ol is represented in diagram an electro-magnet
which communicates with a battery ; and a circuit-closing
key^ by manipulating which we can establish or interrupt
the current from the battery through the coil of the mag-
net. In front of the core hangs a piece of magnetic
metal, called the ar-
mature; and this is
held away from the
magnet by a coiled
spring fastened at its
opposite end to a
fixed post. In Fig.
31, the key is shown
raised ; no current ^
then passes to the ^
coil, and the bar is Fig. si.
not a magnet.
If, however, we press down the key, then the current
from the battery will instantly circulate through the coil ;
the core will become a magnet, and attract its armature ay
indicated by the dotted lines. If we break the circuit
again, the armature, no longer attracted, will be drawn
back by the spring ; and hence we can keep that armature
vibrating to and fro as often as we can make and break
the circuit. As the magnet may be quite strong, it may
attract its armature with much force, so that we can make
the armature drive mechanism. This is how the electro-
magnet converts electricity into mechanical motion in the
82
THE AGE OF ELECTRICITY.
great majority of electrical devices, including the tele-
graph, the electro-motor, and the countless alarms and
kindred apparatus to some of which reference will here-
after be made.
There is still another way in which the electro-magnet
can vibrate its armature ; and that is by reversing the
polarity of the core, by
simply changing the
direction of flow of the
current. Suppose, in
Fig. 32, a current cir-
culated around the bar
N
Jlrniatwe
Fig. 32.
or core, in the direc-
tion of the arrow ; then
the right-hand end would be the north pole. If, instead
of suspending before our electro-magnet an armature of
magnetic material, we suspended an armature itself a
magnet, having north and south poles, as marked in the
diagram, then, when the nearest end of the electro-magnet
became north, the armature would be attracted, because
unlike magnetic poles would be opposed. But if we
reversed the current, as
8
Fig. 33.
shown in Fig. 33, then
like magnetic poles would
be opposed, and the arma-
ture would be repelled.
So that, by simply making
the current travel first in one way and then in the other,
we can set a magnet or polarized armature into vibra-
tion. If the armature were not polarized, of course the
changing of the current would have no effect on it ;
either pole of a magnet attracting a simple magnetic
body not itself a magnet. We shall find this contriv-
ance largely used in the various practical applications
THE ELECTRO-MAGNET. 83
of electricity ; although perhaps to not so great an extent
as the first-mentioned arrangement,, with which, just as
the steam-engine can be controlled by throttling the steam,
so the magnet is controlled by throttling the current.
As we shall see farther on, electro-magnets can be made
to exert sufficient power to drive locomotives, and do other
heavy mechanical work : so that it is quite important to
know something as to how they acquire this. A magnet,
whether electrical or permanent, has no power of its own.
It can only exert whatever energy is put into it. It is
like a clock-spring : wind it up, and it drives the clock,
not by some inherent clock-driving capacity peculiar to
springs, like the inherent meat-roasting quality ascribed
by Martinus Scriblerus to roasting-jacks, but because
it has been wound up. When a body is rendered mag-
netic, whether by electricity, or by natural means, or by
rubbing, energy is imparted to it. When the magnet
exerts itself, it parts with some of that energy. If it
moves a heavy armature up to its pole, it may expend all
the energy it can exert, and will affect other bodies not
at all. If a permanent magnet thus draws its armature,
it can do no more until the armature is withdrawn. To
take away that armature, requires just as much force as
the magnet used in attracting it ; so that, by this action,
the energy expended by the magnet in attracting ,the
armature is restored to it.
To the electro-magnet, we impart power by the current.
The stronger the current, the stronger the magnet, up to a
certain point. Eventually, however, the iron of the core be-
comes " saturated," that is, it reaches a state when it can
apparently be no longer affected. If the current is kept con-
stant, and the magnet below saturation, then, the greater the
number of turns of wire applied, the stronger the magnet.
An electro-magnet is easily made of a central bar or
84
THE AGE OF ELECTRICITY.
core of iron, around which the insulated wire is coiled like
a spool of thread. Usually the core is made in the form
of a horse-shoe, so that both poles may be applied to one
iron armature. The coil is then divided into two parts, as
shown in Fig. 34. In this engraving the magnet is rep-
resented as having attracted its armature, the plate
immediately beneath the coils, and is sustaining weights
Fig. 34.
on a platform dependent therefrom. An electro-magnet
was designed by Professor Joule, capable of supporting
in this way over a ton, and of exerting an attraction on
its armature of about two hundred pounds per square inch.
The Stevens Institute of Technology possesses one of
the largest electro-magnets in the world. It weighs about
sixteen hundred pounds, and has a lifting force of nearly
forty tons.
THE ELECTRO-MAGNET. 85
It is generally believed that the effect of magnetizing
the iron core is to cause each particle of the iron to try
to set itself at right angles to the direction of the current
in the coil, just as Oersted's needle places itself at right
angles to the wire conveying a current. The result is,
that the irregularly shaped particles place themselves with
their longer axes parallel to the core ; and, as they all do
this, the core as a unit becomes longer and thinner. Of
course it is very hard to realize how this can happen in a
body as dense and hard as iron ; and so it is difficult to
imagine the vibration of the atoms when iron is heated, or
to conceive of the infinitesimal shortness of the paths over
which they must move. Still it is quite certain that this
is what does occur. By actual measurement a rod of iron
magnetized to saturation is found to have increased to the
extent of ^oVon f its length. And even if this change
is too small for our eyes to perceive, it is perfectly easy to
hear it ; for the core can be arranged not only so that it
will give out a very perceptible tick when magnetized, but,
if the current be sent from a telephone transmitter, it will
sing and talk, the sounds being produced simply by
changes in the bar itself.
There is hardly a parallel instance, in the history of
electricity, of a discovery being so rapidly turned to prac-
tical account as was that of Oersted. He performed- his
successful experiment in causing the free needle to be
moved by a current traversing a wire, as we have stated,
in the summer of 1820. Arago and Ampere, in France,
at once began investigations. By the end of the follow-
ing September, Arago announced that he had ascertained
that iron-filings were attracted "by the connecting-wire
of the battery, exactly as by a magnet," and that he had
magnetized a sewing-needle permanently by the galvanic
current. Ampere reported almost immediately, that a
86 THE AGE OF ELECTRICITY.
spiral or helical arrangement of the galvanic conducting-
wire was most advantageous for magnetizing needles.
Early in November, he " perfectly imitated a magnet by a
helical galvanic conducting- wire." Four years later, Wil-
liam Sturgeon made the electro-magnet, using a core of
iron bent in horse-shoe form, coated with varnish, and sur-
rounded with a spiral coil of naked copper wire. Shortly
afterwards, Professor Joseph Henry made his famous
experiments at the Albany Academy, which revealed for
the first time the extraordinary power of the electro-mag-
net. Henry followed the plan, previously suggested by
Schweigger, of covering his wire, instead of merely putting
the insulating material around the coil as Sturgeon had
done. With a magnet wound with twenty-six strands of
copper bell-wire covered with cotton thread, the aggre-
gate length of the core being 728 feet he had suspended
nearly a ton weight. Afterwards, with a small horse-shoe
of round iron, one inch in length and six-tenths of an
inch in diameter, wound with but three feet of brass wire,
he raised a weight 420 times greater than that of the mag-
net itself. Sir Isaac Newton describes a lodestone weigh-
ing three grains, which he wore in a ring, and which is
said to have raised 746 grains, or 250 times its own weight.
This is the greatest recorded strength of any permanent
magnet. Natural magnets, or lodestones, are stronger
than those artificially made. The former usually carry a
load of about twenty times, while the latter are rarely able
to lift a mass exceeding five times, their own weight.
Within recent years, however, very powerful permanent
magnets, equal to the lifting of twenty-five times their
own weight, have been constructed by M. Jamin ; the
advantage being gained through the use of very thin leaves
of thoroughly magnetized steel, bound together to form
the magnet.
Let us sum up some of the strange phenomena thus
THE ELECTRO-MAGNET. 87
far briefly outlined. We have seen that the electrical
current is competent to produce effects not merely in its
channel or conductor, like water turning a wheel,
but to influence bodies entirely outside of that channel.
It causes, around its conductor, a peculiar aura or atmos-
phere like that around the poles of a magnet, but differing
from the latter as a whirlwind differs from a steady gale.
It converts the conductor into a magnet, which, like other
magnets, is capable of influencing magnetic bodies to be-
come magnets. It also converts magnetic bodies, around
which the conductor is wound, into magnets ; and a bar of
iron in this way is given all the properties which it would
have were it normally and naturally a magnet, or piece of
lodestone. This is an electro-magnet. But the magnetic
state of this bar is controllable. It is a magnet, or not,
in accordance as we permit the current to flow, or inter-
rupt it. As a magnet, the bar has different poles, at
opposite ends ; but these poles change reciprocally in
accordance with the direction of the current. By making
and breaking the current, we can make the electro-magnet
attract and release alternately a piece of magnetic mate-
rial, placed in front of either of its poles, and called an
armature. If, however, the armature be itself a magnet,
then we can make the electro-magnet attract or release it
without breaking the current, but by simply changing the
direction of the current, this because, when the magnet
opposes an unlike pole to the adjacent pole of the arma-
ture, the latter will be attracted ; but when the magnet
presents a like pole, the armature will not be attracted, or,
if already attracted, will be released.
Why the magnet, and the conductor carrying a current,
produce this singular atmosphere ; why other bodies act
as they do in that atmosphere ; what the medium is which
carries this unknown force between the separated magnet
and armature, are all unsolved problems.
88 THE AGE OF ELECTRICITY.
CHAPTER VII.
THE DYNAMO-ELECTRIC MACHINE, AND THE CONVERSION OF
MAGNETISM AND MECHANICAL MOTION INTO ELECTRICITY.
Is electricity magnetism ? or is magnetism electricity?
Are these phenomena two different forms of energy? or
are they phases merely of the same form? The last is
probably true.
By means of the electric current, a body capable of
being magnetized may be, as we have seen, converted
into a magnet. We have now to note even more extraor-
dinary results following the reverse of this ; namely, the
production of electrical currents by magnets.
In the fall of 1831, Professor Faraday announced that
from a magnet he had obtained electricity. On the 8th
of February, 1832, he entered in his note-book: "This
evening, at Woolwich, experimented with magnet, and
for the first time got the magnetic spark myself. Con-
nected ends of a helix into two general ends, and then
crossed the wires in such a way that a blow at a b would
open them a little. Then bringing a b against the poles
of a magnet, the ends were disjoined, and bright sparks
resulted. ' '
Next day he repeated this experiment, and then, as was
his habit, invited some of his friends to see the new light.
He had a piece of soft iron, surrounded by coils of wire
insulated with calico and tied by common string. When
THE DYNAMO-ELECTRIC MACHINE.
89
he touched the pole of a magnet with the soft iron, the
ends of the coil, as he says, opened a little, and a spark
passed between them. An electrical current had been
caused in the coil, and Herbert Mayo described it in the
following neat impromptu :
"Around the magnet, Faraday
Was sure that Volta's lightnings play;
But how to draw them from the wire ?
He drew a lesson from the heart :
"Tis when we meet, 'tis Vhen we part,
Breaks forth the electric fire."
Faraday's experiment is very easily repeated with the
aid of the little apparatus represented in Fig. 35. The
operator holds in one
hand an ordinary horse-
shoe magnet, and in the
other a bar of iron around
which is wound a little
coil of insulated copper
wire. On one end of
the coil is a small disk
of copper. The other
end is sharpened to a
point, and brought in
contact with the disk.
On placing the bar across
the poles of the magnet,
and then suddenly breaking contact, the point and the
disk become separated at the same time, and the spark
appears.
Some fifty years earlier, one of those intensely practical
individuals who see no outcome in the results of scientific
discovery unless the same can be immediately estimated
Fig. 35.
90 THE AGE OF ELECTRICITY.
at a money value, rather superciliously asked Franklin
what use there was in the facts proved by certain of his
experiments.
44 What's the use of a baby? " the philosopher retorted.
Faraday's reply to those who saw nothing gained by the
development of the little spark, and who demanded its
utility, was equally sententious. "Endeavor to make it
useful," he said. He left to others the immediate work
of doing so. Some twenty-five years later, he saw that
tiny flash expanded into the magnificent blaze of the
famous South Foreland light-house. To-day it illuminates
the thoroughfares of the great cities of the civilized
world.
The first practical magneto-electric machine was con-
structed by M. Hippolyte Pixii of Paris, in September,
1832. His apparatus consisted of an ordinary horse-shoe
magnet, under the poles of which a powerful steel horse-
shoe was rotated by a shaft. On the steel horse-shoe was
coiled a wire ; and as the ends of the horse-shoe were moved
up to and removed from the poles of the magnet, electric
currents were produced in the coil. The best form of
this apparatus was probably that produced by Clarke
of London, in 1834. This is represented in Fig. 36. It
embodies a large permanent magnet AB, beside the poles
of which are rotated two pieces, or cores, of soft iron,
each encircled by a coil of fine wire, and mounted at the
ends of arms supported on a horizontal shaft ; the shaft
being rotated by turning the large belt-wheel by its handle.
When the coils are rotated in front of the magnet, cur-
rents are produced in them. The coils are connected to
separate metal plates on each side of the shaft, from
which plates the current is led, by springs touching them,
to binding-posts to which conducting-wires may be
attached.
THE DYNAMO-ELECTRIC MACHINE.
91
It will be apparent that these machines are merely
convenient mechanical contrivances for doing just what
Faraday did in the little experiment first described in this
chapter. We have, however, by no means recognized all
that Faraday then discovered.
Fig. 36.
As we have seen, he determined that an electrical cur-
rent was produced in a closed coil of wire when a magnet
was brought up to the coil, or the reverse. The coil
might be moved in front of the pole of the magnet, as in
92
THE AGE OF ELECTRICITY.
Fig. 87.
Clarke's machine above described ; or the magnet may be
moved up to or into the coil, as represented in Fig. 37.
In the latter case, the ends Jf' of the coil may be connected
with a galvanometer, which will
reveal the presence of the current.
It must not be understood that
the mere proximity of the magnet
to the coil produces any current,
for that is not the fact. It is the
motion of the coil to the magnet,
or of magnet to coil, which pro-
duces the current. The actual
mechanical work which we per-
form in moving either coil or mag-
net is converted into the other
form of energy which we call elec-
tricity. But how this is done, is not
easy to realize. We have seen that all around a magnet
exists the so-called field of force, and that magnetic
bodies become magnets on being simply placed therein.
Here, however, is a new property of that mysterious at-
mosphere. If a closed circuit is moved in that Held, a
current will traverse the wire ; or if the field itself, by
moving the magnet,
be brought nearer to
or farther from the
coil, the same thing
will happen.
It is necessary,
however, that the
motion should be
made in a certain way ; that is, so that, by reason of the
change of its position, either more or less of these singu-
lar endless lines of force which make up the magnetic
THE DYNAMO-ELECTRIC MACHINE.
93
field shall pass through the coil. There are various ways
of doing this. We can move our coil from a place where
the lines of force are very numerous, as near the pole
of a magnet, to a place where they are not so numerous,
as indicated by the positions 1 and 2 of the ring in Fig.
Fig. 39.
Fig- 40.
38, or 1, 2, and 3, in Fig. 39. Or, we can turn the coil
on its axis, as in Fig. 40 ; in which case, fewer lines of
force will pass through it when it lies horizontal than when
it stands upright. Or, we can move the coil simply past
the pole, as in Fig. 41 ; the coil here travelling in the
direction of the arrow successively into the positions 1, 2,
3, so that it thus moves into and out of the field of the
magnet. If, however, the coil should be so moved that
the number of lines of force passing through it is not
changed, then no current would be produced in its con-
volutions.
94
THE AGE OF ELECTRICITY.
We can easily imagine lines of force extending from the
pole B of the magnet in Fig. 37 ; and hence it will be
apparent that more or less of these lines will be cut, or,
rather, that more or less of them will enter the enclosing
coil, whether the magnet be moved into or out of the coil,
or, conversely, whether the coil be moved on and off the
magnet.
If, for the permanent magnet of Fig. 37, we substitute
an electro-magnet as in Fig. 42, the results will be the
same. The field of force now
produced at the pole or end of
the core resembles the field of
force of the natural magnet ;
and the same movements of
either coil or magnet, as de-
scribed with reference to the
preceding figure, will cause
currents in the large coil.
Fields of force, however,
exist not merely around the
poles of magnets, but around
wires conveying currents ; and
the properties of the atmos-
pheres, in either case, are simi-
lar. If this be true, then it
should follow, that if, in Fig. 42, we remove the magnet
bar altogether, and retain simply the wire coil, the current
circulating in that coil should produce around it a field
of force which should set up a current in another and
adjacent coil. This is the fact, and it forms a later dis-
covery by Faraday.
In Fig. 43, the small coil of wire connected with the
battery, and hence conveying a current, is introduced into
and removed from the large coil connected with the gal-
Fig. 42.
THE DYNAMO-ELECTRIC MACHINE.
95
vanometer. Whenever this is done, the galvanometer
needle swings, proving the existence of a current in the
larger coil.
So far, we have dealt with moving bodies. A magnet,
permanent or electro, moved with reference to a closed
coil, produces in the latter a current. The coil, moved
with reference to the magnet, accomplishes a like result.
A coil of wire in which a current is flowing, moved with
reference to a closed coil in which there is no current,
Fig. 43.
causes a current in the latter : conversely, if the closed
coil be moved. In all of these cases, it is the energy of
motion, as we have stated, which causes the electrical
current.
There is, however, one instance where we can cause a
current in the closed coil, from the coil in which the cur-
rent is circulating, without moving either of the coils ; and
that is simply by starting and stopping the current. The
coils are placed in proximity, .as one within the other, and
so fixed. When there is no current in one coil, there is
96 THE AGE OF ELECTEICITY.
of course no atmosphere of force to enter the other. The
instant the current is established, the atmosphere exists.
It comes into being, and affects the outer coil, for example,
the same as if the inner coil were moved into it. So, when
it disappears, the effect is as if the inner coil were moved
out. This is the principle of the inductorium, or induction
coil, which is fully described in another chapter.
To recapitulate, therefore : If we bring a closed coil of
wire into the strange magnetic atmosphere, we shall cause
a current in the coil. So when we take it out. So when
we move it from a dense to a thin part of the atmosphere,
or vice versa. And it makes no difference, in substance,
whether we bring the coil into the atmosphere, or move
the atmosphere (by moving the thing which it surrounds)
into proximity to the coil, or cause the atmosphere sud-
denly to come into existence around the coil.
Whatever happens is the result either of the coming
into or going out of existence, or of proximity, of the
magnetic atmosphere, with relation to the coil ; or of
changes in the position of the coil in that atmosphere.
To speak .of the coil enclosing more or less of the lines of
force, and the current in the coil attending the change, is
one convenient way of realizing what occurs. We can
express the same idea by saying, that, in order that the
coil may have a current in it, it must cut the lines of force
in its motion, that is, move across them. These theories
are, however, waning. The more modern view is, that the
molecules of the wire in the coil are in a condition of
equilibrium, liable to instant change ; and this occurs the
moment the particles enter the magnetic atmosphere, or
field of force, where they become subject to new strains
and stresses, which introduce new conditions of balance.
In effecting the necessary molecular changes, an expendi-
ture of energy is involved, which results in the current.
THE DYNAMO-ELECTRIC MACHINE. 97
This theory has been very fully elaborated by Professor
Sprague.
Of course the three theories are, after all, only different
ways of saying the same thing. If a coil moves from one
part of the field to the other, so that more or less lines of
force pass through it, it must cut or pass across lines
of force in so moving ; and similarly, if, in order to have a
current caused in it, it must proceed from one part of the
field to another, in which the strains and stresses due to
the lines of force shall be different, it follows necessarily
that it must go to a place where different lines of force
(more or less) exist.
It is not necessary, however, to proceed farther into the
realm of theory. For present purposes it is sufficient to
recognize that there is a very broad distinction between
producing an electric current in a coil of wire by reason
of the actual motion of the coil in the magnetic field, or
of the field about the coil ; and by reason of the establish-
ment or change of strength in a magnetic field about a
stationary coil. In the one case, we convert the energy of
mechanical motion into electricity : in the other, the energy
of one current engenders another current.
With the apparatus wherein the character of the current
is changed by the induction of one stationary coil upon
another, we have nothing to do in this chapter.
We have frequently referred to the field of force which
surrounds the magnetic pole, or current-conducting wire,
as an atmosphere. This is a convenient way of thinking
of it ; but in fact it is nothing material or tangible, as the
air, for example, is which surrounds our earth. The same
effects are present, even when the most perfect vacuum
exists around the magnet ; so that it is probable that the
magnetic action is propagated through space, by move-
ments or pressure in the ether which is supposed to per-
98 THE AGE OF ELECTRICITY.
vade the entire universe, to exist between the atoms of
all bodies, however solid, as an infinitely thin though jelly-
like medium.
One other important fact remains to be noted, before
we examine the construction of the machines which pro-
duce electricity ; and that is the changes in the direction of
movement of current in the coil. In referring to the elec-
tro-magnet, in the preceding chapter, we have found that
the poles of the magnet depend on the direction of the
current traversing the wire, and that we can reverse the
pole simply by reversing the direction of the current.
The direction of the current of a coil which is moving in
a magnetic field depends upon whether the coil is moving
from a place where it encloses more lines, to a place where
it encloses less lines, or the reverse. The current moves
in one direction in one case, in the opposite direction in
the other ; and we shall' presently see the effect of this
reversal in practice.
In the upper part of the Western Union Telegraph
Company's building in New York, there is a large room
in which are disposed tier upon tier of galvanic cells.
There is no clatter and rush of machinery, no noise except
such as rises from the busy street without, or comes from
the numberless telegraph-instruments in another part of
the building. Here are generated the electrical currents
which are to find their way over thousands of miles of
wire, and carry the messages of the great metropolis
throughout the country.
Not far from the telegraph-offices is the establishment
of one of the corporations which provide the electric
lights which now illuminate the city thoroughfares ; and
here are generated the currents which feed these miniature
suns. But now, instead of the perfect silence with which
THE DYNAMO-ELECTRIC MACHINE. 99
the mighty forces of chemical affinity do their work in the
battery, there is the thunder of great engines, the roar of
the escaping steam, and the bewildering whirr of the huge
dynamos. The visitor is warned away from the wires : it
is death to touch them. Here and there are brilliant flashes
of light. An odd odor is in the air. But above all there
is motion, as driving, as headlong, as impetuous, as
unremitting, as that of the locomotive in its hurried
course.
As we become accustomed to the confusion and noise,
we find that the source of power is a steam boiler, and
that the steam drives a steam-engine, no different from
other steam-engines except that it is constructed to run
with especial steadiness and uniformity. The work of
this steam-engine is to turn the "dynamo; " and in and
by the dynamo, the electricity is produced. This is ob-
viously very unlike the production of the current by a
battery. There are no chemicals here, no zinc consumed.
The engine simply rotates the dynamo shaft ; and in the
wires leading from the machine the current circulates, and
goes to the lamps.
The idea will perhaps occur to us, that, inasmuch as
here is a machine which is rotated, and which produces
electricity, we perhaps have in the dynamo only some
more modern and improved form of the old frictional or
static machine, in which the glass or sulphur cylinder is
excited by rubbing. This is very wide of the truth. If
we could see into the dynamo, and it is quite possible
to do so, in some forms of the apparatus, we should at
once discover that the thing revolved does not rub against
any thing, but apparently turns freely in the air. We
should also notice that the revolving object is substantially
a solid mass ; that there is nothing moving inside of it.
On closer examination, we should find it to be a bundle
100 THE AGE OF ELECTRICITY.
of wires ; and if we examined the mass of metal which
surrounds this rotating mass of wire, we should find that
the same was a magnet or perhaps several magnets.
We thus recognize the dynamo as a machine wherein
coils of wire are moved in a very intense magnetic field
produced by the encompassing magnets ; and, from what
has been before explained, we know that it is simply
requisite to dispose these coils so that they will be carried
through this field, embracing at times more and at times less
of the pervading lines of force, to cause in them currents of
electricity. This, however, is exactly what is done in the
old Clarke magneto machine, represented in Fig. 36 ; so
that there is no difference in principle between the dynamo
and the magneto-electric machine as an electrical generator.
But we shall further find, that in lieu of the perma-
nent magnet, for producing the field, the dynamo has an
electro-magnet ; and we have seen that the strength of
an electro-magnet is not a permanent and fixed quantity,
but, up to the point of so-called saturation, depends upon
the strength of the current in the coils surrounding its core.
In this way we can make immensely strong magnets, and,
consequently, immensely strong fields of force ; and, the
stronger the field, the more lines of force there are in
it. Hence if we rotate coils of wire through that field, they
will cut large numbers of lines of force ; and the conse-
quence of this is very strong currents produced in the coils.
And thus it becomes possible to obtain, from dynamo-
electric machines, currents of electricity far stronger and
more powerful than ever could be got from magneto-
electric machines.
Let us now analyze this mechanical generator of elec-
tricity a little more closely. The two principal parts of
the machine are the magnets which make the field of lines
of force, or the field-magnets, and the body which
THE DYNAMO-ELECTRIC MACHINE.
101
r
Iron
Fig. 44.
revolves in that field. This body is called the armature ;
and it consists of a core or mass of magnetic metal, such
as iron, and the coils wound thereon. We have already
seen, that, when an armature of iron is placed before the
poles of a magnet,
the lines of force
will apparently run
into the armature.
Consequently, if we
place the coil which
is to receive and to
cut these lines of
force, on an iron
body, we place it on
something which will
apparently draw the
lines of force into the coil. If we made the support for the
coil of wood, for example, then very much fewer lines of
force would pass through the coil. This difference will be
clear from Figs. 44 and 45, which show the lines passing to
an iron armature, and the lines
unaffected by the wooden one.
Now let us see what happens
when a coil which, for con-
venience, we will represent by
a simple ring moves around
between two strong magnetic
poles. In Fig. 4G, these poles are represented at N and
S ; the ring is supposed to assume the several positions
represented. We are going to see a paradoxical state of
affairs, which will require some thought which the reader
can avoid, if he chooses, by skipping the next page or so,
and reading only the conclusion of the explanation.
The lines of force pass almost directly between the
N
Fig. 46.
102 THE AGE OF ELECTRICITY.
poles, as represented by the dotted lines. Beginning at
the left, the ring at first stands nearly horizontal, so
that hardly any of the lines of force thread through it.
As it is carried upward and around, in the direction of
the arrow, toward a vertical position, the number of lines of
force passing through, however, increases ; and a current
is set up in the ring, in the direction of the small arrows.
As it moves farther, it receives more and more lines ;
and finally when it reaches the central point, marked by
the vertical dotted line, the number of lines passing
through reaches a maximum. Then the ring begins to
turn flat-ways again ; the lines passing through it now
commence to decrease in number, and the current in the
ring changes direction. The decrease in the lines goes
on until the ring becomes once more horizontal. Now the
ring enters the lower right-hand quadrant, and begins to
thread more lines of force. But here the current does
not appear to change direction. This is because we have
reversed the ring itself, and the lines of force are entering
the opposite side from that hitherto presented ; so that,
although we have an increase in the lines of force, the
current apparently continues in the same direction. This
state of affairs goes on until the ring passes the central
point, when the lines of force running through it begin to
decrease. This reverses the current in the ring, which
after passing through the left-hand lower quadrant reaches
its starting-point.
It is not particularly easy to understand this, chiefly
because it is necessary to bear in mind both the reversal
of the current and the reversal of the ring. The current
changes in space on passing the pole where the lines de-
crease or increase, so that there is no variation from the
law. But it does not change with reference to the ring.
This can be shown rather neatly in the following way :
THE DYNAMO-ELECTRIC MACHINE. 103
Let the black circle of Fig. 47 represent the ring, with the
currents flowing in it in the direction of the arrows,
that is, in the direction in which the hands of a watch
move. Now let the reader hold this page up to the light,
and look at the figure from the rear of the page. It will
look like Fig. 48. According to the
arrows, the current will be moving op-
posite the hands of a watch, and in just
the reverse direction from before. That
comes from simply reversing the ring.
Suppose, however, that when we looked
at the ring reversed by ourselves, the
currents reversed simultaneously on
their own account : then, instead of the arrows appearing
as in Fig. 48, they would appear in the reverse direction as
in Fig. 49. But Fig. 49 is just the same as Fig. 47 , which,
as the geometry says, was to be proved.
The sum and substance of all this is, that, when the
coil is carried around in front of the poles, the current
produced in it reverses in direction every time it passes
the neutral line between the poles.
This is what electricians call an alter-
nating current ; and, while it is not
particularly important for the non-pro-
fessional reader to consider very deeply
why or how it thus alternates, it is of
48. some moment that the difference be-
tween what is meant by an alternating
current which is constantly changing its direction like
a pendulum, and a continuous direct current which flows
but in one way like a river, be understood. From the
difference in their capacity to produce either au alternat-
ing or a continuous direct current, dynamo and magneto
electric machines may be divided into two distinct classes.
104 THE AGE OF ELECTRICITY.
Returning now to Fig. 46, it will be apparent, that,
if we arrange a number of coils around a circular disk,
and between the poles of a magnet, we shall get alter-
nating currents from each coil, and thus a succession of
rapid alternations as the coils move swiftly past the neutral
points between the poles. If we had but a single coil,
then, in addition to the current constantly changing direc-
tion, it would, while flowing, vary in strength. This dif-
ficulty we overcome, in a measure, by multiplying the coils
so that each shall be brought successively into operation,
the current beginning in one coil before it has ceased in
another.
Alternating currents are very useful in many cases, but
for most purposes we need a direct,
continuous flow. We find alternating
action in mechanical devices very useful
in pumps and steam-hammers ; but if a
locomotive, for example, could be moved
only a little way in one direction, and
then a little way in the other, it would
not be of much use to draw trains.
Yet this is how the piston in the locomotive-cylinder
travels ; and the piston, in turn, moves the whole great
machine. But the locomotive does not follow the to-and-
fro movement of the piston ; because, when that move-
ment reaches the wheels, it is converted into a uniform
rotary movement by the crank, which pushes the wheel
above the hub, and pulls it below, so that the wheel can
turn in one direction, and the engine goes straight ahead.
There is a little contrivance connected with alternating-
current machines, called a commutator, which does for the
alternating current about what the crank does for the alter-
nating steam-pressure. In its simplest form this is repre-
sented in Fig. 50, and it can be seen on a small scale in
THE DYNAMO-ELECTEIC MACHINE. 105
the engraving of Clarke's magneto machine, Fig. 36
This consists of a simple piece of brass or copper tube,
slit longitudinally into two portions, and fixed upon the
axis of revolution of the armature so as to revolve with
it ; the two halves of the split tube being fixed upon a
small cylinder of ivory or other insulating material. One
half of the tube is attached to one end of the wire of the
coil, or, where there are several coils, to like ends of
the wires of all the coils, and the other half to the other
end or ends. Against the split tube are pressed two
springs or brushes, A A.
Suppose the armature
carrying the coil or coils
to be rotating in the direc-
tion indicated by the arrow
in the engraving. During
one half of the revolution
the current will flow to-
Fig. 50.
ward the commutator, and
during the other half the current will flow from it ; be-
cause, as we have seen, the current reverses during each
revolution of the coil. Now, as each end of the wire is
connected to a separate part of the commutator, it follows
that while the armature is passing one part of its revolu-
tion, say, the upper part, the current will flow to
the commutator plate which is uppermost ; and while the
armature is completing the other part of its revolution,
the current (reversed) will flow from the other, or lower,
commutator plate. Consequently each half of the split
tube will, as it passes over the top of its axis, deliver to
the upper contact spring or brush the current flowing into
it, while the lower contact brush will always (apparently)
be feeding the return currents back to the lower half of
the split commutator tube. So that, if we connected our
106
THE AGE OF ELECTRICITY.
circuit wires to the two brushes, or springs, we should
have a continuous current flowing in the wire from the
upper brush to the lower one.
In general it may be stated, that, in all apparatus of the
alternating-current type, there are a number of coils placed
on the rim of a wheel which revolves, and is surrounded
by fixed magnets. Alternating currents that is, cur-
rents alternately in opposite directions are produced in
the coils, and are either used as alternating currents, or
N
Fig. 51.
are converted into direct currents by being passed through
a commutator before they go to the line wire.
There are two types of direct-current machines, known
after their inventors as the Gramme and the Siemens
forms. A simple diagram of the Gramme apparatus is
given in Fig. 51. The armature is a ring of soft iron,
around which the wire is wound in a continuous spiral,
forming a closed circuit. It revolves between two poles
of opposite names, the lines of force from which termi-
nate in the ring ; as shown in Fig. 52, which represents a
section made through Fig. 51 by a plane in the line NS
THE DYNAMO-ELECTRIC MACHINE.
107
of Fig. 51 and at right angles to the plane of the paper.
As the ring revolves, these lines of force are cut by the
Fig. 52.
moving wires, and electro-motive forces are generated in
the two halves of the ring, in opposite directions, so
that they meet and op-
pose one another at the
neutral points JVP, as in
Fig. 53. As long as no
further connections are
made, no current is gener-
ated. If, however, the/y
points NP are connected
by a wire in circuit, through
a number of lamps, for ex-
ample, as in Fig. 54, then
a current will flow from
P to N. In order to col- fig. 63.
lect the currents from the
ring, a special device, called a collector, is employed.
This is usually made of a cylinder of wood or other
108
THE AGE OF ELECTRICITY.
insulating material, upon which are placed longitudinally
a number of insulated metal strips. Each strip or bar is
connected by a wire to the part of the spiral coil imme-
diately opposite to it, as represented in Fig. 55. At the
points PN, where the opposite electro-motive forces diverge
and join again, two metal brushes rub against the strips ;
and with these brushes the external circuit is connected.
Fig. 54.
The second type of direct-current dynamo emplo} T s the
Siemens or drum armature, in which the coils of wire are
wound lengthways over a drum or spindle ; the wire being
carried along the drum parallel to its axis, across the end,
back along the drum on the side opposite, and so around
to the starting-point ; the separate turns, or groups of
turns, being spaced out at regular intervals all around the
THE DYNAMO-ELECTRIC MACHINE.
109
Fig. 55.
drum. This method of winding is illustrated in Fig. 56.
In each of the wires, as it rises past the south pole, cur-
rents are generated which flow towards the front ; whilst
in the other half of
their revolution, in
descending past the
north pole, the cur-
rents generated in
them flow from the
front towards _ /y
the back. The
method of joining the
coils to the commuta-
tor bars insures that
the currents shall fol-
low one another, and
flow into the upper
contact brush.
We have now recognized the two principal types of
mechanical electrical generators, namely, the alternat-
ing-current apparatus and the direct-current apparatus ;
the difference being in the construction of the armature.
The magnets may
be either perma-
nent or electro, so
that the classifi-
cation applies to
either magneto or
dynamo electric
~ ~ * x machines ; but in
fact all so far
described was invented some years before the modern
dynamo may be said to have begun its existence.
The Siemens armature was devised by Dr. C. W. Sie-
110 THE AGE OF ELECTRICITY.
mens, in 1856 ; and the continuous-ring armature was con-
trived by Dr. Pacinotti of Florence, Italy, in 1860. The
compound multipolar armature dates back farther than
either.
In 1867 Mr. H. Wilde replaced the permanent field-mag-
nets by electro-magnets ; and these he excited by means
of a small separate magneto electric machine having
itself permanent steel magnets. This was a very ma-
terial improvement ; because the small magneto machine
utilized all its current in exciting the electro-magnets of
the larger apparatus, which thus were enabled to produce
a very intense field of force. Following this came the
quadruple yet independent discoveries of Hjorth, Varley,
Siemens, and Wheatstone, that there was no need of a
separate exciting machine, for the generator could be
made to excite itself. This is somewhat paradoxical at
first, but in reality not at all difficult to understand. It
is necessary, to begin with, that the field magnets should
have some little magnetism of their own. A very little is
quite sufficient. If they are magnetic at all, they have
a field of force ; and in the coils of an armature rotating
in that field, there is therefore produced a very weak
current.
Now suppose that the wire which constitutes the arma-
ture coil forms also the enveloping coil of the field-mag-
nets : then the current produced on the armature will
circulate around the field - magnets, and increase their
magnetism. Then, of course, their field of force will
become stronger, and so will the current in the arma-
ture ; and in this way the cycle will be completed. The
result is, that, in a few seconds after the armature is
set rotating, the field-magnets are magnetized to satura-
tion, or to as great a degree as they are capable of
reaching. This is called the dynamo electric machine ;
THE DYNAMO-ELECTRIC MACHINE.
Ill
in centra-distinction to the apparatus already described,
wherein the magnets are permanent, or always of the
same strength.
When the dynamo is intended to produce alternating
currents, the separate-excitation system is employed. This
is illustrated in Fig. 57. A small separate magneto ma-
chine, not shown, energizes the large field-magnets S N
by circulating in the coil surrounding the same, as shown
Fig. 57.
Fig. 58.
by the arrows. The current produced by the dynamo,
whose magnets are thus excited, moves in a separate
circuit, as shown.
Fig. 58 represents- a self-exciting dynamo, on what is
termed the series system. Here the current, taken at one
of the brushes of the commutator, passes around the field-
magnets, and then through the main circuit, and so back
to the other brush.
Fig. 59 represents a self-exciting dynamo on the so-
112
THE AGE OF ELECTRICITY.
called shunt system. In this arrangement, the current
is divided ; part going from the brushes around the mag-
nets by way of the thin line of wire, and part going by
the main line to the external circuit.
Various other arrangements of the circuit wires for ex-
citing the field-magnets in dynamos have been invented.
The foregoing are, however, the most important.
Inasmuch as the currents pro-
duced by a dynamo-electric gener-
L| _____ ator depend upon the cutting of
tj | \ the lines of the field of force by
the armature, it follows that it is
necessary, in order to obtain pow-
erful currents, to cause the arma-
ture coils to cut as many of these
lines as possible in the shortest
time. To this end, the armature is
made to rotate very rapidly, and
is given a large number of turns
of wire, or coils enclosing as much
area as possible. In order that the
current may not be wasted in over-
coming the resistance of the arma-
ture coils, these are made to offer as little resistance as
possible ; and, finally, as the number of lines of force
to be cut depends on the strength of the field of force,
the field-magnets are placed to concentrate the lines of
force as much as possible across the space where the
armature revolves.
There is an immense variety of forms of dynamo and
magneto electric apparatus ; and to review them, even in
the briefest manner, would far exceed our present limits.
Only a few typical machines are therefore given.
Fig. GO represents the De Meritens magneto-electric
Fig. 59.
THE DYNAMO-ELECTRIC MACHINE.
113
machine. This contains one or more rings carrying coils
which revolve between the poles of powerful steel magnets.
As the wheel revolves, the polarities of the cores are con-
stantly reversed, and currents are therefore induced on
Fig. 60.
the wires. The ring is of light brass, and the coils are
wound upon iron cores. This is an example of an alter-
nating-current magneto machine.
An alternating-current dynamo is represented in the
114
THE AGE OF ELECTRICITY.
Siemens machine shown in Fig. 61. This consists of
two fixed iron rings carrying electro-magnets, which are
excited by a small auxiliary direct-current machine. The
polarity of the magnets in each ring is alternately north
and south, and the polarity of each is opposite to that of
Fig. 61.
the magnet facing it on the other ring. Each magnet has
an extended flat pole plate, as shown. Between the two
rings of magnets, revolves a wheel partly of wood, partly
of metal, carrying in its circumference a number of coils
equal to the number of magnets in each ring. As the
wheel revolves, currents are induced in these coils in the
THE DYNAMO-ELECTRIC MACHINE.
115
manner already explained. The currents are taken off by
springs.
The Brush machine belongs to the same general class
as the foregoing, but differs in the construction of its
armature, which consists of a wrought-irou ring, around
which the wire is wound in the hollow channels, as shown
in Figs. 62 and 63. The ring revolves between magnets
having extended pole pieces, the two opposed poles at the
same side of the ring being of the same name.
The Siemens machine represented in Fig. 64 has an
armature in the form of an
iron cylinder, around which
the wire is wound longitu-
dinally so that the wire is
parallel to the axis. The
collector consists of a num-
Fig. 62.
Fig. 63.
ber of strips of metal fixed on an insulating barrel. The
magnets are bars of wrought iron, straight at the ends and
curved in the middle. The current in the magnetizing-coils
has such directions that the whole of the curved portion of
the magnets at the top of the machine has one polarity,
and that at the bottom of the machine the opposite. The
outer ends of the upper and lower magnets, which are of
opposite polarities, are connected by yoke plates in the
usual way.
116
THE AGE OF ELECTRICITY.
Fig. 65 represents a large Edison machine. The arma-
ture consists of a number of disks of thin iron plate, sep-
arated by paper, and grouped together to form a barrel
about three feet six inches in length. A number of cop-
per bars are laid on the circumference of this barrel, par-
allel to the axis. The diameter of the barrel outside the
bars is twenty-eight and a half inches. The bars are con-
nected so as to form a continuous circuit, analogous to
Fig. 64.
the longitudinally wound wire in the Siemens machine.
The whole armature revolves between the poles of a very
large electro-magnet ; these poles being immense blocks
of cast iron, which nearly meet, but are kept apart by the
brass distance pieces seen in the front of Fig. 65. The
lines of force from the magnets terminate in the central
iron barrel. The magnet coils are twelve in number, and
are each eight feet long. This machine will maintain
from a thousand to twelve hundred lamps of sixteen-
Fig. 65.
THE DYNAMO-ELECTRIC MACHINE. 117
candle power each. Its total weight is about twenty-five
tons.
The foregoing examples will suffice to give a general
idea of how dynamos are constructed. Of the two prin-
cipal types, those which give the direct current are the
best for general use. For electro-plating and other electro-
lytic operations, a direct current is, in fact, essential ; and
it is necessary, of course, to maintain the continuous mag-
netization of electro-magnets.
Alternating-current machines are simpler in construc-
tion ; and their current, as will be seen hereafter, is espe-
cially adapted to incandescent lamps. They cannot excite
their own magnets, nor can they drive existing electro-
motors. Good dynamo machines will return from seventy
to eighty per cent of the power expended in driving them,
in the form of electricity. This, however, refers to large
machines : small apparatus, intended to be driven by hand,
cannot be depended upon to utilize much over one-fifth of
the power ; and, in fact, it is better not to use the dynamo
on a small scale, but in such case to substitute permanent
magnets for the electro-magnets. One of the best forms
of machines of this class contains a Gramme ring arma-
ture, revolving between cast-iron pole pieces fitted with a
form of magnet devised by M. Jamin. The Jamin mag-
nets are exceedingly powerful, and are made of successive
layers of hoop-steel let into and riveted to the pole pieces.
118 THE AGE OF ELECTRICITY.
CHAPTER VIII.
THE ELECTRIC LIGHT. THE CONVERSION OF ELECTRICAL
ENERGY INTO HEAT AND LIGHT.
WHEN a current of electricity flows along a wire, it is
opposed by the resistance of the wire ; just, for example,
as a current of water is retarded by its friction against
the pipe which encloses it. Every one knows that when
a body is rubbed against another body, friction results.
When there is friction, there is heat ; and when there is
much friction, the heat may become intense enough to set
either or both bodies on fire if they are of inflammable
material, or, if not inflammable, to cause them to glow or
become red or white hot. The ordinary friction-match is
an example of an inflammable body thus set on fire. The
line attached to a whaler's harpoon, after the whale is
struck, is dragged over the side of the boat so rapidly
that water must be poured on it to keep the wood rubbed
from being set on fire. The brake-shoes of a railway-
car, rubbing against the wheels when the brakes are put
down, cause, by their friction, brilliant streams of intensely
heated minute particles of iron. The journals of these
wheels, or of any machinery, become highly heated by
the rubbing friction when no lubricant is present. A
piece of iron pounded smartly with a hammer becomes
hot. The striking of a bullet or cannon-ball upon a mass
of iron is attended by intense heat produced at the place
THE ELECTRIC LIGHT. 119
of impact, and a bright flash of light. We apply friction
to members of the body benumbed by cold, rubbing
our hands together to warm them.
Of course it should not be understood that there is
really mechanical friction between a current of electricity,
and the wire through which it passes. As has already
been explained, we speak of electricity as a thing, or
corporeal substance, merely for convenience' sake in talk-
ing about it. Its effect, however, in traversing a con-
ductor, resembles that which might follow the movement
of a body through that conductor, despite the apparent
solidity of the latter, in that the conductor becomes the
more heated as it offers more resistance to the flow.
Consequently, the more resistance there is, the more of
the energy of the current is expended in overcoming it ;
the more work is done at the place where it is overcome.
Just as the energy of the movement of the hand which
strikes a friction-match is converted into the heat which
raises the inflammable material to a condition when it
bursts into flame, so the energy of the seemingly moving
current in overcoming the obstacle offered by the wire
raises the temperature of the wire. If the wire is long
or thick, this elevation of temperature may be so much
distributed as not to be noticeable ; but if we make the
wire very thin, the heat produced may be sufficient to
cause it to become red hot or white hot and so dazzlingly
bright, or, if the wire is not of a refractory material, to
melt it. If, to illustrate, we connect the poles of a power-
ful galvanic battery with a short piece of fine platinum
wire, platinum because it will withstand a high tempera-
ture, we shall see the platinum become intensely hot
and glow. This is because the energy of the current,
opposed by the resistance of the very narrow path through
which it is driven, heats its channel.
120 THE AGE OF ELECTRICITY.
As a fine red-hot wire will burn its way easily through
many substances, instruments containing such wires are
used in surgery for the performance of operations in
which the cautery of the wire attending its cutting action
is desirable ; and there have been devices proposed for
cutting timber and shearing sheep in the same way. In
these cases, the heat of the wire is utilized.
When the heat of a body of metal is greatly augmented,
it becomes intensely luminous, so much so, that it is
impossible to gaze upon molten steel in the furnace with-
out the aid of some means for protecting the eyes. The
sun itself is in this intensely heated and luminous state.
If we use a resisting body which will not melt, we can
raise its temperature so high by a strong electric current
that it will glow with a brilliancy which is exceeded only
by that of the sun ; and the luminosity so caused is
termed the electric light.
The electric light, therefore, is the direct application of
the heat produced by the energy of the electric current.
This energy is caused to overcome the resistance, usually,
of a short interval of highly resisting material, short
because it is advantageous to concentrate the heat, and so
have its utmost intensity in the smallest possible space.
The electric light is not produced from electricity.
This sounds paradoxical, but only so because of our false
thinking again of the current as a tangible thing. If we
start with a certain quantity of electricity, such, for
example, as is generated by the consumption of a given
amount of zinc in a battery, that same quantity will go
through its conductor, and may be, so to speak, gathered,
wholly regardless of whether it heats the conductor or
not. It makes no difference whether it goes straight from
the cell to an electro-plater's bath, where it may cause the
deposition of a certain amount of copper ; or whether,
THE ELECTRIC LIGHT. 121
on its way thither, it heats an electric lamp : only it will
take longer to go through the circuit in the last case. If
we clammed a certain amount of water in a mill-pond,
with which to drive a water-wheel, we know perfectly well
that all the water will go through or over the wheel which
is driven by it. The wheel simply takes the energy of
the water. It does not consume the water itself. So in
the steam-engine. We heat water to make steam. We
use the energy thus imparted to it ; and after we are done
with the steam, it condenses back to water again. Of
course it all ciphers down to the fundamental law that the
matter and force in the universe are alike indestructible,
and that we can merely change them from one form to
another, without addition to or subtraction from the total
amount. This, however, is the deep water of science ;
and this chapter is about the electric light, and not the
abstractions of philosophy.
Whenever, then, an electric current meets resistance in
its passage, heat is developed. If a body intensely
charged with electricity approaches a non-electrified body,
then the current tends to pass from the former to the
latter. If the energy of the current can overcome the
resisting medium between the bodies, it will do so" ; and
in doing so, it will develop heat. Now, air is a substance
which offers the highest resistance to the current. Hence,
as we have seen, it requires electricity of enormous electro-
motive force to pass over a very small air interval. Thus
a cloud may become electrified very intensely ; and'when
it approaches a cloud oppositely electrified, or of lower
potential, then the current will force its way through the
intervening air. In overcoming that resistance, its energy
will be converted into heat and light. The flash thus
caused we call lightning ; and so the electric light existed
from the beginning. But think of the fate which would
122 THE AGE OF ELECTRICITY.
have awaited the impious Roman or Greek, a couple of
thousand years ago, who should venture the prediction
that the streets of Rome or Athens would one day be lit
by Jupiter's thunderbolts, quietly blazing on the tops of
long poles !
The first electric light produced by human agency was
obtained by Burgomaster Von Guericke, from his revolv-
ing sulphur globe. Priestley says that Robert Boyle got
" a glimpse of the electric light " before Von Guericke ;
Fig. 66.
"for he found that a curious diamond which Mr. Clayton
brought from Italy, gave light in the dark when it was
rubbed against any kind of stuff ; and he found that by
the same treatment it became electrical."
In Gravesande's "Mathematical Elements of Natural
Philosophy" (1731), appear the engravings Figs. 66 and
67, which are reproduced from that work in facsimile.
These represent the earliest methods of production of the
electric light, other than by the simple rubbing of amber
and like substances by hand. In Fig. 66 is shown a glass
globe which is to be " briskly whirl'd in a dark place, the
Hand all the while being held against it, to give it Attri-
THE ELECTRIC LIGHT.
123
tion. If the Globe be exhausted of its Air, it will appear
all luminous within, but mostly so where the Hand touches
the Glass. But if the Globe has Air in it and being
whirl' d in the same Manner, the Hand be applied to it,
no Light appears, either in the inner or outer surface of
the Glass ; but Bodies at a
small distance from the Glass
(as for Example at a Quar-
ter of an Inch, or nearer) be-
come luminous ; and so only
those Farts of the Hand held
against the Glass, which
terminate or rather environ
the Parts that immediately
touch the Globe, are lumi-
nous."
Observe the reason : u that
Glass contains in it and has
about its surface a certain
Atmosphere which is excited
by Friction and put into Vi-
bratory Motion : the Fire
contained in the Glass is
expelled by the Action of
this Atmosphere, ' ' and ' ' this
Atmosphere and Fire is more
easily moved in a Place void
of Air."
Farther on, the author concludes that quicksilver con-
tains fire ; "for if mercury well cleaned be shak'd about
in an exhausted Glass it will appear luminous ; " and then
he suggests the apparatus represented in Fig. G7, which is
a bell-glass from which air has been exhausted, and into
which mercury is caused to spout by the pressure of the
Fig. 67.
124 THE AGE OF ELECTRICITY.
external atmosphere. " The experiment must be made in
a dark place, and the mercury will appear luminous."
These experiments were devised by Hawksbee in 1709.
He called the mercury jet the "mercurial phosphorus,"
and did not consider the glass as in any way concerned
in producing the light. "The greatest electric light Mr.
Hawkesbee produced," says Priestley, "was when he
enclosed one exhausted cylinder within another not ex-
hausted, and excited the outermost of them, putting them
both in motion. Whether their motions conspired or not,
he observed, made no difference. When the outer cylin-
der only was in motion, he says, the light was very con-
siderable, and spread itself over the surface of the inner
glass. What surprised him most was, that after both
glasses had been in motion some time, during which the
hand had been applied to the surface of the outer glass,
the motion of both ceasing, and no light at all appearing ;
if he did but bring his hand again near the surface of the
outer glass, there would be flashes of light, like lightning,
produced on the inner glass : as if, he says, the effluvia
from the outer glass had been pushed with more force
upon it by means of the approaching hand."
For a long time after Hawkesbee, no further experi-
ments on the electric light were made. In fact, the use
of the rotating globe machine was discontinued ; and to
this circumstance Priestley ascribes the slow progress
afterwards made in electrical discoveries. Meanwhile the
idea that the electric spark could be utilized as a light
did not seem to strike any one. The philosophers kept
getting shocks from different things, and discovering after-
wards that they were electrical. They obtained fine flashes
from cats, and pondered long over the problem of why
cats gave sparks; until one Waitz, having procured "a
dry dog," applied vehement friction to the unhappy aui-
THE ELECTRIC LIGHT. 125
mal, and so found, not only that dogs gave sparks as well
as cats, but that these sparks were electrical. "This,"
remarks Priestley in his most owlish manner, " had been
supposed, but was not accurately ascertained before."
One is tempted to ask why ; but Priestley vouchsafes no
further information.
It will be remembered, that in describing the extraor-
dinary effects of the shock of the Leyden-jar upon the
electricians of the period, when it was first produced, we
adverted to the exaggerations of these learned persons.
It is difficult to trace the history of electricity without
experiencing a sense of mild wonder as to whether there
is not, perhaps, some subtle influence of the mysterious
current exerted upon the moral faculties of those who
deal with it, or, rather, invent around it, which in-
duces them to view facts differently from most people.
And it is singular how this peculiar obliquity of vision
affects those who have to do with the electric light ; not
in these times (ns every one who precipitately sold his gas
stock during the electric-light scare of 1879-80 can tes-
tify), but, of course, a hundred years ago.
There was Boze of Wittenberg, who some time before
had wanted to die from the effects of a shock for the sake
of personal advertisement ; and who had discovered, by
the way, that water running from a vessel in drops would
escape in a constant stream when electrified, a valuable
idea long afterwards utilized by Sir William Thomson
in his siphon recorder. Boze was a most meritorious in-
vestigator, until he became entangled in an electric-light
scheme. He said that he gave light, not sparks of the
cat-and-dog order, but that he himself had only to be elec-
trified, and he would become a perfect illumination. He
called it a " beatification ; " and furthermore, with all the
vigor of the man who prophesies that by next Christmas
126 TIIE AGE OF ELECTRICITY.
gas will be extinct in every dwelling in the land, he assev-
erated that a glory would form around his head, just like
the rings or miniature auroras represented by painters
about the heads of saints. It is all solemnly recorded in
4 ' Philosophical Transactions." Although the reader may
look in vain through that erudite work, for any reference
to the Boze Electric Light Company (limited), this re-
markable announcement to quote Priestley once more
" set all the electricians in Europe to work, and put them
to a great deal of expense."
Among these electricians was Dr. Watson ; who, having
failed to see why there should be such a thing as Boze
electricity any more than cat electricity or dry-dog electri-
city, or, in other words, disbelieving Boze's whole story,
caused himself to be electrified while perched on a huge
cake of pitch, just as Boze described. He candidly
admitted, that, so far as he was concerned,* he felt the
skin of his head tingle, and the rather disagreeable sensa-
tion of things creeping over him ; but despite his remain-
ing, with exemplary patience, several hours in the dark,
under these not wholly pleasant conditions, no truthful
person could be found who for a single moment would
admit that any light was visible.
It is perhaps as well that the argument which Watson
thereupon addressed to Boze is not set down. Ultimately,
however, Boze confessed that he had dressed himself in a
suit of metal armor covered with points, many of which
radiated from the helmet, and the sparks were produced
from these in the usual way (brush discharge) when a
strong charge was conducted to them.
There was a poetic justice in the penalty inflicted on
Boze. He claimed afterwards to have discovered that he
could invert the poles of a magnet "by electricity only,
to destroy their virtue, and restore it again." He did net
THE ELECTRIC LIGHT. 127
describe his method : what it may have been, or how far
it may have foreshadowed the electro-magnet, no one
knows. He got no hearing, apparently, from the Royal
Society ; and his chronicler contemptuously remarks, that,
" considering that no person in England could succeed in
this attempt, and that we are now (17G9) able to do it but
imperfectly, it is hardly probable that he did it at all."
And that was the fate of the first philosopher who pre-
tended that he had an electric light which he did not have,
and who put the other philosophers u to a great deal of
expense."
In 1745 Mr. Gottfried Gummert of Biala, Poland, in
order to observe whether a tube from which the air was
exhausted would give light when it was electrified, as well
as when it was excited, presented one, some eight inches
in length and about a third of an inch in diameter, to the
electrified conductor of a machine. He was surprised to
find the light dart vividly the whole length of the tube.
This light in vacuo, Gummert proposed to make sse of
" in mines and places where common fires and other lights
cannot be had." This appears to have been the first
announcement of the discovery, that, by rarefying the
air, the discharging distance, or the space over which the
spark will pass, is augmented, while the discharge itself is
caused to pass silently. It is now known that every atten-
uated gas has its own color when traversed by the dis-
charge, and that the rosy color of the light seen when
rarefied air is used is due to the nitrogen of our atmos-
phere. The same color appears in the aurora borealis,
which has the same origin. Tubes containing attenuated
gas are called vacuum or Geissler tubes. Their light is
faint, and has not been practically applied as yet to illu-
minating purposes. Many. of the phenomena observed
with these tubes remain unexplained.
128 THE AGE OF ELECTRICITY.
Referring to other modes of causing electric illumination,
Priestley, writing in 1769, says, "A variety of beautiful
appearances may be exhibited by means of the electrical
light, even in the open air if the room be dark. Brushes
of light from points electrified positively and not made
very sharp, or from the edges of metallic plates, diverge
in a very beautiful manner, and may be excited to a great
length by presenting to them a finger or the palm of the
hand."
The first voltaic pile was constructed in 1800. Eight
years later Humphry Davy obtained from the battery of
the Royal Institution, the first electric light produced by
the constant galvanic current. This battery consisted of
two thousand cells, arranged in two hundred porcelain
troughs. The fluid was a mixture of sixty parts of water
with one of nitric and one of sulphuric acid. The plates
were zinc and copper, square in form, and thirty-two
square inches in surface. " When pieces of charcoal,"
says Davy, " about an inch long and one-sixth of an inch
in diameter, were brought near each other (within the
thirtieth or fortieth part of an inch) , a bright spark was
produced, and more than half the volume of the charcoal
became ignited to whiteness ; and, by withdrawing the
points from each other, a constant discharge took place
through the heated air in a space equal at least to four
inches, producing a most brilliant ascending arch of light,
broad and conical in form in the middle."
Davy used pencils of common charcoal, which wasted
away rapidly ; and as no means of regulating the distance
between them had been devised, the light was of short
duration. For some thirty years, the production of the
voltaic arc remained an interesting though fruitless labora-
tory experiment. The power derived from available bat-
teries was weak ; their construction was expensive ; and
THE ELECTRIC LIGHT. 129
these difficulties were added to the lack of proper carbons
and of controlling apparatus therefor. In 1836 Grove's,
and in 1842 Bunsen's, batteries were invented. In Grove's
cell the attacked electrode is zinc plunged in dilute sulphu-
ric acid, and contained in a porous jar ; in the outer vessel
is platinum immersed in nitric or nitro-sulphunc acid.
Bunsen's cell has already been described. Both of these
batteries give a high electro-motive force ; their currents
were therefore better adapted to overcome the resistance
of the carbons and the intervening air space than those of
any cells previously invented.
In 1844 Le*on Foucault replaced the slides of common
charcoal, used since Davy's time, with pieces of gas car-
bon, and employed the Bunsen cell as a current-generator.
He also contrived a means of regulating the lamp by hand.
With this apparatus M. Deleuil took photographs ; and in
French treatises he is often accorded the credit of being
the first person to use the electric light for such a purpose.
This, however, is not the fact. In November, 1840, Prof.
B. A. Silliman, jun., and Dr. W. H. Goode obtained "pho-
tographic impressions by galvanic light reflected from
the surface of a medallion to the iodized surface of a
daguerrotype plate," using the large battery of nine hun-
dred cells belonging to the laboratory of Yale College.
Two pictures were obtained : one ' ' made up of a blur or
spot produced by the light from the charcoal points, the
image of the retort-stand on which a medallion of white
plaster rested, and the image of the medallion;" the
other picture was of the medallion only. An interesting
account of this experiment was published in the Journal
of the Franklin Institute in 1843.
One evening in December, 1844, during a thick fog, the
people who were passing the Place de la Concorde in Paris
were astonished by suddenly finding that they could see
130 THE AGE OF ELECTRICITY.
clearly, although the gas-lamps at a distance of a few yards
were invisible. A very intense light traversed the atmos-
phere, and illuminated even the remotest corners of the vast
square. This was an electric light, and the occurrence is
believed to mark the first illumination of a public thorough-
fare therewith. The Parisians were more than delighted
with the magnificence of the light. In rapid succession
electric lamps were established on the Pont Neuf to illu-
minate the Seine beneath, on the Arc de Triomphe, in the
court of the Palais Royal, and at the Porte St. Martin.
It was simply necessary for an inventor to allege that he
had a new form of lamp, to secure a public trial. With
characteristic ingenuity the scenic artists of the opera
seized upon the light as a means of introducing new and
startling effects into the mise en scene. Rossini's " Moses "
was put on the stage, on a scale of great magnificence ;
and the beams of the electric light were shed upon the
figure of the inspired prophet, investing him with a super-
natural radiance. In the final scene, the spectrum of the
light was used to imitate the rainbow. The Israelites
were grouped on the front of the stage ; while in the far
distance, the Egyptians, immersed in partial darkness, are
seen perishing in the waters. Moses, upon a high rock,
holds the tables of the Law. The light, gradually increas-
ing, represents the break of day ; at the same moment, as
the symbol of the new covenant, a rainbow appears. One
lamp was placed behind the rock in the foreground, and
its light concentrated upon the characters ; the rest of the
stage being in obscurity. The beam of a second lamp,
after dispersion by a prism, painted itself as a rainbow
upon the scene at the back.
The mode of producing the voltaic arc is quite simple.
The two rods of carbon are first placed in contact. The
THE ELECTRIC LIGHT. 131
current then passes from one to the other ; and while it is
so passing, the rods are gradually separated. During this
action, the current heats the air, and also vaporizes a por-
tion of the conductor, so that the interval between the rods
becomes filled with carbon probably in a gaseous state.
This carbon vapor, while it conducts the current, offers a
high resistance. It becomes white hot. The plus carbon
or that from which the current flows is usually the
uppermost, and, being the more highly heated by the cur-
rent, burns away most rapidly : particles of this carbon are
carried off, and transferred to the negative carbon, which
thus assumes the form of a pointed cone, while the plus
carbon forms a hollow crater of intense brightness, and
acts as a sort of reflector to throw a large proportion of
the light downward.
The temperature of the arc is immensely high, and is
the most intense of all artificial sources of heat. " Plati-
num," wrote Davy, in the account which he has left of
his famous experiment, " was melted as readily as wax
in the flame of a common candle : quartz, the sapphire,
lime, magnesia, all entered into fusion." The diamond
a very refractory body when placed in the arc be-
comes white hot, swells out, fuses, and gradually trans-
forms into a black crumbling mass. Carbon itself has been
softened so that it can be easily bent and welded. The
temperature of the arc is estimated at about 8700 Fah. ;
but this is not settled. In point of brilliancy, it is rather
less than one-third as bright as the sun. Its characteristic
color is a bluish white ; the carbons giving a white light,
and the arc a bluish purple. The effect is rather ghastly,
owing to the excess of blue rays. The light may be pro-
duced not only in air, but also under the surface of water
and other non-conducting liquids, in oils, and in a vacuum ;
so that it appears to be due to the incandescence, and not
132 THE AGE OF ELECTRICITY.
to the oxidation, of the carbon. The pressure of the
current required to maintain an arc one-tenth of an inch
in length is sixty volts, increasing quickly up to a quarter
of an inch, and after that at the rate of fifty-four volts
per inch. To supply such high pressure, obviously, a
large number of battery cells would be required, with
attendant large expense due to the consumption of zinc.
All the early arc lamps were thus supplied.
Inasmuch as the carbon rods slowly burn away, it is
necessary that one of them should be continuously fed
forward by suitable machinery, so as to keep the resist-
ance of the arc as constant as possible. Upon the uni-
form working of this feeding mechanism, greatly depends
the steadiness of the light. A great many different forms
of apparatus for this purpose exist. We shall therefore
refer to but a few of the most typical forms.
For street illumination, it is important that the lamp
should give a steady light. In construction it should be
not too heavy to be supported by an ordinary lamp-post,
and it is important that the mechanism should all be above
the lamp so that no shadows may be cast downward.
In the Brush lamp, the feed is actuated by gravity as
will be understood from the diagram of the lamp mechan-
ism (Fig. 69). The upper carbon A descends by its own
weight until it meets the lower one B. Then the current,
moving in the direction of the arrows, is established, and
passes between the carbons, and through the coil C of a
hollow electro-magnet. In this magnet is a soft iron,
plunger Z), which, when the magnet is excited, is drawn
upward. Through the intervention of a lever and an
ingenious annular clutch at E, surrounding the rod of the
upper carbon A like a washer, the upper carbon is lifted
away from the lower carbon, and thus the arc is established.
As the carbons burn away, the arc has a tendency to
THE ELECTRIC LIGHT.
133
become longer ; and this, by reducing the strength of the
current, diminishes the supporting power of the coil C.
The latter then allows its plunger to descend, thus lower-
ing the carbon, and so shortening the arc until the proper
strength of the current is restored, when the rising of the
plunger once more holds the carbon in position. There is
also an ingenious contrivance whereby each lamp in a cir-
cuit is enabled to .control itself independently of the action
of all the others in the circuit. Ordinary Brush lamps
such as are used for street-lighting give a light equal to
that of about eight hundred candles ; but very large ap-
JJyncuno
Fig. 69.
paratus of this kind has been made, in which the carbons
are three and a half inches in diameter, giving a light
equal to that of a hundred and fifty thousand candles.
An ordinary Brush street-light such as is used in New-
York City is represented in Fig. 70.
The Siemens lamp depends on what is termed the differ-
ential principle, which is illustrated in the diagram, Fig.
71. Here the lower carbon B is stationary. The upper
carbon A is attached to the end of a rocking arm or lever
O, at the other end of which is a core D of soft iron.
134
THE AGE OF ELECTRICITY.
This core enters two coils E and F, one above and the
other below the lever. The coil E offers a high resistance
to the current, because it is of fine wire. The coil jP, on
the other hand, is of thick wire, and offers little resistance.
The current, starting from the dynamo, goes by a wire
to the point G. It may
now take either of two
roads, through the coil
F, the lever C, and the
carbons AB, and so by the
wire //back to the dynamo,
thus completing the circuit ;
or it may pass through the
coil E, and thence by the
wire G to the wire /T, and
so to the dynamo, in this
case, not passing through
the carbons at all. Now,
the current having two pos-
sible paths will divide itself
through both, the most
current going through
the path which offers the
least resistance. If we
suppose that at the out-
set the carbons are wholly
separated, then there is a
very great resistance in
the first of the paths above noted : consequently the cur-
rent will flow around the other path. But in passing
through the coil E, it converts that coil into a magnet,
which draws up the core D; and when the core D is
drawn up, the outer end of the lever C moves down, and
thus the carbons are brought into contact. Then the
Fig. 70.
THE ELECTRIC LIGHT.
135
current is free to pass through the carbons ; and it does
so until they become burned away, too widely separated,
and hence the space between them offers so much resist-
ance to the current that the latter again travels through
the coil E, and so causes the lever C to bring the carbons
nearer together again. When the current passes through
the coil F, which it does when supplying the carbons, this
coil also acts as a magnet to move the lever in the oppo-
site direction to that in which it is moved by the coil E.
The actions of the
two coils balance each
other when the resist-
ance of the arc is
uniform.
The two lamps
above described are
types of the two prin-
cipal systems in use.
The Brush lamp is
based on what is termed
the gravity plan, where-
in, as we have seen,
the weight of one carbon causes its approach to the other,
and the magnetism of the current acts against this to
separate the carbons. The Siemens lamp, on the other
hand, is constructed on the differential system ; the differ-
ence between the opposite actions of the two magnets
being utilized to control the carbon.
For light-house purposes, it is of course absolutely
necessary that the light shall never be extinguished for
an instant, and that the mechanism shall be very strong.
Expense, weight, and bulk are matters of no moment ;
and slight pulsations of the light are not a serious defect.
For this use, a comparatively old form of lamp, the
Dynamo
Fig. 71.
136 THE AGE OF ELECTRICITY.
Serrin, is still employed. As the light must be kept in
the focus of the reflector, both carbons are fed forward ;
this being effected by clock-work mechanism actuated by
the weight of the upper carbon, so that, as the upper
carbon descends, the lower one rises to meet it.
Hitherto we have referred simply to the lamps which
are known as " arc lamps," and which, as has been seen,
depend upon the production of the voltaic arc between
the ends of separated carbon rods. These constitute one
principal class. Another class of electric lamp, of much
greater importance, for its applicability is far wider,
is the incandescent lamp, which consists of a thin fila-
ment or wire of carbon enclosed in a glass globe from
which the air has been exhausted.
The idea of using a body rendered incandescent by the
heating action of a current, as a means of illumination,
appears to have been first described by Mr. Frederic de
Moleyns, who in 1841 patented in England an electric
lamp in which a platinum wire enclosed in an exhausted
glass globe was to receive a shower of plumbago parti-
cles. There is nothing practicable about De Moleyns'
idea ; and it would doubtless have remained forever in
oblivion, had not the English writers on the subject found
De Moleyns' patent a convenient peg on which to hang a
claim that the incandescent electric lamp is a British in-
vention. The real inventor of the lamp appears to have
been J. W. Starr of Cincinnati, O. Starr used an ex-
hausted glass globe in which was a thin strip of graphite
held between two clamps affixed to a porcelain rod ; the
latter being suspended by a platinum wire sealed in the
globe. Starr died in 1847, but twenty-five years of age ;
a victim to overwork, and disappointment in his endeavors
to perfect this lamp and a magneto-electric machine to
drive it. It gave an excellent light. Starr was evidently
THE ELECTRIC LIGHT. 137
a prophet without honor in his own country ; for his
endeavors to interest others in his invention met with
failure, and critics were not wanting who openly asserted
that he was simply invoking perpetual motion. This,
apparently, because he proposed to utilize a magneto-
electric machine to supply his lamp. "The Cincinnati
Advertiser" of Sept. 4, 1844, published a letter from a
correspondent who stated as follows :
" 1. That this light is magneto-electrical.
" 2. That it is produced by permanent magnets, which
may be increased to an indefinite extent. The apparatus
now finished by the inventors and discoverers in this case
will contain twenty magnets.
"3. That it supplies a light whose brilliancy is insup-
portable to the naked eye.
"4. That a tower of adequate height will enable a
light to be diffused all over Cincinnati, equal for practical
purposes to that of day.
"5. That this light, when once set in operation, will
continue to illuminate without one cent of additional
expense.
" 6, and lastly. That the inventors in this process have
nearly solved the long-sought problem, perpetual mo-
tion. ... I suppose this light will prove the greatest
discovery of modern times. It is needless to add how
much it gratifies me, that Cincinnati is the place, and two
of its native sons J. Milton Sanders and John Starr
the authors, of the discovery."
Starr appears thus to have been the first to suggest the
lighting of cities by electric lights 011 high towers. Shortly
afterwards, Mr. W. H. Weekes in England proposed sup-
plying lights thus elevated, from earth batteries formed
of huge plates of zinc and copper buried beneath the
structures. Several years before, he had suggested ele-
138 THE AGE OF ELECTRICITY.
rating oxyhydrogen lights in the same way. On the
strength of that suggestion, the English journals, as
usual, claimed Starr's invention as British ; and when
Starr's patent appeared, in 1846, they insisted that it
was anticipated by De la Rive, who had employed coke
cylinders surrounded by rings of metal, between which
rings and cylinders the arc passed ; and by Grove, who
had used platinum spirals. Neither Grove nor De la
Rive enclosed an incandescent carbon rod in a globe ex-
hausted of air ; but a small difference of that sort did
not stand in the way of denying to an American the honor
and credit that was his due. It was carrying Sydney
Smith's sneering comment, " Who reads an American
book ? " a little farther by the habitual refusal to believe
that any thing good whatever could come out of the
Nazareth of the United States.
One of the most extraordinary claims to the honor
of the same invention was made not long ago, by M. de
Changy, who asserted that as far back as 1838 his friend
M. Jobard of Brussels suggested the idea that a small
carbon, employed as a conductor of a current in a vacuum,
would give an electric lamp with an intense fixed and
durable light. Acting on this suggestion, De Changy in-
vented several forms of lamps, using platinum spirals, and
even devised systems for the electric lighting of mines,
luminous buoys, submerged lamps for fishing, and nauti-
cal telegraphy by means of colored tubes containing the
incandescent wires. The whole matter was brought be-
fore the French Academy of Sciences ; and a commission,
of which M. Desprez was the chief, was appointed to
examine the invention. De Changy claimed to have suc-
ceeded at this time in arranging several lamps in one cir-
cuit, which could be lighted simultaneously in groups, or
separately without affecting the normal intensity of each.
THE ELECTRIC LIGHT. 139
Desprez wrote for a detailed account of the invention ;
which was declined by Jobard, on the ground that the
exposure would affect a pending patent. Thereupon
Desprez with that singular fatuity concerning patents,
now happily confined to medical practitioners said that
De Changy evidently desired to make money out of his
invention, and so did not merit the name of savant, and
that the Academy had no further interest in his work.
This so disheartened De Changy, that he abandoned his
labors, and as a consequence, if his statements be cor-
rect, the incandescent light was lost to the world for
more than a quarter of a century. In that interval, how-
ever, the Academy changed its views. It decreed the
award of the Volta prize to Mr. Alexander Graham Bell,
upon his claim to the invention of the speaking telephone,
an instrument which has yet to be given freely to the
world.
The incandescent lamp which forms one of the great
classes of electric illuminating devices, as now constructed,
consists of a thin filament or wire of carbon enclosed in
a glass globe from which the air has been exhausted.
When a current of electricity of suitable strength passes
through the filament, it becomes white hot, or incandes-
cent, and so yields a light of from one to one hundred
candles, according to its surface, and for a given surface
according to the temperature to which it is raised. There
are many forms of incandescent lamps, differing mainly
in detail and more especially in the mode of preparing the
carbon filaments. New forms are constantly appearing.
In all of these, however, the filament is of vegetable fibre,
carbonized by heat. The ends of this filament are con-
nected to two platinum wires which pass through a neck
formed on the globe. These are melted into the glass
itself ; and platinum is chosen because it expands by heat
140 THE AGE OF ELECTRICITY.
at about the same rate as the glass itself does, so that the
latter does Dot crack in cooling. The exhaustion of the
air in the globe must necessarily be as nearly perfect as
possible. Without the Sprengel air-pump, it would prob-
ably be impracticable to produce an efficient vacuum.
This pump consists of glass tubes, down which mercury
flows in a broken stream or in drops. Near the top of
the tubes are side openings connected to the chamber to
be exhausted. Air enters from this chamber, and, becom-
ing compressed between consecutive mercury drops, is
carried away ; and the process is repeated until the cham-
ber is completely exhausted. While the lamp is still at-
tached to the pump, a current of electricity is sent through
the filament, sufficient to raise it to a somewhat higher
degree of incandescence than will be used in actual work.
All the gas driven out of the carbon is at once removed
by the pump, and the lamp is sealed while the current is
still passing.
The incandescent lamps in most general use are respec-
tively those devised by Edison and Swan, and these may
be taken as typical. Mr. Edison's experiments upon the
materials and construction of incandescent lights are prob-
ably the most elaborate and far-reaching ever conducted.
On the other hand, it is doubtful whether any inventor
ever undertook an investigation more abundantly provided
with the means for carrying it to successful termination.
He began by studying conductors made of an alloy of
platinum and indium, and also of platinum alone ; but
found that the effect of incandescence upon the wires ex-
perimented upon was to produce, all over their surface,
innumerable cracks, and in a few hours these fissures
united, and the wire fell to pieces. With characteristic
ingenuity he contrived a way of heating the wires by a
current in vacuo so as actually to weld together the edges
THE ELECTRIC LIGHT. 141
of these minute cracks ; and finally succeeded in producing
metals in a state such as had never been known before,
increasing their hardness and density to an extraordinary
degree, and raising their fusing- points so high that they
remained unaffected at temperatures at which most sub-
stances would be melted or consumed, and very many
would be converted into vapor. By his process he ren-
dered platinum wire competent to yield a light of twenty-
five standard candles ; while the same wire not treated
would give a light of not more than four candles before
it fused.
Ingenious as this discovery was, it did not solve the
problem. The inventor then turned his attention to car-
bon, that extraordinary substance which was already
playing the principal part in the operation of the speaking
telephone, the galvanic battery, and the voltaic arc light.
As usual, he carbonized about every thing within reach,
"cotton and linen thread, wood splints, paper coiled in
various ways, also lamp-black, plumbago, and carbon in
various forms," in his endeavor to make a carbon filament
or wire. Later on he settled upon paper, "Bristol
board," which he punched into narrow elliptical strips.
Finally he determined that the carbon should be purely
structural in character ; that is, its natural structure, cell-
ular or otherwise, should be preserved unaltered, and not
modified by any treatment " which tends to fill up the cells
or pores with unstrtictural carbon, or to increase its den-
sity, or alter its resistance." Farther on we shall see that
just the opposite view is taken by the inventor of the
Swan lamp ; and the curious fact is presented, of two
forms of the same apparatus, both fairly successful, yet
dependent on radically opposite deductions from experi-
ment.
The fibre now used in the Edison lamps is that of a
142
THE AGE OF ELECTRICITY.
grass from South America, called ' ' monkey-bast ; ' ' each
blade of which is generally round, and composed of a
great number of elementary fibres held together by a nat-
ural cement or resin, which, carbonizing, locks all the ele-
mentary fibres together into a homogeneous filament. The
ordinary form of Edison lamp is represented in Fig. 72.
The ends of the carbon filament are connected to platinum
wires, and these are attached to a screw, and a sole plate
stamped from thin copper, and insulated from each other
by plaster-of-paris, which surrounds the
neck of the envelope, and forms a firm
and rigid attachment. The socket into
which this fitting screws is simply a
counterpart of the thread on the lamp.
In lieu of using a so-called structural
carbon, Mr. Swan in his lamp prefers a
filament as far as possible devoid of struc-
ture. He steeps a cotton thread in a solu-
tion of sulphuric acid and water until the
tissue is entirely destroyed, and a horny
homogeneous filament is produced, which
before carbonization is rendered uniform
in density by compression. Fig. 73 repre-
sents the present form of Swan lamp.
Tue filament is connected, as usual, to platinum wires,
which terminate outside the neck of the globe, in small
loops. The globe is entirely separate from the holder ;
the latter being of ebonite, provided with a screw plug
for attachment to the fixture. On the side of the holder
are binding posts for the connection of the circuit wires.
These posts communicate with platinum hooks, which
engage the loops of the globe wire. The neck of the
globe rests in a spiral spring, which steadies it, and at
the same time causes a slight strain on the hooks, so that
c ig. 72.
THE ELECTRIC LIGHT.
143
the hooks and loops make a very excellent electrical joint.
The whole arrangement is about the neatest and most
elegant which has thus far been devised for the purpose.
The form of the Swan filament is distinctive, it being
shaped in a spiral.
M. Muthel, a German
inventor, has made an
incandescent lamp
which requires no vacu-
um in the globe. He
makes a wire of a mix-
ture of bodies which
are conductors and non-
conductors of electrici-
ty, in which fusion is
wholly overcome ; the
non-conducting sub-
stances preventing the
melting of the metallic
parts. It is supposed
that the electric spark
jumps, so to speak,
from one particle to
another, and in this
way causes a heating
of the other substances,
which, being brought
to incandescence, emit
a more intense light.
There are two ways of arranging electric lamps in order
to distribute the current to them. They can be placed
one after another in a single circuit or wire connecting the
two poles or brushes of the generator ; as shown in Fig. 74,
where M is the generator or machine, and LL the lamps.
Fig. 73.
144 THE AGE OF ELECTRICITY.
In this case the current requires to have a high electro-
motive force in order to overcome the added resistances
of the whole number of lamps. Such a current is supplied
by the Brush generator or the peculiar form of Gramme
generator employed by Jablochkoff. The other way of
arranging the lamps is to connect them singly or in little
groups by cross wires between two main conductors joined
to the brushes of the generator, as shown at LL in Fig.
t, X)
"L L
M
f:
\
Fig. 74.
75. Then the current, instead of traversing one lamp
after another, splits up between the lamps, part going
through one lamp or group, and part through another.
The resistance of any particular path or channel for the
current is in such a case not very great, and the electro-
motive force of the current need not be dangerously
high. It is on this plan that incandescent lamps are
generally arranged for domestic purposes, and the cur-
*
Fig. 75.
rents flowing in the wires about a house would of course
be harmless. These lamps can be mounted on an ordinary
chandelier.
There is still a third form of electric-light apparatus,
which, however, has not come into extended use. This
is known as the incandescence arc system. It is an inter-
mediate arrangement between the arc and the incandescent
lights. The illumination is produced by the passage of
THE ELECTRIC LIGHT. 145
the electric current through a rod of carbon of a diameter
so small that its extremity becomes heated nearly to white-
ness. This is one of the oldest forms of electric light.
It was originally patented in England in 1846.
The " electric candle," so called, is a very re-
markable form of arc light which on its introduc-
tion in 1878 created great popular interest. It
probably did more to turn the attention of invent-
ors to the possibilities of improving the electric
light, after thirty years' neglect of the subject,
than any other recent invention, excepting proba-
bly the Gramme dynamo. It was originally in-
vented by M. Paul Jablochkoff, a Russian officer
of engineers ; and, as first produced, consisted of
two carbon rods fixed parallel to one another, a
slight distance apart, and separated by an insu-
lating medium which is consumed at the same rate
as the carbons themselves. As soon as the cur-
rent commences to pass, the voltaic arc plays
across the free ends of the carbons. The ad-
jacent insulating material becomes consumed, and
slowly uncovers the pair of carbons just as the
wax of a candle gradually uncovers the wick.
The usual form of Jablochkoff candle is repre-
sented in Fig. 76. There are two cylindrical
carbons about nine inches long by sixteen-hun-
dredths of an inch in diameter. The insulating
material between them is a mixture of sulphate of
lime and sulphate of barytes. As a candle will
last but for about two hours, it is necessary to ar-
range several of them in a holder, so that the total period
of lighting may range up to sixteen hours. Whatever may
be the number of candles to be lighted, one after another,
to afford a continuous light for a given time, it is neces-
146 THE AGE OF ELECTRICITY.
sary to employ a device by which, as soon as one candle
has burnt out, the current feeding it shall be switched off
to the one adjacent. This is effected either by hand or
by the use of an automatic commutator.
The Soleil light stands midway between the electric
candle and the incandescence arc light. It has, however,
some remarkable characteristics peculiar to itself. A
block of refractory material, such as marble, lime, or
granite, has a cavity on one side, shaped like a truncated
cone, to the face of which penetrate the carbons, travers-
ing the mass through inclined cylindrical holes. When
the arc passes between the two points, it plays on the
face of the recess, heats it, and transforms it into a small
crater, whence the luminous rays escape in a conical beam.
The light is slightly golden in color. It consumes more
power than many arc lights, but is very durable and
simple.
When a conductor conveying a powerful electric current
is suddenly broken, a bright flash, called the extra spark,
appears at the point of separation. The extra spark will
appear, although the current is not sufficient to sustain an
arc of any appreciable length at the point of separation.
In order to obtain a continuous light from this spark,
Professors Thomson and Houston have devised an appara-
tus in which one or both of the carbon electrodes are
caused to vibrate to and from each other, so as to touch
momentarily at each vibration. These motions follow
each other at such a rate that the effect of the light pro-
duced is continuous ; for, as is well known, when flashes
of light follow one another at a rate greater than twenty-
five to thirty per second, the effect of an uninterrupted
glow is produced.
The applications of the electric light are very numerous.
The most extensive in point of magnitude which has been
THE ELECTRIC LIGHT. 147
proposed is the establishment of an electric sun of eigh-
teen-million-candle power, on the summit of a tower
twelve hundred feet high, for the illumination of Paris.
For military use, the powerful beams of the arc light are
employed to illuminate fortifications under bombardment,
or reveal the approach of an enemy. Projectors have
been devised whereby the beam can be given a range of
eighty-six thousand feet. For submarine purposes, the
electric light is of great value : it has been employed in
removing sunken obstructions in the Suez Canal ; for
illuminating the sea depths, and so attracting deep-sea
fish ; and for lighting floating buoys. This last applica-
tion is of considerable ingenuity. By the motion of the
buoy, due to its rise and fall on the waves, air is com-
pressed within the buoy, which acts intermittently to drive
a dynamo, and also to sound a whistle. When the air
reaches a certain degree of compression, the dynamo
rotates, and the lamp glows brilliantly. On shipboard, arc
lamps are used for running lights, and also at the mast-
heads of steamers ; and incandescent lights illuminate
between decks. The steamship " Arizona," for example,
carries two dynamos capable of supplying six hundred
lights; and the Sound steamer " Pilgrim " is fitted with
nine hundred and twelve incandescent lamps.
It has been proposed to use a balloon filled with hydro-
gen, and containing inside an incandescent lamp, for sig-
nalling purposes ; the whole globe becoming illuminated
whenever the lamp glows. For lighting carriages, electric
lamps are arranged both inside and beside the coachman's
seat, and are conveniently fed by storage batteries. The
arc light forms an excellent head-light for locomotives ;
the jarring action of the vehicle being prevented by con-
trolling the carbons by hydraulic pressure.
Electric lights of immense power are used in light-
148 THE AGE OF ELECTRICITY.
houses. The condensed beam of the great light at Souta
Point, England, is equal in power to eight hundred thou-
sand candles. The South Foreland lights, two in number,
are of one hundred and eighty thousand candle power
each.
The incandescent electric light has been found espe-
cially useful in coal-mines, where the fire-damp atmosphere
renders the presence of any exposed flame exceedingly
dangerous.
In medicine the electric light has been adapted with
various forms of carrying apparatus, whereby it is used
to illuminate the larynx, the stomach, and the
cavities of the mouth. Combined with a photo-
graphic camera, it allows of accurate photographs
being taken of diseased parts which the eye can-
not see. Its latest application is to the ophthal-
moscope. Fig. 77 represents one of the miniature
lamps used for surgical purposes. Water circu-
lates in the space between the lamp itself and an
outer glass tube, to keep the lamp cool enough to permit of
its introduction into the internal parts of the living body.
Miniature lamps have also been set in brooches and shirt-
studs, and made to form the petals of artificial flowers.
Sometimes they are incased in masses of colored glass cut
in facets to imitate jewels.
During the political campaign of 1884, as part of one
of the torchlight processions, quite a large body of men
marched with incandescent lamps on their heads. The
participants formed a hollow square, in the middle of
which was a large dynamo driven by a forty-horse-power
engine, these machines being on trucks. Steam was pro-
vided from the boiler of a large steam fire-engine. The
dynamo current was conducted through copper wires
through a rope some twelve hundred feet long. At inter-
THE ELECTRIC LIGHT. 149
vals of five feet along the rope was an ordinary cut-out,
or lamp-receptacle, within which screwed a safety catch
carrying two wires which led up the sleeve of the person
holding the rope at that point, and through the back of
his helmet to a sixteen-candle-power incandescent lamp
on the top of it. Other lamps there were some three
hundred in all were distributed on the trucks and on the
harness of the horses. The effect was exceedingly bril-
liant and novel.
One of the comicalities of the electrical exposition of
1884, in Philadelphia, was a negro who distributed cards,
while wearing upon his helmet a very brilliant incandes-
cent light. Two wires led from the lamp, under his jacket,
down each leg, and terminated in copper disks fastened
to his boot-heels. Squares of copper of a suitable size
for him to stand naturally upon were placed at intervals
in the floor, and were electrically connected with the dy-
namo. Folks from the rural districts inquired cost, as
useful to have around the house.
For theatrical effects, the incandescent electric light in
its various forms is frequently employed. In a recent
performance of "Faust" in England, the actor personat-
ing Mephistopheles produced the most unearthly colors
on his countenance by means of small incandescent lights
contained in globes of various colored glass, fastened
beneath the visor of his cap. In the duel scene between
Faust and Valentine, in which Mephistopheles takes a
sinister part, whenever the sword of the demon crossed
that of Valentine, a continuous flash of fire appeared.
The combatants had a metal plate under foot, connected
with a battery ; and both Valentine and Mephistopheles
wore shoes provided with metal soles, which were con-
nected by a concealed wire with their sword-blades. The
continuous discharge of electricity was produced by the
150 THE AGE OF ELECTRICITY.
saw-like edges of the weapons, each tooth giving off its
spark. For ballets and fair} 7 scenes, small incandescent
lamps are fastened on the heads of the performers, and
are supplied by storage batteries concealed on their per-
sons. In the aquatic circus in Paris, the great circular
tank of water, which replaces the usual ring, is illumi-
nated by submerged electric lamps. When all other lights
in the auditorium are extinguished, very novel and curious
effects are produced by swimmers, representing mermaids,
naiads, etc., moving about in the illuminated water.
A series of important experiments were conducted by
the late Sir William Siemens, upon the influence of the
electric light upon vegetation. He fitted up in his large
greenhouses two arc lamps, each capable of emitting a
light of about five thousand candle power. Among the
vegetables planted were pease, French beans, wheat,
barley, oats, cauliflowers, and a variety of berries and
flowering plants. It was found that the electric light was
capable of producing upon plants effects comparable to
those of solar radiation ; that chlorophyll was produced
by it, and that bloom, and fruit rich in aroma and color,
could be developed by its aid. The experiments also went
to prove that plants do not, as a rule, require a period of
rest during the twenty-four hours of the day, but make
increased and vigorous progress if subjected (in winter
time) to solar light during the day and to electric light
during the night.
Very beautiful effects can be produced by the aid of the
electric light when reflected from below into a jet of water.
By simply placing pieces of colored glass before the lamp,
the jets can be differently colored, so that the appearance
of a fountain of luminous jewels is caused.
It was for a long time believed that electric lights were
far inferior to oil or gas lights in their capacity to pene-
THE ELECTRIC LIGHT. 151
trate fog. Recent investigations have shown, however,
that the advantage in favor of oil and gas is not more
than one per cent.
With regard to the energy consumed in electric lighting,
in Edison's incandescence system, one horse-power of work
yields from 99 to 189 candle power light ; in Swan's sys-
tem, about 150 candle power. With existing galvanic
batteries, the yearly cost of operating incandescent lamps
is about seven times as much as when the dynamo is em-
ployed. A good incandescent lamp will last from seven
hundred to a thousand hours.
Recent electric-lighting statistics show that at the pres-
ent time (1886) there are in the United States upwards of
ninety-five thousand arc and nearly two hundred and fifty
thousand incandescent lamps, distributed in over four hun-
dred cities and towns. Not less than seventy millions of
dollars is invested in the business of electric lighting in
this country alone. In Paris, in 1878, the cost to the city
was at the rate of twenty-nine cents per hour for a lamp
of from five hundred to seven hundred candle power.
The city of New York, at the present date, pays at the
rate of about six cents per hour for a lamp of two thou-
sand candle power.
152 THE AGE OF ELECTRICITY.
CHAPTER IX.
ELECTRO-MOTORS, AND THE CONVERSION OF ELECTRICAL
ENERGY INTO MECHANICAL ENERGY.
THE electro-motor, or electro-magnetic engine, is an
engine driven by electricity ; or, more correctly, it is an
apparatus wherein electrical energy is converted into me-
chanical energy. Unscientifically defined, it is one of
those contrivances which appear especially to have been
"for man's illusion given." It has caused more waste
of time, more useless expenditure of money, and more
heart-breaking disappointments, than perhaps any other
single device evolved by human ingenuity. From the very
beginning, it has exercised an irresistible fascination upon
the inventive mind. Its possibilities were within easy
range of speculation, from the outset. That it might
prove a substitute for the steam-engine with its heat and
smoke and danger and waste, was apparent. A few
pounds of zinc, noiselessly consumed in the battery, would
replace the explosive boiler dependent upon coal only to
be obtained at an expense increasing as the supply dimin-
ished. The tremendous power exerted could be arrested,
or set in operation, or governed, by the touch of a child's
finger. It could be conveyed anywhere and everywhere,
by slender wires, to objects moving as well as stationary.
It could drive ships and locomotives, and all the machinery
of the world. In brief, as the power of falling water and
of the moving wind had supplanted the power of the horse,
ELECTEO-MOTOES. 153
and as the power of steam in turn had taken the place of
the power of wind and water, so in the future electricity
would do the work of steam. All this was as plain fifty
years ago as it is now. It is far from being a delusion :
we are advancing toward its realization with wonderful
rapidity. But in that it all could be accomplished by the
ways and means of the third and fourth decades of this
century, lay the error, one that still is being repeated,
and always with the same result, loss and disappoint-
ment.
The idea of a machine to be driven by electrical power,
and capable of doing useful work, followed as a necessary
consequence upon the discovery of the immense attractive
strength of the electro-magnet. Why, it was argued,
should that ignis fatuus, that other form of the perpetual
motion, the cutting-off the magnetism of a permanent
magnet by a screen of something to be interposed by the
attraction of the magnet itself, be further sought, when
the electro-magnet could be made to exert its huge
strength, or be rendered powerless, instantly and at will,
by the mere contact or separation of the ends of a wire?
"When the current is established in its coil, the electro-
magnet attracts its armature : when the current is inter-
rupted, the armature is released to fall back into its
original position, or to lie retracted by a simple spring.
If the current is established and broken alternately, then
the armature will reciprocate to and fro like the piston of
a steam-engine ; and, like the piston, it may operate other
mechanism to produce rotaiy or any other form of motion.
The lazy boy who was set to work the valve of the old
engine, in order to let in steam at the proper time to move
the piston in the cylinder to and fro, found out that if he
attached the string wherewith he pulled open the valve,
to the moving machine, the latter would itself admit the
154 THE AGE OF ELECTRICITY.
steam at the right intervals. The same idea, applied to
the electro-magnet and its armature, made the motor
automatic. When the armature is attracted, in moving
it may draw apart the ends of the wire whereby the cur-
rent is led to the magnet. Then the magnet will release
the armature. In falling back, the armature again brings
the ends of the conductor into contact. Then it will be
once more attracted. And thus it will go on vibrating to
and fro before the pole of the magnet, as long as the
supply of current is kept up.
This idea came to inventors all over the civilized world,
at about the same time. Electro-motors varying only in
details of construction appeared simultaneously in Eng-
land, France, Germany, Italy, and the United States.
Modern research has shown that probably the first ma-
chine was constructed by the Abbe" Salvatore dal Negro,
professor in the University of Padua, in 1830 ; although
the earliest published description of it appeared some two
or three years later. Dal Negro suspended a permanent
magnet between the poles of a horseshoe-shaped electro-
magnet, in the coils of which the current was alternately
reversed, so that the end of the suspended magnet was
first attracted and then repelled from side to side. By
means of a simple mechanism the swinging magnet turned
a wheel slowly and with little power.
Professor Joseph Henry, in this country, constructed
an exceedingly powerful electro-magnet, capable of lifting-
six or seven hundred pounds with a pint or two of liquid
and a battery of corresponding size ; nor did he desist
until, a short time after, he lifted thousands of pounds by
a battery of larger size, but still' very small. Subsequently
Henry constructed an electro-magnetic engine, having
a beam suspended in the centre which performed regular
vibrations in the manner of the beam of a steam-engine.
ELECTRO-MO TORS
155
Bourbouze in France devised the remarkable machine
which is represented in Fig. 78. Here two electro-
magnet coils successively attract two pieces of soft iron ;
and each of these, placed at the extremities of an oscil-
lating beam, is drawn into the interior of the coil. When
the current passes into one coil, the iron armature, being
drawn down, causes the end of the beam to which it is
Fig. 78.
attached to descend : when the current passes into the
other coil, the other end of the beam goes down. The
beam in vibrating turns a crank, and so rotates the fly-
wheel. The battery is placed in the base of the machine,
and communicates witli a special piece of metal, the pur-
pose of which is to interrupt the current and throw it
alternately from one side to the other. This arrangement
is carried out simply by means of two small bits of iron,
separated by a plate of ivory. A metallic spring rests
156 THE AGE OF ELECTRICITY.
upon the iron and ivory at the end and at the beginning
of its course, now on the first bit of iron, then on the
second, and so alternating ; and thus the current is led
first into one coil, and then into the other.
In all mechanical contrivances, where motion is rapidly
reversed, there is a great waste of power ; this because
the momentum of the moving part must be overcome
before the direction of motion can be changed. It was
soon found that this principle applied very cogently to
reciprocating electro-motors.
The first rotary electro-motor was described in "The
Mechanics' Magazine" of June, 1833. The apparatus
consisted of a bent electro- magnet, "an arc of iron
measuring about two-thirds of a circle, and supposed to
be armed with a helix of wire, and connected with a
galvanic battery." The armature was solid, and upon it
were fixed permanent magnets built of steel bars ; the
poles of the magnets being placed so that they would move
" all but in contact" with the poles of the arc magnet.
The communication is anonymously signed, but is of espe-
cial interest from the fact that the writer describes, with
great clearness, an apparatus which embodies every thing
that is essential to the construction of electro-motors of
the class to which it belongs, and includes features sub-
sequently patented over and over again as original with
numerous claimants to the invention.
In the fall of 1835 the Rev. Mr. McGawley exhibited
to the British Association a motor in which a pendulum
vibrated between two electro-magnets, the poles of which
were alternately reversed, so that first one magnet at-
tracted and the other repelled the pendulum, and vice
versa. This created considerable scientific interest, and
was pronounced the " best attempt yet made, of the many
schemes that had been proposed for producing motive
EL ECTR O-MO TOR ft. 157
power by the electro-magnet." McGawley's invention,
like that of Dal Negro which it very much resembled, is
in fact of little value as an electro-magnetic engine ; but
it is of much historical importance for the reason that it
contained the first automatic circuit-breaker, wires dip-
ping alternately first into one cup of mercury and then
into another. This was subsequently patented in the
United States to Professor Page of Washington ; a pro-
ceeding difficult to understand, in view of the fact that
Page himself had written to Sir David Brewster, the
chairman managing a relief-fund for McGawley's heirs,
conceding in explicit terms the invention to McGawley.
The fortunes of Thomas Davenport with his electro-
motor constitute a curious chapter in the history of the
apparatus. Davenport was a country blacksmith, living
in Brandon, Vt. By accident he became possessed of one
of Henry's magnets, and by dint of hard work and per-
severance for he had no special education he con-
trived to master the principles involved. This was in
1833. By the summer of 1834 Davenport had invented
his rotary motor, which he subsequently patented in this
country in 1837. It was substantially like the apparatus
described by the anonymous writer in "The Mechanics'
Magazine" of 1833; except that the armature had elec-
tro-magnets instead of permanent magnets, and the field
magnet was a permanent magnet instead of an electro-
magnet, the apparently earlier contrivance being to this
extent reversed. Subsequently he suppressed permanent
magnets altogether, and used electro-magnets only, both
as field and armature. The machine worked well. It
was exhibited in Washington before the President, and
subsequently in Saratoga, whither great crowds of people
flocked to see it, and lost their heads over it. So did the
newspapers, scientific and unscientific. " The American
158 THE AGE OF ELECTRICITY.
Journal of Science and Arts " concluded that the " power
generated by electro-magnetism may be indefinitely pro-
longed . . . and increased beyond any limit hitherto at-
tained." Davenport thought that a battery "as big as
a barrel " would drive the largest machinery, and that
' ' half a barrel of blue vitriol and a hogshead or two of
water would send a ship from New York to Liverpool."
The American people seem to have contented them-
selves with purely mental speculation as to the future of
the machine, and to have declined pecuniary investment.
Consequently Davenport sent the apparatus to England.
It captivated John Bull at first sight. Abundant funds
were subscribed to build a u big machine," the invari-
able requirement, since time immemorial, of the investor
in new inventions. Accordingly one was constructed hav-
ing four huge electro-magnets aggregating in weight some
three hundred pounds. A battery " as big as a barrel"
was made to charge it. It had a cast-iron wheel six feet
in diameter, and weighing six hundred pounds, which
revolved at seventy-five turns a minute.
Among the scientific men who came to see this new
wonder, were Wheatstone (already famous for his inven-
tions in telegraphy), Daniell (equally renowned for his
invention of the Daniell battery), and Faraday, then in
the zenith of his fame as a discoverer. Wheatstone
praised the machine in glowing terms ; Daniell waxed
enthusiastic over it, and predicted the time when ships
would be run across the Atlantic with the aid of a few
sheets of zinc and a little acid, yea, not even acid, for
the waters of the ocean would supply its place.
Faraday came last of all. He looked at the huge wheel
flying around, with surprise ; and then fixed his gaze more
intently on the great spark which was given off every time
the current was broken, yielding enough light to illuminate
ELECTRO-MOTORS. 159
brightly the whole room. The promoters of the machine
stood silent, expectantly waiting the verdict from the fore-
most scientific authority in the land. After a while, Fara-
day walked to the nearest corner, and picked up a broom.
Then he placed the handle on the periphery of the wheel,
and it was seen that under a slight pressure the speed
of the wheel became slower. He did not quite stop the
motion, but simply and without a word demonstrated how
easily this could be done. Then he called the promoters
aside into another room, and gently suggested that his
opinion, if made public, would greatly injure the sale of
the patent. The interested parties thought it wiser not to
press him for that opinion, and he left without giving it.
He had found, as others did later, that the power yielded
was wholly inadequate for practical use.
After this Davenport started a paper in New- York
City, called "The Electro-Magnet and Mechanics' Intelli-
gencer," the first number of which appeared on Jan. 18,
1840. He announced it as the first paper ever printed on
a press propelled by electro-magnetism. The public re-
garded the enterprise rather apathetically. In his second
issue, Davenport particularly requested "those who would
wish to advance the cause of philanthropy to come for-
ward and assist us in our experiment." Perhaps he failed
to make clear the connection between his newspaper and
the u cause of philanthropy;" or perhaps the public,
after three years excitement over his machine, had tired
of the subject: at all events, the paper ceased publica-
tion, and in the technical journals of the day no further
record of Davenport's motor appears.
One of the best of the early forms of rotary motor was
that devised in France by M. Froment, which is represented
in Fig. 79. Around the periphery of a skeleton drum are
arranged eight pieces of iron, which serve as armatures.
160
THE AGE OF ELECTRICITY.
In the frame of the machine are fixed six couples of elec-
tro-magnets. (The two upper couples are omitted in the
engraving.) When the current is diverted into one of
these coils, one of the armatures is attracted, and is
moved to a position in front of the pole of the magnet.
The wheel is so turned over a certain distance. As soon,
however, as the armature has thus placed itself, the cur-
rent is thrown from the first coil into the next one, which
draws the armature to its pole in turn. As all six electro-
magnets act in this way, the wheel is continuously rotated.
The interest aroused by the exhibitions made by Daven-
port in London extended over all Europe ; and in the fall
of 1838 Professor Jacobi was invited by the Emperor of
ELECTEO-MOTOES. 161
Russia to conduct experiments on a large scale, with the ob-
ject of determining the practicability of the electro-motor
for marine propulsion. Jacobi's vessel was a ten-oared
shallop, equipped with paddle-wheels, to which rotary
motion was communicated by an electro-magnetic engine.
In general there were ten or twelve persons on board ; and
the voyage, which was made on the River Neva, was con-
tinued for entire days. The difficulty of managing the
batteries, and the imperfect construction of the engine,
were sources of frequent interruption, which could not be
well remedied on the spot. After these difficulties were
in some degree removed, the professor gives, as a result
of his experiments, that a battery of twenty square feet
of platinum will produce a power equivalent to one horse,
but he hoped to be able to obtain the same power with
about half that amount of battery surface. The vessel
went at the rate of four miles per hour, which is certainly
more than was accomplished by the first little boat pro-
pelled by the power of steam. Jacobi's boat was 28 feet
long and 1\ feet in width, and drew 2f feet of water.
The machine, which occupied little space, was worked by
a battery of sixty-four pairs of platinum plates, each hav-
ing thirty-six square inches of surface, and charged, ac-
cording to the plan of Grove, with nitric and sulphuric
acid. The boat, with a party of twelve or fourteen . per-
sons on board, went against the stream at the rate of three
miles per hour. This experiment was tried in 1839, and
shows what great progress had been made in the period of
about one year ; for in 1838, when it was attempted to
propel the same boat by the same machine, a battery of
about five times the size was required. Jacobi's batteries
generated so much gas, that the fumes seriously discom-
moded the operators, and -at times compelled them to
abandon their experiments ; and even the spectators on
162 THE AGE OF ELECTRICITY.
the banks were forced to retire when the wind blew in
their direction.
Jacobi wrote a letter, describing his results, to Faraday ;
and this, being published, elicited one from Professor
Forbes of King's College, Aberdeen, in which for the
first time the labors of Mr. Robert Davidson of that place
were brought to light. Davidson's most remarkable per-
formance was his locomotive. He used two batteries,
arranged at each end of his carriage, which energized a
number of large electro-magnets. On the wheel-axles
were large cylinders, on the peripheries of which were
fastened masses of iron. These masses were attracted
by the magnets ; and in this way the cylinders were re-
volved, so rotating the wheels. The carriage, Davidson
claimed, was once tested on the Edinburgh and Glasgow
Railway, where it ran at the rate of about four miles per
hour. It was sixteen feet in breadth, and weighed some
five tons. This report has always, as the newspapers say,
"lacked confirmation."
Davidson's experiments had, however, gone far to show
the disadvantages of carrying the batteries on the locomo-
tive. In the fall of 1845, "The Mechanics' Magazine "
published a letter signed " J. M.," which contained this
significant suggestion :
" Now, suppose we have a railway ten miles long, and
that at one terminus is placed an enormous stationary gal-
vanic battery, might we not make the rails themselves the
conducting lines of the battery? and, the wheels being so
arranged as to break the connection where required, a
rotating magnet might revolve by the electro-magnetism
thus communicated. . . . Perhaps some fertile brain may
take the hint, and bring forth soon the 4 electric rail-
way/ "
A fertile brain on this side of the Atlantic was already
ELECTRO-MOTORS. 163
working on this idea ; and it was carried into practical
execution by Mr. John B. Lilly, who in 1846 exhibited in
Pittsburg, Penn., a model which was driven by a current
passing up one rail and down another, and through the
magnets on the car. "Heretofore," says "The Pitts-
burgh Journal" of the time, "the propelling power has
been used on the car itself : in this instance, however, the
power is in the rails ; and an engineer might remain in
one town , and with his battery send a locomotive and train
to any distance required."
Five years later Professor Page of Washington made a
trial trip, with an electro-magnetic locomotive, between
Bladensburg and Washington. It was claimed to be of
sixteen horse power, and was provided with a hundred
cells of Grove's nitric-acid battery, each having platinum
plates eleven inches square. It is stated that the progress
of the locomotive was at first so slow that a boy was en-
abled to keep pace with it for several hundred feet ; but
the speed was soon increased, and Bladensburg, five miles
and a quarter distant, was reached in thirt}'-nine minutes.
When within two miles of that place, the power of the
battery being fully up, the locomotive began to run on
nearly a level plane, at the rate of nineteen miles an hour.
This velocity was kept up for about a mile, when some of
the battery cells cracked, and their liquids became inter-
mixed. Considerable time was lost in stoppages ; but
the return trip was safely accomplished, the entire running
time being one minute less than two hours. It was found
on subsequent trials, that the least jolt, such as that caused
by the end of a rail a little above the level, threw the bat-
teries out of working order, and the result was a halt.
This defect, it is said, could not be overcome ; and Pro-
fessor Page reluctantly abandoned his endeavors.
In the same year Thomas Hall of Boston constructed
164 THE AGE OF ELECTRICITY.
a small locomotive which ran on a track some twenty feet
long, and took the current from the rails, the wheels being
insulated. It has been claimed for Hall, that he utilized
not only a battery to supply his current, but also a dy-
namo-electric machine.
Some twenty-one years had now elapsed since the first
electro-motor Dal Negro's mere toy had been pro-
duced. In that period both forms of the machine, beam
and rotary, had been invented. It had been applied to
the propulsion of vessels and of locomotives ; the last
being operated by batteries carried by themselves, as is
the steam-boiler of the modern railway-engine, and by
batteries at a distance, which transmitted their current to
the motor through the rails. About all the principal adap-
tations of the electric engine had been made. It had
claimed the attention and labors of the most noted scien-
tists of the world. It had been backed by an emperor of
unlimited power, and capitalists representing unbounded
wealth had endeavored again and again to make it the
basis of successful enterprise. And yet when the success
of the electric telegraph, which had seemed far the greater
impracticability, aroused the wonder and admiration of
the world, the electric motor worked usefully for no man.
What was the reason?
As we have seen, the inventors of the early machines
found no trouble in making them go. The beams vibrated,
or the wheels spun around, fast enough to make people
with vague ideas about speed and power believe that
almost limitless energy could be got out of a pint pot.
The early inventors, and those who promoted their pro-
jects, are not the only persons chargeable with this delu-
sion. It exists yet, and crops out occasionally. In 1871
a New- Jersey discoverer asserted that he could make a
fifty-pound electro-magnet sustain a weight of one hundred
ELECTRO-MOTORS. 165
and twenty tons with a battery of four Daniell's cells,
and drive a five-hundrecl-horse-power engine by the same
means, at an expense of but twenty cents a day. An
electro-magnetic engine company as usual was organ-
ized ; capital, three millions. The engine was to be ex-
hibited on the 4th of July year indefinite. Also as
usual there was an element of mystery introduced, in
the assertion that the battery was merely a connecting
link between the machine and some storehouse of mag-
netic energy, and therefore, that, while the battery was
apparently the source of power, it really was not ; bearing
a relation thereto, similar to that of a percussion-cap which
fires the charge which impels the cannon-shot. Public
interest in this great discovery or, rather, that section
of the public interest which is ignorant enough to give
such discoveries consideration was transferred two years
later to the Keely motor ; which was obviously of much
greater importance, because it did not even require the
pint pot wherefrom to obtain limitless power.
The great vicissitude which invariably came to promoters
of electro- magnetic engines driven by batteries, was the
discovery that they do not pay ; and no amount of glowing
anticipations in prospectuses could prevent stockholders
becoming painfully aware of this, in the end. It is much
cheaper besides far easier to take the mere fuel used
in extracting the zinc from its ore, and burn it under a
steam-boiler, to drive a steam-engine, and so obtain power
in that way, than to go through the roundabout process
of extracting the zinc, consuming it in a galvanic cell,
and so generating a current wherewith to drive a motor.
Zinc, as we have already pointed out, yields about one-
seventh the energy of coal, and costs about twenty times
as much. Merely comparing the energies derivable from
zinc and coal, a steam-engine should be about a hundred
166 THE AGE OF ELECTRICITY.
and forty times more economical than an electro-motoi
driven by a battery. But the best steam-engine and boiler
can utilize no more than about two-ninths of the energy
of the burning coal ; all the rest being wasted. This
reduces the difference : it is " not so deep as a well, nor
so wide as a church-door, but 'tis enough," since it leaves
the motor some thirty times as expensive in the produc-
tion of power as the steam-engine. The efficiency of
the motor has no part in this question. The battery is the
hopelessly inefficient part of the system ; and it will
remain so, no matter how much the motor itself may
hereafter be improved. According to Professor Joule,
the cost of zinc expended in the Daniell battery, to main-
tain one horse power for twenty- four hours, would be
$6.25 ; in an ordinary steam-engine, the cost of the same
power for the same period would be about twenty-one
cents. From a "business" point of view, no further
argument is necessary to show why electro-motors driven
from galvanic batteries, as were all the early machines,
could find no place in the world's work.
While one set of investigators and inventors were study-
ing how to convert electricity into mechanical power,
another set, almost simultaneously, were endeavoring to
convert mechanical power into electricity. The researches
of these last culminated in the modern dynamo electric
machine. Now, the machines which generate electricity
from motion bear a strong resemblance, in point of gen-
eral construction, to those which generate motion from
electricity. Let us repeat one illustration already given,
to show this.
Fig. 80 we have already described as a hollow coil of
wire, the ends of which are connected to a galvanometer,
which shows by the movement of its needle whenever a
current circulates in that coil. Into that coil we insert
ELECTRO-MOTORS.
167
a smaller coil, the ends of which are connected to a bat-
tery. We have seen, that, when the small coil is moved
to and fro inside the large one, then the galvanometer will
show that a current is being generated in the large coil.
We are thus converting the energy of the motion given
to the small coil, into electricity.
Now, let us simply reverse the arrangement of the
battery, connecting it to the ends of the large coil, remov-
ing the galvanometer. Let us also join the ends of the
Fig. 80.
small coil together. Then when the current passes through
the large coil, on holding the smaller coil in -the position
shown in the engraving we shall feel the large coil pull
the smaller one into it, release it when the current is
broken, and, if we draw out the small coil, on re-estab-
lishing the current it will be pulled back again, so moving
to and fro. Here the electricity circulating in the large
coil is converted into motion.
The same thing can be done with the arrangement rep-
resented in Fig. 81. We have seen, that, when the per-
168
THE AGE OF ELECTRICITY.
manent magnet is moved into and out of the coil, a current
is caused in the latter. If the current be sent directly
through the coil in one direction, the magnet will be drawn
in : if in the opposite direction, it will not be attracted,
Or if, instead of the magnet, we use simply a piece of soft
iron, then, whenever the current is established, the iron
will be drawn inward, and when broken it will be free to
be moved out, as by a spring, for example.
If the foregoing be compared
with the engraving of Bourbouze's
electro-magnetic engine on p. 155,
it will be seen that that apparatus
depends exactly on the opeiation
last described. An electro-motor
is in fact a dynamo or magneto
electric machine reversed. If a
dynamo is rotated by mechanical
power, it will produce an electric
current. If an electric current be
conducted into a dynamo, its arma-
ture will be rotated. Good dynamo
machines, in fact, make the best
motors ; and the latter, like the dynamos, resolve them-
selves, as we have seen, into two types, distinguished by
the production of alternating and continuous currents in
the armature. There are, however, certain functional
differences between motors and dynamos, which require
to be met in different ways, and particularly in the pro-
portioning of the parts, and the relation of the field and
armature systems. These need not be discussed in detail
here.
As the dynamo machine became more and more efficient,
it became evident that here was a means of producing
electricity which could be used to drive a motor, as well
Fig. 81.
ELECTEO-MOTOES. 169
as supply an electric lamp, and which would depend for
economy not upon zinc, but upon coal. And thus the
modern system of electro-motors, and the transmission of
power thereto at a distance, came into existence : and
of this the essentials are a heat engine steam or gas
to drive a dynamo, which supplies the current to a second
dynamo ; and this last converts the energy of the elec-
tricity, so supplied, into mechanical motion and work.
We know that the revolution of the armature of a
dynamo produces a current ; and that in large dynamos,
producing a very strong current, it is necessary to use
powerful engines to turn the armature. But if the circuit
in the armature is broken, no such power is required. It
is only when the current is being yielded, that hard work
must be done to rotate the armature ; and we therefore
say that this work has its equivalent in the electric current
which flows and in the heat which is caused in the circuit,
which is rendered visible by the incandescence of, for ex-
ample, an electric lamp placed therein. Now, whether the
armature of a dynamo be rotated directly by an engine, or
whether it be rotated by a current sent into the machine,
a new current will be produced. If the dynamo be turned
by the engine, this current will of course be the only one
in the circuit ; but if there is already a current existing
there, as when the dynamo is driven by electricity, then
the new current will be in the opposite direction to the
original one, and tend to diminish the latter. This makes
complications ; and the result, among other things, is a
quantity of mathematical calculation which, if printed
here, might perhaps make the non-professional reader
shut up this book in despair.
It will suffice, therefore, to say briefly, that, when the
speed of the electro-motor is increased, this back current
is also increased. If the motor be loaded so as to do
170 THE AGE OF ELECTRICITY.
work by moving slowly against considerable forces, then
the back current will be small, and only a portion of the
energy of the current will be turned into useful work. If,
on the other hand, it be run rapidly so as to make con-
siderable back current, it will utilize a larger proportion of
the energy of the direct current, but can only be run fast
enough to do this if its load be very light. When a motor
is desired to do its work at the quickest possible rate,
it is best operated at such a speed that the supply current
is reduced to half its strength ; but when speed is not
necessary, a greater economic efficiency is attainable by
letting the machine do lighter work, and run faster, so
that the back current is nearly equal to the original current,
which is thereby reduced to a small fraction of its strength.
A Siemens dynamo-electric machine used as a motor can
attain an efficiency of over eighty-five per cent. A good
dynamo can turn eighty-five per cent of the mechanical
power it receives, into the energy of the electric current ;
and the electro-motor can convert back eighty-five per cent
of the current energy (or seventy-two per cent of the ori-
ginal power) into work, losses in the conductor and from
leakage being neglected.
The simplest form of electro-motor is that used on
electric bells. This consists of an electro-magnet which
moves a hammer backward and forward, alternately attract-
ing and releasing it. In Fig. 82, E is the electro-magnet,
and C the hammer. By touching the push-button P,
which is also shown enlarged in section, the circuit from
the battery L is completed, and a current flows along the
line and around the coils of the electro-magnet, which
attracts a small piece of soft iron attached to the lever $,
which terminates in the hammer C. The lever is itself
included in the circuit, the current entering it below and
quitting it by a contact-breaker A, consisting of a spring
ELECTRO-MOTORS.
171
tipped with platinum, resting against the platinum tip of
a screw from which a return wire passes back to the bat-
tery. As soon as the lever S is attracted forward, the
circuit is broken at A by the spring moving away from
contact with the screw : hence the current stops, and the
electro-magnet ceases to attract the armature. The lever
and hammer therefore fall back again, establishing con-
tact at A, whereupon the hammer is once more attracted
forward, and so on.
Fig. 82.
The most important modern application of electro-
motors is to the driving of locomotives. The credit of
the first successful electrical railway is due to Dr. Werner
Siemens, who built in Berlin, in 1879, a narrow-gauge line,
laid down in a circle some nine hundred yards in length.
A train of three or four carriages was placed upon it ;
and on the first carriage a dynamo-electric machine was
fixed to the axle of one pair of wheels, in such a manner
as to rotate the wheels when the armature of the machine
was rotated by the passage of a current through its coils.
172
THE AGE OF ELECTRICITY.
The rails were laid upon wooden sleepers, which, even in
wet weather, insulated the rails very well for this length of
line. A third rail ran between the other two, and it was by
this central conductor that the current was led from the
generating-machine placed at one terminus of the line.
The current was drawn from this rail to the armature of the
machine on the locomotive, by means of a brush of cop-
per wires ; and after traversing the coils of the armature,
it was led to the axle of the driving-wheels, which was
insulated from the body of the car, and thence by the
driving-wheels to the outer rails, and by them back to
the dynamo ma-
chine at the termi-
nus. Fig. 83 repre-
sents a section
through the loco-
motive, showing
the dynamo - elec-
tric machine 5,
and the central rail
JV, with the metal
brush for abducting
the current.
Between twenty and thirty persons could be accom-
modated on the train at a time, including the conductor,
who rode on the first carriage ; and during the course of
the summer no fewer than a hundred thousand were con-
veyed over the line at a speed of from fifteen to twenty
miles an hour. Crowded trains left the stations every
five or ten minutes, and a considerable sum was earned
in this way for the benefit of charitable institutions.
The locomotive was capable of exerting five horse-power ;
and instead of being fitted with a steam valve like a
locomotive to start or stop it, it was simply provided with
Fig. 83.
ELECTRO-MOTORS. 173
a commutator for closing or opening the circuit of the
current.
On the Siemens railway at the Paris exhibition of Sep-
tember, 1881, a distance of over sixteen hundred feet was
traversed in a minute, which is at the rate of nearly
twenty miles per hour.
In this country, electric railways have in many locali-
ties replaced ordinary street-railway systems depending
on horses and dummy engines. At South Bend, Ind.,
for example, two twenty-horse-power dynamos are driven
by a water-wheel, and supply current to one ten-horse-
power and three five-horse-power motors. The track is
laid with the ordinary flat rail, the rails being connected
by copper plates. The other part of the circuit consists
of a copper wire suspended above the track. From the
under side of this wire hangs a carriage fastened to a
flexible cable, passing to the inside of the car, where it
is in connection with the switches, the motor, etc. When
full current is turned on, the maximum speed of eight
miles per hour is attained, this being the highest rate of
travel allowable in the city limits. An electric railway
was constructed in the fall of 1885 at the New-Orleans
Exposition. Others are in successful operation in Balti-
more, Minneapolis, Montgomery (Ala.) ; and there are
probably few large cities in the country in which some
system of electric railway has not been projected. At
the date of writing (1886), experiments have for some
time been in progress with the object of substituting elec-
tric engines for the steam-engines on the elevated-railway
lines in the city of New York. On the Ninth-avenue
road, arrangements have been made to employ the form
of electric locomotive devised by Mr. Leo Daft. The
total weight of the machine as constructed is 8f tons.
The current is taken from the rails, which are insulated,
174 THE AGE OF ELECTEICITY.
and is supplied by dynamos situated at a main station.
A third rail between the track rails is employed for the
return current, and contact is made with this by means of
a wheel which can be moved into or out of position. The
maximum gradient of the road is one of a hundred and
five feet to the mile. This has been surmounted with
ease, with fairly well loaded trains ; and an average
speed of twenty miles per hour has been attained. The
latest, as well as the most efficient electro-locomotive, is
that devised by Mr. F. J. Sprague. This, also, at the
present time, is being experimented upon on the elevated
railways of New- York City. To describe the construc-
tion of Mr. Sprague's apparatus, would necessitate much
technical detail not suited to these pages ; but the prac-
tical results which he has attained, especially in control of
speed, prevention of loss of power, and facility of stopping
and starting, renders his motor a decided and very meri-
torious advance in electric propulsion.
It is impossible to fix a limit to the possible speed of
electric locomotives ; but it is not improbable that eventu-
ally it will be found practicable to drive them at much
higher velocities than the steam-locomotive has ever at-
tained. The advantages of electricity over steam for
railway propulsion are so great as to render the former
almost an ideal prime motor. The locomotive itself is
virtually done away with, for in many cases the electric
motor can be placed under the car. As regards economy,
it has recently been pointed out that " the evaporation of
pounds of water to each pound of coal to make steam
in locomotive-boilers does not average over 3J pounds of
water, using the best grades of bituminous coal ; while
with stationary boilers, set to burn coal-screenings for
fuel, an evaporation of nine pounds of water to one
pound of fuel is made, and the reduction in cost of fuel
ELECTRO-MOTORS. 175
is from one-third to one-half." The cost, therefore, of
making the electric power, is already greatly less than
that of generating steam-power in moving locomotives :
and when electricity comes to be supplied, as it eventually
will be, like gas and water, from great central generating
stations, to be used for all purposes, the expense of its
production will without doubt be still further lessened.
Add to the above advantages, freedom from smoke and
sparks, noiseless machinery and motion, and absolute con-
trol by the mere pressure of a finger, and one may predict
with every certainty that the electric steed will replace the
steam horse, as certainly as the latter did the horse of
flesh and blood.
Electric power is already sold from central stations, in
many places, just as steam-power is sold, with profit to
both seller and buyer. The price at present is about the
same as that for steam for small powers. In Boston,
steam is generated from coal-screenings, to drive the
engine which actuates the dynamos ; and the power is
transmitted all over the city, being used for running all
kinds of machinery, including sewing-machines, ventilator-
fans, printing-presses, elevators, etc.
It appears that ordinarily the loss in the process of con-
version of power into electricity, and transmitting power
from the dynamo to the receiver, amounts to from forty
to fifty per cent. "Electrical transmission," says a
recent writer, "has the unparalleled advantage of being
superior to the obstacle presented by distance. Then,
again, it operates its miracles in perfect silence and
repose. No force appears in the wire, such as appears in
shafting, in pipes with compressed air or water, in endless
chains or belts ; and in case of powerful currents, insula-
tion is easy. The conductor can be bent or shifted in any
way while transmitting many horse-power ; provided, of
176 THE AGE OF ELECTRICITY.
course, its continuity be not interrupted. It can be car-
ried round the sharpest corners, through the most private
rooms, into places where no other transmitter or power
could possibly be taken. There is nothing to burst or
give away. In short, such a method of transmission is
the acme of dynamical science."
Electro-motors have been ingeniously adapted to the
driving of tricycles by Professors Ayrton and Perry. The
motor is suspended beneath a platform under the seat,
and is driven by several cells of storage-battery, which
are supported on a second and lower platform. The
machine has been driven at a speed of about six miles per
hour.
Electric launches have also been constructed. One
built by Messrs. Yarrow & Co., in 1883, measures forty
feet in length by six feet beam, and is capable of carry-
ing forty passengers. The motor is a Siemens machine,
driven by a storage-battery ; the weight of motor and bat-
teries being about two and a quarter tons. The speed of
the boat is about eight miles per hour. For the propul-
sion of ships' boats, electrical motors possess marked
advantages over steam-engines ; as an electric launch is
much more easily swung from a ship's davits than a steam-
launch, it has no fire to be put out in case of shipping
seas, and the machinery will work under water.
The application of an electric motor to the guiding of a
balloon has been made by M. Gaston Tissandier, with
fairly successful results. The balloon used was lenticular
in form. The motor was arranged in the car, and caused
to rotate a large propelling-fan. The current was obtained
from a number of bichromate-of-potash batteries. The
motor was so arranged that its speed might be varied from
sixty to a hundred and eighty revolutions per minute.
With the high speed, the forward motion of the balloon
ELECTRO-MOTORS. 177
under the influence of its propeller was plainly observable,
and for a short period it maintained its place even against
a moderate breeze. It was also found possible to swerve
the balloon from the direction of the wind.
Telpherage is a name coined by the late Professor Flee-
ming Jenkin, to designate a system devised by him, by
which the transmission of vehicles by electricity to a dis-
tance is effected independently of any control exercised
from the vehicle. It is an aerial electrical railway, as at
present projected, in which the track is either a single or
double wire rope from which the carriages or skips are
suspended. The line is divided into sections, each a hun-
dred and twenty feet in length ; and each section is in-
sulated from its neighbor. A train is made up of a loco-
motive and a series of skips held at uniform intervals
apart by wooden poles extending from skip to skip. The
skips hang below the line from V-wheels supported by
arms which project out sideways so as to clear the sup-
ports at the posts : the motor or dynamo on the locomo-
tive is also below the line. The entire train is a hundred
and twenty feet in length, the same length as that of a
section. A wire connects one pole of the motor with the
leading- wheel of the train, and a second wire connects
the other pole with the trailing-wheel : the other wheels
are insulated from each other. Thus the train, wherever
it stands, bridges a gap separating the insulated from the
uninsulated section. The insulated sections are supplied
with electricity from a dynamo driven by a stationary
engine ; and the current passing from the insulated section
to the uninsulated section, through the motor, drives the
locomotive. This wilt be easily understood from the dia-
gram Fig. 84. Here one pole of the dynamo is connected
to the left-hand extremity of the conductor represented by
the continuous line ; the other pole being connected to the
178 THE AGE OF ELECTRICITY.
uninsulated line shown dotted. M and ^/"represent two
trains. When these are in the position shown, it will be
evident that a portion of the dynamo current will go
through each train as indicated by the arrows ; and this
current passing through the motor in the locomotive sets
it in motion, and so propels the train.
Vhinmtdfad
Fig. 84.
Another arrangement, called the series system, is illus-
trated in the diagram Fig. 85. Here there is but a single
wire, on which the trains are supported ; this consisting of
a series of spans. The breaks between these spans are
normally kept closed by means of switches. Each switch
is opened automatically as soon as a train bridges it, so
Fig. 85.
that the current is thus caused to pass through the train,
and so keep it in motion. When a train has passed over
a break, the switch is automatically closed, so that the
continuity of the circuit through the wire is preserved.
Telpherage is as yet in its infancy, and, in fact, has not
been tried on a sufficiently extensive scale to determine
ELECTRO-MO TOES.
179
even the most salient questions bearing upon its econom-
ical efficiency. So far as can be foreseen, the invention
bids fair to be of great practical value. Professor Jenkin
has pointed out that " wherever railways and canals do
not exist, telpher lines will provide the cheapest mode of
180 THE AGE OF ELECTRICITY.
inland conveyance for all goods such as corn, coal, root-
crops, herrings, hides, etc., which can be conveniently sub-
divided into parcels of one, two, or three hundred weight.
In new colonies, the lines will often be cheaper to make
than roads, and will convey goods far more cheaply. In
war they will give a ready means of sending supplies
to the front. Moreover, wherever a telpher line exists,
power is thereby laid on ; and this power may be used for
other purposes than locomotion. A flexible wire attached
to the line will serve to drive a one, two, or three horse
engine, which may be used for any imaginable purpose,
such as digging, mowing, threshing, or sawing." Tel-
pher lines will also act as " feeders of great value to the
railways, extending into districts which could not support
the cost even of the lightest railway." Fig. 86, from a
photograph, represents Professor Jenkin's first line. The
buckets, or skips, weighed about three hundred pounds
each, the locomotive the same. Each skip carried as a
useful load about two hundred and fifty pounds. The
projected speed was five miles per hour, at which it was
estimated about ninety-two and a half tons hourly of
freight could be conveyed.
General Thayer, U.S.A., has devised a remarkable sys-
tem of war balloons, which are designed to travel upon
wires or light cables stretched across the country on ordi-
nary poles. The balloon itself is in the shape of a cir-
cular spindle, and supports a deck for the transport of
troops, cannon, etc. The electricity is generated at the
end of the line, and is conveyed along the wires to a motor
on the deck of the balloon. The motor drives the wheels
which impel the balloon along the cable. General Thayer
states that such a road could be built at the rate of from
three to four miles a day, at a cost of fifteen hundred dol-
lars per mile, and the speed attained might be from sixty
ELECTRO-MOTORS. 181
to seventy miles per hour. The wire could be run across
country in a direct line, where it would be impossible to
build a railway. Men and ammunition could thus be
rapidly transported ; and, as an army advances into an
enemy's country, the balloon-way could be put up in its
rear, and thus establish a line of communication with its
base of supplies.
182 THE AGE OF ELECTRICITY.
CHAPTER X.
ELECTROLYSIS. ELECTRO-METALLURGY AND THE STORAGE-
BATTERY.
IN the galvanic battery a chemical re-action takes place,
and the result is the production of an electric current. If,
conversely, we place in a decomposable liquid two con-
ducting bodies, and thus enable a current of electricity to
pass through the liquid, we shall find that the result is a
chemical decomposition. This decomposition by means
of the electric current is called electrolysis ; the liquid
decomposed is known as an electrolyte, and the two con-
ducting bodies are termed electrodes. In a galvanic cell,
a definite amount of chemical action evolves a current,
and transfers a certain quantity of electricity through the
circuit : so, conversely, a definite quantity of electricity,
in passing through an electrolytic cell, will perform a
definite amount of chemical work. An electrolytic cell
is, therefore, the converse of a voltaic cell.
The discovery of the decomposing effects of the electric
current was made by accident, and followed almost im-
mediately after the invention of Volta's pile. Volta
addressed a letter to Sir Joseph Banks, then President
of the Royal Society, on March 20, 1800, wherein he an-
nounced the discovery of his pile. The first portion only
of this letter, which described the construction of the ap-
paratus, was sent on the above date ; and the remainder
ELECTROLYSIS. 183
followed during the succeeding month of June. Until the
latter date, the whole missive was not published ; but in
the meanwhile Sir Joseph Banks showed such parts as he
had received, to Mr. W. Nicholson and Mr. (afterwards
Sir) Anthony Carlisle. These two gentlemen at once con-
structed a pile composed of silver half-crown pieces, alter-
nated with equal disks of copper, and cloth soaked in
a weak solution of common salt. It so happened, that a
drop of water was used to make good the contact of the
conducting wire with a plate to which the electricity was
to be transmitted. In noticing this, Carlisle observed a
disengagement of gas from the water ; and Nicholson rec-
ognized the "odor of hydrogen " coming from it. They at
once took measures to determine the cause of this singular
Pile
Fig. 87.
effect ; and, using the first materials at hand, filled a piece
of glass tube with water, plugging both ends with cork,
and inserting through each cork a piece of brass wire, as
shown in Fig. 87. When the wires P and N were put in
communication with opposite ends of the pile, bubbles of
gas were evolved from the point of the wire by which the
current left the tube, and the end of the wire by which
the current entered became tarnished. The gas evolved
appeared on examination to be hydrogen ; and the tarnish
was found to proceed from the oxidation of the entrance,
or positive, wire. In order to prevent this oxidation of
the material of the wire itself, another apparatus was
made, in which platinum wires were used. Then gas was
evolved from both wires ; and this, ascending through the
184 THE AGE OF ELECTRICITY.
water, was collected separately in two tubes. The con-
tents of the tubes being examined, hydrogen was found
in one, and oxygen in the other ; the two gases being
almost exactly in the proportions known to constitute
water.
In this way the decomposing power of the electric cur-
rent was established very shortly after the first knowledge
of Volta's invention had reached England. Of course,
experiments so remarkable attracted the attention of other
investigators. Cruickshank decomposed a variety of com-
pound substances, and found, that, as a consequence of
decomposition, the acids and oxygen always collected
around the positive wire, by which the current came in ;
and hydrogen, metals, and the alkalies, around the nega-
tive wire, by which the current went out. The pile as
Volta had made it became manifestly inadequate to the
production of the strong and uniform currents that were
needed ; and to meet this want Cruickshank devised his
well-known trough battery, in which zinc and copper
plates were fixed in vertical grooves, the liquid being in-
terposed between the successive pairs of plates. Cruick-
shank's battery, or modifications of it, are still in common
use.
Meanwhile, a young German chemist, Ritter of Jena,
had also independently discovered the electro-decomposi-
tion of water and saline compounds ; and, more than this,
he had found out that this singular decomposing power
could be transmitted through sulphuric acid, so that, if on
both sides of the acid there were water, oxygen and hydro-
gen would still be evolved from the wires clipping in the
water. It seemed, therefore, that one or the other of the
elements of water must have passed through the sulphuric
acid : for, clearly, if the water was decomposed at the
positive wire, where only oxygen appeared, the hydrogen
ELECTROLYSIS. 185
must somehow get across to the negative wire ; while, if
the decomposition occurred at the negative wire, then
oxygen must also in some unexplained way cross over to
the positive wire.
This was the singular phenomenon which attracted the
notice of a scientific student who was then just com-
mencing the labors which earned for him an imperish-
able name. Humphry Davy wondered whether, if the
two wires were immersed each in a glass of pure water,
the gases would be produced. He tried it : nothing
happened. Then he put a finger of his right hand in
one glass, and a finger of his left hand in the other.
It was very extraordinary : then the gases appeared.
Next he got three people to stand in a row, hand in
hand, forming a chain between the glasses : still the
gases appeared. It was a simple experiment, the ex-
periments of most great thinkers are simple, but it
demonstrated conclusively, that, if any material princi-
ple passed between the wires, it must have been trans-
mitted through his body, or the bodies of all three
people who formed the line of communication between
the gases.
Then in October, 1800, began Davy's famous experi-
ments which stand and will stand forever as the founda-
tions of a great branch of electrical science. Beginning
upon the voltaic pile itself, he found that the chemical
changes in it were the cause of its electrical effects, and
that the action in a cell is similar to the decomposition of
water at the extreme wires of the pile ; that a battery
could be made of liquid elements with conducting-plates
of identical material placed in them. And then, branching
from the chemical to the calorific properties of the battery,
he constructed a huge apparatus whereby he fused wire,
and for the first time produced the electric arc between
186 THE AGE OF ELECTRICITY.
carbon points. Brilliant as Davy's discoveries then were,
they were merely the prelude of others which startled the
world.
When water was first decomposed, it was noted that at
the positive electrode there were always present indica-
tions of an acid, while at the negative electrode an alkali
appeared. There were not wanting philosophers who
jumped to the conclusion that here were new things in
water, not known in anybody's philosophy. One wanted
to suppose an "electric acid," a neat example of the
art of explaining something which is not understood, by
giving a name to it. Another insisted that the acid and
alkali were ' ' generated ' ' out of the elements of the water
by voltaic action ; thus anticipating the later claims to
other singular things ' ' generated ' ' from water by the
inventor of the so-called Keely motor. One peculiarly
conscienceless individual announced that the most care-
fully distilled water nevertheless yielded "muriate of
soda." Why "muriate of soda," he failed to explain;
and some people, anxious to know about this, who called
at the address appended to his memoir, came back,
and said that nobody of the author's name lived there.
Altogether, although the fact of electro-decomposition
had been established, the subject as a w r hole was in a
state of confusion ; and it was to bring order but of
this chaos, that Davy resumed his investigations into
electro-chemistry.
The first thing he did was to explode thoroughly and elabo-
rately the notion that any thing but hydrogen and oxygen
could be got out of water ; provided the water was pure, and
such disturbing causes as acids and alkalies in the vessels
used were eliminated, not in the vessels in the sense of
contained in them, but in their substance, be it noted.
And from this singular circumstance, that the current
ELECTROLYSIS.
187
was powerful enough to drag acids and alkalies out of
the very material of cups of agate and glass, grew the
idea that the same power might be brought to bear on
other bodies, and thus force from substances hitherto
considered simple and elementary, the secrets of their
complex composition.
Davy's first efforts were directed to potash. The alkali
liquefied by heat was placed on a platinum disk, which
was connected with the negative pole of a battery, while
a wire connected with the positive pole was applied to its
upper surface. At the upper surface there was a dis-
engagement of gas ; at the lower surface, small metallic
globules appeared, like mercury in appearance. Some of
these burned by contact
with air. The gas dis-
engaged at the positive
wire was oxygen ; and
the metal deposited was
the base of the alkali
afterwards called po-
tassium, thus for the
first time revealed. In like manner, from soda Davy pro-
duced the metal sodium ; and then from baryta, strontia,
lime, and magnesium, came barium, strontium, calcium,
and magnesium. Still more refractory materials were then
attacked ; and alumina, silica, zirconia, and glucinia
yielded silicium, aluminum, glucinium, and zirconium.
Davy not only found that the electric current was capa-
ble of decomposing compound bodies, but also of trans-
ferring or, if the term maybe permitted, of decanting
their constituents from one vessel to another. Some
of the results of his experiments were most singular.
Three cups were arranged as shown in Fig. 88 ; the posi-
tive wire entering the cup P, and the negative wire enter-
Fig. 88.
188 THE AGE OF ELECTRICITY.
ing the cup N. I is an intermediate cup, between which
and the cups P and ^V extend strips of asbestos, A, which
act as siphons. The current then passed from the positive
wire through the liquid in cup P, thence by the asbestos
through the liquid in cup /, by the asbestos again to the
liquid in cup JV, and so out to the negative wire. The
negative cup jVwas filled with a solution of sulphate of
potash ; the centre cup, with water in which litmus had
been infused ; and the positive cup P contained simply
distilled water. When the current passed, the acid con-
stituent of the sulphate of potash should appear at the
positive pole P ; but, to get there, it obviously would
have to traverse the litmus solution in the middle cup /.
Now, litmus is a very delicate test for the presence of an
acid, inasmuch as, normally dark blue, it at once reddens
when acid is added to it ; and hence the passage of the
acid should thus be at once revealed. But, strange to say,
although the acid of the sulphate went over to the positive
pole, and actually through the litmus solution, no redden-
ing of the latter followed. If the acid thus seemingly
lost its power, in transit, to affect vegetable solutions,
what would happen if a strong alkali were put in the
middle cup? Would the acid and alkali instantly rush
together by reason of their affinity, as they had done since
the beginning of the world ? No : sulphuric acid went
directly through a solution of ammonia, without produ-
cing chemical change. Hydrochloric and nitric, strongest
of the acids, were driven through concentrated alkalies :
conversely, strong alkalies were passed through strong
acids. It seemed as if either alkali or acid, when in the
control of the current, was powerless until the current
had forced it to its destination. One exception appeared
to this rule : sulphuric acid could not be driven through
stroutia or baryta, nor the latter through sulphuric acid ;
ELECTROLYSIS. 189
precipitation occurred in the middle cup. The result of
the affinity was, however, an insoluble substance ; and so
it was determined, that, wherever the element transmitted
forms, with the medium through which it passes, an
insoluble compound, the passage is stopped. But that in
other cases the transmission did go on, and the affinities
of the substances were suspended, was evident from the
fact, that, when the current was broken for a moment,
combination of acid molecules with the alkali through
which they were travelling instantly occurred.
In 1826 Nobili discovered, that when a current of elec-
tricity is passed into a solution of acetate of lead by
means of a plate of platinum, and out of it by means of a
platinum wire, rings of beautiful colors, caused by the for-
mation of thin films of peroxide of lead, appeared on the
platinum plate. These colors are very like those produced
on steel in tempering, and on the surface of molten lead,
which are due to a film of oxide overspreading the metal.
In another chapter we have alluded to the splendid
discoveries in magneto-electricity, made by Faraday in
1831. Three years later he supplemented these with
the investigations which established the laws of electro-
chemistry. He found that the amount of chemical action
in the cell is always proportional to the quantity of elec-
tricity passing through it ; and that the quantities of sub-
stances dissolved and set free by electrolysis are in definite
proportions by weight, and these proportions are identical
with the ordinary chemical equivalents of the substances.
From the first law we know that a current of a certain
strength will always liberate just so much hydrogen, for
example, from water, and will cause the solution of just
so much zinc in the cell whence the current is derived.
To illustrate the second law: nine grains of water, for
example, contain eight grains of oxygen and one grain
190
THE AGE OF ELECTRICITY.
of hydrogen ; and hydrogen and oxygen always combine
in these proportions to form water. Now, if we tear
apart, so to speak, the constituents of water, we shall
always find eight grains of oxygen at the positive elec-
trode, and one grain of hydrogen at the negative electrode.
Why this happens, is not definitely proved ; but the gen-
erally accepted theory, that of Grothuss, is neatly illus-
trated in the accompanying engraving, Fig. 89, which
represents the case of hydrochloric acid, each molecule
of which is composed of one atom of hydrogen and one
atom of chlorine. The plate A is the positive electrode,
and the plate B the neg-
f-l \\ ative electrode. The
oval objects are sup-
posed to represent the
molecules ; the white
half of each represent-
ing chlorine, and the
dark half hydrogen.
The row marked 1
shows the molecules
distributed at random, as before the current passes. When
the current is established, the molecules arrange them-
selves in innumerable chains in which every molecule has
its constituent atoms pointing in a certain direction ; for,
as we see, all the chlorine atoms point to the positive plate
A, and all the hydrogen atoms to the negative plate B.
Now, if the current is strong enough, the chlorine half of
the molecule next the positive plate is divorced from its
wedlock with the hydrogen half. Atoms abhor celibacy.
They are polygamous or polyandrous to the last degree ;
but single-blessedness they will have none of if they can
help it. So, no sooner is the hydrogen atom off with the
old love, before it is immediately on with the new ; because
Fig. 89.
ELECTROLYSIS. 191
it promptly appropriates the chlorine partner of its next
neighbor. The thus deserted hydrogen atom helps him-
self to his neighbor's consort in like manner ; and so on
through this singular chain, until at last there is a hydrogen
atom left solitary and alone at the negative plate, matching
the solitary chlorine atom at the positive plate, as in row
3. And so it looks as if all the chlorine atoms had some-
how made their way to one plate, and all the hydrogen
atoms to the other. Faraday called these apparently
migrating atoms ions ; and gave the name anode to the
positive plate, and cathode to the negative plate. Then
the ions which went to the anode were termed anions ;
and those which appeared at the cathode, cathions.
There was a grave and dignified professor once, who by
dint of much persuasion was induced to attend a dancing-
party. Among the complicated figures of the German,
there was one in which the several couples interchanged
partners until a single couple were left unmated. The
professor, who had regarded the proceedings hitherto
rather stoically, and with a somewhat bored expression,
suddenly brightened, and emitted a peculiar pleased
chuckle which the writer well knew from past experience
was of the same character as that which always followed
a neat bit of scientific demonstration, accompanied by a
muttered " Beautiful, ah, beautiful ! "
u Who, professor?" was asked.
"Who? Nobody. It's what they're doing."
" Oh, the German figure. Yes, it is rather "
"German figure? Oh, you mean Grothuss, of course.
But now, doesn't that doesn't this interchange of the
women beautifully beautifully illustrate his idea of the
migration of the ions? Eh? "
Two years after Faraday had made his discoveries, De
la Rue observed the singular fact, that in a peculiar form of
192 THE AGE OF ELECTRICITY.
Daniell's battery the copper plate became covered with a coat-
ing of metallic copper, which took the exact impress of the
plate, even to the fine scratches upon it. In 1837 Dr. Gold-
ing Bird decomposed the chlorides of sodium, potassium,
and ammonium, and deposited their respective metals on a
negative pole of mercury, thus obtaining their amalgams.
It would have been almost a phenomenal occurrence if
the discovery soon to be made, and which ultimately be-
came of such great industrial importance, should have
failed to have more than a single claimant ; but the pro-
cess of electrotypiug differs from most other electrical
discoveries in that all the claimants appeared at once, and
did not come stringing along after the manner of their
kind, for years after some one, bolder than the others, had
announced his success. In 1839 Jacobi in St. Petersburg,
Spencer in Liverpool, and Jordan in London, described
independently a method of converting any line, however
fine, engraved on copper, into a relief, by galvanic pro-
cess, by depositing copper upon the engraved object.
Jacobi published his description in a newspaper ; Jor-
dan wrote a letter to the editor of "The Mechanics'
Magazine;" and Spencer, last of all, read a paper on
the subject before the Liverpool Polytechnic Society,
all in the same year. Their respective adherents argued
about their respective priority of invention, quite steadily
in the public prints, for the next three years, and inter-
mittently contradicted one another for some time after-
wards. Spencer wrote the best account of what he had
done, despite the fact that his opponents sneered at him
for being only a carver and gilder, and not a professor,
which to their minds logically disproved, of course, his
pretensions, and the general public somehow understood
what he wrote about ; for, as a recent writer remarks,
u thousands of persons, of all classes of society, at once
ELECTROLYSIS. 193
became fascinated by the new art.*' At about this time
the Elkingtons of London began coating military and other
metal ornaments with gold and silver, simply by immersing
them in solutions of those metals. In 1840 John Wright,
a surgeon of Birmingham, came to them with the news
that he had succeeded in obtaining electrically a thick,
firm, and white deposit of silver, upon articles treated in
a liquid made by dissolving the cyanide of this metal in
an alkaline cyanide. The Elkingtons saw the value of
his discovery, and did what would have been impossible
in this country, embodied Wright's idea in their patent;
not for the purpose of depriving Wright of his reward,
but in order to perfect and complete the description of a
process which proved to be the basis of all successful
electroplating of gold and silver. Wright, in fact, profited
well, for he was paid a royalty of one shilling an ounce
for every ounce of silver deposited ; and a handsome
annuity was settled on his widow after his death.
The history of electro-chemistry from this point is that
of technical details, out of place here ; so that we pass at
once to practical applications, and these are fourfold :
first, electrotyping, or the copying of types, casts, or other
objects, by deposits of metal ; second, electroplating, or
the covering or plating of objects of baser metal, with a
thin film of another metal, usually gold or silver ; third,
the reduction of metals from solutions of their ores ; and,
fourth, the secondary or storage battery.
Electrotyping finds its widest utilization in the repro-
duction of engravings and pages set in type. A mould
of the object, made in wax, lightly covered with plumbago
so that a conducting surface may be present, is placed in
a bath of saturated solution of sulphate of copper, and
attached to the cathode, or pole at which the current leaves
the bath. A plate of copper is attached to the anode, or
194 THE AGE OF ELECTRICITY.
wire at which the current enters. This plate is decom-
posed at the same rate as the copper is deposited from the
solution, on the plumbago-covered surface of the mould ;
and in this way the strength of the solution is kept uni-
form. The copper, as it is deposited, covers every por-
tion of the surface with a bright layer, usually starting
from the suspending wire and extending itself gradually
over the entire area. Generally the electrotyping opera-
tion takes about twenty-four hours ; but for newspaper
work this time is necessarily much shortened. It is not
uncommon for pages of illustrated papers, especially if
containing important engravings of recent events, to be
electrotyped in eight, six, and even four hours.
When a good adherent film of copper has been depos-
ited over the surface, the mould is removed. The wax
is melted to liberate the electrotype, which is then backed
with an alloy of lead, antimony, and tin. The plate thus
produced is an absolutely exact reproduction of the origi-
nal types or relief engraving from which the wax mould
was made. It only remains to mount the plate upon a
block of wood, type high, when it is ready to take its
place in the form which is placed in the printing-press.
Usually the woodcuts and types are set up and arranged in
page form, and then the whole page is electrotyped. The
pages before the reader have been thus prepared. When
an electrotype is to be submitted to hard usage, as when
a great many impressions are to be taken from it, it is
sometimes coated with a pellicle of electrically deposited
iron. Messrs. Christofle & Co. of Paris have recently
made very beautiful electrotypes by the direct deposition of
nickel in the mould, strengthened by a copper backing.
The electrotyping process has been used on a large
scale for the reproduction of statues of even colossal di-
mensions. In such cases, instead of making moulds the
ELECTROLYSIS. 195
plaster-of -Paris figure itself is sacrificed. The mode of
operation is interesting.
After the figure is well saturated in linseed oil, it is
covered with a film of black-lead, and then placed in
a large cistern of sulphate-of-copper solution, which is
allowed to precipitate its copper on the object until a coat-
ing is formed of about one-sixteenth of an inch in thick-
ness. The object is then lifted from the bath, the copper
envelope cut through at suitable places, the plaster figure
broken away with great care, and the whole of it extracted.
The outer surfaces of the copper forms (with wires
attached) are now thoroughly varnished all over, to pre-
vent any deposit being formed thereon ; the forms exposed
to sulphuretted hydrogen, to prevent adhesion of the depos-
it ; and the parts are immersed in the depositing- vat again,
which is filled with copper solution. A dissolving plate of
pure electrotype copper is suspended within each portion,
and a deposit of copper thus formed all over its interior,
until a considerable thickness, varying from one-eighth to
one- third of an inch, is deposited, which requires a period
of three or four weeks. Each piece is now removed from
the liquid, washed, and the outer shell torn off ; when all
the parts of the figure remain nearly complete, and ready
for fixing together. Some of the objects made by this
process, by the Messrs. Elkington, are colossal. The
statue of the Earl of Eglinton is thirteen and a half feet
high, and weighs two tons ; and the vat in which it was
formed is capable of holding 6,680 gallons of liquid.
The Messrs. Christofle made a statue twenty-nine feet six
inches high, and weighing about five and a half tons.
About ten weeks were required to deposit the metal.
Electroplating is now practised with a great variety of
metals. The ordinary arrangement of a silver-plating
bath, to which a battery-cell supplies current, is represented
196 THE AGE OF ELECTEICITY.
in Fig. 90. Of late years, the nickel-plating of all sorts
of metal articles, from the parts of steam-engines down
to surgical instruments, has become a very important
branch of the industry, replacing to a great extent gold
and silver plating. Nickel-plated articles take a fine pol-
ish, do not tarnish, and their coating is hard and lasting.
The solutions commonly used for nickel-plating were in-
vented by Mr. Isaac Adams, and patented in this coun-
try in 1869. They may be the double chloride of nickel
and ammonium, or the double sulphate of nickel and
Fig. 90.
ammonium ; the bath being neutral, that is, neither acid
nor alkaline, upon which fact the success of the Adams
process greatly depends. The cheapness of nickel, and
the rapidity with which it is deposited, from fifteen min-
utes to an hour, when the dynamo is used to supply cur-
rent, being sufficient time, have resulted in nickel-plating
becoming an eveiy-day process in many engineering work-
shops.
It can hardly be said, however, that nickel-plating is
anywhere carried on on the gigantic scale in which silver-
plating is practised, especially in Europe. The house of
ELECTROLYSIS. 197
Cbristofle & Co. in Paris annually deposits more than thir-
teen thousand pounds of silver, and since its establishment
in 1842 has used not less than a hundred and eighty-five
tons of that metal.
Gold is usually deposited from the double cyanide of
gold, and potassium. The metal is sometimes deposited
in solid form upon moulds for the production of articles
of jewellery having very complex or under-cut ornaments
upon them. By the use of certain solutions, the gold-
plating can be beautifully colored ; and in this way the
red gold, orange gold, etc., of fashionable jewellery, are
produced. In gilding base metals, a film of copper or
brass is generally first produced upon them. The insides
of vessels are gilded by filling the vessel with the gold
solution, suspending a gold anode in the liquid, and pass-
ing the current. Many very beautiful objects of art are
made by incasing in gold, silver, and copper, for exam-
ple, ferns, foliage, flowers, insects, and lizards. So also
anatomical specimens, such as brains, have been thus
treated ; the electro-deposit preserving every minute wrin-
kle and fissure. An even more grim application has re-
cently been proposed by a French chemist who advocates
the coating of the bodies of the dead with impervious
platings of gold, silver, or copper, as a means of preserv-
ing them. He even suggested making statues in this way.
Copper has been deposited upon fabrics and upon glass,
and is almost invariably applied to the carbons of arc
lights.
The electrolytic refining of copper, for the purpose of
obtaining the metal in a chemically pure state, is largely
carried on in Europe. The Keith process of refining lead
is utilized, we believe, in this country only. The precious
metals are commonly separated in the electrolytic bath by
combining them with copper to form an anode and then
198 THE AGE OF ELECTRICITY.
electrically depositing the copper, leaving the gold and
silver as a residuum.
A curious application of electroplating is in the manu-
facture of the so-called compound telegraph-wire, which
consists of a central wire of steel covered with a coating
of copper. This coating is deposited upon the steel by
galvanic action, while the wire is drawn continuously
through a long trough containing the solution. A wire
thus made is found to offer much less resistance to the
current than an ordinary iron wire.
Up to within a few years, the use of electricity for
actual work, such as lighting or driving motors, has been
attended with a great drawback, almost as important as
the high cost of generating the current ; and that is, it
has been necessary to make the electricity as it is needed.
We can store water in a reservoir, and use it to drive a
wheel at one time as well as another. We make gas dur-
ing the day, and store it in huge gasometers from which
a supply is drawn at night. But with electricity it is
necessary to keep a constant current flowing through
the conductor, equal to meeting all likely needs, whether
it is actually utilized or not. Of course this involves
continual expense, unremitting wear of machinery, and
a great deal of additional apparatus ready to take the
place of any thing which may break down or need re-
pair. Inasmuch, also, as the hours of the night when
lights are needed are few, it is necessary to have very
powerful machinery, capable of supplying a great deal of
electricity in a short time. The reader can easily imagine
how much greater the cost of gas would be if all of it
had to be made between the hours of G P.M. and midnight,
instead of its being produced as it is, throughout the day.
In fact, at the present time central stations for the supply
ELECTROLYSIS. 199
of electricity from dynamos employ their capital fruitfully
only about six hours in the twenty-four.
The question of how to store electricity so that we can
generate it at one time, and use it at another, is therefore
of very great moment. We know, however, that electri-
city is not a thing capable of storage, any more than it is
a thing capable of being burned in a lamp. The water
which in falling drives a wheel is not consumed : simply
its energy is expended. If we go a step farther, and
cause the wheel thus driven to wind up a spring, or lift a
weight, we know that we can keep the spring wound up,
or the weight in its lifted position, as long as we choose ;
and that when we release the spring, or drop the weight,
then we can use the energy thus stored. So that we are
not to conceive of the idea of pouring an electrical fluid
into something, and keeping it there ; but of causing the
energy which exists in the form we know as electricity, to
become stored, just as the energy of the water becomes
stored in the wound-up spring or lifted weight. There is,
therefore, no such thing as storage of electricity. What
is really done is the changing of the electrical energy from
the active condition to the potential condition, from the
state in which it may be doing work, to the state in which
it is not doing work but is capable of so doing.
We have already found that if we plunge the ends of
two wires leading from a galvanic cell into water, or,
better, dilute sulphuric acid, bubbles of gas will appear
upon the immersed wires, hydrogen at the wire by which
the current leaves, oxygen at the wire by which it enters.
This experiment is usually shown by means of the appa-
ratus shown in Fig. 91. This consists of a glass vessel
(V) containing water, and also two glass test-tubes (AB)
inverted over a pair of platinum plates projecting up from
the bottom of the cell or vessel. These plates are con-
200 THE AGE OF ELECTRICITY.
nected by wires to the poles of the voltaic battery (O), as
shown ; and therefore they act as electrodes, and pass the
current from the battery through the water. Now, as the
water is decomposed, the hydrogen gas is found to collect
on the cathode, by which the current is supposed to leave
the water, while the oxygen collects on the anode, by which
the current is believed to enter the water ; and as the gases
are lighter than the water, they rise into the upper ends of
the tubes. The volume of hydrogen at the cathode is
A B
Fig. 91.
always twice the volume of oxygen at the anode, and this
agrees with the known constitution of water. Further, the
quantity of water decomposed in a given time is propor-
tional to the strength of the electric current ; and hence, if
the tubes are graduated to show the volume of gases col-
lected in them, the instrument becomes a voltameter, or
current-measurer. Faraday arranged the apparatus in the
form shown in Fig. 92, so that the gas could easily be col-
lected and measured. Here two small platinum plates dip
in the acidulated water, and are connected to wires which
ELECTROLYSIS.
201
pass up through the cork of the bottle : binding-screws
are attached to the upper ends of these wires, and a glass
tube fixed into the cork serves to discharge the gas formed
within. When the binding-screws are connected to the
poles of a battery, the water in the bottle is decomposed,
and the hydrogen and oxygen rise to the surface.
In this voltameter we have two plates and a liquid in a
suitable vessel. If one of these plates were zinc, and the
other copper, we know that the zinc would be attacked by
the acidulated water,
and the apparatus
would at once be a
galvanic cell capable
of yielding its own
current. But here the
plates are both of the
same material, im-
mersed in one liquid ;
and hence one is not
more attacked than the
other, and the arrange-
ment cannot act as a
galvanic cell.
When, however, the electric current from another bat-
tery is sent into the voltameter, then its plates respectively
yield, as we have seen, hydrogen and oxygen ; and these
gases, in fact, coat the plates. Now they have become
different. Hydrogen and oxygen form a galvanic pair
by themselves ; and as soon as the voltameter is discon-
nected from its charging battery, and its wires brought
into contact, a current is set up through that wire, which
goes from the hydrogen to the oxygen within the liquid.
It will be remembered, that, in referring to the so-called
polarization of the primary form of the galvanic battery,
Fig. 92.
202
THE AGE OF ELECTRICITY.
Balttty
Fig. 93.
we noted that after the hydrogen had formed on the un-
attacked element, a current occurred from the hydrogen
to the zinc, which ran opposite to and so greatly weakened
or destroyed the original current. In the voltameter there
is a like action, and the current yielded by the voltameter
is in the reverse direction to that of
the battery current which charged it.
Let us fix this with a diagram (Fig.
93). Here we have first the primary
cell, with its wires joined. The cur-
rent goes in the liquid from zinc to
carbon, and thence back by the wire to
the zinc, the arrows showing the direc-
tion. Next, we connect the cell to the
voltameter (Fig. 94) . Here the current goes from the car-
bon to one plate of the voltameter, and produces oxygen
thereon ; then through the liquid to the other voltameter
plate, where hydrogen is generated ; then back to the zinc,
and so through the cell to the carbon again. Now dis-
connect the voltame-
ter, and join its wires
(Fig. 95). Then the
current goes in the
liquid from the hy-
drogen to the oxy-
gen, and then by the
wire back to the hy-
drogen. Compare
the direction of this
current as indicated by the arrows, with the direction of
the current in the battery cell, similarly indicated, and it
will be seen that the currents move in opposite directions.
We have now accomplished a very important result.
That is, by the action of an electric current we have made
Fig. 94.
ELECTROLYSIS.
203
a contrivance into a galvanic cell which before was not
one ; or, to put it in another way, we have led a current
into something from which, after the source of supply is
wholly disconnected, we can get a current out. This
is electrical storage the misuse of the term aside. It
looks as if we had poured the electricity into the volta-
meter, just as we might pour in the liquid, and afterwards
drawn out the one as we might the other.
The voltameter reversed as above described yields,
however, only a momentary current ; for very little of the
gases stay on the plates, the greater portion mixing and
rising as we have seen. The gases do not act on either
plate, because the material of the latter,
platinum, is not easily attacked.
The first secondary battery was de-
vised by Ritter of Jena, very shortly
after the invention of the voltaic pile.
It had been found, that, if an oblong
slip of wet paper have its extremities in
contact with the poles of the pile, each
half of the slip will be electrified ; and
if it be removed from contact with the pile, by a rod of
glass or other non-conductor, its electric state will continue.
This was observed by Volta, and, according to Dr. Lardner
(writing in 1841), " was the means of suggesting to Ritter
the idea of his secondary pile ; which consisted of a series
of disks of a single metal, alternated with cloth or card
moistened in a liquid by which the metal would not be
affected chemically. If such a pile have its extremities
put in connection, by conducting substances, with the
poles of an insulated voltaic pile, it will receive a charge
of electricity in a manner similar to the band of wet paper,
one half taking a positive and the other a negative
charge ; and, after its connection with the primary pile
204
THE AGE OF ELECTRICITY.
has been broken, it will retain the charge it has thus re-
ceived. The secondary pile, while it retains its charge,
produces the same physiological and chemical effects as
the voltaic apparatus."
In 1859 M. Gaston Plante made a secondary cell based
upon the principles above briefly sketched. Instead of
plates of platinum he used plates of
lead, rolled as shown in Fig. 90. The
consequence was, that, when the cur-
rent passed through these, the oxygen
produced at one plate combined with
the metal, and deposited lead oxide ;
the hydrogen as before remained free
on the other plate. Thus he produced
a cell in which, after the charging cur-
rent was removed, were elements of lead
and lead oxide. These being connected
yielded a current, but, however, for a
short time, because but very little of the
oxide was produced, a mere film on
the surface. Plante" thereupon devised
his so-called "forming" process, which
consisted in first charging his plates,
then discharging, then charging again
with the battery current reversed, and
so on, increasing intervals of rest being left between the
operations ; until finally he produced, through the repeated
oxidations and subsequent reductions of the oxidized ma-
terial to a metallic state, very porous or spongy plates.
These, by reason of their porosity, exposed a very large
surface to the oxidizing action of the current, so that the
result was as if he had charged a plate of great superficial
area.
As we have already shown, when batteries are connected
Fig. 96.
ELECTROLYSIS.
205
in multiple arc, that is, all the zinc plates together,
and all the copper plates together, then the plates of
each kind act as one large plate, the surfaces of all being
added together. Plante found that if he charged a num-
ber of secondary cells connected in this way, and, after
charging, if he arranged his cells in series, that is, the
positive plate of one con-
nected to the negative plate
of the next, and so on, he
could obtain very powerful
currents for short periods of
time.
In 1880 M. Camille Faure
covered Plante" 's lead plates
with red lead, and then put
them in little flannel jackets.
The peculiarity of the red
lead is, that, on sending a
current through it, it is easily
changed into spongy lead ; so
that, instead of the ' ' form-
ing " operation taking weeks
and months, it can be done
in a few days or even hours.
This discovery apparently re-
moved the chief obstacle to
Planters cells becoming of
commercial value ; and when it was announced, it was
hailed as an extraordinary advance.
Since 1880 a great many patents have been obtained
for secondary batteries, and they now exist in many forms.
An example of the Faure type is Reynier's cell, which is
represented in Fig. 97. In a glass jar are placed two
spirals of rolled lead plate, against which the red lead is
Fig. 97.
206 THE AGE OF ELECTRICITY.
held by serge instead of the felt or flannel which Faure
adopted. Mainly, however, the efforts of inventors have
been directed to reducing the weight of the cells, and to
devising new ways of holding the red lead on the plates.
Brush packs his red lead or other active material in a
frame of cast lead containing slots, cells, or openings.
Sellon also makes a plate with receptacles for containing
and holding the active material.
The storage-battery at the present time is simply a sub-
ject for further research and invention. No form of it
exists in which grave defects are not present. The value
and efficiency of many of the cells offered in the market
have been over-estimated, and often greatly misunder-
stood. None are more eager to grasp at possible im-
provements than those who to-day most loudly vaunt the
great merit of their own particular advertised contriv-
ances ; this not infrequently in the hope that the large
amounts of capital already risked may by some stroke of
good fortune be saved from loss.
The commonest defects of the storage-cell are ' ' nee-
dling," "buckling," and "disintegration." Needling is
the formation of the so-called "lead tree," fine spiculae
of metal between the electrodes, which causes short cir-
cuiting and rapid waste of current. Buckling is the defor-
mation or bending of the plates themselves, whereby one
plate often makes contact with another, and short circuit-
ing again follows. Disintegration and buckling also are
usually due to chemical changes in the electrodes. The
plates, disintegrating in time, drop to pieces. Besides
these difficulties, certain solutions cause very high internal
resistance in the cell ; and there are a variety of other
disadvantages.
One of the best forms of storage battery is that devised
by Mr. Willard E. Case, in which he uses a neutral liquid,
ELECTROLYSIS. 207
from which he deposits metal on one electrode while
peroxidizing the other.
Mr. Case's investigations in the storage-battery have
led him to the remarkable discovery that heat can be
directly converted into electricity in the galvanic cell. He
places in his cell an electrode of tin, an electrode of car-
bon, and a liquid which at ordinary temperature will not
attack either electrode. Therefore no current is yielded.
But as soon as the liquid is warmed, and to do this the
cell, which is hermetically sealed once for all, is merely put
into hot water, chlorine is set free from the liquid, and
attacks the tin. Then the current starts, and continues
until all the tin is converted into chloride. Now, if the
cell be allowed to cool, the chlorine releases the tin, and
returns to the liquid ; and so the cell regains its original
state. The chlorine, in fact, is a chemical pendulum,
swinging from liquid to tin, and from tin to liquid, as often
as the heat is applied and removed. Of course the cell
lasts indefinitely ; theoretically, forever. No material is
used up in it. The temperature is never above that of
boiling water. Its electro-motive force is about one-quarter
volt.
In one sense this cell may be regarded as a heat-storage
battery : it is really a wonderfully efficient heat-engine.
It is not merely a most beautiful and ingenious illustration
of the correlation and interconvertibility of the natural
forces, but an advance apparently destined to be of the
highest practical value.
Electrolysis has been applied to the rectification of
alcohols, the improvement of wines, and to the deposition
of aniline dyes.
208 THE AGE OF ELECTRICITY.
CHAPTER XI.
THE ELECTRIC TELEGRAPH.
THE earliest suggestion of the electric telegraph appears
in the Prohisiones Academics of Strada, an Italian Jesuit,
who in 1617 spoke of " the instantaneous transmission
of thoughts and words, between two individuals, over an
indefinite space," caused by a species of loadstone, which
possesses such virtue,- that, if two needles be touched
with it, and then balanced on separate pivots, and the
one turned in a particular direction, the other will sympa-
thetically move parallel to it. These needles were to be
poised and mounted on a dial with the letters of the
alphabet around.
In " The Spectator " of 1712, Addison proposes the
sending of love-letters in this way. In 187G, when the
speaking telephone first appeared, and before many peo-
ple had any conception of its extraordinary capabilities,
4 'The New- York Tribune" suggested that its principal
value might lie in the fact that lovers and diplomatists
could thus secretly converse ; and thus history repeated
itself.
There was no lack of experiments upon electric tele-
graphs during the last century. All of them depended
upon the idea of sending the charge of static or frictional
electricity through one or more wires ; for the galvanic
battery had not yet been invented.
THE ELECTRIC TELEGRAPH. 209
In 1729 Gray and Wheeler produced motion in light
bodies at a distance of 666 feet. In 1747 Dr. Watson,
in the presence of many scientific persons, transmitted
electricity through twenty-eight hundred feet of wire and
eight thousand feet of water, thus making use of the
earth circuit. In the following year Franklin fired spirits
on one side of the Schuylkill River, by the discharge from
an electrical battery on the opposite bank.
Then followed a curious series of endeavors to adapt
the results of the experiments of Watson and Franklin
to every-day use. The first practicable form of electric
telegraph was described in "The Scots Magazine" in
1753, in an anonymous communication over the initials
C. M. The article was entitled " An Expeditious Method
of conveying Intelligence." It was proposed to extend
wires, equal in number to the letters of the alphabet,
between two distant places ; support them at intervals on
glass fixed to solid bodies ; let each wire terminate in a
ball ; place beneath each ball a shred of paper on which
the corresponding letter of the alphabet has been printed.
Bring the farther end of the first wire into contact with
an excited glass tube, and the paper A will instantly rise
to the first ball. Thus the whole alphabet may be repre-
sented. Here, evidently, was the idea of complete insu-
lation of the conducting wire, and at the distant end the
production of a signal which should be either visible or
audible*; for the inventor also proposed a series of bells,
differing in tone from A to Z, instead of the paper.
Very little is known of the inventor. Sir David Brews-
ter asserts that his name was Charles Morrison. It is
frequently quoted as Charles Marshall. In fact, about
the only definite information ever obtained was from a
very old Scotch lady who remembered a "very clever
man, of obscure position, ' who could make lichtnin' write
210 THE AGE OF ELECTRICITY.
an' speak, and who could licht a room wi' coal reek ' (i.e.,
coal smoke)." That a great genius thus became lost to
the world, can hardly be doubted ; for here was a man
who had seen farther into the mysteries of electricity than
Franklin himself. We can easily imagine his fate. Being
ahead of his time, his neighbors those typical neighbors
of the inventor, who mend the adage to make the prophet
not only without honor, but with positive dishonor, in his
own country called him a visionary and a madman.
There is more true pathos in the many stories of the
stout hearts thus broken, than in all the romantic vicissi-
tudes of the Abelards and the Heloises since the Flood.
For several years following, little advance was made.
Lomond in 1787 proposed a single wire and a pith-ball
electrometer. Reizen in 1794 contrived a telegraph like
Marshall's, but added letters of the alphabet cut out in
pieces of tin-foil and rendered visible by sparks. Cavallo
went back to the single-wire idea, and used sparks to
designate the various signals, and an explosion of gas
to alarm the operator.
Then came a lapse of some fifteen years, and mean-
while the voltaic pile was discovered. When the inventors
came to apply this to telegraphy, they went to work in
the same old way. Soemmering, in 1809, used as many
wires as there were signals, but varied these by producing
them by the decomposition of water. The battery not
proving very successful, Mr. (afterwards Sir) Francis
Ronalds abandoned it in favor of the more intense dis-
charge of the Leyden-jar ; and arranged a pith-ball elec-
trometer at the end of his line, wherewith he made his
signals.
This was done in 1816. Seventy years had elapsed
since Watson's experiment proving the possibility of
transmitting the electrical discharge over long distances.
THE ELECTRIC TELEGRAPH. 211
Yet the actual advance made toward a practicable and
useful electric telegraph had been scarcely any thing.
The discharge could be sent over one wire ; and repeated
sparks, or movements of a pith-ball, would indicate sig-
nals the weather permitting. It could be sent over
twenty-six wires, and each wire might then make its own
signal. The signals might be produced by the decomposi-
tion of water or salts, or by explosions, or illuminations of
tin-foil letters. It is not surprising that the Lords of the
Admiralty in 1813, after considering one of the many plans
submitted to them, said that as the war was not over, and
money scarce, they thought best not to carry it into effect.
Oersted's grand discovery came in 1819, and in 1820
Ampere devised the galvanometer. He was quick to see,
that, if the current could deflect the needle at a short
distance, there was a possibility of its doing the same at
a long distance ; but he was unable, apparently, to break
away from the multiple- wire idea. He, too, proposed the
use of as many wires as letters or signals to be indicated.
That happened in the same year that the electro-magnet
was invented by Arago. Looking back on these proceed-
ings now, it seems as if all these philosophers and inventors
of Europe were groping through a labyrinth, one following
the blind lead of the static charge, and another that of
the multiple wire ; some rejecting the very means which
would conduct them to a successful ending, in the belief
that they were merely obstacles ; others clinging to obsta-
cles, in the belief that they were clews. In 1820 the
actual elements of the telegraph of to-day were in their
grasp. They had the electro-magnet, the conducting wire,
and the galvanic battery ; but no eyes to see what could
be accomplished by these means. So far as they knew,
no battery could send its current over a long line, and
magnetize something at the other end.
212 THE AGE OF ELECTRICITY.
The European philosophers kept on groping. At the
end of five years, one of them reached an obstacle which
he made up his mind was so entirely insurmountable,
that it rendered the electric telegraph an impossibility
for all future time. This was Mr. Peter Barlow, fellow
of the Koyal Society, who had encountered the question
whether the lengthening of the conducting wire would pro-
duce any effect in diminishing the energy of the current
transmitted, and had undertaken to resolve the problem.
Here is his conclusion in his own words :
" It had been said that the electric fluid from a common
electrical battery had been transmitted through a wire four
miles in length, without any sensible diminution of effect,
and to every appearance instantaneously ; and if this
should be found to be the case with the galvanic current,
then no question could be entertained of the practicability
and utility of the suggestion before adverted to. I was
therefore induced to make the trial, but I found such a con-
siderable diminution icith only two hundred feet of wire, as
at once to convince me of the impracticability of the scheme."
Barlow's conclusion would possess no especial interest
now, other than that which would necessarily attach to the
views of any eminent observer of the period, were it not
for the singular fact, that the circumstance of its publica-
tion had probably more to do with the later successful
realization of the electric telegraph, than any other occur-
rence in the history of the invention. The year following
the announcement of Barlow's conclusions, a young grad-
uate of the Albany (N.Y.) Academy byname Joseph
Henry was appointed to the professorship of mathemat-
ics in that institution. Henry there began the series of
scientific investigations which is now historic ; thus bril-
liantly opening a career which at its end found him easily
the first among American scientists.
THE ELECTRIC TELEGRAPH. 213
Up to that time, electro-magnets had been made with
a single coil of naked wire wound spirally around the
core, with large intervals between the strands. The core
was insulated as a whole : the wire was not insulated at
all. Professor Schweigger, who had previously invented
the multiplying galvanometer, had covered his wires with
silk. Henry followed this idea, and, instead of a single
coil of wire, used several. He says, " These experiments
conclusively proved that a great development of mag-
netism could be effected by a very small galvanic ele-
ment ; and, also, that the power of the coil was materially
increased by multiplying the number of wires, without
increasing the length of each." He also found that he
could obtain stronger results with the wires so wound that
the pitch of one spiral should be the reverse of that of
the spiral beneath it. And lastly he discovered that a
magnet with a long fine-wire coil must be worked by a
battery having high electro-motive force, composed of
a large number of cells in series, when a distant effect
was required ; and that the greatest dynamic effect close
at hand is produced by a battery of a very few cells of
large surface, combined with a coil or coils of short thick
wire around the magnet.
" But, be this as it may," says Henry, after describing
his discoveries as above very briefly outlined, "the fact
that the magnetic action of a current from a trough is at
least not sensibly diminished by passing through a long
wire is directly applicable to Mr. Barlow's project of form-
ing an electro-magnetic telegraph, and also of material
consequence in the construction of the galvanic coil."
Barlow had said that the gentle current of the galvanic
battery became so weakened, after traversing two hundred
feet of wire, that it was idle to consider the possibility of
making it pass over even a mile of conductor and thec
214 THE AGE OF ELECTRICITY.
affect a magnet. Henry's reply was to point out that the
trouble lay in the way Barlow's magnet was made. The
resistance of the line weakened the current. Start, then,
with a strong current, an " intensity current," Henry
said : let the line resistance weaken it, but make the mag-
net so that the diminished current will exercise its full
effect. Instead of using one short coil, through which
the current can easily slip, and do nothing, make a coil of
many turns ; that increases the magnetic field : make it
of fine wire, and of higher resistance. And then, to prove
the truth of his discovery, Henry put up the first electro-
magnetic telegraph ever constructed. In the academy at
Albany, in 1831, he suspended 1,060 feet of bell-wire,
with a battery at one end and one of his magnets at the
other ; and he made that magnet attract and release its
armature. The armature struck a bell, and so made the
signals.
Annihilating distance in this way was only one part of
Henry's discovery. He had also found, that, to obtain
the greatest dynamic effect close at hand, the battery
should be composed of a very few cells of large surface,
combined with a coil or coils of short coarse wire around
the magnet, conditions just the reverse of those neces-
sary when the magnet was to be worked at a distance.
Now, he argued, suppose the magnet with the coarse short
coil, and the large-surface battery, be put at the receiving-
station ; and the current coming over the line be used
simply to make and break the circuit of that local battery.
That is a very small thing to do, very different from mak-
ing the tired current, so to speak, work a lot of signalling
or recording mechanism. The local battery and magnet
then do the hard labor ; the current coming over the line
merely controls the force : or, in other words, instead of an
engine driven by power coming from a very long distance,
THE ELECTRIC TELEGRAPH. 215
and wasted greatly on its way, we have one operated by
power immediately at hand, but controlled from a point
miles away. This is the principle of the telegraphic
" relay." In 1835 Henry worked a telegraph-line in that
way at Princeton. And thus the electro-magnetic tele-
graph was completely invented and demonstrated. There
was nothing left to do, but to put up the posts, string the
lines, and attach the instruments. The question asked
thousands of years before by the prophet, "Canst thou
send lightnings, that they may go, and say unto thee,
Here we are?" Henry had answered in the affirmative.
It remained for other men, following his example, to go
and do likewise.
It is, as we have said, a common misfortune of invent-
ors, to be ahead of the times in which they live ; and this
was Henry's experience. It is true that he contributed to
the result himself, by refusing to patent his ideas, and so
hiding his light under a bushel. But the fact none the
less remains, that here was a discovery not merely of
transcendent importance, but one which the world had
been eagerly trying to make for years ; and yet, when it
was achieved, no one stood ready to put it to practical
use. So little was it known or appreciated, that when on
April 15, 1837, the Secretary of the Treasury, Hon. Levi
Woodbury, sent out a circular letter proposing inquiries
on the subject of a system of telegraphs for the United
States, the Franklin Institute of Philadelphia, the leading
scientific body of the land, could find nothing better to
recommend than the semaphore, or mechanical telegraph.
The report advocates the erection of forty stations be-
tween New York and Washington ; each station being a
building twenty-two feet square, with a quadrangular
pyramidal roof on which the swinging arms of the sema-
phore were to be mounted. By moving the arms into
216 THE AGE OF ELECTRICITY.
different positions, numbers and letters were to be indi-
cated, and the observer at one station would be enabled to
recognize the signals made at the next station, some seven
miles away, by means of a telescope. "In conclusion,"
says the report, ' ' the committee would respectfully sug-
gest to the Secretary of the Treasury to consider the pro-
priety of causing two telegraphs to be erected, in which
careful experiments may be made on all the points which
bear upon the general questions submitted to him by the
House of Representatives."
Meanwhile one electric telegraph had been erected in
this country. This was based on the use of the static
discharge. It was put up by Harrison Gray Dyer, on a
race-course on Long Island ; and it is a noteworthy fact,
that he strung his wires on glass insulators upon trees and
poles. The electrical discharge, after passing over the
wire, acted upon litmus paper to produce a red mark.
The difference in time between the sparks indicated dif-
ferent letters, arranged in an arbitrary alphabet ; and the
paper was moved by hand. This line was used in 1827-
28.
It will be apparent, therefore, that, at the time the fore-
going report was made by the Franklin Institute, both of
the two known systems of electric telegraphy had been
practically tested in this country ; the static-discharge
telegraph by Dyer, and the electro-magnetic telegraph by
Henry. "In 1832," says Henry, "nothing remained to
be discovered in order to reduce the proposition of the
electro-magnetic telegraph to practice. I had shown that
the attraction of the armature could be produced at any
distance, and had designed the kind of a battery and coil
around the magnet to be used for this purpose. I had
also pointed out the fact of the applicability of my experi-
ments to the electro-magnetic telegraph." Five years
THE ELECTRIC TELEGRAPH. 217
after this, the learned scientists of the Franklin Institute
offered to the Government the services of their committee
to experiment, not upon electric telegraphs, but sema-
phores !
Among the replies forwarded to the Secretary of the
Treasury, in answer to his circular, were three letters
signed Samuel F. B. Morse, all advocating the establish-
ment of an electro-magnetic telegraph. Morse was an
artist of some repute, but not in any sense an educated
electrician. In the latter part of the year 1832, while on
a homeward voyage from Europe, he conceived the idea
of an electric or electro-chemical telegraph, and devised a
system of signs for letters to be marked by the breaking
and closing of the electric circuit. Dr. C. T. Jackson of
Boston was a passenger on the same vessel ; and, being
well versed in electricity, Morse went to him for informa-
tion. It appears, however, that neither Morse nor Jack-
son at that time had conceived of any thing more than an
electro-chemical telegraph, in which the current might de-
compose chemical compounds so as to leave a permanent
mark. Morse's idea, from the beginning, seems to have
been principally to make the current record itself. In
1835 Morse was appointed to a professorship in the Uni-
versity of New York, and then he contrived the mechani-
cal arrangement which formed the basis for his subsequent
inventions. This consisted, at the receiving-station, of a
strip of paper about half an inch in breadth, moved length-
wise over a roller by clock-work. Above the paper hung
a pendulum which vibrated across the paper, and carried
at its lower end a pencil. Normally, as the paper moved
along, the pencil traced a simple straight line. Near the
pendulum was an electro-magnet, the armature of which
was attached to the pendulum. The electro-magnet was
connected to the line wire. Whenever a current came
218 THE AGE OF ELECTRICITY.
over the wire, the magnet was energized, and caused to
attract its armature, and so cause the pencil to move
across the paper, so that zigzag lines were produced,
which represented letters, numbers, etc.
Morse encountered the same trouble which all previous
experimenters before him, Henry alone excepted, had met.
His current was dissipated before it reached the end of
the line. He then adopted the relay plan in the spring of
1837. On Nov. 28, 1837, Morse wrote to the Secretary :
"We have procured several miles of wire, and I am happy
to announce to you that our success has thus far been
complete. At the distance of five miles, with a common
Cruikshank's battery of eighty-seven plates (4 by 3J inches
each plate), the marking was as perfect on the register as
in the first instance of half a mile. We have recently
added five miles more, making in all ten miles, with the
same result ; and we have no doubt of its effecting a
similar result at any distance."
In 1838 Morse took his apparatus to Washington, and
exhibited it to Congress ; but that body, despite the rec-
ommendations of its committees, took no action. Four
years passed by, during which time Morse made appeal
after appeal. He was at last successful.
He says, "My bill had indeed passed the House of
Representatives, and it was on the calendar of the Senate ;
but the evening of the last day had commenced with more
than one hundred bills to be considered and passed upon
before mine could be reached. Wearied out with the anx-
iety of suspense, I consulted one of my senatorial friends.
He thought the chance of reaching it to be so small, that
he advised me to consider it as lost, lu a state of mind
which I must leave you to imagine, I returned to my lodg-
ings to make preparations for returning home the next
day. My funds were reduced to a fraction of a dollar.
THE ELECTRIC TELEGRAPH. 219
In the morning, as I was about to sit clown to breakfast,
the servant announced that a young lady desired to see
me in the parlor. It was the daughter of my excellent
friend and college classmate, the Commissioner of Patents
(Henry L. Ellsworth). She had called, she said, by her
father's permission, and in the exuberance of her own
joy, to announce to me the passage of my telegraph-bill
at midnight, but a moment before the Senate's adjourn-
ment. This was the turning-point of the telegraph inven-
tion in America. As an appropriate acknowledgment for
the young lady's sympathy and kindness, a sympathy
which only a woman can feel and express, I promised
that the first despatch by the first line of telegraph from
Washington to Baltimore should be indited by her : to
which she replied, 'Remember, now, I shall hold you
to your word.' In about a year from that time, the line
was completed ; and, every thing being prepared, I ap-
prised my young friend of the fact. A note from her
enclosed this despatch : ' What hath God wrought.' These
were the first words that passed on the first completed
line of electric wires in America."
Congress appropriated thirty thousand dollars for the
construction of Morse's experimental line between Wash-
ington and Baltimore, a distance of forty miles. It was
put in operation in the spring of 1844, and was shown
without charge until April 1, 1845. Congress, during the
session of 1844-45, made an appropriation of eight thou-
sand dollars to keep it in operation during the year ;
placing it, at the same time, under the supervision of the
Postmaster-General. He fixed the first tariff of charges
at one cent for every four characters made by or through
the telegraph.
The object of imposing a tariff was to test the profita-
bleness of the enterprise. The result of the experiment
220 THE AGE OF ELECTRICITY.
for the four days after April 1 w/is amusing. It was then
very shortly after Folk's inauguration ; and Washington
was crowded with office-seekers, of whom large numbers
came to stare at the telegraph as one of the sights of the
capital. On the morning of April 1, a gentleman walked
into the office, and directed that the operation of the con-
trivance be exhibited to him. The operator said he would
be pleased to do so, at the regular charge of one cent per
four characters, and it would therefore cost very little for
the visitor to send his name to Baltimore, and have it
telegraphed back, or make some other simple test. The
applicant said that he did not propose to pay any thing ;
did not wish to send any message, but merely wanted to
see the thing work. The operator remained firm. Then
the gentleman got angry. He informed the operator that
this was a new administration, and he had unlimited
influence, and if the operator did not at once exhibit
the machine, he would have him removed. The operator
simply referred his visitor to the Postmaster-General, and
the interview terminated.
This was as near as the new telegraph-office got to col-
lecting any revenue for the first three days. On April 4
the same party returned, and renewed his demand, and
finally said he had no money but a twenty-dollar bill and
one cent. He was told that he could have a cent's worth
of telegraphing, if that would answer, to which he agreed.
Thereupon Washington sent Baltimore one signal which by
a pre-arranged code meant, " What time is it? " and Bal-
timore sent back a single signal meaning "One o'clock."
The charge for the two characters was half a cent ; but
the office-seeker laid down the whole cent, and departed
satisfied.
This was the entire income of the Washington office for
the first four days of April, 1845. On the oth, twelve and
THE ELECTRIC TELEGRAPH. 221
a half cents were received. The 6th was Sunday. On
the 7th, the receipts ran up to sixty cents ; on the 8th,
to $1.32 ; on the 9th, to $1.04. It is worthy of remark,
that more business was done by the merchants over the
line after the tariff was laid, than when the service was
gratuitous.
When Morse began his petitions to Congress, several
of Henry's friends, knowing what he had accomplished,
urged that he present, not his claims, for that idea he
would not entertain, but evidence of the fact that the
principles of the electro-magnetic telegraph belonged to
the science of the world. Shortly after this, Henry made
the acquaintance of Morse, whom he describes as an "un-
assuming and prepossessing gentleman, with very little
knowledge of the general principles of electricity, magnet-
ism, or electro-magnetism." Morse made no claims LO
any thing but "his particular machine and process for ap-
plying known principles to telegraphic purposes ; " and
so, adds Henry, " instead of interfering with his applica-
tion to Congress, I gave him a certificate in the form of
a letter, stating my confidence in the practicability of the
electro-magnetic telegraph, and my belief that the form
proposed by himself was the best that had been pub-
lished."
Morse obtained his first patent in June, 1840. Others
were subsequently secured. Infringements of all sorts
followed, and protracted suits, which resulted, however,
in Morse's favor. As a consequence, Morse is popularly
regarded as the inventor of the electro-magnetic telegraph.
He has no right to the title, nor did he himself establish
claim thereto. The true inventor was Joseph Henry.
Neither is Morse entitled to the credit of having devised
the mechanism of the telegraphic instrument attributed
to him ; nor of the dot-and-dash alphabet that bears his
222 THE AGE OF ELECTRICITY.
name. That was the work of Alfred Vail, who was em-
ployed by Morse to improve and develop the invention.
Vail produced the first so-called Morse instrument in the
fall of 1837, entirely of his own design, and without sug-
gestion from Morse, and arranged it to emboss alphabetic
characters devised by himself. Morse, in such late rec-
ognition as he made of what Vail had done, might well
have heeded the lesson in magnanimity given by Henry
to him.
The student who undertakes to glean the history of the
telegraph from English books will note with surprise very
little mention of Henry. In fact, most English writers
claim that the true inventors of the electro-magnetic tele-
graph were Professors Cooke and Wheatstone of England.
This leads us to a brief review of what was going on in
Europe during the period between Henry's first dis-
cover} 7 , and the successful operation of Morse's line in
this country.
In 1820 Ampere merely suggested the idea that a series
of needles could be deflected by currents coming over as
many wires ; eight years later, Trebouillet proposed a
single wire and an electroscope ; and finally in 1832-33
Schilling, a Russian counsellor of state, went back to the
multiple- wire idea. In 1833-35 two German scientists
devised a needle telegraph in which a galvanometer-needle
was made to move by currents generated by a coil moved
to and fro on a magnet ; the transmitter being, in fact, a
small magneto-electric machine.
Meanwhile, in England, Barlow's conclusion that the
electro-magnet could not be worked over long distances
of wire became regarded as a fixed fact. Cooke in 1837,
at the suggestion of Faraday, applied to Professor Wheat-
stone for some way of overcoming his " inability to make
the electro-magnet act at long distances." Wheatstone
THE ELECTRIC TELEGRAPH. 223
says that he at once told Mr. Cooke that this difficulty
was insurmountable, and exhibited to him at Kings Col-
lege experiments which supported the conclusion. This
was not only after Henry's inventions were completed,
but even after Morse had made his applications of them.
But then, what could so distinguished a scientist as
Wheatstone know of the work of a mere professor in an
American college, still less of the ideas of an American
portrait-painter? Besides, how could he be expected to
know more about what American inventors and discoverers
had done, than the Franklin Institute, which held its meet-
ings not fifty miles from Henry's line, and which, neverthe-
less, solemnly advised the Government of the United States
to experiment upon semaphores, and to pay $100,000 first
cost, and $62,500 annual charges, for a series of them
between New York and Washington ?
After they had concluded that the thing could not be
done, Wheatstone and Cooke, in 1837, applied for an
English patent for it, in which, among other devices,
they describe five wires and five needles, two of which
indicated the letters of the alphabet placed around,
and also a method of deflecting telegraphic magnetic
needles by electro-magnets ; these last being in horseshoe
form, placed opposite one another, with the needle between
their poles. The description of Wheatstone's first experi-
ments, published in "Chambers' Journal" in 1870, is
worth quoting: "In July, 1837, wires were laid down
from Eustou Square to Camden Town Stations, by the
sanction of the North-western Railway ; and Professor
Wheatstone sent the first message to Mr. Cooke between
the two stations. The professor says, ; Never did I feel
such tumultuous sensation before, as when, all alone in
the still room, I heard the nee'dles click ; and as I spelled
the words, I felt all the magnitude of the invention now
224 THE AGE OF ELECTRICITY.
proved to be practical beyond cavil or dispute.' The
form of telegraph now in use was substituted because of
the economy of its construction, not more than two wires
(sometimes only one) being required. Of course several
persons claimed to have invented the telegraph before
Professor Wheatstone. In the same month that the pro-
fessor was working upon the North-western Railway, there
was one in operation invented by Steinheil of Munich ;
but Wheatstone' s patent had been taken out in the month
before. An American named Morse claims to have in-
vented it in 1832, but did not put it in operation till 1837.
After this his system was generally adopted in the United
States. It is a recording one."
It is a curious fact that the patent granted to Wheat-
stone and Cooke in this country, for their telegraph, is
earlier in date by just ten days than the first patent ob-
tained by Morse.
It is not possible, within the limits of the present work,
to trace farther the history of the telegraph. Even at
the early period of which we have been writing, it had
resolved itself into two great types, depending upon the
kind of signals given, the visual or needle telegraph,
the electric adaptation of the old semaphore which required
the receiver to watch the oscillations of a needle ; and the
recording telegraph, wherein the current was made to
write its own message upon a slip of paper. The needle
telegraph is not in use in the United States : it is essen-
tially an English instrument, and is still largely employed
in England upon the railways. Recording instruments of
various forms are used in the United States ; but, in the
majority of instances throughout the world, telegraph-
signals are read by the clicking sound produced by the
armature of the receiving magnet.
The amount of mechanical ingenuity expended in devis-
THE ELECTRIC TELEGRAPH. 225
ing telegraphic apparatus has been and still is wonderful.
To explain even the best-known systems in any detail,
would require the dryest of descriptions of complicated
mechanism, extended to the limits of a cyclopaedia. We
shall therefore endeavor to indicate what the telegraph
can do, rather than how its machinery operates ; resorting
to explanation of the latter only where it may be indis-
pensable to an understanding of the results achieved.
If we stretch a wire between the points A and B, and
attach the ends of the wire to plates buried in the earth,
then we have a circuit. If we place a battery in the wire,
as in Fig. 98, then a current will pass from the battery,
to and along the wire, in the direction of the arrow (for
example) , and thence to the distant earth plate. From
this earth plate the current will apparently return by way
of the earth, to the earth plate attached to the battery,
and so back to the battery itself.
But how is it that a current sent, for example, over a
thousand or more miles of wire, can find its way back
through the earth to its source? About this there is a
great deal of confusion. One writer regards the earth as
a reservoir in which the positive electricity on the one side,
and the negative on the other, are absorbed and lost.
Another, considering the earth still as a reservoir, con-
226 THE AGE OF ELECTRICITY.
chides that it offers no sensible resistance to the passage
of a current. A third holds that the electricity is pumped
into the earth at one point, and out of it at another ; and
so on through a variety of hypotheses, to attempt to
reconcile which is simply bewildering.
According to Faraday's theory, the earth plays the part
of a conductor, and becomes polarized by the passage of
a current, the same way as any other part of the circuit.
Recent experiments of Mr. Willoughby Smith go to sub-
stantiate this view. Mr. Smith says that " the current
passes through the earth or water, which amounts to
the same thing as through an ordinary conductor, in
dispersed and curved lines. How far such curves extend,
I am not prepared to speak positively ; " but they prob-
ably " extend over the whole world, and what are termed
the magnetic poles of the same are the immediate cause
of the lines assuming the curved form. From whatever
source a current emanates, it will diffuse itself over the
whole mass of matter interposed, without in any way
mixing or blending with a current or currents emanating
from any other source or sources. The nearest analogy
to this which I can think of is that the mind of each
human being in this world of ours is constantly directing
what are called lines of thought from its brain, or battery,
far and wide, and those numberless lines of thought, so
far as our own knowledge extends, never blend or become
confused, but go and return each one to the source from
which it emanates in precisely the same way as lines of
electro-motive force when similarly manipulated. . . .
Messages by electric signals have been sent and correctly
received through a submarine cable two thousand miles in
length, the earth being one-half of the circuit, by the aid
of electricity generated by means of an ordinary gun-cap
containing one drop of water ; and, small though the
THE ELECTRIC TELEGRAPH. 227
current emanating from such a source naturally was, yet
I believe it not only polarized the molecules of the copper
conductor, but also in the same manner affected the whole
earth through which it dispersed on its way from the out-
side of the gun-cap to its return to the water it contained."
The battery in Fig. 98, the wire, and the earth are in
closed circuit ; that is, there exists a path through which
the current can continuously flow until the battery is
exhausted. If, however, we should break the wire, and
leave the ends separated, then we should have an open
circuit over which no current passes or can. pass until we
unite the separated ends once more. If we attach a lever,
or, as it is called, a key, movable by the hand, to
Wii-e
Fig. 99.
one part of the separated wire, as in Fig. 99, and ar-
range the key so that at will we can cause it to make
contact with the other part of the wire, then, if we leave
the key open, we have an open circuit ; if we bring the
key into contact with the opposite part of the wire, so that
it bridges the interval between the two separated parts,
then the effect is the same as if the wire were continuous,
and we have a closed circuit.
We can therefore start with either an open circuit or a
closed circuit. If we choose an open circuit, every time
we move the key into contact with the opposite part of the
wire, we let the current pass : if we prefer a closed circuit
through which the current constantly travels, we can inter-
rupt the current as often as we desire, simply by moving
228 THE AGE OF ELECTRICITY.
the key out of contact. And by making the periods of
contact or the periods of interruption short or long, or
more or less frequent, we can allow currents varying in
duration and frequency to pass over the line.
At the opposite extremity of the line to that at which
our key is placed, something is necessary to reveal the
currents which come over ; and for this purpose, as we
have already explained, the electro-magnet is employed.
In Fig. 100, there is shown a closed circuit. Whenever
we press down the key, the current which excites the
magnet at the far end of the line is interrupted ; and
the magnet, which has attracted its armature to its pole, re-
leases it. The armature is thus moved from one position
Fig. 100.
to another, and so held as long as the current remains
broken, which is until we move the key into contact and
back to its original position. Then the magnet attracts
its armature back to its original place.
The consequence is, therefore, that the armature at the
distant end of the line copies, so to speak, the movement
of the key at the sending end. If the key is held down,
and the circuit opened, for a certain period, the armature
remains released and retracted for that period : if the key
be held down only for an instant, the armature is instantly
retracted and attracted. Consequently, in order to send
signals, we have simply to manipulate the key very much
as a key of a piano is touched when it is desired to pro-
duce a note of greater or less duration.
THE ELECTRIC TELEGRAPH. 229
It will be remembered, that, in describing Morse's
original apparatus, we stated that a pencil-point rested
upon a slip of moving paper, and by the attraction of a
magnet made sidewise zigzag marks thereon. Leaving
out the idea of sidewise motion, suppose we move the
point at intervals away from the paper, which keeps on
travelling. Then we shall make broken lines, long or
short, depending upon the length of the intervals of time
during which we keep the pencil away from the paper.
For example : suppose above a magnet, as shown in Fig.
101, we arrange an armature fastened to one end of a
pivoted lever which carries a pencil at its opposite end.
Fig. 707.
This pencil bears against the under side of a strip of
paper, which is moved under a roller, by clock-work or
any other suitable means. So long as the current comes
over the line, the magnet will attract its armature, and
keep the pencil-point pressed against the paper, on which
a continuous line will be made. But if the current is
broken, which is done by manipulating the key at the
sending end of the line, as already explained, then the
magnet will no longer attract its armature, and the pencil-
point end of the lever will drop down, or be drawn down
by a spring, so that the pencil will no longer mark. Now,
we have only to agree upon an alphabet made up of short
lines and long ones, arranged in a different way for each
letter, to make the apparatus spell out words.
230
THE AGE OF ELECTRICITY.
The shortest signal that can be made is, of course, a
dot ; and this at the sending end involves opening the cir-
cuit and closing it very quickly by a sudden movement of
the key. The dot is usually taken as the standard ; and
with dots are combined dashes, which may be regarded as
lines produced while the current is passing three times
as long as is necessary to make a dot. The letter A may
therefore be represented by a dot and a dash ; J, by a
single dot ; F, by dot, dash, dot ; and so on, through
various combinations in which the spaces or intervals be-
tween the dots and dashes also are used to cause varia-
tions to produce a different symbol for each letter : so that
any one knowing these
-drrtialttre Jetxtr
Fig. 102.
symbols can read the
message from the marked
paper as easily as from a
printed page.
This is Morse's record-
ing system, which he used
on his first line, and for
which Vail invented the alphabet of dots and dashes still
employed all over the country.
Nowadays, however, telegraph-operators receive mes-
sages by sound ; and the recording part of Morse's con-
trivance is little used. To this end the receiving magnet
is arranged about as indicated in Fig. 102. Here the op-
posite end of the armature moves between fixed stops, and
strikes them alternately, producing a sharp click. It is a
great puzzle to many people, to understand how it is that
a telegraph-operator sitting beside one of these little in-
struments, which appears to be rattling away with great
rapidity, manages to comprehend what it says, apparently
as well as if the instrument actually spoke to him. Of
course long practice has as much to do with this skill, as
THE ELECTRIC TELEGRAPH. 231
it has in enabling any one to comprehend readily a foreign
language. The lever, however, in striking its stops, pro-
duces two distinct sounds, according as it meets one or the
other stop. When a dot is made, the lever strikes one
stop, and instantly afterward the other : when a dash is
signalled, there is a longer delay between the sounds.
The two sounds are in themselves just alike ; but the dot
and dash, to a practised ear, are easily distinguishable,
because there is a longer wait, or delay, between the clicks
which begin and end a dash, than those which begin and
end a dot. We say, to a practised ear, because to the
ordinary organ there is no apparent difference. The
average hearer can of course perceive that there is an
irregularity about the clicks, and that they do not come
at regular intervals like the beats of a clock-pendulum ;
but all the instruction ever given by written description
never made a skilful telegraphic sound-reader, and proba-
bly never will. To learn to manipulate a key so as to send
dots and dashes with fair speed, is not difficult ; but to
translate a bewildering succession of clicks, spelling out
words at the rate of perhaps thirty a minute, simultane-
ously to write down the received message, and to do this
with perhaps other instruments in the room clicking away
at the same time, and perhaps unlimited conversation
going on, and all this with the knowledge that a blunder
may involve the company in an expensive lawsuit, is not
an accomplishment easily acquired. Yet a skilful opera-
tor can send and receive forty-five words per minute.
When a telegraph-line is of considerable length, or for
any other reason offers much resistance to the passage of
the current, Henry's invention of the relay is employed ;
which is placed in the main line, and merely performs the
duty of opening and closing the circuit of a local battery
at the receiving station, which in turn operates the sounder
232
THE AGE OF ELECTRICITY.
Fig. 103.
already described. The diagram (Fig. 103) will render
the relay arrangement easily understood. The current
coming over the line excites the magnet marked "relay,"
which attracts its armature, and thus moves the latter into
contact with a stop. The
circuit of the local battery is
thus established through the
magnet of the sounder.
The closed-circuit system
which is in almost universal
use throughout the United
States is shown in its sim-
plest form in Fig. 104. At
each key there is a circuit-closing lever whereby the line
is kept closed, so that a current constantly traverses the
line. This current goes from the main battery at New
York, for example, through the circuit-closing lever, to
the relay magnet
which attracts its
armature. In Fig.
104 the sounders
and local batteries
are not shown.
But when this
armature is at-
tracted, it makes
contact with a
stop, and thus
completes the circuit from the local battery through the
sounder at New York. Hence, at the New- York end,
both armatures stand normally attracted. After passing
through the New-York relay, the current goes over the
ninety miles or so of line to the Philadelphia relay, which
attracts its armature, and establishes a local circuit through
Fig. 104.
THE ELECTRIC TELEGRAPH. 233
the sounder in Philadelphia. This is the normal condition
of affairs.
Suppose now New York wants to send a despatch to
Philadelphia. The first thing that the New- York operator
does is to open his circuit-closing lever, when all of the
armatures both at his and at the Philadelphia end will
be released. Then he manipulates his key, making and
breaking the current to form the desired signals ; and as
he does so, all of the armatures at both ends of the line
will respond, so that the Philadelphia receiver has merely
to listen to the clicks of his sounder to receive the mes-
sage. Meanwhile the New- York sender's instruments keep
clicking too, which indicates to him that the message is
reaching Philadelphia. If, however, his instruments should
stop, he would know that the Philadelphia man had opened
the circuit. Then he would close his own lever, and wait
for a message from Philadelphia explaining the reason of
the break, such, for instance, as " message not under-
stood," or something of that sort. The instruments at
the Philadelphia end being the same as those at the New-
York end, a message from Philadelphia to New York
would of course be transmitted in the same way. It will
be seen, however, that there is but one main-line battery,
which is at the New- York end. In practice this battery is
usually divided, half of it being placed at each terminal
station. As many as forty intermediate stations are some-
times operated in this manner.
So far we have described simply a main line, the cur-
rent of which establishes a new circuit at the receiving
end, so that the work of recording the message, or of
operating the sounder, is thrown upon a battery at that
end. But suppose we have to telegraph over very long-
distances say from Augusta, Me., to San Francisco,
Cal. A single main-line battery might be wholly unable
234 THE AGE OF ELECTRICITY.
to send its current through so much resistance ; and if we
divided the line into short sections, it would be necessary
for the operator at each station to receive and understand
the message, and then repeat it to the next station. In
the early days of telegraphing, this was in fact done ; but
now it is automatically accomplished by a simple exten-
sion of the relay principle known as "repeating." In-
stead of there being simply a short local circuit in the
receiving station, which is controlled by the arriving cur-
rent, the latter governs a circuit which extends, perhaps,
a long distance to another station. The current which
comes to station No. 2 closes contact in a circuit which
extends still farther to station No. 3, and so on from
station to station, until the sounder at the far-distant end
of the series of lines is operated ; just as if one could fire
a gun, and with the bullet strike the trigger of a distant
gun, the missile from which would fire a third gun, and so
on. So that, in practice, suppose a message to be sent from
Augusta, at which place the battery is located. When the
key is closed, a current goes over the line, and energizes
a magnet at New York, for example. This magnet then
closes the circuit, say, between New York and Chicago,
and in this circuit there is a new battery located at New
York. The current from New York closes at Chicago
the circuit between that city and San Francisco, and finally
San Francisco receives the message on its sounder in the
usual way. Repeaters are also often used for connecting
one or more branch lines with a main line, for the purpose
of transmitting press news, etc., simultaneously to differ-
ent places. This enables all the stations in connection
to communicate with each other as readily as if they were
situated upon the same circuit.
The use of repeaters has aided many very wonderful
feats of rapid long-distance telegraphing. The news of
THE ELECTRIC TELEGRAPH. 235
the Hanlan-Trickett rowing match in England, in 1881,
travelled to Sydney, Australia, a distance of twelve thou-
sand miles, in one hour and twenty minutes. The distance
from Singapore to Sydney, 5,070 miles, was traversed in
thirty-five seconds. There were fourteen repetitions of
the message en route. But perhaps the most extraordi-
nary direct long-distance telegraphing is that now possible
between London and Calcutta, seven thousand miles,
of which a writer in the London ' ' Telegraphist ' ' gives
the following graphic account :
" In the basement of an unpretentious building in Old
Broad Street, we were shown the Morse printer in connec-
tion with the main line from London to Teheran. We
were informed that we were through to Emden ; and with
the same ease with which one ' wires ' from the city to the
West End, we asked a few questions of the telegraphist in
the German town. When we had finished with Emden, we
spoke with the same facility to the gentleman on duty at
Odessa. This did not satisfy us, and in a few seconds we
were through to the Persian capital (Teheran) . There were
no messages about, the time was favorable, and the em-
ployees of the various countries seemed anxious to give us
an opportunity of testing the capacity of this wonderful line.
"T H N (Teheran) said, 'Call Kurrachee ; ' and in
less time than it takes to write these words, we gained the
attention of the Indian town. The signals were good,
and our speed must have equalled fifteen words a minute.
The operator at Kurrachee, when he learnt that London
was speaking to him, thought it would be a good opportu-
nity to put us through to Agra ; and to our astonishment
the signals did not fail, and we chatted pleasantly for a
few minutes with Mr. Malcom Khan, the clerk on duty.
To make this triumph of telegraphy complete, Agra
switched us on to another line, and we soon were talking
236 THE AGE OF ELECTRICITY.
to a native telegraphist at the Indian Government cable
station, Calcutta. At first the gentleman ' at the other
end of the wire ' could not believe that he was really in
direct communication with the English capital, and he
exclaimed in Morse language, ' Are you really London ? '
Truly this was a great achievement. Metallic communi-
cation without a break from London, to the telegraph-
office in Calcutta ! Seven thousand miles of wire ! The
signals were excellent, and the speed attained was not less
than twelve, perhaps fourteen, words per minute."
One of the most paradoxical of all the applications
of electricity is that which appears to solve that rather
insoluble problem of how to make two locomotives pass
each other while moving in opposite directions on a
single track. This is the so-called duplex system of teleg-
raphy, whereby two messages are transmitted over one
wire simultaneously and in opposite directions.
To explain the duplex without resort to technicalities,
is exceedingly difficult, chiefly because it is scarcely pos-
sible to suggest an analogy which meets all conditions.
It should be remembered, that, in dealing with electricity,
our ideas of lapse of time are very apt to lead us alto-
gether astray ; and we frequently consider occurrences as
simultaneous, because they seem so to be to our senses,
when in fact they are necessarily successive. So, in the
case of the duplex, for all practical purposes two mes-
sages do travel in opposite directions on one and the same
wire ; but probably the signals in one direction alternate in
inconceivably small periods of time with those coming
from the opposite direction. To obtain any clear idea
of the duplex, therefore, it is necessary to forget the
apparent paradox, and simply to regard the apparatus as
affording means whereby each of two widely separated
operators may control an instrument at the end of the line
THE ELECTRIC TELEGRAPH. 237
distant from him. On such a line, at each end there is,
of course, a sending key and a receiving instrument.
But ordinarily, when two receivers are thus connected, a
current sent upon the line affects both of them. Hence
if A at one station, while telegraphing to B at the other,
keeps his receiver clicking under his own signals, B at the
other end, in sending to A, cannot exercise the necessary
control over A's receiver ; and in the same way, if B's
receiver is constantly disturbed by B, it cannot correctly
be governed by the signals sent by A. Therefore the
main principle of the duplex is to arrange matters so that
A's signals will affect, not A's receiver, but B's receiver ;
and conversely, so that A's receiver will respond only to
B's signals, and B's receiver to A's signals.
There are several ways of doing this ; but for these, the
reader is referred to the technical treatises.
The diplex is a system by which two messages can be
sent at once in the same direction ; and is called " diplex "
in contradistinction to the "duplex," where two messages
are sent simultaneously in opposite directions. In the
diplex, the two keys are of course at the sending station,
and the two relays are at the receiving station. Ke}' num-
ber one sends a weak current, while key number two sends
a stronger current. The two relays are so arranged that
one will respond to the strong current, and the other to
the weak ; when both currents are sent at once, both re-
lays respond. It is this system, using both poles of the
battery in connection with the so-called bridge duplex,
which forms the so-called quadruples of Edison. A de-
scription of the quadruplex would, however, be altogether
too technical for these pages.
Multiple telegraphic systems have for their object the
transmission of a large number of messages simultaneously
over the same wire. The harmonic system is one of the
238 THE AGE OF ELECTRICITY.
most ingenious of these, although it has never come into
extended practical use. It depends upon thep rinciple of
acoustics, that two tuning-forks or tuned reeds will vibrate in
unison, and be set in vibration one by the other ; whereas,
of two forks not in unison, the reverse is true. Suppose,
for example, half a dozen tuning-forks A, B, (7, />, E, F,
be arranged conveniently together, and suppose three per-
sons should strike three other tuning-forks respectively in
unison with A, B, and C of the series. Then the air-waves
produced by the three forks set in vibration would affect
only A, B, C ; and these three forks would respond, the
others remaining silent. Now suppose the three persons
mentioned should strike their forks simultaneously, and in
a particular way ; as, for instance, say that each person
should make the signals of a different telegraphic mes-
sage in the Morse alphabet by taps on his fork. Clearly,
the result of all these taps sounding together would be a
confused jumble to the ear, but when the combined sounds
reached the three tuning-forks A, B, and C, they would
be disentangled. The tuning-fork A would be entirely
indifferent, audibly, to the vibrations affecting B and (7,
and would not reproduce them, but would pick out and
respond only to those emanating from a fork in unison
with it. So also of forks B and (7; and, consequently,
three messages made simultaneously might thus be trans-
mitted through the air, and analyzed at the receiving
forks. In multiple harmonic telegraphy, these vibrations
are transmitted by the electric current, through a wire,
instead of by waves of condensation and rarefaction in
the air. If two tuned reeds be sounded together, then
the electrical impulses from each, moving at different
rates at the same moment, will traverse the wire simulta-
neously, and these will be disentangled by each of twc
receiving reeds vibrating responsively under the impulse
THE ELECTRIC TELEGRAPH. 239
of the transmitting reed in unison with it. In this manner
two messages are sent simultaneously over a single wire,
and received by sound separately from different reeds.
And the same principle governs the sending of more mes-
sages by the aid of a greater number of reeds, and under-
lies the construction of the harmonic telegraphs of Gray
and others.
One of the most recent inventions in multiple teleg-
raphy is that of Mr. Delany. A great many varieties of
telegraph-apparatus depend upon synchronism between the
movements of certain devices in the transmitting apparatus,
and certain other devices in the receiving apparatus. Two
tuning-forks are said to be synchronous when they make
the same number of vibrations in the same time, and have
motions exactly similar. Mr. Delany has succeeded in
keeping two bodies, separated by hundreds of miles,
in synchronous rotation for periods of upward of seventy
hours, without variation during that time of the one-thou-
sandth part of a second. This is equivalent to two
entirely independent bodies, separated from each other by
hundreds of miles, starting together and passing through
a distance of nearly one hundred miles without varying
the one-hundredth part of an inch in that entire distance,
or the one-thousandth part of a second during that entire
time. The practical consequence is that circuits ranging
in number from six to seventy-two, according to their
capacity, have been obtained over a single wire, admitting
of the possibility of the transmission of from six to
seventy-two separate messages at practically the same
time, either all in one direction or any portion of the
whole number in opposite directions. Another extraor-
dinary performance of Mr. Delany's apparatus was the
automatic transmission of a single dot back and forth
over the same wire between Boston and Providence, at
240 THE AGE OF ELECTRICITY.
practically the same instant of time, travelling over dif-
ferent circuits in rotation backward and forward for five
minutes, during which time it travelled four hundred and
fifty thousand miles. Mr. Delany's system is based on
two main principles : first, that of synchronism, or the
simultaneous motion of similar pieces of apparatus at
two different places ; and, second, that of distributing to
several telegraphists the use of a wire for very short equal
intervals of time, so that, practically, each operator has
the line to himself during these periods.
Farther on, we shall see the great importance of syn-
chronism in fac-simile telegraphy. But, in connection
with the transmission of messages in the usual way, Mr.
Delany's apparatus greatly increases the capacity of every
wire, and probably at the present time allows of more
messages being simultaneously transmitted over a given
conductor, at the same time, than any other telegraphic
system.
It is of course needless here to go into the minute
details and very complex mechanism employed in multiple
telegraphy : nor, in fact, shall we attempt, in the many
forms of intricate devices which must find mention here,
to do more than generally outline what they will accom-
plish. As we have seen, duplex, quadruplex, and other
multiple telegraphic systems increase the capacity of wires,
and expedite business through rendering it possible to
send many messages at one time. There are many sys-
tems, however, which provide for very rapid transmission.
It will easily be understood, that, where telegraphic
transmission depends upon the manipulation of a key by
the human hand, a limit of speed is very soon reached.
And not only this, but the human machine tires and makes
errors ; the signals lose legibility and clearness ; and, in
short, the various accidents and failures incident to all
THE ELECTRIC TELEGRAPH. 241
handiwork become manifest in greater or less degree.
When, however, manipulation by the operator is replaced
by the action of a machine, then not only great speed but
precision within certain limits is obtained : and hence auto-
matic instruments, both for the sending and receiving of
telegraphic messages, have been invented and are in use.
Automatic telegraphy is largely employed in England,
where it was first proposed in 1846 by Alexander Bain.
He punched broad dots and dashes in paper ribbon, which
was drawn with uniform velocity over a metal roller and
beneath brushes of wire, which thus replaced the key ; for,
whenever a hole occurred, a current was sent by the
brushes coming in contact with the roller. The same idea
is now applied to the musical instrument known as the
mechanical orguinette, in which a strip of paper having
apertures of various sizes is moved in front of the melo-
deon reeds so as to control the air supply to them, and
hence the notes produced. Bain used as a recording in-
strument his chemical marker, wherein the current was re-
ceived through a strip of paper moistened with a chemical
solution which became decomposed on the passage of the
current, so that the contact point in touching the paper
caused dots and dashes of a bright blue color to appear.
The apparatus used throughout Great Britain is that
invented by Professor Wheatstone. Its construction is
too complicated for description here ; but, in general
terms, it includes a punching-machine for producing the
perforated strips of paper, a transmitting apparatus
through which these strips are very rapidly passed, and
a receiving device which marks on another strip dots and
dashes in ink. The punching-machine will make the holes
in three or even four strips at a time, and in the hands of
an experienced operator will punch at the rate of forty
words a minute. The disposition of holes in a strip when
242 THE AGE OF ELECTRICITY.
thus prepared is shown in Fig. 105 ; the large openings
being for the message, and the centre row of small ones
serving to receive the teeth of a wheel which in turning
moves the strip along at uniform speed. When the paper
is thus prepared it is run through the transmitter, which is
permitted to operate to send a current whenever certain
moving rods can pass through the holes and establish a
contact, the currents being alternately positive and nega-
tive. If a succession of currents in reverse directions are
caused to pass upon the line, the receiver at the opposite
end will record a series of dots. To make a dash, one
reversal of the current is missed ; and, in brief, the func-
Fig. 1C5.
tion of the paper is so to regulate the motion of the trans-
mitter as to produce reversal, or missing of reversal, of
the current at the proper moments, and thus to cause the
current to flow in such a way as to form dots and dashes.
The speed is determined by the rate at which the receiver
can receive ; because the apparatus contains a controlling
electro-magnet which takes time to be magnetized and
demagnetized, and hence, if the current reverses too
quickly, the marks will run together instead of being
separate, and distinct. The maximum useful speed is
about a hundred and thirty words per minute on a short
line. One strip of punched ribbon will do for any number
of circuits, so that from a central telegraph-station a
single strip disseminates news to many places.
THE ELECTRIC TELEGRAPH. 243
With Edison's system of automatic transmission, a
much greater speed than this has been obtained. The
receiving apparatus here consists simply of a wire tipped
with tellurium, which always rests on the moistened paper.
The effect of the current is to decompose the water in the
paper, and through the effect of the tellurium the contact
point makes a dark mark. Mr. Edison in this way claims
to have transmitted 3,150 words in a minute, on a line
between New York and Washington.
We have now seen what can be done in the way of quick
transmission. Next in importance is legibility at the re-
ceiving end ; or, rather, the possibility of receiving mes-
sages, not in dots and dashes, but in ordinary characters.
For this purpose type-printing and autograph systems are
employed. The first printing telegraph actually used was
that devised by Royal E. House of Vermont in 1846,
now obsolete. It was followed by Hughes's system, in
which the principle of synchronism between the sending
and receiving instruments entered materially into the suc-
cess of its working. Hughes's apparatus is not used in
this country. It has two type-wheels kept rotating syn-
chronously together at each station by means of a train
of gearing provided with a governor. Connected to the
mechanism is a transmitting cylinder, arranged with and
controlled by a keyboard having a key for each letter of
the alphabet. A printing-lever, controlled by an electro-
magnet placed in the main line, causes the printing of a
letter upon a long fillet of paper while the type-wheel is
rapidly moving. This movement is caused by the energiz-
ing of the controlling magnet by the transmission of a
single wave of electricity from the distant station at the
proper time. Simultaneously with the printing of a letter,
the type-wheel, by the action of the printing-lever, is
thrown slightly forward or backward, thus correcting at
244 THE AGE OF ELECTEICITY.
every impression any slight variation in the synchronous
movement of the wheel.
The printed despatches on the long slips of paper now
delivered by the Western Union Telegraph Company are
transmitted by Mr. G. M. Phelps's electro-motor telegraph.
In this system, the gearing of the Hughes apparatus is
replaced by a simple but powerful electro-motor. As in
the Hughes machinery, the transmitting device and type-
wheel of the receiving instrument are caused to revolve
synchronously under control of a governor, and each sepa-
rate letter is printed by a single pulsation of the electric
current, of a determinate and uniform length, transmitted
at a determinate time ; but, unlike the Hughes apparatus,
the motion of the type-wheel is arrested while each letter
is being printed, and it is automatically released the in-
stant the impression has been effected. By this means a
very high speed of transmission has been attained.
There is one form of printing telegraph which is notable
for the danger attending its use. It has probably, inno-
cently, been the means of more injury to the human race
than the most potent of electrical torpedoes, which it re-
sembles occasionally in effect, that is, metaphorically
speaking. We allude to the stock exchange "ticker"
when combined with a widely fluctuating market. For
the benefit of those who have never watched the motions
of the intricate little mechanism, let us say, while wait-
ing for the next quotation, it may be explained, that
there is usually a t} T pe-wheel rotated by a lever from an
electro-magnet. The magnet is excited, and the lever
worked, by pulsations over the wire. The lever turns the
type-wheel step by step. Usually there are two type-
wheels ; one printing the cabalistic letters which indicate
the name of the stock, and the other the quotation in
numbers. When a letter or number is to be printed, the
THE ELECTRIC TELEGRAPH. 245
proper wheel is brought into position, and then another
magnet operates to bring the "tape" into contact with
the type.
Despatches may be sent automatically, and received in
printed characters, by several systems, of which Bonnelli's
is an example. The message is set up in ordinary type,
which are connected to the battery and earth. Over the
face of the type passes a comb of fine points of wire,
each point being connected to a separate line proceeding
to the distant station, and the line wires there being con-
nected to another and similar comb, which is moved over
chemically prepared paper. When the comb at the send-
ing end is rubbed over the raised parts of the characters,
the comb at the receiving end receives a current which
decomposes the chemicals in the paper, producing a mark
similar to the character traversed. Little use has been
made of systems of this character.
The autographic telegraph is one of the most ingenious
of the various known systems. It is not used in this
country, although recently the improvements in effecting
synchronism have directed anew the attention of inventors
to its possibilities. It transmits the handwriting of the
sender, and also simple drawings. Its advantages at pres-
ent appear to depend on whatever benefits may be derived
from these capabilities ; thus it may be useful to send
sketches and illustrations to newspapers, or to verify sig-
natures, or to telegraph bank-checks in facsimile : but
beyond this, it has not much promise. Its operation de-
pends upon synchronism at both ends of the line. Cas-
selli's apparatus, which is used in France, consists of two
large pendulums kept swinging in unison by electro-mag-
nets placed in the line wire. One pendulum transmits
electric waves at certain intervals, which, acting upon the
magnets, cause them to correct variations from exact
246 THE AGE OF ELECTRICITY.
unison of swing. The message for transmission is written
upon metallic foil, with a non-conducting ink : this is laid
upon a platen connected to the earth through a battery.
A fine platinum wire connected to the line wire is recipro-
cated from one end of the foil to the other ; the foil being
advanced one-hundredth of an inch after each reciproca-
tion, until the point has passed over the whole of the foil.
The platinum point, when passing over the foil, allows
the current from the battery to go to the line. At all
points, however, where it passes over the non-conducting
ink with which the message is written, the current is pre-
vented from passing to line. At the distant station a
similar point is reciprocated over a platen upon which is
laid a sheet of chemically prepared paper: the passage
of the circuit through the reciprocated point and moistened
paper causes a blue mark to appear. If both pendulums
are started at the same instant, the form of the metallic
foil upon which the message is written will be reproduced
upon the chemical paper by blue lines blending one into
the other. But owing to the non-transmission of any cur-
rent where the transmitting point passes over the non-
conducting ink, no mark will appear ; hence the message
would be inscribed in white characters on a blue ground,
were it not for an ingenious little device which reverses
the action, causing the characters to appear in blue. In
Fig. 106 is represented a design as prepared and then trans-
mitted in facsimile by Casselli's apparatus. In the more
recent forms of writing telegraph, notably Cowper's, a
different principle is employed ; the message, in fact, being
transmitted by the act of writing it. The idea followed is,
that every position of the point of a pen, as it forms a
letter, can be determined by its distance from two fixed
lines say, the adjacent edges of the paper. Hence if
these distances, so to speak, are transmitted by telegraph,
THE ELECTRIC TELEGRAPH.
247
and recombined, so as to give a resultant motion to a dupli-
cate pen, a duplicate copy of the original writing is pro-
duced. Cowper uses two separate circuits, one to transmit
the vertical, the other the horizontal, movements of his pen.
And now we come to the most wonderful of all tele-
graphs, - that which transmits messages from continent
to continent, for thousands of miles, under the depths of
the sea. "Does it not seem all but incredible to you,'*
said Edward Everett in his oration at the opening of
Original.
Fig. 106.
Facsimile.
Dudley Observatory, " that intelligence should travel for
two thousand miles along those slender copper wires far
down in the all- but fathomless Atlantic, never before pen-
etrated by aught pertaining to humanity, save when some
foundering vessel has plunged with her hapless company
to the eternal silence and darkness of the abyss ? Does
it not seem, I say, all but a miracle of art, that the
thoughts of living men the thoughts that we think up
here on the earth's surface, in the cheerful light of day
about the markets and the exchanges, and the seasons,
and the elections and the treaties and the wars, and all the
fond nothings of daily life, should clothe themselves with
248 THE AGE OF ELECTRICITY.
elemental sparks, and shoot with fiery speed in a moment,
in the twinkling of an eye, from hemisphere to hemi-
sphere, far down among the uncouth monsters that
wallow in the nether seas, along the wreck-paved floor,
through the oozy dungeons of the ray less deep ; that the
last intelligence of the crops, whose dancing tassels will
in a few months be coquetting with the west wind on these
boundless prairies, should go flashing along the slimy
decks of old sunken galleons which have been rotting for
ages ; that messages of friendship and love, from warm
living bosoms, should burn over the cold green bones of
men and women whose hearts, once as warm as ours,
burst as the eternal gulfs closed and roared over them,
centuries ago ! "
It is not definitely known who originated the idea of
submarine telegraph-lines. The notion was often dis-
cussed long before it even approached successful realiza-
tion. The first working-line was laid down by Professor
Morse, between the Battery in New- York City and Gov-
ernor's Island. This was in October, 1842. What Morse
might have demonstrated with that line, can only be con-
jectured. It came to an untimely ending. The very next
morning after it had been laid, some conscienceless mari-
ners hauled up the wire on their anchor, and, probably
realizing its advantages if devoted to splicing their stand-
ing rigging, cut off and confiscated as much of it as they
conveniently could. In the same year Col. Samuel Colt,
of revolver fame, put down a submarine line between Fire
Island and Coney Island and New- York City, and, it is
said, successfully operated it. In Europe the first sub-
marine line was laid by Lieutenant Siemens, between
Deutz and Cologne, across the Rhine, a distance of about
hslf a mile ; and on this wire gutta-percha was first used
as an insulating covering. The first sea-line extended
THE ELECTRIC TELEGRAPH. 249
between Dover and Calais, a distance of twenty-four miles,
and was laid in 1850.
The earliest suggestion of the possibility of a trans-
atlantic cable appears to have been made by Gen. Horatio
Hubbell and Mr. J. H. Sherburne of Philadelphia, who
united in a memorial which was presented to the United-
States Senate by Vice-President Dallas, and to the House
of Representatives by Hon. J. R. Ingersoll, on Jan. 29,
1849. In this memorial the existence of the plateau or
table-land between Newfoundland and Ireland is first
announced to the world as the course over which the tele-
graph cable might be, and over which it finally was, suc-
cessfully laid. The Senate was inclined to ignore the
subject, and not even refer it to the limbo of a committee.
But one senator, Mr. Jefferson Davis, finally moved its
reference to the Committee on Commerce, remarking that
"the world was not yet prepared for the project, but
might be soon." Congress did not grant the memorialists'
request for a vessel to make the necessary soundings ; but
five years later Lieutenant Berryman conducted the sur-
veys of the ocean bottom upon which Lieutenant Maury
made the reports which determined the cable route over
the plateau.
The first attempt to lay a transatlantic cable was made
in August, 1857. After about 380 miles had been sub-
merged, the engineer thought that there was not sufficient
strain on the line, and ordered more applied. It was not
properly done, and the cable snapped. In August, 1858,
the work was successfully accomplished ; the cable extend-
ing from Valentia Bay, Ireland, to Trinity Bay, New-
foundland, a distance of 1,950 miles. Congratulatory
messages were interchanged between the Queen and the
President, and a few other despatches were sent during
the ensuing fortnight ; and then the cable refused to work.
250 THE AGE OF ELECTRICITY.
A defect in it was found, but all attempts to remedy it
proved unsuccessful.
Of course, a good many people had important despatches
coming over the cable, or expected to send them ; and
when it began to fail, there were innumerable messages
sent to Trinity Bay to find out what the trouble was. The
manager there, an electrician named De Sauty, usually
sent back the most re-assuring replies, and continued quite
roseate in his anticipations until the cable positively refused
to transmit any thing more, and then he disappeared from
public gaze. All this has been told in verse by that most
charming of humorists, Dr. Oliver Wendell Holmes, in
the following poem, which, as the Professor at the Break-
fast Table, he declares to be his " only contribution to
the great department of ocean-cable literature. As all
the poets of this country will be engaged for the next six
weeks in writing for the premium offered by the Crystal-
Palace Company for the Burns Centenary (so called, ac-
cording to our Benjamin Franklin, because there will be
na'ry a cent for any of us) , poetry will be very scarce and
dear. Consumers may consequently be glad to take the
present article, which by the aid of a Latin tutor and a
professor of chemistry will be found intelligible to the
educated classes."
DE SAUTY. 1
AN ELECTRO-CHEMICAL ECLOGUE.
PROFESSOR. BLUE-NOSE.
PROFESSOR.
Tell me, O Provincial ! speak, Ceruleo-Nasal !
Lives there one De Sauty extant now among you,
Whispering Boanerges, son of silent thunder,
Holding talk with nations ?
1 Reprinted by kind permission of Dr. Holmes.
THE ELECTRIC TELEGRAPH. 251
Is there a De Sauty ambulant on Tell us
Bifid-cleft like mortals, dormient in night-cap,
Having sight, smell, hearing, food-receiving feature
Three times daily patent ?
Breathes there such a being, O Ceruleo-Nasal ?
Or is he a my thus, ancient word for " humbug,"
Such as Livy told about the wolf that wet-nursed
Romulus and Remus ?
Was he born of woman, this alleged De Sauty,
Or a living product of galvanic action
Like the acarus bred in Crosse's flint solution ?
Speak, thou Cyano-Rhinal!
BLUE-NOSE.
Many things thou askest, jackknife-bearing stranger,
Much-conjecturing mortal, pork-and-treacle waster,
Pretermit thy whittling, wheel thine ear-flap toward me.
Thou shalt hear them answered.
When the charge galvanic tingled through the cable
At the polar focus of the wire electric,
Suddenly appeared a white-faced man among us:
Called himself "Ds SAUTY."
As the small opossum held in pouch maternal
Grasps the nutrient organ whence the term mammalia,
So the~unknown stranger held the wire electric,
Sucking in the current.
When the current strengthened, bloomed the pale-faced
stranger,
Took no drink nor victual, yet grew fat and rosy,
And from time to time in sharp articulation
Said, "All right! DE SAUTY."
From the lonely station passed the utterance, spreading
Through the pines and hemlocks to the groves of steeples,
Till the land was filled with loud reverberations
Of "All right! DE SAUTY."
252 THE AGE OF ELECTRICITY.
When the current slackened, drooped the mystic stranger,
Faded, faded, faded, as the stream grew weaker,
Wasted to a shadow, with a hartshorn odor
Of disintegration.
Drops of deliquescence glistened on his forehead,
Whitened round his feet the dust of efflorescence,
Till one Monday morning, when the flow suspended,
There was no De Sauty;
Nothing but a cloud of elements organic,
C, O, H, N, Ferrum, Chlor., Flu., Sil., Potassa,
Calc.,Sod., Phosph., Mag., Sulphur, Mang. (?), Alumin. (?),
Cuprum ( ?),
Such as man is made of.
Born of stream galvanic, with it he had perished.
There is no De Sauty, now there is no current !
Give us a new cable, then again we'll hear him
Cry "All right! DE SAUTY."
Shortly after the failure of the first Atlantic cable,
other deep-sea cables became inoperative, and immense
sums of money were lost. In 1865 the immense " Great
Eastern" steamship, which had proved a veritable white
elephant to its owners, was fitted for service to transport
a new cable. After about half of this line had been laid,
it broke, and the hapless promoters of the enterprise
feared that some three million dollars had been added to
the great aggregate of losses already incurred. Prepara-
tions were, however, at once made for another attempt
during the following year. The managers of the enter-
prise, at the head of which was Mr. Cyrus W. Field, had
indomitable faith in its practicability. A close watch
was kept on the broken line, now resting on the ocean-
bed. u Night and day," says an English journal of
the time, " for a whole year an electrician was always
THE ELECTRIC TELEGRAPH. 253
on duty, watching the tiny ray of light through which
signals are given ; and twice every day the whole length
O f w i re 1,240 miles was tested for conduction and
insulation. The object of observing the ray of light
was of course not any expectation of a message, but
simply to keep an accurate record of the condition of the
wire. Sometimes, indeed, wild incoherent messages from
the deep did come ; but these were merely the results of
magnetic storms and earth-currents, which deflected the
galvanometer rapidly, and spelt the most extraordinary
words, and sometimes even sentences of nonsense, upon
the graduated scale before the mirror. Suddenly, early
one morning the observer noticed a peculiar flicker of the
light which to his experienced eye showed that a message
was on hand. In a few minutes afterward, the unsteady
flickering was changed to coherency, and at once the cable
began to speak, to transmit the appointed signals which
indicated human purpose and method at the other end,
instead of the hurried signs, broken speech, and inarticu-
late cries of the still illiterate Atlantic. After the long
interval in which it had brought nothing but the moody
and often delirious mutterings of the sea stammering
over its alphabet in vain, the words ' Canning to Glass '
must have seemed like the first rational word uttered by
a fever-patient when the ravings had ceased. The exact
spot in the trackless ocean where that cable had parted
had been found ; the slender wire had been picked up,
although two miles down under the sea; and from the
great ship the signals were being sent."
Meanwhile the new cable, stronger, lighter, and more
flexible than its predecessors, had been successfully car-
ried across the Atlantic by the " Great P^astern," and was
in working order. Then the ship went back, and, as
already stated, picked up the broken end. How this
254 THE AGE OF ELECTRICITY.
wonderful feat of engineering was accomplished, Mr.
Field thus graphically tells :
"After landing the cable safely at Newfoundland, we
had another task, to return to mid-ocean, and recover
that lost in the expedition of last year. This achievement
has perhaps excited more surprise than the other. Many,
even now ' don't understand it,' and every day I am asked
how it was done. Well, it does seem rather difficult to
fish for a jewel at the bottom of the ocean two and a half
miles deep. But it is not so very difficult when you know
how. It was the triumph of the highest nautical and
engineering skill. We had four ships, and on board of
them some of the best seamen in England, men who knew
the ocean as a hunter knows every trail in the forest.
There was Captain Moriarty, who was in the ' Agamem-
non ' in 1857-58. He was in the ' Great Eastern ' last
year, and saw the cable when it broke ; and he and Cap-
tain Anderson at once took their observations so exact
that they could go right to the spot. After finding it,
they marked the line of the cable by a row of buoys ; for
fogs would come down, and shut out sun and stars so that
no man could take an observation. These buoys were
anchored a few miles apart. They were numbered, and
each had a flagstaff on it so that it could be seen by day,
and a lantern by night. Thus having taken our bearings,
we stood off three or four miles, so as to come broadside
on, and then, casting over the grapnel, drifted slowly
down upon it, dragging the bottom of the ocean as we
went. At first it was a little awkward to fish in such deep
water ; but our men got used to it, and soon could cast a
grapnel almost as straight as an old whaler throws a har-
poon. Our fishing-line was of formidable size. It was
made of rope, twisted with wires of steel, so as to bear
a strain of thirty tons. It took about two hours for the
THE ELECTRIC TELEGRAPH. 255
grapnel to reach the bottom, but we could tell when it
struck. I often went to the bow, and sat on the rope,
and could feel by the quiver that the grapnel was dragging
on the bottom two miles under us. But it was very slow
business. We had storms and calms and fogs and squalls.
Still we worked on day after day. Once, on the 17th of
August, we got the cable up, and had it in full sight for
five minutes, a long, slimy monster, fresh from the ooze
of the ocean's bed ; but our men began to cheer so wildly
that it seemed to be frightened, and suddenly broke away,
and went down into the sea. This accident kept us at
work two weeks longer ; but finally, on the last night of
August, we caught it. We had cast the grapnel thirty
times. It was a little before midnight on Friday that we
hooked the cable, and it was a little after midnight Sunday
morning when we got it on board. What was the anxiety
of those twenty-six hours ! The strain on every man's
life was like the strain on the cable itself. When finally
it appeared, it was midnight : the lights of the ship and
in the boats around our bows, as they flashed in the faces
of the men, showed them eagerly watching for the cable
to appear in the water. At length it was brought to the
surface. All who were allowed to approach crowded to
see it. Yet not a word was spoken : only the voices of
the officers in command were heard giving orders. All
felt as if life and death hung on the issue. It was only
when it was brought over the bow and on the deck, that
men dared to breathe. Even then they hardly believed
their eyes. Some crept toward it to feel of it, to be sure
it was there. Then we carried it along to the electrician's
room, to see if our long-sought- for treasure was alive or
dead. A few minutes of suspense, and a flash told of
the lightning current set free. Then did the feeling long
pent up burst forth. Some turnt away their heads, and
256 THE AGE OF ELECTRICITY.
wept. Others broke into cheers, and the cry ran from
man to man, and was heard down in the engine-rooms,
deck below deck, and from the boats on the water and
the other ships, while rockets lighted up the darkness of
the sea. Then with thankful hearts we turned our faces
again to the west. But soon the wind rose, and for thirty-
six hours we were exposed to all the dangers of a storm
on the Atlantic. Yet in the very height and fury of the
gale, as I sat in the electrician's room, a flash of light
came up from the deep, which, having crossed to Ireland,
came back to me in mid-ocean, telling that those so dear
to me, whom I had left on the banks of the Hudson, were
well and following us with their wishes and their prayers.
This was like a whisper of God from the sea, bidding me
keep heart and hope. The ' Great Eastern ' bore herself
proudly through the storm, as if she knew that the vital
cord which was to join two hemispheres hung at her stern ;
and so, on Saturday the 7th of September, we brought
our second cable safely to the shore."
As we all know, other cables have since been laid across
the Atlantic with comparative ease, by the aid of special
machinery and specially constructed vessels. The French
cable between St. Pierre and Duxbury, Mass., went into
operation in 1869 ; followed by the direct cable between
Ballinskilligs Bay, Ireland, and Rye, N.H., via Nova
Scotia, in 1875 ; and the Mackay-Bennett cable ten years
later.
The cable laid by the "Great Eastern " in 18G5-6G is
represented in Fig. 107. The current is conducted by a
strand of copper wires ; the remainder of the cable serving
to secure insulation, and to protect it from abrasion, etc.
The transmission of telegraphic signals through a long
submarine cable is a very different matter from accom-
plishing the same thing over a land line of similar length ;
THE ELECTRIC TELEGRAPH. 257
and it is therefore necessary to explain, in as simple terms
as possible, some of the principal difficulties encountered,
and how the cable is made to operate in spite of them.
In describing the invention of the Leyden-jar, in an
earlier chapter, we noted the curious fact, that, while elec-
tricity cannot pass through an insulating substance such
as glass or air, it can act across the same by induction.
And in the Leyden-jar we have an illustration of this ;
for, when a plus charge of electricity is imparted to the
inner coating, it acts inductively on the outer coating,
attracting a minus charge into the face of the outer coat-
ing nearest the glass, and repelling a plus charge to the
outside of the outer coating, and this through the hand
Fig. 107.
or wire to the earth. After the jar has acquired its full
charge, it will, as we have already seen, retain it for a
considerable period of time.
When a quantity of electricity flows through a line, in
the form of a current, the first portion of the current is
retained or accumulated upon the surface of the wire in
the same way that a charge is retained and accumulated
upon the surface of a Leyden-jar. The wire itself answers
to one of the conducting coatings of the jar ; the earth,
or other wires connected to earth, to the other conducting
coating ; and the air, to the glass or separating di-electric.
The quantity of electricity thus accumulated depends
upon the length and surface of the wire, upon its proxim-
ity to the earth, and upon the insulating medium that sepa-
258 THE AGE OF ELECTRICITY.
rates it from the earth. This power of retaining a charge
is called the electro-static capacity of the circuit.
The effect of this accumulation is to hold back or pre-
vent the appearance of the first portion of the current sent
at the distant station ; and, furthermore, before a current
in the reverse direction can be sent through the circuit,
the whole of this charge upon the wire must be withdrawn
or neutralized before a second charge of opposite sign can
be accumulated upon it. The result of this is to prolong
the current flowing out at the distant end.
In submarine cables, the conducting wires are separated
from the earth upon which the cable rests, and the water
which surrounds it, simply by the insulating covering ;
and hence the whole cable becomes one huge Leyden-jar
of much capacity. The consequence is, that the current
is retarded so much, that, unless the signals are sent very
slowly, they will run together and be illegible. The retar-
dation upon an Atlantic cable is about four-tenths of a
second. Twenty dots per second can be firmly and clearly
recorded on a short overground line, with little induction ;
while on a long cable, not more than two dots per second
can be received.
Besides the difficulties due to retardation, earth-cur-
rents varying in strength are set up in the cable, by rea-
son of its connecting portions of the earth which happen
to be of different potentials. These were the cause of the
strange signals which came from the broken cable of 1865 ;
and at times they acquire such magnitude as to become
" electric storms," interrupting the circuits to such an
extent as greatly to hinder working, and sometimes en-
dangering the safety of the cable itself. It is necessary,
therefore, in cable telegraphy, to counteract the ill effects
of earth-currents, and also to reduce to the lowest possi-
ble point the retarding influence of induction ; and the
THE ELECTRIC TELEGRAPH.
259
n
^al
m^^Mlfc////A Lx
\
a z
ordinary apparatus used in telegraphing upon land lines
becomes useless for this purpose.
Two new instruments, not necessary upon land lines,
are therefore introduced ; the. first being the condenser,
which prevents induction, and sharpens the signals ; and
the second being the mirror galvanometer, or siphon
recorder, which indicates or records them.
The condenser is simply a modified form of Leyden-jar,
of large surface, and constructed to have any desired capa-
city. It is usually made of alternate layers of paraffined
paper or mica and
tin-foil ; as indicat- 1
ed in Fig. 108, in
which the dark lines
a a 1 a 2 , b b 1 6 2 , repre-
sent tin-foil, and the
shaded intermediate
portions, the paraf-
fined paper. The
series a a 1 a? of tin-
foil sheets are con-
nected together, thus forming one of the coatings of the
Leyden-jar ; and the alternating sheets b b 1 b 2 are united
to form the other coating. If we connect one pole of a
battery to the sheets a a 1 a 2 , and the other pole to the
sheets b b 1 b 2 , the condenser will be charged with a quantity
of electricity depending upon the number of battery-cells
used, upon the surface of the plates opposed to each other,
and upon the number of plates in the respective sets. In
this way condensers of any desired capacity can be made,
having a charge varying from that accumulated upon one
mile of overground wire up to that accumulated upon an
Atlantic cable. The unit or standard of reference by
which capacity is known is called the microfarad, and is
Fig. 108.
260 THE AGE OF ELECTRICITY.
equivalent to the charge contained by about three miles of
cable.
The conventional mode of representing a condenser is
by two parallel lines as a 6 : in Fig. 109, from which illus-
tration the operation of the condenser, when applied to a
telegraphic line, will easily be understood.
Let us suppose that A B is a cable crossing the Atlantic.
At one end is an ordinary key and battery, and at the
other a condenser having one set of its conducting plates
connected to the cable, and the other set to a galvanometer
which in turn is connected to earth. The circuit is evi-
dently broken at the condenser, so that it is impossible
%J^ -CaMc
L
Credit
-m^Uct
k &vy
^\Eart/i- coiutcctioit JEart/v
Fig. 109.
for the battery current to proceed directly to the galva-
nometer ; but if we depress the key, a current flows from
the battery into the cable to charge it. The plate a of
the condenser, being thus charged in (say) positive elec-
tricity, attracts across the paraffined paper interposed
between it and the opposite plate 6, electricity of opposite
name, and repels electricity of the same name, which
apparently passes to earth through the galvanometer in
the form of a short current or pulsation. When the key
is returned to its normal position, the cable is discharged,
the positive charge on b is released, and it flows to earth
in the reverse direction through the galvanometer, in the
THE ELECTEIC TELEGRAPH.
261
form of a second current or pulsation. Thus, whenever
we depress the key, we affect the galvanometer with a
reversal.
By using galvanometers or other receiving apparatus
of the most sensitive character, which are actuated by
the first appearance of the current, cables are worked
with the smallest electro-motive force ; and generally by
suitably determining the size of the condenser, the num-
ber of cells, and the delicacy of the galvanometer, we
can transmit signals which give the maximum speed with
the minimum expenditure of power. In practice the con-
densers used have a capacity equal to that of about sev-
enty miles of cable. From four to ten cells of one form
of Daniell's battery furnish the current.
The receiving apparatus is either a mirror galvanometer
or a siphon recorder, both instruments of remarkable
sensitiveness, devised by Sir William Thomson. The
general arrangement of the mirror galvanometer is shown
in Fig. 110, where C is a coil of fine insulated wire, sur-
262 THE AGE OF ELECTRICITY.
rounding a small magnetic needle hung by a silk fibre,
and carrying a tiny mirror attached to it. The details
are shown in the lower figure, where C C are sections
through the coil. At M is the magnet-needle, carrying
in front of it a small mirror. This needle is enclosed
in a small chamber, glazed by a lens 6r, and inserted in
the hollow of the coil C. A curved magnet H is sup-
ported over the coil to adjust the position of the smaller
magnet in the chamber. Now a ray of light from a lamp
L in front of the galvanometer is thrown upon the tiny
mirror, and reflected back upon a white screen or scale
S. The coil C is connected between the end of the con-
ductor of the cable and the earth-plate, as in the land
circuit ; a condenser, however, being usually interposed
between the cable and the galvanometer.
Then the signal currents in passing through the coil
deflect the tiny magnet hung within it ; and the mirror,
being carried by the magnet, throws the beam of light off
in a different direction. Positive, or " dot," currents are
arranged to throw the spot of light toward the left side
of the scale ; and negative, or " dash," currents throw it
to the right side. Thus the wandering of the spot of light
on the screen, watchfully followed by the eye of the clerk,
is interpreted by him as the message. Letter by letter he
spells it out, and a fellow-clerk writes it down word for
word.
Sometimes the fellow-clerk .is a lady, frequently per-
haps now, since the fair sex has proven its ability to
manage the key, and this circumstance may account
for the publication in a scientific journal, some years ago,
of the following capital parody on Tennyson's " Bugle
Song:" 1
i By Professor J. Clerk Maxwell.
THE ELECTRIC TELEGRAPH. 263
A LECTURE ON THOMSON'S GALVANOMETER
Delivered to a Single Pupil, in an Alcove with Drawn Curtains.
The lamp-light falls on blackened walls,
And streams through narrow perforations ;
The long beam trails o'er pasteboard scales,
With slow decaying oscillations.
Flow, current, flow ! set the quick light spot flying !
Flow, current! answer, light spot ! flashing, quivering, dying.
Oh, look ! how queer ! how thin and clear,
And thinner, clearer, sharper growing,
This gliding fire with central wire
The fine degrees distinctly showing.
Swing, magnet, swing ! advancing and receding ;
Swing, magnet ! answer, dearest, what's your final reading ?
O love ! you fail to read the scale
Correct to tenths of a division ;
To mirror heaven those eyes were given,
And not for methods of precision.
Break, contact, break ! set the free light spot flying.
Break, contact ! rest thee, magnet ! swinging, creeping, dying.
This receiver, however, like the sounder, has the disad-
vantage of leaving no permanent record ; and Sir William
Thomson has therefore introduced his siphon recorder on
several long cables, for instance, the Eastern Telegraph
Company's lines to India, and the Anglo-American Com-
pany's cables across the Atlantic. The principle of its
action is just the reverse of the mirror galvanometer. In
that instrument, a tiny magnet moved within a fixed coil
of wire ; in the siphon recorder, a light coil of wire moves
between the poles of a powerful magnet. The signal
currents pass through the suspended coil to earth ; and in
doing so the coil turns to left or right, according as the
currents are positive or negative. These movements of
264 THE AGE OF ELECTRICITY.
the coil are communicated by a connecting thread to a
fine glass siphon, which is constantly spurting ink upon
a band of travelling paper ; and hence the trace of the
ink on the paper follows and delineates the movements of
the coil. So fine is the bore of the siphon, that the ink
will not run unless it is electrified. A specimen of the
message it furnishes is given in Fig. Ill, which represents
the alphabet.
That some day we shall be able to transmit pictures by
telegraph, is not without the bounds of reasonable possi-
bility ; not drawings or designs, such as can now be sent
by the autographic systems, but actual photographs, images
of things existing in front of the transmitting instrument,
so that a person in one place can see what is going on in
-n^nFNT/ 1 -^^
TA/ir- y lnhA^^
Fig. 111.
another. The first step in this direction has already been
accomplished by Mr. Shelford Bidwell, in his exceedingly
ingenious telephotograph, by means of which it is now
quite possible to transmit shadows or silhouettes. The
principle of Mr. Bid well's apparatus is based upon the
fact that the resistance of crystalline selenium varies with
the intensity of the light falling upon it. Its operation
depends, as in the autographic telegraph, upon the syn-
chronous movement of two cylinders at opposite ends of
the line, and will be easily followed by the aid of the
diagram, Fig. 112.
The transmitting instrument consists of a cylindrical
brass box, mounted upon but insulated from a metal spin-
dle. The spindle is divided in the middle ; and the halves,
while rigidly joined together, are insulated from each
THE ELECTEIC TELEGRAPH.
265
other by a layer of wood. One of the ends of the spin-
dle has a fine screw-thread cut on it ; the other end is
plain. The spindle is arranged to revolve in metal bear-
ings, one of which is threaded so that when the spindle
rotates it also has an endwise longitudinal movement like
Fig. 112.
that of the cylinder of the phonograph. At a point mid-
way between the ends of the brass box mounted on the
spindle, a small hole is drilled ; and behind this hole is
fixed a selenium cell, the two terminals of which are con-
nected respectively to the halves of the spindle, and the
bearings of this last are connected electrically to binding-
266 THE AGE OF ELECTRICITY.
screws on the base of the instrument. In the engraving,
Y represents the transmitter. The hole in the cylinder is
at 77, and at S is the selenium cell.
The receiving instrument shown at X (Fig. 112) con-
tains another cylinder, similar to that of the transmitter,
and mounted on a similar spindle, which, however, is not
divided nor insulated from the cylinder. An upright pil-
lar 7), fixed midway between the two bearings, and slight-
ly higher than the cylinder, carries an elastic brass arm
with a platinum point P, which presses normally upon
the surface of the cylinder. To the brass arm, a binding-
screw is attached, and a second binding-screw in the stand
is joined by a wire to one of the brass bearings.
In operation the cylinder of the transmitter Y is brought
to its middle position, and a picture not more than two
inches square is focussed upon its surface by means of a
lens. The cylinder of the receiver is covered with paper
soaked in a solution of potassium iodide.
The two cylinders are caused to rotate slowly and syn-
chronously. The pin-hole at H, in the course of its spiral
path, will cover successively every point of the picture
focussed upon the cylinder ; and the amount of light fall-
ing at any moment upon the selenium cell will be propor-
tional to the illumination of that particular spot of the
projected picture which for the time beiug is occupied by
the pin-hole. During the greater part of each revolution,
the point P will trace a uniform brown line ; but when the
hole happens to be passing over a bright part of the pic-
ture this line is enfeebled and broken. The spiral traced
by the point is so close as to produce, at a little distance,
the appearance of a uniformly colored surface ; and the
breaks in the continuity of the line constitute a picture
which, if the instrument were perfect, would be a mono-
chromatic counterpart of that projected upon the trans-
THE ELECTRIC TELEGRAPH. 267
mitter. Fig. 113 represents an image as projected by a
magic-lantern upon the transmitter, and Fig. 114 the same
reproduced by the receiver. A selenium cell whereby the
Fig. 113.
electrical resistance to the current is varied, is also used
in connection with the photophone hereafter described.
Telegraphy is by no means confined to communication
between fixed stations. It is now perfectly possible to
Fig. 774.
communicate with express-trains travelling at high speed,
and it is not unlikely that some means will be found of
maintaining telegraphic communication with ships at sea.
Probably the earliest suggestion of transmitting a current
268 THE AGE OF ELECTRICITY.
to a moving vehicle was that made by Wright and Bain in
1842. These inventors proposed the ingenious plan of
having a pilot-engine run some live miles ahead of the
locomotive of a rail way- train, and of establishing electri-
cal communication between the two, so that in event of
any accident, such as the derailment of the pilot-engine,
the fact would be instantly known to the driver of the
locomotive. The battery was to be carried on the loco-
motive ; and circuit was made from the battery to an
electro-magnet, and thence to a continuous conductor laid
between the rails, along which contact-springs on the loco-
motive rubbed. The pilot-engine also carried springs held
in contact with the central conductor ; and the current
thence passed to a governor on the pilot, which, while the
engine was in motion, was driven by the wheels. So long
as the pilot-engine was running all right, tho governor
kept the circuit closed ; but if the engine stopped, the
governor balls fell, opening the circuit, so de-energizing
the electro-magnet on the following locomotive. The
magnet was thus caused to release its armature, and thus
to sound an alarm, and move a pointer on a dial to the
word "Danger." A somewhat analogous system exists
on several European railways, in which a contact brush or
plate on the locomotive closes a circuit through the rails,
so that the approach of the train is thus signalled to a
station, or the driver is warned, by the sounding of an
alarm, that a switch before him is not properly set. By
the same means, the engine-whistle may also be blown, or
the brakes automatically set in operation to stop the train.
Two systems of telegraphic apparatus have recently been
devised for communicating with moving trains. Phelps's
arrangement is based on the well-known fact that if two
w r ires are extended parallel, near but not touching each
other, and a current is sent through one, a momentary
THE ELECTRIC TELEGRAPH. 269
current is excited in the other wire, opposite in direction
to that flowing in the first. A telegraph-wire is arranged
in the centre of the railway-track, and another wire is
attached to the bottom of the railway-car, with which last-
mentioned wire is connected a telegraph-sounder within
the car. Whenever an electrical signal is sent through
the track telegraph wire, it produces by induction a cor-
responding current in the wire attached to the car, and
this current works the sounder, thus delivering the mes-
sage. It matters not how fast the train may be moving,
if the wire on the bottom of the car is brought within a
short distance of the telegraph or track wire, any strong
electric impulses, such as telegraph signals, that are pass-
ing along the track wire, will be taken up by induction by
the car wire, and delivered by the sounder ; and, vice
versa, when the operator on the moving car operates the
lever of his telegraph instrument, and sends electrical im-
pulses or messages through the wire that hangs below the
floor of the car, these impulses will be taken up by induc-
tion by the track wire, and conveyed to .the sounding
instrument of the railway-station. By this system com-
munication has been successfully maintained with a train
running forty miles per hour.
In another system devised by Edison and others, the
induction takes place between the wires strung in the
usual way on poles beside the track, and the metal roofs
of the cars which are electrically connected together. An
insulated wire runs from the roof of the telegraphing car,
to a switch at the operator's desk ; and by means of this
switch the circuit may be completed through a receiving
or a transmitting instrument. The receiver may either be
an ordinary telephone, or a pair may be used and held to
the ears somewhat after the manner of ear-muffs. After
coming from the receiver, the wire is carried under the
270 THE AGE OF ELECTRICITY.
car, and connected to a strip of copper which is pressed
against a copper cylinder on one of the axles by means of
a spring, thus giving a ground connection by the axle and
wheel. When, however, a message is to be transmitted,
the switch connects the roof to the secondary wire of an
induction coil, with the primary of which a battery, a
Morse key, and a vibrating circuit-breaker are in circuit.
When the current is established, the vibrator, which con-
tains a metallic reed, is thrown into rapid movement ; the
free end of the reed at each vibration striking against a
button, and so sharply making and breaking the circuit
into a great number of waves or pulsations. These pul-
sations in the primary coil induce currents of high poten-
tial in the secondary coil, which, so to speak, charge the
roof as if it were one plate of a condenser. The wires
on the poles thus become charged by induction, as the
opposite plate of a condenser is charged, through the inter-
vening air ; and as this charge is governed by the
manipulation of the Morse key, which throws the vibrator
into and out of action, dots and dashes of the Morse
alphabet can be signalled.
New applications of the telegraph are constantly being
invented. We are only at the very beginning of its utili-
zation in the affairs of every-day life, and yet its developed
capabilities are bewildering. There is little exaggeration
in the statement that one can sit at home, and "steer a
torpedo boat in New- York harbor, or ring the bells in
Boston, or play the organ in St. Peter's, or explode a
mine in China, or write a letter on the desk of a cor-
respondent in Constantinople," and perhaps, in the
future, talk to a friend in Australia, and even see him
face to face.
From forty miles in 1844, the total length of telegraph-
wires in the United States has increased to 671,000 miles
THE ELECTEIC TELEGRAPH. 271
in 1886 : enough to extend to the moon and back again,
and then go nine times around the earth. Nearly two
millions of miles of wire form an iron network over the
globe ; and the great army of the telegraphers numbers
over three hundred thousand souls.
272 THE AGE OF ELECTRICITY.
CHAPTER XII.
THE SPEAKING TELEPHONE.
THE principle underlying all forms of apparatus for
transmitting intelligence between distant points, by the
aid of electricity, is to cause certain mechanical motions
produced at one point to be imitated at the other. And
these mechanical motions may range from the slow move-
ment of a telegraph-key worked by the human hand, to
the very rapid and complex vibrations of the air which the
ear and brain translate into the sensation of sound. The
motion of the telegraph-key is copied by the motion of
the sounder armature, or that of the recording stylus ; in
autographic telegraphy, the movement of the point which
traces the design is imitated by that of the point which re-
produces the same ; and the various synchronic systems
have for their object the exact duplication at the separated
stations of definite mechanical movements occurring at
the same rate in the same time.
The simplest way of transmitting mechanical motion
between distant points is by means of some solid body
extending between them. The connecting-rod of an en-
gine transmits movement from piston-rod to fly-wheel ; by
means of belts, we can cause one rotating shaft to move
another at a considerable distance away ; by pulling a
cord or wire in one part of a house, we can ring a bell at
another. In all of these instances, the whole of the com-
THE SPEAKING TELEPHONE. 273
municating body whether it be rod or belt or wire
moves simultaneously.
Motion, however, may also be transmitted by means of
waves or pulsations in the communicating body, which
then does not move as a whole. In such case, the move-
ment is first imparted to the particles of the body nearest
the source. These are set vibrating, or swinging to and
fro ; and in so travelling they communicate their motion
to a succeeding set of particles, which in turn swing or
vibrate ; these, again, in turn actuate the particles next in
advance ; and so the vibration or wave travels from one
end of the body to the other. This is called wave or
vibratory^ motion. Light, for example, is propagated by
motion of this kind, in an assumed luminiferous ether ;
heat, sound, and probably electricity, by wave-motions in
the molecules of matter. We see this vibratory motion
constantly at work in waves on water.
When any body vibrates in air or water, or any material
substance, the air or other substance is set in motion,
and the waves are propagated farther and farther from
the impelling source, until finally their energy becomes
exhausted. This movement of the air, on reaching the
human ear, causes the sensation of sound, provided it is
competent to affect the mechanism of hearing. It has
been determined that the ear cannot perceive sounds when
the number of vibrations is less than sixteen, or more than
thirty-two thousand, per second ; but the limits of hear-
ing vary greatly. If the vibrating body be in the open
air, the impulses spread equally on all sides around ;
sometimes having great mechanical force, as when an
explosion of dynamite shatters walls even at a consider-
able distance. So also the air is competent to carry very
minute vibrations ; as, for instance, those which, as we
shall see hereafter, cause the different quality of human
274 THE AGE OF ELECTRICITY.
voices. In order to prevent the diminution in intensity of
the air-waves caused by the vibration of our vocal organs
in speaking, clue to their spreading in all directions, the
speaking-tube is employed ; and this is the most common
mode of carrying the voice between distant points. Here
the column of air is enclosed in a pipe, and the pulsations
are passed on from end to end, almost without loss, over
short distances.
Solids such as wood, metal, the earth, and liquids such
as water, are much better conductors of sound than air or
other gases. A faint scratch of a pin on a long board is
very easily heard through the board many feet away, even
though it may not be audible through the air to the per-
son making it. Savages often discover the proximity of
enemies or of prey by applying an ear to the ground, and
hearing the tread. The mutterings of earthquakes, due
to subterranean explosions or upheavals, are heard through
amazing distances of earth. The velocity of sound in
air is about 1,120 feet per second ; in water, about four
times, and in metals from four to sixteen times, as great.
The idea of transmitting sounds of the voice through
solid conductors is known to date back to 1G67. At that
date Dr. Robert Hooke wrote : "It is not impossible to
hear a whisper at a furlong's distance, it having already
been done ; and perhaps the nature of the thing would not
make it more impossible though that furlong should be ten
times multiply 'd. And though some famous authors have
affirmed it impossible to hear through the thinnest plate of
muscovy glass : yet I know a way by which it is easie
enough to hear one speak through a wall a yard thick.
It has not yet been thoroughly examin'd how far otacous-
ticons may be improv'd nor what other wayes there may
be of quick'ning our hearing or conveying sound through
other bodies than the air : for that that is not the only me-
THE SPEAKING TELEPHONE. 275
dium I can assure the reader, that I have by the help of a
distended wire propagated the sound to a very considerable
distance in an instant or with as seemingly quick a motion
as that of light, at least incomparably quicker than that
which at the same time was propagated through the air,
and this not only in a straight line or direct but in one
bended at many angles."
In 1819 Sir Charles Wheatstone invented his magic
lyre, and in 1831 exhibited it at the Polytechnic Institution
in London. He called it the telephone, thus inventing the
name. Performers on various instruments were placed in
the basement of the building, and the sounds which they
produced were conducted by solid rods through the princi-
pal hall, in which they were inaudible, to sounding-boards
in a concert- room on an upper floor, where the music was
heard by the audience precisely as if it were being per-
formed there. It is related, that, shortly after Sir Charles
Wheatstone had invented the above device, he invited a
distinguished foreign musician a noted performer on
the violoncello to dine with him. In order to surprise
his guest, he suspended a violoncello in his entrance-hall,
arranging in contact with it a concealed rod which com-
municated with a like instrument in another room. On
the arrival of the visitor, he was left alone in the hall,
and naturally his attention was at once attracted by the
strains of music apparently coming from no visible source,
yet clearly being produced in the same apartment. Finally
he traced them to the instrument on the wall, examined
it critically, could find no reason for them ; and then as
if struck with sudden terror, with a cry of dismay, the
affrighted musician rushed out of the house. Nothing
could convince him that the instrument was not bewitched,
nor induce him to trust himself again in its proximity.
Meanwhile there had been known probably since time
276 THE AGE OF ELECTRICITY.
immemorial, for the Chinese are said to have used it ages
ago an apparatus called the "lover's telegraph," in
which sounds of the voice were transmitted between dis-
tant points, over a stretched string or wire. The contriv-
ance will easily be understood from Fig. 115, in which A
and B are hollow cylinders, usually of tin, each having
one end covered with a piece of membrane. The string
is fastened at each extremity to the centres of the mem-
branes, and is strained taut when the instrument is used.
Words spoken into one cylinder are very clearly heard by
a listener at the open end of the other. Just how and
why this little device operates, is by no means clear.
Fig. 115.
The membrane spoken to, however, vibrates correspond-
ingly to the air-waves made by the speaker's voice ; and
probably the impulses passing over the string move the
other membrane so that it copies the motions of the first,
and thus becomes a body vibrating in a particular way,
an,d competent in turn to make air- waves which the ear
recognizes as speech, just as if the vocal organs of the
original speaker had been transported to the distant end of
the line. We say " probably," because it is by no means
certain that this happens ; and, in fact, there is a great deal
to be discovered about the instrument. Whatever may be
the true reason, it is certain that speech is very clearly
transmitted and reproduced ; and in its more improved
modern forms the device now known as the acoustic tele-
THE SPEAKING TELEPHONE. 277
phone is much more efficient for short lines, where the wire
can be suspended clear of other objects, than any telephone
depending on electricity, which of course this does not.
In tracing the history of the telegraph, we have noted
some of the early attempts made to produce sound-signals
at the far end of the line. Prior to Morse's invention, it
was difficult to record the operation of the current ; and
to rely on visual signals was to depend on the watchfulness
of the receiving operator at all times. One inventor pro-
posed explosions which would very effectually alarm the
sleepiest attendant ; another rang bells, and so on. For
several years succeeding the introduction of Wheatstone's
needle telegraph in England, this problem was widely
studied. In 1837 Professor Page of Washington discov-
ered that an electro-magnet when magnetized and demag-
netized gives forth a sound ; and when the current through
its coil is rapidly established and broken, these sounds
may succeed each other with sufficient velocity to produce
a musical tone, the pitch of which will depend upon
the number of times the sound is produced per second.
Page's discovery was made the basis of further investiga-
tions by Wertheim and others.
In 1854 M. Charles Bourseul published one of those
curious speculations which have so often foreshadowed
remarkable inventions. It is very frequently sometimes
too frequently the case, that the imagination of the
reader, after the event, causes him to detect in these prior
records the recital of ideas never broached until long
afterwards ; just as one can find in Milton such lines as
these :
" When with one virtuous touch
The arch-chymic sun, so far from us remote,
Produces with terrestrial humor mixed
Here in the dark, so many precious things
Of color glorious, and effect so rare,"
278 THE AGE OF ELECTRICITY.
and thence argue that photography must have been known
in Milton's time. Bourseul, however, wrote much less
oracularly than is common in the circumstances. He
says, " I have, for example, asked myself whether speech
itself may not be transmitted by electricity ; in a word,
if what is spoken in Vienna may not be heard in Paris.
The thing is practicable in this way. We know that
sounds are made by vibrations, and are adapted to the
ear by the same vibrations which are reproduced by the
intervening medium. But the intensity of the vibrations
diminishes very rapidly with the distance ; so that it is,
even with the aid of speaking-tubes and trumpets, impossi-
ble to exceed somewhat narrow limits. Suppose that a
man speaks near a movable disk, sufficiently flexible to
lose none of the vibrations of the voice, that this disk al-
ternately makes and breaks the current from a battery : you
may have at a distance another disk ivhich will simulta-
neously execute the same vibrations. It is true that the
intensity of the sounds produced will be variable at the
point of departure at which the disk vibrates by means of
the voice, and constant at the point of arrival where it
vibrates by means of electricity ; but it has been shown
that this does not change the sounds. It is, moreover,
evident that the sounds will be reproduced at the same
pitch. The present state of acoustic science does not
permit us to declare a priori if this will be precisely the
case with the human voice. The mode in which these
syllables are produced has not yet been sufficiently inves-
tigated. It is true that we know that some are uttered
by the teeth, others by the lips, and so on ; but this is
all.
" However this maybe, observe that the syllables can
only reproduce upon the sense of hearing the vibrations
of the intervening medium : reproduce precisely these vi-
THE SPEAKING TELEPHONE. 279
brat ions, and you will reproduce precisely these syllables.
... It need not be said that numerous applications of
the highest importance will immediately arise from the
transmission of speech by electricity. Any one who is
not deaf and dumb may use this mode of transmission,
which would require no apparatus except an electric bat-
tery, two vibrating disks, and a ivire."
There can be no question as to the remarkable knowl-
edge possessed by the writer, especially as indicated by the
words Italicized. Bourseul had undoubtedly realized the
fundamental principle, that, in order to reproduce sounds
in air at the distant end of a wire, the apparatus must be
competent to copy the vibrations which originally were
imposed on the sending apparatus by the voice. He
clearly saw, however, that his conception was by no means
adequate to the object.
Thus two ideas were well established before 1860 : first,
that it might be possible to cause an object to vibrate
by the voice, so as to make and break a current passing
upon a telegraph-line, causing in that current pulsations
corresponding in frequency with the vibrations due to the
sounds produced ; and, second, that when a current, rap-
idly interrupted, entered the coils of an electro-magnet,
the magnet would yield a sound which would be a musical
tone depending for its pitch upon the number of times the
current was interrupted per second.
But Bourseul, who proposed the making and breaking
of the current by the disk moved by the voice, apparently
knew nothing about reproducing the tone by the electro-
magnet ; and Page, who invented "galvanic music," knew
nothing about interrupting the current by voice-controlled
mechanism. And this brings .us to the remarkable history
of Philipp Reis, the man in whom his Fatherland persists
in recognizing the true inventor of the speaking telephone.
280 THE AGE OF ELECTRICITY.
A tablet so inscribed marks the house in which he was
born, and a like inscription is graven on the monument
publicly reared in his honor.
Johann Philipp Reis was born at Gelnhaussen in the
principality of Cassel, Germany, in 1834. His father, a
master baker, gave him a good education, and finally ap-
prenticed him to a color-manufacturer. A natural taste
for scientific subjects led to his becoming in 1851 a mem-
ber of the Physical Society of Frankfort, where he began
the studies which subsequently led him to take up teaching
as a profession. In 1858 Reis became a tutor in Gamier' s
Institution for Boys at Friedrichsdorf, and this was his
position in life when he began his electrical experiments.
The instrument which, in probable ignorance of Wheat-
stone's long-prior use of the name, he called u das Tele-
plion," was devised in I860 ; and he lectured on it publicly
at various times between 1861 and 1864. Between those
who misunderstood it entirely, and those who, like Pog-
gendorf, refused even to publish Reis' memoir on the
apparatus because the transmission of speech by electricity
was regarded as too chimerical for serious consideration,
the invention met with little or no appreciation. Various
professors lectured upon it, and several instruments were
sold to physical laboratories throughout the world ; but
outside of Reis himself and a few intimate friends, it is
doubtful if any one regarded the invention as more than
a scientific curiosity creditable, of course, to its origina-
tor, but by no means giving him any title to fame. Reis
lived until 1874, but his labors upon his telephone appear
to have ended ten years before his death. His opponents
say, that, having failed to transmit speech by his appara-
tus, he perforce dropped it ; his friends, that he laid it
aside partly from ill health, but mainly from a feeling of
deep disappointment because of the lack of appreciation
THE SPEAKING TELEPHONE. 281
which it encountered among his brother scientists. It
does not appear that he made any other inventions ; and
to his early decease may perhaps be attributed the fact
that he rose to nothing higher than an humble tutorship.
What with ill health, and the sense of many rebuffs prey-
ing upon him, his life, he says in his autobiographical
notes, was one of "labor and sorrow ; " yet there is little
in Reis' history to support this conclusion, especially when
contrasted with the records of the privations and hardships
which have fallen to the lot of many of the world's great-
est inventors. Reis does not appear ever to have suffered
from poverty, nor to have depended in any sense upon
the success of his invention for support. He was able to
leave a useful trade, to prosecute studies which fitted him
for his own chosen occupation, teaching, and equally
able to secure a permanent position as a tutor, which
afforded him not only leisure for the prosecution of his
investigations, but congenial associates who have testified
to their appreciation of his efforts. Contrast this with the
long penury and want of Howe, of Whitney, of Henry
Cort, and a host of others, and Reis' lot in life was
comparatively enviable.
Reis, moreover, lacked that peculiarity of inventors,
persistence. It is enough to say, that, if he had the
knowledge of the immense importance of his invention
which is now ascribed to him, his failure to prosecute it
for the last ten years of his life between the ages of
thirty and forty, when the enthusiasm of youth has hardly
begun to be tempered with the conservatism which comes
with later years is simply phenomenal. Most inventors
imbued with a great thought, like Stephen Gray, never
relinquish it until death ; and in the face of suffering and
poverty, their devotion to their ideals too often results in
sacrifices and self-denials far greater than those which,
282 THE AGE OF ELECTRICITY.
when otherwise directed, have provoked the admiration
of the world, and made men heroes.
Reis devised several forms of telephonic instruments,
including many merely experimental, and substantially
embodied in more complete devices. His manipulative
skill was of a very low order. He had an actual poverty
of resource in adapting means to ends. He differed from
the generality of inventors, who construct means first, and
evolve theories afterwards.
In order to understand what Reis did, it is necessary to
recall a few salient facts relative to sound, to some of
which reference has already been made.
Sound, as we have seen, is due simply to wave-motion
or vibration of the air, or other material medium in which
the motion is propagated. The waves or vibrations may
differ in length, in frequency, or in shape. We can always
see on the ocean long waves and short waves, waves fol-
lowing each other rapidly or slowly, and waves smooth
and glassy, like the ground-swell, or broken up on their
surfaces into multitudinous smaller waves, as when the
wind blows strongly. The length of a sound-wave
that is, the path over which the air-particles swing to and
fro determines the loudness of the resulting sound; the
frequency of the waves, the pitch of the sound, a higher
or lower note on the musical scale ; and the shape of the
wave governs the quality or timbre of the sound, upon
which depends the difference between the sound of a flute
and that of a violin, between the sweet note of the night-
ingale and the screech of a peacock, and between articu-
late speech and a groan or a howl or a moan.
We can thus form some notion of what a complex thing
an air-wave produced by speech is. We are constantly
raising and lowering our voices, and hence there are waves
of all conceivable lengths. We are also constantly using
THE SPEAKING TELEPHONE. 283
different notes of the musical scale, and modulations of
all sorts, even in talking ; and so the waves are set in
motion by our vocal apparatus with all degrees of fre-
quency. And, finally, we articulate, we use inflections ;
our voice is rough or harsh, or sweet and melodious ; and
so imposed on the air-waves are all sorts of ripples, smaller
waves, which contort and change their shapes.
It is not difficult to conceive that the simple frequency
of the waves of sound may set a disk free to be moved,
like a drum-head, vibrating with like frequency ; so
that, as Bourseul points out, we can cause that disk to
make or break an electrical current as many times per
second as there are air-vibrations in that time. But when
the same disk is made, by the same waves, to vibrate over
a long path or a short path, and even, at different periods
of its motion, to travel slower or faster for infinitesimal
intervals of time, corresponding to the little waves which
articulation imposes on the large ones, how are we to
modify the electric current by these motions? Merely
making and breaking the current will simply cause it to
set Page's needle, at the other end of a line, into vibra-
tion as many times per second as the current is made and
broken per second ; and, if the " makes " and " breaks "
are fast enough, the needle will sing in its own voice a
note of corresponding pitch. There will be no variations
in loudness, and the sound produced will not resemble the
sound transmitted, except that both will be pitched on
the same note. The needle will sound just the same when
the same note is sung to the circuit-breaking disk by a
Patti, or a stearn-whistle, just the same if the sound be
produced by the most silvery-tongued of orators, or a
hyena. Nothing but the pitch of the sound, nothing but
the succession of vibrations making that pitch, will modify
the current.
284 THE AGE OF ELECTRICITY.
Heis, as we have said, knew all about these curious and
Complex characteristics of the sound-wave. He was a
professor of physics, and it was his business to know
them. Beyond this he knew of an ingenious little piece
of apparatus called the phonautograph, which consisted of
a cylinder, over one end of which was stretched a sheet
of membrane ; to the membrane a little stylus was fas-
tened, the free end of which rested on a rotating cylinder
covered with lamp-black. When any one talked into the
phonautograph, the membrane diaphragm vibrated ; and
when the cylinder was turned, and at the same time moved
lengthwise, the little stylus fastened to the membrane
traced queer curves and sinuosities characteristic of the
sounds produced : and so, in fact, in this way the sounds
wrote down their own peculiarities.
Now we can see the problem which was before Reis.
Bourseul had proposed to make the thing which under the
influence of the current was to vibrate, and so reproduce
the sounds at the receiving end, copy the movements of
the thing vibrated by the voice at the sending end. Reis
knew how complex the vibrations were, and equally knew
that a stretched membrane would follow them, and could
be set in motion by them. But how was the current to be
controlled by the membrane, so that it in turn would gov-
ern something else far off at the other end of a wire, and
make it copy the movements of that membrane ? Let the
reader think for a moment on the enormous difficulty in-
volved. Not only must the current be modified in some
way, to copy the frequency and amplitude (length) of the
air-vibrations, but every little minor peculiarity of the vi-
brations superimposed on those vibrations, these over-
vibrations, these ripples on the large waves, often occur-
ring at the rate of tens of thousands per second. Imagine
a mechanism made by human hands capable of doing this !
THE SPEAKING TELEPHONE.
285
Reis may be said to have exposed the tremendous ob-
stacles which lay in the path of any one who should attempt
to carry into practice Bourseul's theory ; and for this he is
entitled to lasting credit. Knowing what obstacles there
are, is next best to knowing how to surmount them. But
the first does not involve invention ; the second does.
Reis began by carving a model of a human ear out of a
piece of oak. Figs. 116 and 117
show it in
and section.
Fig. 116.
Fig. 117.
Through this he made a hole which he closed by a piece of
thin membrane at b (Fig. 117), to imitate the drum of the
natural ear. On the back he fastened a tin plate which
served as a support for a little lever c d, pivoted to the plate
at its middle, and resting at its lower end c against the
membrane, and its upper end d against a strip of spring-
metal g which was fastened by the two screws represented
to the under edge of the ear. The screw h was intended to
regulate the pressure of the spring g on the lever d. One
286 THE AGE OF ELECTRICITY.
wire from the battery went to the spring g; and the cur-
Fig. 118.
rent was conducted, therefore, through that spring, through
the little lever c d, then to the tin supporting plate, and
THE SPEAKING TELEPHONE.
287
then to the line. This is a transmitting instrument into
which speech is to be uttered. This instrument, in its
most improved form, is represented in Fig. 118 ; and it is
hardly necessary to point out how slight the modification
that was effected. Instead of the carved ear, there is a
tube a, closed as before with a membrane b. On the tube
is a support e, which carries a little pivoted lever c as
before, one end resting against the membrane, the other
against a spring d which can be adjusted to the lever.
The current goes from the battery to the spring, so to
Fig. 119.
the lever, to the metal tube and its support, and so to
line.
Reis' last form of transmitter is represented in Fig. 119.
It is simply a box A, into the side of which passes a
speaking-tube. In the lid of the box is a round hole, in
which is arranged as before a membrane diaphragm. On
this diaphragm is fastened a flat bit of platinum, which
is electrically connected to a binding-post by a strip of
copper. Above the platinum rests a point of the same
metal, which was fastened at the apex of a loose angular
piece of metal. The angle piece is supported at the end of
288 THE AGE OF ELECTRICITY.
one leg b by a sort of pivot ; and at the end of its other leg
a it has a point dipping into a little cup of mercury. This
mercury cup is connected by a wire to the binding-screw
/, in the engraving, so that the current from the battery
might be said to enter at the screw /, thence go to the
little tripod or angle piece ; and as the point at the apex
of this rests by gravity simply on the scrap of platinum
fastened on the diaphragm, the current proceeds to the
platinum, and so by the copper strip to the screw d,
hence to line.
Reis made two receiving instruments, one of which is
shown in Fig. 119 in connection with the transmitter just
described. It is simply and purely Page's needle, which
is seen passing through two supports, surrounded by its
coil, and resting on a sounding-box. Reis' other receiver,
which he abandoned in favor of the needle instrument, is
represented in Fig. 118. It was modified from a telegraph-
sounder ; m m being the usual electro-magnets, before
which was suspended an armature *', loosely hung in a
standard &, and provided with adjusting screws / and o.
The current passed through the magnet coils in the usual
way.
The reader has now before him substantially all that
Reis did. The instruments represented in Fig. 119 were
those manufactured for the market, and they found their
way to the United States. They were exhibited in New
York in 1869, 1870, and 1871.
But how do these instruments work? And how, if at
all, do they transmit speech? And, if they transmit
speech, why did the world not have the speaking tele-
phone twelve or fifteen years earlier than it did? It has
cost already several hundred thousand dollars just to talk
about those questions, and the end of the expense is not
yet in this country, at least. However existing contro-
THE SPEAKING TELEPHONE. 289
versies may be decided, three irreconcilable views of Reis'
instruments will always be taken ; and these are :
First, That Reis merely combined Bourseul's contact-
breaking disk and wire with Page's singing needle ; using
the voice to make the disk vibrate, and so make and
break the circuit correspondingly with the frequency of
the vibrations. This doctrine denies the possibility of
Reis' apparatus ever having transmitted speech, or ever
having been able to do so, because an electrical current now
interrupted and now established must during the periods
of interruption cease altogether. Hence the necessary
vibrations are constantly being dropped out, and can never
be reproduced at the receiver, because never existing on
the line ; while those .that do affect the current simply
cause the needle to sing in its own voice, depending, as
we have already explained, upon the rapidity or frequency
of the closing of the circuit.
Second, That Reis' instruments, even if they do make
and break the circuit in the manner described, will never-
theless transmit speech by virtue of the making and break-
ing. This is absurd ; and although it has been gravely
advanced, and innumerable specious contrivances devised
to establish its truth, all that these show is that speech
can be transmitted through certain things different from
Reis' apparatus even despite occasional interruptions in
the circuit, just as an occasional pressure on the wind-
pipe may stop speech from time to time, and yet the
speaker manage to make himself understood.
Third, That Reis' contact points above noted never
broke circuit at all, but were always held together by the
weight of the superimposed angle piece in Fig. 119, or
the spring in Fig. 118. When this is the case, Reis'ttrans-
mitter if carefully used will transmit spoken words.
If Reis' transmitter was not capable of transmitting
290 THE AGE OF ELECTRICITY.
speech, it is of course immaterial whether his receiver
could reproduce speech or not. He never could have
known whether it was or was not operative for the pur-
pose. If, however, Reis' transmitter could and did trans-
mit speech, then it is very important to know whether his
receiving instrument would reproduce speech, for a like
reason. It will suffice here to say, that, with a fully
operative transmitter, either of Reis' receivers can be
made to reproduce the speech sent.
At the time that this work is written (1886), a contest
of unexampled bitterness, into which even the Government
of the United States has been drawn as a party, rages
over the question who invented the arc of transmitting
articulate speech by electricity, and the speaking tele-
phone. It is scarcely possible to make even the simplest
statements without risking acrimonious contradiction from
some quarter or other : even to doubt, is often to invite
instant condemnation. In the recital which follows, it
has been the endeavor to state facts, without partisan
color.
The multiple harmonic telegraph of Mr. Elisha Gray,
which has already been described in the chapter on teleg-
raphy, was widely exhibited throughout the United States
in the years 1875 and early in 1876, under the name of
the " telephone." During this period, and for some time
before, Mr. Gray had been studying the problem of articu-
late transmission. It is alleged, that, as early as 1874,
he invented an apparatus which is a complete speaking
telephone ; but it appears that he did not construct it, nor
in any wise test it, until some years afterwards. At the
time Gray was lecturing upon his harmonic telegraph,
or musical telephone, as it was then commonly called,
and prosecuting his other researches, Mr. Alexander
Graham Bell, then a teacher of a system of visible speech
THE SPEAKING TELEPHONE.
291
to the deaf and dumb in a public institution in Boston,
was likewise at work upon telegraphic inventions. Foi
several years, beginning in 1870, Mr. Bell was studying
multiple telegraphic transmission by musical tones. He
devised various forms of apparatus for that purpose, and,
among other things, a receiving instrument which is rep-
resented in Fig. 120. This consists simply of an electro-
magnet placed vertically, over the poles of which extends
a thin bar of steel clamped to a support. This con-
trivance was contrived for use with a device for mechani-
cally interrupting the current, the latter consisting in a
steel reed kept in continuous vibration by an electro-
magnet and a local
battery. The reed in
vibrating made and
broke the current to
the line ; and this cur-
rent, passing to the
electro-magnet in the
receiving apparatus,
caused that magnet to attract
steel bar before it. If
Fig. 120.
and release the elastic
the normal rate of vibration of
the transmitting reed was the same as that of the re-
ceiving reed, then the latter would vibrate strongly, and
yield a note of the same pitch as that of the transmitting
reed ; but if the normal rates of vibration of the two reeds
were different, then the receiver would keep silent. The
principle of this is fully explained on page 238, in refer-
ence to Gray's harmonic telegraph.
During 1874 Mr. Bell did a great deal of thinking about
transmitting speech by electricity, and a little work on his
harmonic telegraph ; and this state of affairs continued
until the summer of 1875. On the second day of June
of that year, w r hile experimenting with his multiple tele-
292 THE AGE OF ELECTRICITY.
graph apparatus, Mr. Bell made an accidental discovery
which, he says, " convinced me in a moment that the
speaking telephone I had devised in the summer of 1874
would if constructed prove a practically operative instru-
ment." The Italics are ours. Mr. Bell had arranged in
his workshop three experimental telegraph-stations, at one
of which were several of his circuit-breaking transmitting
reeds, and at each of the others an equal number of re-
ceivers, of the form represented in Fig. 120. Thus there
were three transmitters tuned to notes of different pitch,
as A, B, and C, at one station ; and at each of the other
stations, three receivers tuned to the same notes, A, B, C.
When transmitter A was in operation, only the reeds A
at the two distant stations should respond ; and so, for
transmitters B and C, only the reeds B and C should
correspondingly vibrate. While the experiment was in
progress, Mr. Bell's assistant, Mr. Watson, finding that
one of the reeds of the receivers at the station where he
was located adhered to the pole of the magnet, forcibly
plucked it away. At the same moment Mr. Bell, at the
other receiving station, noticed a motion in the reed of
the receiver, which corresponded to the receiver whose
reed had been plucked. "At all events," he says, "the
reed of the receiver at station 2 vibrated at a time when
no vibration was expected, so that the fact of its vibra-
tion immediately attracted my attention. I therefore kept
Mr. Watson plucking the reed at station 3 while I made
various changes at stations 1 and 2. These changes
proved that the vibration I had observed had indeed been
caused by the plucking of the reed at station 3, even when
there was no battery upon the circuit at the time. To
make the matter perfectly sure, we separated the receivers
B of stations 2 and 3, and connected them upon a circuit
by themselves, as shown in Fig. 5 of my March 7, 187G,
THE SPEAKING TELEPHONE.
293
patent, but without any battery in the circuit. [The figure
here referred to by Professor Bell is represented in Fig.
121. EE are the two receivers, each having an electro-
magnet, in front of the pole of which is arranged a spring
armature or reed A. The reed is fastened at one end at
h.~\ Upon plucking the reed of one of the receivers, the
reed of the other was thrown into very considerable vibra-
tion. The vibrations produced by the plucking were still
more intense when a battery was included in the circuit. A
number of experiments were made to prove that the con-
siderable amplitude of movement noticed was not caused by
any vibrations mechanically conducted along the wire frorj
one instrument to the other, but that the vibration of tha
one receiving reed was due to electrical undulations caused
by the vibration of the other receiving reed. The discovery
therefore that was made on the 2d of June, 1875, teas that
the vibrations caused in the armature of a receiving instru-
ment, by electrical undulations occasioned by the vibration
of the armature of another instrument in the same circuit
as the first, would be of very considerable force. As I have
already explained, I had had the idea since the summer
of 1874, that vibrations produced in this way would be of
very slight amplitude, and that they might not prove suffi-
ciently violent to produce audible effects that would prove
practically useful either for the purpose of the reproduc-
tion of articulate speech, or for the purposes of multiple
telegraphy. The experiments described above convinced
294 THE AGE OF ELECTRICITY.
me that this was a mistake. The vibrations produced in
tuned reeds were so great in amplitude that I felt sure
that they were even sufficiently great to be mechanically
utilized in any system of multiple telegraphy. Even when
the reeds of the two instruments connected in circuit (Fig.
124), (but without a battery), were not in tune with one
another, that is, did not have the same normal rate of
vibration, the feeble forced vibrations electrically pro-
duced in the one by the mechanical plucking of the other,
though barely sufficient to produce a visible motion, were
quite sufficient to cause a very perceptible sound."
The reader has now before him Mr. Bell's own descrip-
tion, not exactly of how he invented the speaking tele-
phone, but how he became convinced that a speaking
telephone which he had in his mind would prove " a prac-
tically operative instrument."
So far he had simply observed that the current produced
in the coil of an electro-magnet, by vibrating an armature
in front of the pole of that electro-magnet, was stronger
than he had believed ; that is, it was strong enough, after
passing over a telegraph-line, to set another armature, in
front of another electro-magnet, vibrating audibly.
Mr. Bell's next step was to try whether he could move
the armature the reed of the sending instrument by
the air-waves produced by the voice, instead of mechani-
cally by the finger. Just as Reis had done before him,
and the inventor of the phon autograph before Reis, he
made a hollow tube, and covered one end with a piece of
membrane. He fastened his vibrating reed to the centre
of that membrane. The apparatus as Mr. Bell says he
made it is represented in Fig. 122. The electro-magnet is
placed above the membrane diaphragm ; the armature fas-
tened to the centre of the membrane. In order to leave
the armature free to follow the membrane, the former was
THE SPEAKING TELEPHONE.
295
hinged to its support. Mr. Bell supposed that when some
one talked to the diaphragm of this instrument, the magnet
being connected to a line of wire, another person listening
at a similar instrument also connected to the line would
hear what was said. Unfortunately, when he caused the
instruments to be made, they would not operate. He says
he " knew from theory that the articulation was there ; "
but there is obviously a wide difference between knowing
of the presence of a thing by theory, and producing it.
This was the condition of affairs when Professor Bell
obtained his celebrated
patent which has since
been judicially con-
strued to cover the
whole art of transmit-
ting speech by electri-
city. Like Reis, he had
formulated theories in
his own mind, and had
made apparatus which
he hoped would practi-
cally realize them. But
neither Reis so far as the world knew, nor Bell so far as
he knew, had ever successfully transmitted one word by
electricity, at the respective times when death ended the
labors of the one, and when the monopoly of a great
public need fell into the hands of the other.
By the summer of 1876 Mr. Bell had considerably
modified the form of his apparatus ; and at the Centennial
Exposition he exhibited it before various distinguished
persons, and succeeded in transmitting a few simple and
easily recognizable words and phrases.
During the following year Mr. Bell applied himself
assiduously to the improvement of his apparatus, and
Fig. 122.
296
THE AGE OF ELECTRICITY.
finally by June, 1877, brought it to the familiar form in
which it has remained ever since. Our engraving (Fig.
123) shows it split in two lengthwise. The outer casing is
of hard rubber. Through the middle runs a bar magnet,
on the end of which is the wire coil. The ends of the coil
Fig. 123.
are connected by wires running through the case to two
binding-posts, to which the circuit connections are fas-
tened. Between the cover and case proper is clamped the
diaphragm of thin sheet-iron which is disposed as close to
the end of the magnet as possible without touching it.
fig. 124.
Finally, in the cover there is a recess which serves to con-
verge the sounds uttered into the instrument toward the
central sound aperture. This is known as a magneto
telephone, and may be used both as a transmitter and
a receiver, that is, it may be employed at both ends of a
line as shown in Fig. 124, which is simply a diagram of the
THE SPEAKING TELEPHONE. 297
important parts ; A and B being two permanent magnets,
C and D being diaphragms respectively in front of each,
and E and F being the coils. One end of each coil may
be connected to ground, and the other ends connected to
line. When permanent magnets are used, the transmitting
instrument produces its own current : when a battery is
placed in circuit, the telephone current is, as already
stated, superposed on the main current. The first tel-
ephone lines commercially employed had magneto tele-
phones for both transmitters and receivers, but at the
present time in this country the magneto telephone is used
solely as a receiver.
It is a matter of history, that Mr. Bell has been the
recipient of great honors, not merely as the inventor of
the electric speaking telephone, but of the art of teleph-
ony, of transmitting and receiving articulate speech
by the aid of the electrical current. And it is also well
known, that, under Mr. Bell's earliest patent bearing date
March 7, 1876, a gigantic corporation has asserted an in-
flexible control in the United States over every telephone
line. This control mainly is based on the famous fifth
claim of Mr. Bell's patent, which is as follows :
"The method and apparatus for transmitting vocal or
other sounds telegraphically, as herein described, by caus-
ing electrical undulations similar in form to the vibrations
of the air accompanying the said vocal or other sounds,
substantially as set forth."
We have already alluded incidentally to the undulatory
current in contradistinction to the intermittent or inter-
rupted current. The so-called undulatory-current theory
is that which is most commonly accepted to explain the
action of the telephone. It involves the idea that only
an unbroken current, variable in strength, can be modified
by all the characteristics of a sound-wave ; that such a
298
THE AGE OF ELECTRICITY.
current will be undulatory in form, and that its undula-
tions will copy or correspond to all the undulations of the
sound-waves affecting the transmitting telephone, however
minute, and, after passing over a wire, will cause in the
receiving instrument the reproduction of the original
sounds in all their characteristics. This is substantially
the undulatory-current theory.
There are two principal ways in which an electric cur-
rent is subjected to the influence of the voice. One, we
have already seen, involves an armature in the form of a
thin plate, which is vibrated by the sound-waves due to
Fig. 125.
speech in front of the pole of an electro-magnet, as rep-
resented in Fig. 124. The other method depends simply
on interposing in a closed circuit, two pieces of conducting
material in loose but constant contact as represented in
Fig. 125. One of these pieces, A, may be attached to the
plate vibrated by the speaker's voice, and the other piece,
B, may be held in constant contact with the first by a
spring, for example. The battery current passes from
one piece to the other, then to the line, and to a magneto
receiving instrument. When speech is uttered before the
diaphragm, the vibrations of the plate communicate them-
selves to the loose joint, and create variations in the re-
sistance offered by this joint to the current. The result
THE SPEAKING TELEPHONE. 299
is, that the current is modified by the diaphragm vibrations,
just as it is when the diaphragm is moved before the pole
of a magnet ; only, in the one case a current already flow-
ing is more or less diminished in strength, and in the other
it is more or less increased in strength. To illustrate :
Suppose there is attached to a bucket of water a flexible
pipe, as in Fig. 126, through which the water can freely
flow. Then, by compressing the pipe in the hand, the
escape of the water can be more or less prevented, while
some flow always continues. The contact pieces -4, /?,
in Fig. 125, when governed by the diaphragm, act like the
hand in Fig. 126. Again, suppose the case of a railway-
train, which can be made to move faster while constantly
Fig. 126.
running, by turning on more or less steam to the engine :
that represents the conditions of the magneto telephone.
So also, while running at a given speed, the train can be
more or less checked by the brakes ; that represents the
conditions of the resistance telephone. In both cases, the
train keeps on moving, but its speed is varied.
The reader will doubtless notice at once the similarity
between the resistance form of telephone represented in
Fig. 125, and Reis' transmitter represented in Fig. 118.
The whole controversy as to Reis hinges simply on the
question whether Reis did or did not maintain his loose
contact pieces in constant contact. If he did, he had a
resistance telephone, using an unbroken current, which
will transmit speech : if he did not, he had simply a ,
300 THE AGE OF ELECTRICITY.
circuit-breaker, causing a broken current, which will not
transmit speech.
Leaving the Reis question aside, however, it is a singu-
lar fact, that the first articulate speech obtained by Mr.
Bell was transmitted not only after his patent had been
obtained, but with an apparatus which Mr. Bell had never
before made, or even described so that any one else could
make it. In fact, the first words sent by Mr. Bell were
not transmitted by the magneto telephone at all, but by a
very imperfect form of resistance instrument, the con-
struction of which was first described, not by Mr. Bell,
but by Mr. Elisha Gray. It consisted of a membrane
vibrated by the voice, and carrying a wire which dipped
in water. A battery current was conducted to the water,
passed to the wire, and so to the line. When the mem-
brane was vibrated, it moved the wire up and down in the
water, and so altered the length of the non-submerged
portion of the wire, thus varying its resistance to the
passage of the current. For practical purposes this ap-
paratus is of no value, but it will always be of great
historical interest for the reasons above stated.
In May, 1878, Professor D. A. Hughes announced his
discovery of the microphone, so called because it rendered
audible very minute sounds ; and this discovery was, that,
if two pieces of conducting material be supported in very
delicate contact, then the resistance offered by the joint
to a current passing through it will be modified by very
faint sounds, and the current, correspondingly affected,
caused to reproduce them in a receiving telephone. This
is of course the principle of the resistance telephone,
which, in fact, is now commonly known as the microphone.
Hughes made his microphone in the form represented in
Fig. 128, in which A is a stick of hard carbon pointed at
its ends, and held between two supports of like material
THE SPEAKING TELEPHONE.
301
projecting from an upright board. The battery current
was led, as indicated by the wires, to one support through
the carbon, and out through the other support ; and a re-
ceiving telephone was connected in the circuit. A great
many stories about hearing flies' footsteps, etc., were
published when this apparatus first appeared, which were
more fantastic than accurate. It is true that some faint
sounds can at times be recognized ; but as a general rule,
true of all over-delicate microphonic contacts, the breaks
Fig. 127.
in continuity of the circuit caused by vibrations being
strong enough to actually separate the parts of the loose
joint, result simply in explosive cracks and snaps in the
receiver, which practically obliterate all other sounds. In
the resistance telephone, the transmitter of the present
day, the chief problem has always been the devising of
mechanical means of holding the contact pieces together
so delicately that they will be under control of the minut-
est speech vibrations, and yet not so lightly that the
grosser vibrations as when words are loudly spoken
can throw them apart.
302 THE AGE OF ELECTRICITY.
Shortly after the announcement by Hughes of his
microphone, Mr. T. A. Edison laid claim to the discov-
ery, asserting that he had some time prior found out that
"semi-conductors" whatever they may be, including
carbon, however vary their resistance with pressure.
Mr. Edison at various times has contrived telephones in
which a block of carbon, for example, is pressed against
a diaphragm. It has been conclusively demonstrated by
many investigators, that the pressure, greater or less, on
carbon, has nothing to do with variations of resistance
offered by that material to a current. Mr. Edison's
instruments for a short time were commercially used in
this country.
Of the various claimants to the invention of the tele-
phone, none has presented a more remarkable history
than Daniel Drawbaugh. Mr. Drawbaugh is one of
those universal geniuses capable of turning his hand to
any mechanical work, and of doing it well. He has
always resided in an out-of-the-way little hamlet called
Eberly's Mills, near Harrisburg, Penn. As an electri-
cian, he is self taught. Between the years 18G7 and
1876, he claims to have invented and actually used
every type of telephone now known. He began with a
transmitter made out of a jelly- tumbler, in which he used
powdered carbon to vary the resistance correspondingly
to the motion of a diaphragm vibrated by the voice ; and
a receiver contrived from a mustard-can, but in other
respects nearly identical with the first telephones made
by Professor Bell. From these devices as starting-points,
onward, he has constructed a series of telephones, more
and more specialized in construction, until finally the
instruments which he claims to have had at the time
when Professor Bell made his earliest experiments ap-
proach closely in efficiency to the best forms of the pres-
THE SPEAKING TELEPHONE. 303
ent day. Mr. Drawbaugh has produced a large number
of his telephones, and many witnesses to prove that he
had them at the times he fixes. His claims are at this
writing before the courts for adjudication. If they are
ultimately sustained, there can be no question but that
Mr. Drawbaugh's position as an electrical discoverer will
be wholly unrivalled. Within the last four years, he has
invented over thirty new telephones.
At the date of this work (1886) , over a thousand patents
in the United States alone have been granted for various
forms of telephones, and devices thereunto appertaining.
The great majority of instruments differ merely in unes-
sential details. With the resistance transmitters, changes
on means for holding the two contact pieces together have
been rung to such an extent that it seems that every con-
ceivable contrivance for the purpose must have been sug-
gested. Magneto telephones are not used commercially
as transmitters ; for the modifications they produce in the
current are feeble compared with those caused by the
resistance instrument. They are, however, commonly
employed as receivers ; and, as has been already stated,
the form which they now have has undergone no material
change for some nine years. An immense amount of
ingenuity has also been expended in devising telephone
circuits and systems so as to allow of intercommunication
between exchanges and subscribers.
The form of transmitting telephone in common use
throughout the United States is that known as the Blake
transmitter, a sectional view of which is given in Fig.
128. The contact pieces are here a platinum point which
is supported on a light spring c, and a button of carbon,
7i, held in a heavy mass or anvil e, which is supported by
a spring d. Both springs c and d are held in a plate F,
which is itself sustained by a spring plate g upon a bracket
304
THE AGE OF ELECTRICITY.
B'. The platinum point rests against the diaphragm, and
also against the carbon button ; these parts being held in
light contact by the several springs. On the lower part
of the plate F is an inclined plane against which bears
the point of an adjusting-screw G. The current from the
battery is conducted
through the primary wire
of the induction coil /,
thence through the con-
tact pieces, and so back
to battery. The second-
ary wire of the induction
coil communicates with
the line. The Blake
transmitter is by no
means the best, or even
one of the best, of the
carbon transmitters.
Various forms of trans-
mitters have been devised,
in which springs for hold-
ing the carbon contact
pieces together are omit-
ted, and the action of
gravity substituted. One
of the simplest instru-
ments of this kind was
devised by Mr. Daniel
Drawbaugh in 1881, and
is illustrated in Fig. 129. To the rear side of a diaphragm
A is attached a little prism B of hard carbon ; and a simi-
lar prism C is secured to the back-board of the instrument.
These prisms do not touch each other, but resting upon
their inclined faces is a cylinder />, also of carbon. The
Fig. 128.
THE SPEAKING TELEPHONE.
305
battery current passes through the three pieces of carbon,
which remain always in proper adjustment simply by the
weight of the carbon cylinder. This instrument has been
adopted by the United States Signal Service, and has been
officially pronounced of special efficiency
for military purposes in the field, etc.
For producing loud sounds in the re-
ceiving instrument, the transmitters which
use blocks or buttons of carbon are far
inferior to those employing carbon in
comminuted form. The usual construc-
tion of these instruments is represented
in Fig. 130, in which A is a diaphragm
of metal, B a fixed plate of metal, and
C a mass of pulverized coke placed
between the two. The current passes
from the diaphragm through the coke, to the back plate,
and so out. This telephone operates by reason of the
immense number of contacts occurring between
the particles of carbon. It is necessary simply
to cause the air-vibrations due to the voice to jar
or shake the mass. Fig. 131 represents a pulver-
ized-carbon transmitter constructed by the author,
in its full working size. It consists simply of a
cylindrical box of hard rubber, lined within with
a ring of brass, A, to
which one of the con-
ducting wires is fast-
ened. A disk of brass
fig. 129.
Fig, 130.
Fig. 131.
B is firmly attached to
one of the inner faces, so as not to touch the ring A. The
space in the box is loosely filled with comminuted coke,
and then the cover is permanently fastened in place. In
external appearance the instrument is nothing but a button
306 THE AGE OF ELECTRICITY.
from which the connecting wires extend. This contrivance
transmits speech clearly when held in the fingers close
to the mouth. Just why conducting bodies in loose but
constant contact will cause a variation in the resistance
to, and so render an electrical current capable of copying,
speech vibrations, is not definitely known. Any pieces
of conducting material will so operate, even silver, the
best of electrical conductors. The results, however, are
much better when the contact pieces are of carbon, or
other material of comparatively low conductivity. It ap-
pears probable that the true cause of the effect is varia-
tions in t 
