



Produced by Sigal Alon, Marcia Brooks, Fox in the Stars
and the Online Distributed Proofreading Team at
http://www.pgdp.net









LITTLE MASTERPIECES OF SCIENCE

[Illustration: George Stephenson.]




Little Masterpieces
of Science

Edited by George Iles




INVENTION AND DISCOVERY


_By_


Benjamin Franklin   Alexander Graham Bell
Michael Faraday     Count Rumford
Joseph Henry        George Stephenson


[Illustration]


NEW YORK

DOUBLEDAY, PAGE & COMPANY

1902


Copyright, 1902, by Doubleday, Page & Co.

Copyright, 1877, by George B. Prescott

Copyright, 1896, by S. S. McClure Co.

Copyright, 1900, by Doubleday, McClure & Co.




PREFACE


To a good many of us the inventor is the true hero for he multiplies the
working value of life. He performs an old task with new economy, as when
he devises a mowing-machine to oust the scythe; or he creates a service
wholly new, as when he bids a landscape depict itself on a photographic
plate. He, and his twin brother, the discoverer, have eyes to read a
lesson that Nature has held for ages under the undiscerning gaze of
other men. Where an ordinary observer sees, or thinks he sees,
diversity, a Franklin detects identity, as in the famous experiment here
recounted which proves lightning to be one and the same with a charge of
the Leyden jar. Of a later day than Franklin, advantaged therefor by new
knowledge and better opportunities for experiment, stood Faraday, the
founder of modern electric art. His work gave the world the dynamo and
motor, the transmission of giant powers, almost without toll, for two
hundred miles at a bound. It is, however, in the carriage of but
trifling quantities of motion, just enough for signals, that electricity
thus far has done its most telling work. Among the men who have created
the electric telegraph Joseph Henry has a commanding place. A short
account of what he did, told in his own words, is here presented. Then
follows a narrative of the difficult task of laying the first Atlantic
cables, a task long scouted as impossible: it is a story which proves
how much science may be indebted to unfaltering courage, to faith in
ultimate triumph.

To give speech the wings of electricity, to enable friends in Denver and
New York to converse with one another, is a marvel which only
familiarity places beyond the pale of miracle. Shortly after he
perfected the telephone Professor Bell described the steps which led to
its construction. That recital is here reprinted.

A recent wonder of electric art is its penetration by a photographic ray
of substances until now called opaque. Professor Roentgen's account of
how he wrought this feat forms one of the most stirring chapters in the
history of science. Next follows an account of the telegraph as it
dispenses with metallic conductors altogether, and trusts itself to that
weightless ether which brings to the eye the luminous wave. To this
succeeds a chapter which considers what electricity stands for as one of
the supreme resources of human wit, a resource transcending even flame
itself, bringing articulate speech and writing to new planes of facility
and usefulness. It is shown that the rapidity with which during a single
century electricity has been subdued for human service, illustrates that
progress has leaps as well as deliberate steps, so that at last a gulf,
all but infinite, divides man from his next of kin.

At this point we pause to recall our debt to the physical philosophy
which underlies the calculations of the modern engineer. In such an
experiment as that of Count Rumford we observe how the corner-stone was
laid of the knowledge that heat is motion, and that motion under
whatever guise, as light, electricity, or what not, is equally beyond
creation or annihilation, however elusively it may glide from phase to
phase and vanish from view. In the mastery of Flame for the superseding
of muscle, of breeze and waterfall, the chief credit rests with James
Watt, the inventor of the steam engine. Beside him stands George
Stephenson, who devised the locomotive which by abridging space has
lengthened life and added to its highest pleasures. Our volume closes by
narrating the competition which decided that Stephenson's "Rocket" was
much superior to its rivals, and thus opened a new chapter in the
history of mankind.

GEORGE ILES.




CONTENTS


  FRANKLIN, BENJAMIN

  LIGHTNING IDENTIFIED WITH ELECTRICITY

    Franklin explains the action of the Leyden phial or jar.
    Suggests lightning-rods. Sends a kite into the clouds during
    a thunderstorm; through the kite-string obtains a spark
    of lightning which throws into divergence the loose fibres
    of the string, just as an ordinary electrical discharge
    would do.                                                        3


  FARADAY, MICHAEL

  PREPARING THE WAY FOR THE ELECTRIC DYNAMO AND MOTOR

    Notices the inductive effect in one coil when the circuit in
    a concentric coil is completed or broken. Notices similar
    effects when a wire bearing a current approaches another
    wire or recedes from it. Rotates a galvanometer needle by
    an electric pulse. Induces currents in coils when the magnetism
    is varied in their iron or steel cores. Observes the lines
    of magnetic force as iron filings are magnetized. A magnetic
    bar moved in and out of a coil of wire excites electricity
    therein,--mechanical motion is converted into electricity.
    Generates a current by spinning a copper plate in a horizontal
    plane.                                                           7


  HENRY, JOSEPH

  INVENTION OF THE ELECTRIC TELEGRAPH

    Improves the electro-magnet of Sturgeon by insulating its
    wire with silk thread, and by disposing the wire in several
    coils instead of one. Experiments with a large electro-magnet
    excited by nine distinct coils. Uses a battery so powerful
    that electro-magnets are produced one hundred times more
    energetic than those of Sturgeon. Arranges a telegraphic
    circuit more than a mile long and at that distance sounds
    a bell by means of an electro-magnet.                           23


  ILES, GEORGE

  THE FIRST ATLANTIC CABLES

    Forerunners at New York and Dover. Gutta-percha the indispensable
    insulator. Wire is used to sheathe the cables. Cyrus W.
    Field's project for an Atlantic cable. The first cable fails.
    1858 so does the second cable 1865. A triumph of courage,
    1866. The highway smoothed for successors. Lessons of the
    cable.                                                          37


  BELL, ALEXANDER GRAHAM

  THE INVENTION OF THE TELEPHONE

    Indebted to his father's study of the vocal organs as they
    form sounds. Examines the Helmholtz method for the analysis
    and synthesis of vocal sounds. Suggests the electrical actuation
    of tuning-forks and the electrical transmission of their
    tones. Distinguishes intermittent, pulsatory and undulatory
    currents. Devises as his first articulating telephone a harp
    of steel rods thrown into vibration by electro-magnetism.
    Exhibits optically the vibrations of sound, using a preparation
    of a human ear: is struck by the efficiency of a slight
    aural membrane. Attaches a bit of clock spring to a piece
    of goldbeater's skin, speaks to it, an audible message is
    received at a distant and similar device. This contrivance
    improved is shown at the Centennial Exhibition, Philadelphia,
    1876. At first the same kind of instrument transmitted and
    delivered, a message; soon two distinct instruments were
    invented for transmitting and for receiving. Extremely small
    magnets suffice. A single blade of grass forms a telephonic
    circuit.                                                        57


  DAM, H. J. W.

  PHOTOGRAPHING THE UNSEEN

    Roentgen indebted to the researches of Faraday, Clerk-Maxwell,
    Hertz, Lodge and Lenard. The human optic nerve is affected
    by a very small range in the waves that exist in the ether.
    Beyond the visible spectrum of common light are vibrations
    which have long been known as heat or as photographically
    active. Crookes in a vacuous bulb produced soft light from
    high tension electricity. Lenard found that rays from a
    Crookes' tube passed through substances opaque to common
    light. Roentgen extended these experiments and used the rays
    photographically, taking pictures of the bones of the hand
    through living flesh, and so on.                                87


  ILES, GEORGE

  THE WIRELESS TELEGRAPH

    What may follow upon electric induction. Telegraphy to a
    moving train. The Preece induction method; its limits.
    Marconi's system. His precursors, Hertz, Onesti, Branly
    and Lodge. The coherer and the vertical wire form the essence
    of the apparatus. Wireless telegraphy at sea.                  109


  ILES, GEORGE

  ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT

    Electricity does all that fire ever did, does it better,
    and performs uncounted services impossible to flame. Its
    mastery means as great a forward stride as the subjugation
    of fire. A minor invention or discovery simply adds to human
    resources: a supreme conquest as of flame or electricity,
    is a multiplier and lifts art and science to a new plane.
    Growth is slow, flowering is rapid: progress at times is
    so quick of pace as virtually to become a leap. The mastery
    of electricity based on that of fire. Electricity vastly
    wider of range than heat: it is energy in its most available
    and desirable phase. The telegraph and the telephone contrasted
    with the signal fire. Electricity as the servant of mechanic
    and engineer. Household uses of the current. Electricity
    as an agent of research now examines Nature in fresh aspects.
    The investigator and the commercial exploiter render aid to
    one another. Social benefits of electricity, in telegraphy, in
    quick travel. The current should serve every city house.       125


  RUMFORD, COUNT (BENJAMIN THOMPSON)

  HEAT AND MOTION IDENTIFIED

    Observes that in boring a cannon much heat is generated:
    the longer the boring lasts, the more heat is produced. He
    argues that since heat without limit may be thus produced
    by motion, heat must be motion.                                155


  STEPHENSON, GEORGE

  THE "ROCKET" LOCOMOTIVE AND ITS VICTORY

    Shall it be a system of stationary engines or locomotives?
    The two best practical engineers of the day are in favour
    of stationary engines. A test of locomotives is, however,
    proffered, and George Stephenson and his son, Robert, discuss
    how they may best build an engine to win the first prize.
    They adopt a steam blast to stimulate the draft of the furnace,
    and raise steam quickly in a boiler having twenty-five small
    fire-tubes of copper. The "Rocket" with a maximum speed of
    twenty-nine miles an hour distances its rivals. With its
    load of water its weight was but four and a quarter tons.      163




INVENTION AND DISCOVERY




FRANKLIN IDENTIFIES LIGHTNING WITH ELECTRICITY

     [From Franklin's Works, edited in ten volumes by John Bigelow, Vol.
     I, pages 276-281, copyright by G. P. Putnam's Sons, New York.]


Dr. Stuber, the author of the first continuation of Franklin's life,
gives this account of the electrical experiments of Franklin:--

"His observations he communicated, in a series of letters, to his friend
Collinson, the first of which is dated March 28, 1747. In these he shows
the power of points in drawing and throwing off the electrical matter,
which had hitherto escaped the notice of electricians. He also made the
grand discovery of a _plus_ and _minus_, or of a _positive_ and
_negative_ state of electricity. We give him the honour of this without
hesitation; although the English have claimed it for their countryman,
Dr. Watson. Watson's paper is dated January 21, 1748; Franklin's July
11, 1747, several months prior. Shortly after Franklin, from his
principles of the _plus_ and _minus_ state, explained in a satisfactory
manner the phenomena of the Leyden phial, first observed by Mr. Cuneus,
or by Professor Muschenbroeck, of Leyden, which had much perplexed
philosophers. He showed clearly that when charged the bottle contained
no more electricity than before, but that as much was taken from one
side as thrown on the other; and that to discharge it nothing was
necessary but to produce a communication between the two sides by which
the equilibrium might be restored, and that then no signs of electricity
would remain. He afterwards demonstrated by experiments that the
electricity did not reside in the coating as had been supposed, but in
the pores of the glass itself. After the phial was charged he removed
the coating, and found that upon applying a new coating the shock might
still be received. In the year 1749, he first suggested his idea of
explaining the phenomena of thunder gusts and of _aurora borealis_ upon
electric principles. He points out many particulars in which lightning
and electricity agree; and he adduces many facts, and reasonings from
facts, in support of his positions.

"In the same year he conceived the astonishingly bold and grand idea of
ascertaining the truth of his doctrine by actually drawing down the
lightning, by means of sharp pointed iron rods raised into the regions
of the clouds. Even in this uncertain state his passion to be useful to
mankind displayed itself in a powerful manner. Admitting the identity of
electricity and lightning, and knowing the power of points in repelling
bodies charged with electricity, and in conducting fires silently and
imperceptibly, he suggested the idea of securing houses, ships and the
like from being damaged by lightning, by erecting pointed rods that
should rise some feet above the most elevated part, and descend some
feet into the ground or water. The effect of these he concluded would be
either to prevent a stroke by repelling the cloud beyond the striking
distance or by drawing off the electrical fire which it contained; or,
if they could not effect this they would at least conduct the electrical
matter to the earth without any injury to the building.

"It was not until the summer of 1752 that he was enabled to complete his
grand and unparalleled discovery by experiment. The plan which he had
originally proposed was, to erect, on some high tower or elevated place,
a sentry-box from which should rise a pointed iron rod, insulated 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 evident to the senses by sparks being emitted when a
key, the knuckle, or other conductor, was presented to it. Philadelphia
at this time afforded no opportunity of trying an experiment of this
kind. While 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 fastening two cross
sticks to a silk handkerchief, which would not suffer so much from the
rain as paper. To the upright stick was affixed an iron point. The
string was, as usual, of hemp, except the lower end, which was silk.
Where the hempen string terminated, a key was fastened. With this
apparatus, on the appearance of a thundergust approaching, he went out
into the commons, 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 sign of electricity appeared. He almost
despaired of success, when suddenly he observed the loose fibres of his
string to move towards an erect position. He now presented 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. If he succeeded, his name would rank high among those who
had improved science; if he failed, he must inevitably be subjected to
the derision of mankind, or, what is worse, their pity, as a
well-meaning man, but a weak, silly projector. The anxiety with which he
looked for the result of his experiment may easily be conceived. Doubts
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. Repeated sparks were drawn from the key, a phial was
charged, a shock given, and all the experiments made which are usually
performed with electricity."




FARADAY'S DISCOVERIES LEADING UP TO THE ELECTRIC DYNAMO AND MOTOR

     [Michael Faraday was for many years Professor of Natural Philosophy
     at the Royal Institution, London, where his researches did more to
     subdue electricity to the service of man than those of any other
     physicist who ever lived. "Faraday as a Discoverer," by Professor
     John Tyndall (his successor) depicts a mind of the rarest ability
     and a character of the utmost charm. This biography is published by
     D. Appleton & Co., New York: the extracts which follow are from the
     third chapter.]


In 1831 we have Faraday at the climax of his intellectual strength,
forty years of age, stored with knowledge and full of original power.
Through reading, lecturing, and experimenting, he had become thoroughly
familiar with electrical science: he saw where light was needed and
expansion possible. The phenomena of ordinary electric induction
belonged, as it were, to the alphabet of his knowledge: he knew that
under ordinary circumstances the presence of an electrified body was
sufficient to excite, by induction, an unelectrified body. He knew that
the wire which carried an electric current was an electrified body, and
still that all attempts had failed to make it excite in other wires a
state similar to its own.

What was the reason of this failure? Faraday never could work from the
experiments of others, however clearly described. He knew well that from
every experiment issues a kind of radiation, luminous, in different
degrees to different minds, and he hardly trusted himself to reason upon
an experiment that he had not seen. In the autumn of 1831 he began to
repeat the experiments with electric currents, which, up to that time,
had produced no positive result. And here, for the sake of younger
inquirers, if not for the sake of us all, it is worth while to dwell for
a moment on a power which Faraday possessed in an extraordinary degree.
He united vast strength with perfect flexibility. His momentum was that
of a river, which combines weight and directness with the ability to
yield to the flexures of its bed. The intentness of his vision in any
direction did not apparently diminish his power of perception in other
directions; and when he attacked a subject, expecting results, he had
the faculty of keeping his mind alert, so that results different from
those which he expected should not escape him through pre-occupation.

He began his experiments "on the induction of electric currents" by
composing a helix of two insulated wires, which were wound side by side
round the same wooden cylinder. One of these wires he connected with a
voltaic battery of ten cells, and the other with a sensitive
galvanometer. When connection with the battery was made, and while the
current flowed, no effect whatever was observed at the galvanometer.
But he never accepted an experimental result, until he had applied to
it the utmost power at his command. He raised his battery from ten cells
to one hundred and twenty cells, but without avail. The current flowed
calmly through the battery wire without producing, during its flow, any
sensible result upon the galvanometer.

"During its flow," and this was the time when an effect was
expected--but here Faraday's power of lateral vision, separating, as it
were from the line of expectation, came into play--he noticed that a
feeble movement of the needle always occurred at the moment when he made
contact with the battery; that the needle would afterwards return to its
former position and remain quietly there unaffected by the _flowing_
current. At the moment, however, when the circuit was interrupted the
needle again moved, and in a direction opposed to that observed on the
completion of the circuit.

This result, and others of a similar kind, led him to the conclusion
"that the battery current through the one wire did in reality induce a
similar current through the other; but that it continued for an instant
only, and partook more of the nature of the electric wave from a common
Leyden jar than of the current from a voltaic battery." The momentary
currents thus generated were called _induced currents_, while the
current which generated them was called the _inducing_ current. It was
immediately proved that the current generated at making the circuit was
always opposed in direction to its generator, while that developed on
the rupture of the circuit coincided in direction with the inducing
current. It appeared as if the current on its first rush through the
primary wire sought a purchase in the secondary one, and, by a kind of
kick, impelled backward through the latter an electric wave, which
subsided as soon as the primary current was fully established.

Faraday, for a time, believed that the secondary wire, though quiescent
when the primary current had been once established, was not in its
natural condition, its return to that condition being declared by the
current observed at breaking the circuit. He called this hypothetical
state of the wire the _electro-tonic state_: he afterwards abandoned
this hypothesis, but seemed to return to it in after life. The term
electro-tonic is also preserved by Professor Du Bois Reymond to express
a certain electric condition of the nerves, and Professor Clerk Maxwell
has ably defined and illustrated the hypothesis in the Tenth Volume of
the "Transactions of the Cambridge Philosophical Society."

The mere approach of a wire forming a closed curve to a second wire
through which a voltaic current flowed was then shown by Faraday to be
sufficient to arouse in the neutral wire an induced current, opposed in
direction to the inducing current; the withdrawal of the wire also
generated a current having the same direction as the inducing current;
those currents existed only during the time of approach or withdrawal,
and when neither the primary nor the secondary wire was in motion, no
matter how close their proximity might be, no induced current was
generated.

Faraday has been called a purely inductive philosopher. A great deal of
nonsense is, I fear, uttered in this land of England about induction and
deduction. Some profess to befriend the one, some the other, while the
real vocation of an investigator, like Faraday, consists in the
incessant marriage of both. He was at this time full of the theory of
Ampere, and it cannot be doubted that numbers of his experiments were
executed merely to test his deductions from that theory. Starting from
the discovery of Oersted, the celebrated French philosopher had shown
that all the phenomena of magnetism then known might be reduced to the
mutual attractions and repulsions of electric currents. Magnetism had
been produced from electricity, and Faraday, who all his life long
entertained a strong belief in such reciprocal actions, now attempted to
effect the evolution of electricity from magnetism. Round a welded iron
ring he placed two distinct coils of covered wire, causing the coils to
occupy opposite halves of the ring. Connecting the ends of one of the
coils with a galvanometer, he found that the moment the ring was
magnetized, by sending a current through _the other coil_, the
galvanometer needle whirled round four or five times in succession. The
action, as before, was that of a pulse, which vanished immediately. On
interrupting the current, a whirl of the needle in the opposite
direction occurred. It was only during the time of magnetization or
demagnetization that these effects were produced. The induced currents
declared a _change_ of condition only, and they vanished the moment the
act of magnetization or demagnetization was complete.

The effects obtained with the welded ring were also obtained with
straight bars of iron. Whether the bars were magnetized by the electric
current, or were excited by the contact of permanent steel magnets,
induced currents were always generated during the rise, and during the
subsidence of the magnetism. The use of iron was then abandoned, and the
same effects were obtained by merely thrusting a permanent steel magnet
into a coil of wire. A rush of electricity through the coil accompanied
the insertion of the magnet; an equal rush in the opposite direction
accompanied its withdrawal. The precision with which Faraday describes
these results, and the completeness with which he defined the boundaries
of his facts, are wonderful. The magnet, for example, must not be passed
quite through the coil, but only half through, for if passed wholly
through, the needle is stopped as by a blow, and then he shows how this
blow results from a reversal of the electric wave in the helix. He next
operated with the powerful permanent magnet of the Royal Society, and
obtained with it, in an exalted degree, all the foregoing phenomena.

And now he turned the light of these discoveries upon the darkest
physical phenomenon of that day. Arago had discovered in 1824, that a
disk of non-magnetic metal had the power of bringing a vibrating
magnetic needle suspended over it rapidly to rest; and that on causing
the disk to rotate the magnetic needle rotated along with it. When both
were quiescent, there was not the slightest measurable attraction or
repulsion exerted between the needle and the disk; still when in motion
the disk was competent to drag after it, not only a light needle, but a
heavy magnet. The question had been probed and investigated with
admirable skill by both Arago and Ampere, and Poisson had published a
theoretic memoir on the subject; but no cause could be assigned for so
extraordinary an action. It had also been examined in this country by
two celebrated men, Mr. Babbage and Sir John Herschel; but it still
remained a mystery. Faraday always recommended the suspension of
judgment in cases of doubt. "I have always admired," he says, "the
prudence and philosophical reserve shown by M. Arago in resisting the
temptations to give a theory of the effect he had discovered, so long as
he could not devise one which was perfect in its application, and in
refusing to assent to the imperfect theories of others." Now, however,
the time for theory had come. Faraday saw mentally the rotating disk,
under the operation of the magnet, flooded with his induced currents,
and from the known laws of interaction between currents and magnets he
hoped to deduce the motion observed by Arago. That hope he realized,
showing by actual experiment that when his disk rotated currents passed
through it, their position and direction being such as must, in
accordance with the established laws of electro-magnetic action, produce
the observed rotation.

Introducing the edge of his disk between the poles of the large
horseshoe magnet of the Royal Society, and connecting the axis and the
edge of the disk, each by a wire with a galvanometer, he obtained, when
the disk was turned round, a constant flow of electricity. The direction
of the current was determined by the direction of the motion, the
current being reversed when the rotation was reversed. He now states the
law which rules the production of currents in both disks and wires, and
in so doing uses, for the first time, a phrase which has since become
famous. When iron filings are scattered over a magnet, the particles of
iron arrange themselves in certain determined lines called magnetic
curves. In 1831, Faraday for the first time called these curves "lines
of magnetic force;" and he showed that to produce induced currents
neither approach to nor withdrawal from a magnetic source, or centre, or
pole, was essential, but that it was only necessary to cut appropriately
the lines of magnetic force. Faraday's first paper on Magneto-electric
Induction, which I have here endeavoured to condense, was read before
the Royal Society on the 24th of November, 1831.

On January 12, 1832, he communicated to the Royal Society a second paper
on "Terrestrial Magneto-electric Induction," which was chosen as the
Bakerian Lecture for the year. He placed a bar of iron in a coil of
wire, and lifting the bar into the direction of the dipping needle, he
excited by this action a current in the coil. On reversing the bar, a
current in the opposite direction rushed through the wire. The same
effect was produced, when, on holding the helix in the line of dip, a
bar of iron was thrust into it. Here, however, the earth acted on the
coil through the intermediation of the bar of iron. He abandoned the bar
and simply set a copper-plate spinning in a horizontal plane; he knew
that the earth's lines of magnetic force then crossed the plate at an
angle of about 70 deg.. When the plate spun round, the lines of force were
intersected and induced currents generated, which produced their proper
effect when carried from the plate to the galvanometer. "When the plate
was in the magnetic meridian, or in any other plane coinciding with the
magnetic dip, then its rotation produced no effect upon the
galvanometer."

At the suggestion of a mind fruitful in suggestions of a profound and
philosophic character--I mean that of Sir John Herschel--Mr. Barlow, of
Woolwich, had experimented with a rotating iron shell. Mr. Christie had
also performed an elaborate series of experiments on a rotating iron
disk. Both of them had found that when in rotation the body exercised a
peculiar action upon the magnetic needle, deflecting it in a manner
which was not observed during quiescence; but neither of them was aware
at the time of the agent which produced this extraordinary deflection.
They ascribed it to some change in the magnetism of the iron shell and
disk.

But Faraday at once saw that his induced currents must come into play
here, and he immediately obtained them from an iron disk. With a hollow
brass ball, moreover, he produced the effects obtained by Mr. Barlow.
Iron was in no way necessary: the only condition of success was that the
rotating body should be of a character to admit of the formation of
currents in its substance: it must, in other words, be a conductor of
electricity. The higher the conducting power the more copious were the
currents. He now passes from his little brass globe to the globe of the
earth. He plays like a magician with the earth's magnetism. He sees the
invisible lines along which its magnetic action is exerted and sweeping
his wand across these lines evokes this new power. Placing a simple loop
of wire round a magnetic needle he bends its upper portion to the west:
the north pole of the needle immediately swerves to the east: he bends
his loop to the east, and the north poles moves to the west. Suspending
a common bar magnet in a vertical position, he causes it to spin round
its own axis. Its pole being connected with one end of a galvanometer
wire, and its equator with the other end, electricity rushes round the
galvanometer from the rotating magnet. He remarks upon the "_singular
independence_" of the magnetism and the body of the magnet which carries
it. The steel behaves as if it were isolated from its own magnetism.

And then his thoughts suddenly widen, and he asks himself whether the
rotating earth does not generate induced currents as it turns round its
axis from west to east. In his experiment with the twirling magnet the
galvanometer wire remained at rest; one portion of the circuit was in
motion _relatively_ to _another portion_. But in the case of the
twirling planet the galvanometer wire would necessarily be carried along
with the earth; there would be no relative motion. What must be the
consequence? Take the case of a telegraph wire with its two terminal
plates dipped into the earth, and suppose the wire to lie in the
magnetic meridian. The ground underneath the wire is influenced like the
wire itself by the earth's rotation; if a current from south to north be
generated in the wire, a similar current from south to north would be
generated in the earth under the wire; these currents would run against
the same terminal plates, and thus neutralize each other.

This inference appears inevitable, but his profound vision perceived its
possible invalidity. He saw that it was at least possible that the
difference of conducting power between the earth and the wire might
give one an advantage over the other, and that thus a residual or
differential current might be obtained. He combined wires of different
materials, and caused them to act in opposition to each other, but found
the combination ineffectual. The more copious flow in the better
conductor was exactly counterbalanced by the resistance of the worst.
Still, though experiment was thus emphatic, he would clear his mind of
all discomfort by operating on the earth itself. He went to the round
lake near Kensington Palace, and stretched four hundred and eighty feet
of copper wire, north and south, over the lake, causing plates soldered
to the wire at its ends to dip into the water. The copper wire was
severed at the middle, and the severed ends connected with a
galvanometer. No effect whatever was observed. But though quiescent
water gave no effect, moving water might. He therefore worked at London
Bridge for three days during the ebb and flow of the tide, but without
any satisfactory result. Still he urges, "Theoretically it seems a
necessary consequence, that where water is flowing there electric
currents should be formed. If a line be imagined passing from Dover to
Calais through the sea, and returning through the land, beneath the
water, to Dover, it traces out a circuit of conducting matter one part
of which, when the water moves up or down the channel, is cutting the
magnetic curves of the earth, while the other is relatively at rest....
There is every reason to believe that currents do run in the general
direction of the circuit described, either one way or the other,
according as the passage of the waters is up or down the channel." This
was written before the submarine cable was thought of, and he once
informed me that actual observation upon that cable had been found to be
in accordance with his theoretic deduction.

Three years subsequent to the publication of these researches, that is
to say on January 29, 1835, Faraday read before the Royal Society a
paper "On the influence by induction of an electric current upon
itself." A shock and spark of a peculiar character had been observed by
a young man named William Jenkin, who must have been a youth of some
scientific promise, but who, as Faraday once informed me, was dissuaded
by his own father from having anything to do with science. The
investigation of the fact noticed by Mr. Jenkin led Faraday to the
discovery of the _extra current_, or the current _induced in the primary
wire itself_ at the moments of making and breaking contact, the
phenomena of which he described and illustrated in the beautiful and
exhaustive paper referred to.

Seven and thirty years have passed since the discovery of
magneto-electricity; but, if we except the _extra current_, until quite
recently nothing of moment was added to the subject. Faraday entertained
the opinion that the discoverer of a great law or principle had a right
to the "spoils"--this was his term--arising from its illustration; and
guided by the principle he had discovered, his wonderful mind, aided by
his wonderful ten fingers, overran in a single autumn this vast domain,
and hardly left behind him the shred of a fact to be gathered by his
successors.

And here the question may arise in some minds, What is the use of it
all? The answer is, that if man's intellectual nature thirsts for
knowledge then knowledge is useful because it satisfies this thirst. If
you demand practical ends, you must, I think, expand your definition of
the term practical, and make it include all that elevates and enlightens
the intellect, as well as all that ministers to the bodily health and
comfort of men. Still, if needed, an answer of another kind might be
given to the question "what is its use?" As far as electricity has been
applied for medical purposes, it has been almost exclusively Faraday's
electricity. You have noticed those lines of wire which cross the
streets of London. It is Faraday's currents that speed from place to
place through these wires. Approaching the point of Dungeness, the
mariner sees an unusually brilliant light, and from the noble lighthouse
of La Heve the same light flashes across the sea. These are Faraday's
sparks exalted by suitable machinery to sun-like splendour. At the
present moment the Board of Trade and the Brethren of the Trinity House,
as well as the Commissioners of Northern Lights, are contemplating the
introduction of the Magneto-electric Light at numerous points upon our
coasts; and future generations will be able to refer to those guiding
stars in answer to the question, what has been the practical use of the
labours of Faraday? But I would again emphatically say, that his work
needs no justification, and that if he had allowed his vision to be
disturbed by considerations regarding the practical use of his
discoveries, those discoveries would never have been made by him. "I
have rather," he writes in 1831, "been desirous of discovering new facts
and new relations dependent on magneto-electric induction, than of
exalting the force of those already obtained; being assured that the
latter would find their full development hereafter."

In 1817, when lecturing before a private society in London on the
element chlorine, Faraday thus expresses himself with reference to this
question of utility. "Before leaving this subject, I will point out the
history of this substance as an answer to those who are in the habit of
saying to every new fact, 'What is its use?' Dr. Franklin says to such,
'What is the use of an infant?' The answer of the experimentalist is,
'Endeavour to make it useful.' When Scheele discovered this substance,
it appeared to have no use; it was in its infancy and useless state, but
having grown up to maturity, witness its powers, and see what endeavours
to make it useful have done."




PROFESSOR JOSEPH HENRY'S INVENTION OF THE ELECTRIC TELEGRAPH

     [In 1855 the Regents of the Smithsonian Institution, Washington, D.
     C., at the instance of their secretary, Professor Joseph Henry,
     took evidence with respect to his claims as inventor of the
     electric telegraph. The essential paragraphs of Professor Henry's
     statement are taken from the Proceedings of the Board of Regents of
     the Smithsonian Institution, Washington, 1857.]


There are several forms of the electric telegraph; first, that in which
frictional electricity has been proposed to produce sparks and motion of
pith balls at a distance.

Second, that in which galvanism has been employed to produce signals by
means of bubbles of gas from the decomposition of water.

Third, that in which electro-magnetism is the motive power to produce
motion at a distance; and again, of the latter there are two kinds of
telegraphs, those in which the intelligence is indicated by the motion
of a magnetic needle, and those in which sounds and permanent signs are
made by the attraction of an electro-magnet. The latter is the class to
which Mr. Morse's invention belongs. The following is a brief exposition
of the several steps which led to this form of the telegraph.

The first essential fact which rendered the electro-magnetic telegraph
possible was discovered by Oersted, in the winter of 1819-'20. It is
illustrated by figure 1, in which the magnetic needle is deflected by
the action of a current of galvanism transmitted through the wire A B.

[Illustration: Fig. 1]

The second fact of importance, discovered in 1820, by Arago and Davy, is
illustrated in Fig. 2. It consists in this, that while a current of
galvanism is passing through a copper wire A B, it is magnetic, it
attracts iron filings and not those of copper or brass, and is capable
of developing magnetism in soft iron.

[Illustration: Fig. 2]

The next important discovery, also made in 1820, by Ampere, was that two
wires through which galvanic currents are passing in the same direction
attract, and in the opposite direction, repel, each other. On this fact
Ampere founded his celebrated theory, that magnetism consists merely in
the attraction of electrical currents revolving at right angles to the
line joining the two poles of the magnet. The magnetization of a bar of
steel or iron, according to this theory consists in establishing within
the metal by induction a series of electrical currents, all revolving in
the same direction at right angles to the axis or length of the bar.

[Illustration: Fig. 3]

It was this theory which led Arago, as he states, to adopt the method of
magnetizing sewing needles and pieces of steel wire, shown in Fig. 3.
This method consists in transmitting a current of electricity through a
helix surrounding the needle or wire to be magnetised. For the purpose
of insulation the needle was enclosed in a glass tube, and the several
turns of the helix were at a distance from each other to insure the
passage of electricity through the whole length of the wire, or, in
other words, to prevent it from seeking a shorter passage by cutting
across from one spire to another. The helix employed by Arago obviously
approximates the arrangement required by the theory of Ampere, in order
to develop by induction the magnetism of the iron. By an attentive
perusal of the original account of the experiments of Arago, it will be
seen that, properly speaking, he made no electro-magnet, as has been
asserted by Morse and others; his experiments were confined to the
magnetism of iron filings, to sewing needles and pieces of steel wire of
the diameter of a millimetre, or of about the thickness of a small
knitting needle.

[Illustration: Fig. 4]

Mr. Sturgeon, in 1825, made an important step in advance of the
experiments of Arago, and produced what is properly known as the
electro-magnet. He bent a piece of iron _wire_ into the form of a
horseshoe, covered it with varnish to insulate it, and surrounded it
with a helix, of which the spires were at a distance. When a current of
galvanism was passed through the helix from a small battery of a single
cup the iron wire became magnetic, and continued so during the passage
of the current. When the current was interrupted the magnetism
disappeared, and thus was produced the first temporary soft iron
magnet.

The electro-magnet of Sturgeon is shown in Fig. 4. By comparing Figs. 3
and 4 it will be seen that the helix employed by Sturgeon was of the
same kind as that used by Arago; instead however, of a straight steel
wire inclosed in a tube of glass, the former employed a bent wire of
soft iron. The difference in the arrangement at first sight might appear
to be small, but the difference in the results produced was important,
since the temporary magnetism developed in the arrangement of Sturgeon
was sufficient to support a weight of several pounds, and an instrument
was thus produced of value in future research.

[Illustration: Fig. 5]

The next improvement was made by myself. After reading an account of the
galvanometer of Schweigger, the idea occurred to me that a much nearer
approximation to the requirements of the theory of Ampere could be
attained by insulating the conducting wire itself, instead of the rod to
be magnetized, and by covering the whole surface of the iron with a
series of coils in close contact. This was effected by insulating a long
wire with silk thread, and winding this around the rod of iron in close
coils from one end to the other. The same principle was extended by
employing a still longer insulated wire, and winding several strata of
this over the first, care being taken to insure the insulation between
each stratum by a covering of silk ribbon. By this arrangement the rod
was surrounded by a compound helix formed of a long wire of many coils,
instead of a single helix of a few coils, (Fig. 5).

In the arrangement of Arago and Sturgeon the several turns of wire were
not precisely at right angles to the axis of the rod, as they should be,
to produce the effect required by the theory, but slightly oblique, and
therefore each tended to develop a separate magnetism not coincident
with the axis of the bar. But in winding the wire over itself, the
obliquity of the several turns compensated each other, and the resultant
action was at right angles to the bar. The arrangement then introduced
by myself was superior to those of Arago and Sturgeon, first in the
greater multiplicity of turns of wire, and second in the better
application of these turns to the development of magnetism. The power of
the instrument with the same amount of galvanic force, was by this
arrangement several times increased.

The maximum effect, however, with this arrangement and a single battery
was not yet obtained. After a certain length of wire had been coiled
upon the iron, the power diminished with a further increase of the
number of turns. This was due to the increased resistance which the
longer wire offered to the conduction of electricity. Two methods of
improvement therefore suggested themselves. The first consisted, not in
increasing the length of the coil, but in using a number of separate
coils on the same piece of iron. By this arrangement the resistance to
the conduction of the electricity was diminished and a greater quantity
made to circulate around the iron from the same battery. The second
method of producing a similar result consisted in increasing the number
of elements of the battery, or, in other words, the projectile force of
the electricity, which enabled it to pass through an increased number of
turns of wire, and thus, by increasing the length of the wire, to
develop the maximum power of the iron.

[Illustration: Fig. 6]

To test these principles on a larger scale, the experimental magnet was
constructed, which is shown in Fig. 6. In this a number of compound
helices were placed on the same bar, their ends left projecting, and so
numbered that they could be all united into one long helix, or variously
combined in sets of lesser length.

From a series of experiments with this and other magnets it was proved
that, in order to produce the greatest amount of magnetism from a
battery of a single cup, a number of helices is required; but when a
compound battery is used, then one long wire must be employed, making
many turns around the iron, the length of wire and consequently the
number of turns being commensurate with the projectile power of the
battery.

In describing the results of my experiments, the terms _intensity_ and
_quantity_ magnets were introduced to avoid circumlocution, and were
intended to be used merely in a technical sense. By the _intensity_
magnet I designated a piece of soft iron, so surrounded with wire that
its magnetic power could be called into operation by an _intensity_
battery, and by a _quantity_ magnet, a piece of iron so surrounded by a
number of separate coils, that its magnetism could be fully developed by
a _quantity_ battery.

I was the first to point out this connection of the two kinds of the
battery with the two forms of the magnet, in my paper in _Silliman's
Journal_, January, 1831, and clearly to state that when magnetism was to
be developed by means of a compound battery, one long coil was to be
employed, and when the maximum effect was to be produced by a single
battery, a number of single strands were to be used.

These steps in the advance of electro-magnetism, though small, were such
as to interest and astonish the scientific world. With the same battery
used by Mr. Sturgeon, at least a hundred times more magnetism was
produced than could have been obtained by his experiment. The
developments were considered at the time of much importance in a
scientific point of view, and they subsequently furnished the means by
which magneto-electricity, the phenomena of dia-magnetism, and the
magnetic effects on polarized light were discovered. They gave rise to
the various forms of electro-magnetic machines which have since
exercised the ingenuity of inventors in every part of the world, and
were of immediate applicability in the introduction of the magnet to
telegraphic purposes. Neither the electro-magnet of Sturgeon nor any
electro-magnet ever made previous to my investigations was applicable to
transmitting power to a distance.

The principles I have developed were properly appreciated by the
scientific mind of Dr. Gale, and applied by him to operate Mr. Morse's
machine at a distance.

Previous to my investigations the means of developing magnetism in soft
iron were imperfectly understood. The electro-magnet made by Sturgeon,
and copied by Dana, of New York, was an imperfect quantity magnet, the
feeble power of which was developed by a single battery. It was entirely
inapplicable to a long circuit with an intensity battery, and no person
possessing the requisite scientific knowledge, would have attempted to
use it in that connection after reading my paper.

In sending a message to a distance, two circuits are employed, the
first a long circuit through which the electricity is sent to the
distant station to bring into action the second, a short one, in which
is the local battery and magnet for working the machine. In order to
give projectile force sufficient to send the power to a distance, it is
necessary to use an intensity battery in the long circuit, and in
connection with this, at the distant station, a magnet surrounded with
many turns of one long wire must be employed to receive and multiply the
effect of the current enfeebled by its transmission through the long
conductor. In the local or short circuit either an intensity or a
quantity magnet may be employed. If the first be used, then with it a
compound battery will be required; and, therefore on account of the
increased resistance due to the greater quantity of acid, a less amount
of work will be performed by a given amount of material; and,
consequently, though this arrangement is practicable it is by no means
economical. In my original paper I state that the advantages of a
greater conducting power, from using several wires in the quantity
magnet, may, in a less degree, be obtained by substituting for them one
large wire; but in this case, on account of the greater obliquity of the
spires and other causes, the magnetic effect would be less. In
accordance with these principles, the receiving magnet, or that which is
introduced into the long circuit, consists of a horseshoe magnet
surrounded with many hundred turns of a single long wire, and is
operated with a battery of from twelve to twenty-four elements or more,
while in the local circuit it is customary to employ a battery of one or
two elements with a much thicker wire and fewer turns.

It will, I think, be evident to the impartial reader that these were
improvements in the electro-magnet, which first rendered it adequate to
the transmission of mechanical power to a distance; and had I omitted
all allusion to the telegraph in my paper, the conscientious historian
of science would have awarded me some credit, however small might have
been the advance which I made. Arago and Sturgeon, in the accounts of
their experiments, make no mention of the telegraph, and yet their names
always have been and will be associated with the invention. I briefly,
however, called attention to the fact of the applicability of my
experiments to the construction of the telegraph; but not being familiar
with the history of the attempts made in regard to this invention, I
called it "Barlow's project," while I ought to have stated that Mr.
Barlow's investigation merely tended to disprove the possibility of a
telegraph.

I did not refer exclusively to the needle telegraph when, in my paper, I
stated that the _magnetic_ action of a current from a trough is at least
not sensibly diminished by passing through a long wire. This is evident
from the fact that the immediate experiment from which this deduction
was made was by means of an electro-magnet and not by means of a needle
galvanometer.

[Illustration: Fig. 7]

At the conclusion of the series of experiments which I described in
_Silliman's Journal_, there were two applications of the electro-magnet
in my mind: one the production of a machine to be moved by
electro-magnetism, and the other the transmission of or calling into
action power at a distance. The first was carried into execution in the
construction of the machine described in _Silliman's Journal_, vol. xx,
1831, and for the purpose of experimenting in regard to the second, I
arranged around one of the upper rooms in the Albany Academy a wire of
more than a mile in length, through which I was enabled to make signals
by sounding a bell, (Fig. 7.) The mechanical arrangement for effecting
this object was simply a steel bar, permanently magnetized, of about ten
inches in length, supported on a pivot, and placed with its north end
between the two arms of a horseshoe magnet. When the latter was excited
by the current, the end of the bar thus placed was attracted by one arm
of the horseshoe, and repelled by the other, and was thus caused to move
in a horizontal plane and its further extremity to strike a bell
suitably adjusted.

I also devised a method of breaking a circuit, and thereby causing a
large weight to fall. It was intended to illustrate the practicability
of calling into action a great power at a distance capable of producing
mechanical effects; but as a description of this was not printed, I do
not place it in the same category with the experiments of which I
published an account, or the facts which could be immediately deduced
from my papers in _Silliman's Journal_.

From a careful investigation of the history of electro-magnetism in its
connection with the telegraph, the following facts may be established:

1. Previous to my investigations the means of developing magnetism in
soft iron were imperfectly understood, and the electro-magnet which then
existed was inapplicable to the transmission of power to a distance.

2. I was the first to prove by actual experiment that, in order to
develop magnetic power at a distance, a galvanic battery of intensity
must be employed to project the current through the long conductor, and
that a magnet surrounded by many turns of one long wire must be used to
receive this current.

3. I was the first actually to magnetize a piece of iron at a distance,
and to call attention to the fact of the applicability of my experiments
to the telegraph.

4. I was the first to actually sound a bell at a distance by means of
the electro-magnet.

5. The principles I had developed were applied by Dr. Gale to render
Morse's machine effective at a distance.




THE FIRST ATLANTIC CABLES

GEORGE ILES

     [From "Flame, Electricity and the Camera," copyright Doubleday,
     Page & Co., New York.]


Electric telegraphy on land has put a vast distance between itself and
the mechanical signalling of Chappe, just as the scope and availability
of the French invention are in high contrast with the rude signal fires
of the primitive savage. As the first land telegraphs joined village to
village, and city to city, the crossing of water came in as a minor
incident; the wires were readily committed to the bridges which spanned
streams of moderate width. Where a river or inlet was unbridged, or a
channel was too wide for the roadway of the engineer, the question
arose, May we lay an electric wire under water? With an ordinary land
line, air serves as so good a non-conductor and insulator that as a rule
cheap iron may be employed for the wire instead of expensive copper. In
the quest for non-conductors suitable for immersion in rivers, channels,
and the sea, obstacles of a stubborn kind were confronted. To overcome
them demanded new materials, more refined instruments, and a complete
revision of electrical philosophy.

As far back as 1795, Francisco Salva had recommended to the Academy of
Sciences, Barcelona, the covering of subaqueous wires by resin, which
is both impenetrable by water and a non-conductor of electricity.
Insulators, indeed, of one kind and another, were common enough, but
each of them was defective in some quality indispensable for success.
Neither glass nor porcelain is flexible, and therefore to lay a
continuous line of one or the other was out of the question. Resin and
pitch were even more faulty, because extremely brittle and friable. What
of such fibres as hemp or silk, if saturated with tar or some other good
non-conductor? For very short distances under still water they served
fairly well, but any exposure to a rocky beach with its chafing action,
any rub by a passing anchor, was fatal to them. What the copper wire
needed was a covering impervious to water, unchangeable in composition
by time, tough of texture, and non-conducting in the highest degree.
Fortunately all these properties are united in gutta-percha: they exist
in nothing else known to art. Gutta-percha is the hardened juice of a
large tree (_Isonandra gutta_) common in the Malay Archipelago; it is
tough and strong, easily moulded when moderately heated. In comparison
with copper it is but one 60,000,000,000,000,000,000th as conductive. As
without gutta-percha there could be no ocean telegraphy, it is worth
while recalling how it came within the purview of the electrical
engineer.

In 1843 Jose d'Almeida, a Portuguese engineer, presented to the Royal
Asiatic Society, London, the first specimens of gutta-percha brought to
Europe. A few months later, Dr. W. Montgomerie, a surgeon, gave other
specimens to the Society of Arts, of London, which exhibited them; but
it was four years before the chief characteristic of the gum was
recognized. In 1847 Mr. S. T. Armstrong of New York, during a visit to
London, inspected a pound or two of gutta-percha, and found it to be
twice as good a non-conductor as glass. The next year, through his
instrumentality, a cable covered with this new insulator was laid
between New York and Jersey City; its success prompted Mr Armstrong to
suggest that a similarly protected cable be submerged between America
and Europe. Eighteen years of untiring effort, impeded by the errors
inevitable to the pioneer, stood between the proposal and its
fulfilment. In 1848 the Messrs. Siemens laid under water in the port of
Kiel a wire covered with seamless gutta-percha, such as, beginning with
1847, they had employed for subterranean conductors. This particular
wire was not used for telegraphy, but formed part of a submarine-mine
system. In 1849 Mr. C. V. Walker laid an experimental line in the
English Channel; he proved the possibility of signalling for two miles
through a wire covered with gutta-percha, and so prepared the way for a
venture which joined the shores of France and England.

[Illustration: Fig. 58.--Calais-Dover cable, 1851]

In 1850 a cable twenty-five miles in length was laid from Dover to
Calais, only to prove worthless from faulty insulation and the lack of
armour against dragging anchors and fretting rocks. In 1851 the
experiment was repeated with success. The conductor now was not a single
wire of copper, but four wires, wound spirally, so as to combine
strength with flexibility; these were covered with gutta-percha and
surrounded with tarred hemp. As a means of imparting additional
strength, ten iron wires were wound round the hemp--a feature which has
been copied in every subsequent cable (Fig. 58). The engineers were fast
learning the rigorous conditions of submarine telegraphy; in its
essentials the Dover-Calais line continues to be the type of deep-sea
cables to-day. The success of the wire laid across the British Channel
incited other ventures of the kind. Many of them, through careless
construction or unskilful laying, were utter failures. At last, in 1855,
a submarine line 171 miles in length gave excellent service, as it
united Varna with Constantinople; this was the greatest length of
satisfactory cable until the submergence of an Atlantic line.

In 1854 Cyrus W. Field of New York opened a new chapter in electrical
enterprise as he resolved to lay a cable between Ireland and
Newfoundland, along the shortest line that joins Europe to America. He
chose Valentia and Heart's Content, a little more than 1,600 miles
apart, as his termini, and at once began to enlist the co-operation of
his friends. Although an unfaltering enthusiast when once his great idea
had possession of him, Mr. Field was a man of strong common sense. From
first to last he went upon well-ascertained facts; when he failed he did
so simply because other facts, which he could not possibly know, had to
be disclosed by costly experience. Messrs. Whitehouse and Bright,
electricians to his company, were instructed to begin a preliminary
series of experiments. They united a continuous stretch of wires laid
beneath land and water for a distance of 2,000 miles, and found that
through this extraordinary circuit they could transmit as many as four
signals per second. They inferred that an Atlantic cable would offer but
little more resistance, and would therefore be electrically workable and
commercially lucrative.

In 1857 a cable was forthwith manufactured, divided in halves, and
stowed in the holds of the _Niagara_ of the United States navy, and the
_Agamemnon_ of the British fleet. The _Niagara_ sailed from Ireland; the
sister ship proceeded to Newfoundland, and was to meet her in mid-ocean.
When the _Niagara_ had run out 335 miles of her cable it snapped under
a sudden increase of strain at the paying-out machinery; all attempts at
recovery were unavailing, and the work for that year was abandoned. The
next year it was resumed, a liberal supply of new cable having been
manufactured to replace the lost section, and to meet any fresh
emergency that might arise. A new plan of voyages was adopted: the
vessels now sailed together to mid-sea, uniting there both portions of
the cable; then one ship steamed off to Ireland, the other to the
Newfoundland coast. Both reached their destinations on the same day,
August 5, 1858, and, feeble and irregular though it was, an electric
pulse for the first time now bore a message from hemisphere to
hemisphere. After 732 despatches had passed through the wire it became
silent forever. In one of these despatches from London, the War Office
countermanded the departure of two regiments about to leave Canada for
England, which saved an outlay of about $250,000. This widely quoted
fact demonstrated with telling effect the value of cable telegraphy.

Now followed years of struggle which would have dismayed any less
resolute soul than Mr. Field. The Civil War had broken out, with its
perils to the Union, its alarms and anxieties for every American heart.
But while battleships and cruisers were patrolling the coast from Maine
to Florida, and regiments were marching through Washington on their way
to battle, there was no remission of effort on the part of the great
projector.

Indeed, in the misunderstandings which grew out of the war, and that at
one time threatened international conflict, he plainly saw how a cable
would have been a peace-maker. A single word of explanation through its
wire, and angry feelings on both sides of the ocean would have been
allayed at the time of the _Trent_ affair. In this conviction he was
confirmed by the English press; the London _Times_ said: "We nearly went
to war with America because we had no telegraph across the Atlantic." In
1859 the British government had appointed a committee of eminent
engineers to inquire into the feasibility of an Atlantic telegraph, with
a view to ascertaining what was wanting for success, and with the
intention of adding to its original aid in case the enterprise were
revived. In July, 1863, this committee presented a report entirely
favourable in its terms, affirming "that a well-insulated cable,
properly protected, of suitable specific gravity, made with care, tested
under water throughout its progress with the best-known apparatus, and
paid into the ocean with the most improved machinery, possesses every
prospect of not only being successfully laid in the first instance, but
may reasonably be relied upon to continue for many years in an efficient
state for the transmission of signals."

Taking his stand upon this endorsement, Mr. Field now addressed himself
to the task of raising the large sum needed to make and lay a new cable
which should be so much better than the old ones as to reward its owners
with triumph. He found his English friends willing to venture the
capital required, and without further delay the manufacture of a new
cable was taken in hand. In every detail the recommendations of the
Scientific Committee were carried out to the letter, so that the cable
of 1865 was incomparably superior to that of 1858. First, the central
copper wire, which was the nerve along which the lightning was to run,
was nearly three times larger than before. The old conductor was a
strand consisting of seven fine wires, six laid around one, and weighed
but 107 pounds to the mile. The new was composed of the same number of
wires, but weighed 300 pounds to the mile. It was made of the finest
copper obtainable.

To secure insulation, this conductor was first embedded in Chatterton's
compound, a preparation impervious to water, and then covered with four
layers of gutta-percha, which were laid on alternately with four thin
layers of Chatterton's compound. The old cable had but three coatings of
gutta-percha, with nothing between. Its entire insulation weighed but
261 pounds to the mile, while that of the new weighed 400 pounds.[1] The
exterior wires, ten in number, were of Bessemer steel, each separately
wound in pitch-soaked hemp yarn, the shore ends specially protected by
thirty-six wires girdling the whole. Here was a combination of the
tenacity of steel with much of the flexibility of rope. The insulation
of the copper was so excellent as to exceed by a hundredfold that of the
core of 1858--which, faulty though it was, had, nevertheless, sufficed
for signals. So much inconvenience and risk had been encountered in
dividing the task of cable-laying between two ships that this time it
was decided to charter a single vessel, the _Great Eastern_, which,
fortunately, was large enough to accommodate the cable in an unbroken
length. Foilhommerum Bay, about six miles from Valentia, was selected as
the new Irish terminus by the company. Although the most anxious care
was exercised in every detail, yet, when 1,186 miles had been laid, the
cable parted in 11,000 feet of water, and although thrice it was
grappled and brought toward the surface, thrice it slipped off the
grappling hooks and escaped to the ocean floor. Mr. Field was obliged to
return to England and face as best he might the men whose capital lay at
the bottom of the sea--perchance as worthless as so much Atlantic ooze.
With heroic persistence he argued that all difficulties would yield to a
renewed attack. There must be redoubled precautions and vigilance never
for a moment relaxed. Everything that deep-sea telegraphy has since
accomplished was at that moment daylight clear to his prophetic view.
Never has there been a more signal example of the power of enthusiasm to
stir cold-blooded men of business; never has there been a more striking
illustration of how much science may depend for success upon the
intelligence and the courage of capital. Electricians might have gone on
perfecting exquisite apparatus for ocean telegraphy, or indicated the
weak points in the comparatively rude machinery which made and laid the
cable, yet their exertions would have been wasted if men of wealth had
not responded to Mr. Field's renewed appeal for help. Thrice these men
had invested largely, and thrice disaster had pursued their ventures;
nevertheless they had faith surviving all misfortunes for a fourth
attempt.

In 1866 a new company was organized, for two objects: first, to recover
the cable lost the previous year and complete it to the American shore;
second, to lay another beside it in a parallel course. The _Great
Eastern_ was again put in commission, and remodelled in accordance with
the experience of her preceding voyage. This time the exterior wires of
the cable were of galvanized iron, the better to resist corrosion. The
paying-out machinery was reconstructed and greatly improved. On July 13,
1866, the huge steamer began running out her cable twenty-five miles
north of the line struck out during the expedition of 1865; she arrived
without mishap in Newfoundland on July 27, and electrical communication
was re-established between America and Europe. The steamer now returned
to the spot where she had lost the cable a few months before; after
eighteen days' search it was brought to the deck in good order. Union
was effected with the cable stowed in the tanks below, and the prow of
the vessel was once more turned to Newfoundland. On September 8th this
second cable was safely landed at Trinity Bay. Misfortunes now were at
an end; the courage of Mr. Field knew victory at last; the highest
honors of two continents were showered upon him.

    'Tis not the grapes of Canaan that repay,
    But the high faith that failed not by the way.

[Illustration: Fig. 59.--Commercial cable, 1894]

What at first was as much a daring adventure as a business enterprise
has now taken its place as a task no more out of the common than
building a steamship, or rearing a cantilever bridge. Given its price,
which will include too moderate a profit to betray any expectation of
failure, and a responsible firm will contract to lay a cable across the
Pacific itself. In the Atlantic lines the uniformly low temperature of
the ocean floor (about 4 deg. C.), and the great pressure of the
superincumbent sea, co-operate in effecting an enormous enhancement both
in the insulation and in the carrying capacity of the wire. As an
example of recent work in ocean telegraphy let us glance at the cable
laid in 1894, by the Commercial Cable Company of New York. It unites
Cape Canso, on the northeastern coast of Nova Scotia, to Waterville, on
the southwestern coast of Ireland. The central portion of this cable
much resembles that of its predecessor in 1866. Its exterior armour of
steel wires is much more elaborate. The first part of Fig. 59 shows the
details of manufacture: the central copper core is covered with
gutta-percha, then with jute, upon which the steel wires are spirally
wound, followed by a strong outer covering. For the greatest depths at
sea, type _A_ is employed for a total length of 1,420 miles; the
diameter of this part of the cable is seven-eighths of an inch. As the
water lessens in depth the sheathing increases in size until the
diameter of the cable becomes one and one-sixteenth inches for 152
miles, as type _B_. The cable now undergoes a third enlargement, and
then its fourth and last proportions are presented as it touches the
shore, for a distance of one and three-quarter miles, where type _C_ has
a diameter of two and one-half inches. The weights of material used in
this cable are: copper wire, 495 tons; gutta-percha, 315 tons; jute
yarn, 575 tons; steel wire, 3,000 tons; compound and tar, 1,075 tons;
total, 5,460 tons. The telegraph-ship _Faraday_, specially designed for
cable-laying, accomplished the work without mishap.

Electrical science owes much to the Atlantic cables, in particular to
the first of them. At the very beginning it banished the idea that
electricity as it passes through metallic conductors has anything like
its velocity through free space. It was soon found, as Professor
Mendenhall says, "that it is no more correct to assign a definite
velocity to electricity than to a river. As the rate of flow of a river
is determined by the character of its bed, its gradient, and other
circumstances, so the velocity of an electric current is found to depend
on the conditions under which the flow takes place."[2] Mile for mile
the original Atlantic cable had twenty times the retarding effect of a
good aerial line; the best recent cables reduce this figure by nearly
one-half.

In an extreme form, this slowing down reminds us of the obstruction of
light as it enters the atmosphere of the earth, of the further
impediment which the rays encounter if they pass from the air into the
sea. In the main the causes which hinder a pulse committed to a cable
are two: induction, and the electrostatic capacity of the wire, that is,
the capacity of the wire to take up a charge of its own, just as if it
were the metal of a Leyden jar.

Let us first consider induction. As a current takes its way through the
copper core it induces in its surroundings a second and opposing
current. For this the remedy is one too costly to be applied. Were a
cable manufactured in a double line, as in the best telephonic circuits,
induction, with its retarding and quenching effects, would be
neutralized. Here the steel wire armour which encircles the cable plays
an unwelcome part. Induction is always proportioned to the conductivity
of the mass in which it appears; as steel is an excellent conductor, the
armour of an ocean cable, close as it is to the copper core, has induced
in it a current much stronger, and therefore more retarding, than if the
steel wire were absent.

A word now as to the second difficulty in working beneath the sea--that
due to the absorbing power of the line itself. An Atlantic cable, like
any other extended conductor, is virtually a long, cylindrical Leyden
jar, the copper wire forming the inner coat, and its surroundings the
outer coat. Before a signal can be received at the distant terminus the
wire must first be charged. The effect is somewhat like transmitting a
signal through water which fills a rubber tube; first of all the tube
is distended, and its compression, or secondary effect, really transmits
the impulse. A remedy for this is a condenser formed of alternate sheets
of tin-foil and mica, _C_, connected with the battery, _B_, so as to
balance the electric charge of the cable wire (Fig. 60). In the first
Atlantic line an impulse demanded one-seventh of a second for its
journey. This was reduced when Mr. Whitehouse made the capital discovery
that the speed of a signal is increased threefold when the wire is
alternately connected with the zinc and copper poles of the battery. Sir
William Thomson ascertained that these successive pulses are most
effective when of proportioned lengths. He accordingly devised an
automatic transmitter which draws a duly perforated slip of paper under
a metallic spring connected with the cable. To-day 250 to 300 letters
are sent per minute instead of fifteen, as at first.

[Illustration: Fig. 60.--Condenser]

In many ways a deep-sea cable exaggerates in an instructive manner the
phenomena of telegraphy over long aerial lines. The two ends of a cable
may be in regions of widely diverse electrical potential, or pressure,
just as the readings of the barometer at these two places may differ
much. If a copper wire were allowed to offer itself as a gateless
conductor it would equalize these variations of potential with serious
injury to itself. Accordingly the rule is adopted of working the cable
not directly, as if it were a land line, but indirectly through
condensers. As the throb sent through such apparatus is but momentary,
the cable is in no risk from the strong currents which would course
through it if it were permitted to be an open channel.

[Illustration: Fig. 61.--Reflecting galvanometer L, lamp; N, moving spot
of light reflected from mirror]

A serious error in working the first cables was in supposing that they
required strong currents as in land lines of considerable length. The
very reverse is the fact. Mr. Charles Bright, in _Submarine Telegraphs_,
says:

"Mr. Latimer Clark had the conductor of the 1865 and 1866 lines joined
together at the Newfoundland end, thus forming an unbroken length of
3,700 miles in circuit. He then placed some sulphuric acid in a very
small silver thimble, with a fragment of zinc weighing a grain or two.
By this primitive agency he succeeded in conveying signals through twice
the breadth of the Atlantic Ocean in little more than a second of time
after making contact. The deflections were not of a dubious character,
but full and strong, from which it was manifest than an even smaller
battery would suffice to produce somewhat similar effects."

[Illustration: Fig. 62.--Siphon recorder]

At first in operating the Atlantic cable a mirror galvanometer was
employed as a receiver. The principle of this receiver has often been
illustrated by a mischievous boy as, with a slight and almost
imperceptible motion of his hand, he has used a bit of looking-glass to
dart a ray of reflected sunlight across a wide street or a large room.
On the same plan, the extremely minute motion of a galvanometer, as it
receives the successive pulsations of a message, is magnified by a
weightless lever of light so that the words are easily read by an
operator (Fig. 61). This beautiful invention comes from the hands of Sir
William Thomson [now Lord Kelvin], who, more than any other electrician,
has made ocean telegraphy an established success.

[Illustration: Fig. 63.--Siphon record. "Arrived yesterday"]

In another receiver, also of his design, the siphon recorder, he began
by taking advantage of the fact, observed long before by Bose, that a
charge of electricity stimulates the flow of a liquid. In its original
form the ink-well into which the siphon dipped was insulated and charged
to a high voltage by an influence-machine; the ink, powerfully repelled,
was spurted from the siphon point to a moving strip of paper beneath
(Fig. 62). It was afterward found better to use a delicate mechanical
shaker which throws out the ink in minute drops as the cable current
gently sways the siphon back and forth (Fig. 63).

Minute as the current is which suffices for cable telegraphy, it is
essential that the metallic circuit be not only unbroken, but unimpaired
throughout. No part of his duty has more severely taxed the resources of
the electrician than to discover the breaks and leaks in his ocean
cables. One of his methods is to pour electricity as it were, into a
broken wire, much as if it were a narrow tube, and estimate the length
of the wire (and consequently the distance from shore to the defect or
break) by the quantity of current required to fill it.


FOOTNOTES:

[1] Henry M. Field, "History of the Atlantic Telegraph." New York:
Scribner, 1866.

[2] "A Century of Electricity." Boston, Houghton, Mifflin & Co., 1887.




BELL'S TELEPHONIC RESEARCHES

     [From "Bell's Electric Speaking Telephones," by George B. Prescott,
     copyright by D Appleton & Co., New York, 1884]


In a lecture delivered before the Society of Telegraph Engineers, in
London, October 31, 1877, Prof. A. G. Bell gave a history of his
researches in telephony, together with the experiments that he was led
to undertake in his endeavours to produce a practical system of multiple
telegraphy, and to realize also the transmission of articulate speech.
After the usual introduction, Professor Bell said in part:

It is to-night my pleasure, as well as duty, to give you some account of
the telephonic researches in which I have been so long engaged. Many
years ago my attention was directed to the mechanism of speech by my
father, Alexander Melville Bell, of Edinburgh, who has made a life-long
study of the subject. Many of those present may recollect the invention
by my father of a means of representing, in a wonderfully accurate
manner, the positions of the vocal organs in forming sounds. Together we
carried on quite a number of experiments, seeking to discover the
correct mechanism of English and foreign elements of speech, and I
remember especially an investigation in which we were engaged
concerning the musical relations of vowel sounds. When vocal sounds are
whispered, each vowel seems to possess a particular pitch of its own,
and by whispering certain vowels in succession a musical scale can be
distinctly perceived. Our aim was to determine the natural pitch of each
vowel; but unexpected difficulties made their appearance, for many of
the vowels seemed to possess a double pitch--one due, probably, to the
resonance of the air in the mouth, and the other to the resonance of the
air contained in the cavity behind the tongue, comprehending the pharynx
and larynx.

I hit upon an expedient for determining the pitch, which, at that time,
I thought to be original with myself. It consisted in vibrating a tuning
fork in front of the mouth while the positions of the vocal organs for
the various vowels were silently taken. It was found that each vowel
position caused the reinforcement of some particular fork or forks.

I wrote an account of these researches to Mr. Alex. J. Ellis, of London.
In reply, he informed me that the experiments related had already been
performed by Helmholtz, and in a much more perfect manner than I had
done. Indeed, he said that Helmholtz had not only analyzed the vowel
sounds into their constituent musical elements, but had actually
performed the synthesis of them.

He had succeeded in producing, artificially, certain of the vowel sounds
by causing tuning forks of different pitch to vibrate simultaneously by
means of an electric current. Mr. Ellis was kind enough to grant me an
interview for the purpose of explaining the apparatus employed by
Helmholtz in producing these extraordinary effects, and I spent the
greater part of a delightful day with him in investigating the subject.
At that time, however, I was too slightly acquainted with the laws of
electricity fully to understand the explanations given; but the
interview had the effect of arousing my interest in the subjects of
sound and electricity, and I did not rest until I had obtained
possession of a copy of Helmholtz's great work "The Theory of Tone," and
had attempted, in a crude and imperfect manner, it is true, to reproduce
his results. While reflecting upon the possibilities of the production
of sound by electrical means, it struck me that the principle of
vibrating a tuning fork by the intermittent attraction of an
electro-magnet might be applied to the electrical production of music.

I imagined to myself a series of tuning forks of different pitches,
arranged to vibrate automatically in the manner shown by Helmholtz--each
fork interrupting, at every vibration, a voltaic current--and the
thought occurred, Why should not the depression of a key like that of a
piano direct the interrupted current from any one of these forks,
through a telegraph wire, to a series of electro-magnets operating the
strings of a piano or other musical instrument, in which case a person
might play the tuning fork piano in one place and the music be audible
from the electro-magnetic piano in a distant city.

The more I reflected upon this arrangement the more feasible did it seem
to me; indeed, I saw no reason why the depression of a number of keys at
the tuning fork end of the circuit should not be followed by the audible
production of a full chord from the piano in the distant city, each
tuning fork affecting at the receiving end that string of the piano with
which it was in unison. At this time the interest which I felt in
electricity led me to study the various systems of telegraphy in use in
this country and in America. I was much struck with the simplicity of
the Morse alphabet, and with the fact that it could be read by sound.
Instead of having the dots and dashes recorded on paper, the operators
were in the habit of observing the duration of the click of the
instruments, and in this way were enabled to distinguish by ear the
various signals.

It struck me that in a similar manner the duration of a musical note
might be made to represent the dot or dash of the telegraph code, so
that a person might operate one of the keys of the tuning fork piano
referred to above, and the duration of the sound proceeding from the
corresponding string of the distant piano be observed by an operator
stationed there. It seemed to me that in this way a number of distinct
telegraph messages might be sent simultaneously from the tuning fork
piano to the other end of the circuit by operators, each manipulating a
different key of the instrument. These messages would be read by
operators stationed at the distant piano, each receiving operator
listening for signals for a certain definite pitch, and ignoring all
others. In this way could be accomplished the simultaneous transmission
of a number of telegraphic messages along a single wire, the number
being limited only by the delicacy of the listener's ear. The idea of
increasing the carrying power of a telegraph wire in this way took
complete possession of my mind, and it was this practical end that I had
in view when I commenced my researches in electric telephony.

[Illustration: Fig. 1]

In the progress of science it is universally found that complexity leads
to simplicity, and in narrating the history of scientific research it is
often advisable to begin at the end.

In glancing back over my own researches, I find it necessary to
designate, by distinct names, a variety of electrical currents by means
of which sounds can be produced, and I shall direct your attention to
several distinct species of what may be termed telephonic currents of
electricity. In order that the peculiarities of these currents may be
clearly understood, I shall project upon the screen a graphical
illustration of the different varieties.

The graphical method of representing electrical currents shown in Fig. 1
is the best means I have been able to devise of studying, in an accurate
manner, the effects produced by various forms of telephonic apparatus,
and it has led me to the conception of that peculiar species of
telephonic current, here designated as _undulatory_, which has rendered
feasible the artificial production of articulate speech by electrical
means.

A horizontal line (_g g'_) is taken as the zero of current, and impulses
of positive electricity are represented above the zero line, and
negative impulses below it, or _vice versa_.

The vertical thickness of any electrical impulse (_b_ or _d_), measured
from the zero line, indicates the intensity of the electrical current at
the point observed; and the horizontal extension of the electric line
(_b_ or _d_) indicates the duration of the impulse.

Nine varieties of telephonic currents may be distinguished, but it will
only be necessary to show you six of these. The three primary varieties
designated as intermittent, pulsatory and undulatory, are represented in
lines 1, 2 and 3.

Sub-varieties of these can be distinguished as direct or reversed
currents, according as the electrical impulses are all of one kind or
are alternately positive and negative. Direct currents may still
further be distinguished as positive or negative, according as the
impulses are of one kind or of the other.

An intermittent current is characterized by the alternate presence and
absence of electricity upon the circuit.

A pulsatory current results from sudden or instantaneous changes in the
intensity of a continuous current; and

An undulatory current is a current of electricity, the intensity of
which varies in a manner proportional to the velocity of the motion of a
particle of air during the production of a sound: thus the curve
representing graphically the undulatory current for a simple musical
note is the curve expressive of a simple pendulous vibration--that is, a
sinusoidal curve.

And here I may remark, that, although the conception of the undulatory
current of electricity is entirely original with myself, methods of
producing sound by means of intermittent and pulsatory currents have
long been known. For instance, it was long since discovered that an
electro-magnet gives forth a decided sound when it is suddenly
magnetized or demagnetized. When the circuit upon which it is placed is
rapidly made and broken, a succession of explosive noises proceeds from
the magnet. These sounds produce upon the ear the effect of a musical
note when the current is interrupted a sufficient number of times per
second....

[Illustration: Fig. 2]

For several years my attention was almost exclusively directed to the
production of an instrument for making and breaking a voltaic circuit
with extreme rapidity, to take the place of the transmitting tuning fork
used in Helmholtz's researches. Without going into details, I shall
merely say that the great defects of this plan of multiple telegraphy
were found to consist, first, in the fact that the receiving operators
were required to possess a good musical ear in order to discriminate the
signals; and secondly, that the signals could only pass in one direction
along the line (so that two wires would be necessary in order to
complete communication in both directions). The first objection was got
over by employing the device which I term a "vibratory circuit breaker,"
whereby musical signals can be automatically recorded....

I have formerly stated that Helmholtz was enabled to produce vowel
sounds artificially by combining musical tones of different pitches and
intensities. His apparatus is shown in Fig. 2. Tuning forks of different
pitch are placed between the poles of electro-magnets (_a1_, _a2_, &c.),
and are kept in continuous vibration by the action of an intermittent
current from the fork _b_. Resonators, 1, 2, 3, etc., are arranged so as
to reinforce the sounds in a greater or less degree, according as the
exterior orifices are enlarged or contracted.

[Illustration: Fig. 3]

Thus it will be seen that upon Helmholtz's plan the tuning forks
themselves produce tones of uniform intensity, the loudness being varied
by an external reinforcement; but it struck me that the same results
would be obtained, and in a much more perfect manner, by causing the
tuning forks themselves to vibrate with different degrees of amplitude.
I therefore devised the apparatus shown in Fig. 3, which was my first
form of articulating telephone. In this figure a harp of steel rods is
employed, attached to the poles of a permanent magnet, N. S. When any
one of the rods is thrown into vibration an undulatory current is
produced in the coils of the electro-magnet E, and the electro-magnet E'
attracts the rods of the harp H' with a varying force, throwing into
vibration that rod which is in unison with that vibrating at the other
end of the circuit. Not only so, but the amplitude of vibration in the
one will determine the amplitude of vibration in the other, for the
intensity of the induced current is determined by the amplitude of the
inducing vibration, and the amplitude of the vibration at the receiving
end depends upon the intensity of the attractive impulses. When we sing
into a piano, certain of the strings of the instrument are set in
vibration sympathetically by the action of the voice with different
degrees of amplitude, and a sound, which is an approximation to the
vowel uttered, is produced from the piano. Theory shows that, had the
piano a very much larger number of strings to the octave, the vowel
sounds would be perfectly reproduced. My idea of the action of the
apparatus, shown in Fig. 3, was this: Utter a sound in the neighbourhood
of the harp H, and certain of the rods would be thrown into vibration
with different amplitudes. At the other end of the circuit the
corresponding rods of the harp H would vibrate with their proper
relations of force, and the _timbre_ [characteristic quality] of the
sound would be reproduced. The expense of constructing such an apparatus
as that shown in figure 3 deterred me from making the attempt, and I
sought to simplify the apparatus before venturing to have it made.

[Illustration: Fig. 4]

[Illustration: Fig. 5]

[Illustration: Fig. 6]

I have before alluded to the invention by my father of a system of
physiological symbols for representing the action of the vocal organs,
and I had been invited by the Boston Board of Education to conduct a
series of experiments with the system in the Boston school for the deaf
and dumb. It is well known that deaf mutes are dumb merely because they
are deaf, and that there is no defect in their vocal organs to
incapacitate them from utterance. Hence it was thought that my father's
system of pictorial symbols, popularly known as visible speech, might
prove a means whereby we could teach the deaf and dumb to use their
vocal organs and to speak. The great success of these experiments urged
upon me the advisability of devising method of exhibiting the vibrations
of sound optically, for use in teaching the deaf and dumb. For some time
I carried on experiments with the manometric capsule of Koeenig and with
the phonautograph of Leon Scott. The scientific apparatus in the
Institute of Technology in Boston was freely placed at my disposal for
these experiments, and it happened that at that time a student of the
Institute of Technology, Mr. Maurey, had invented an improvement upon
the phonautograph. He had succeeded in vibrating by the voice a stylus
of wood about a foot in length, which was attached to the membrane of
the phonautograph, and in this way he had been enabled to obtain
enlarged tracings upon a plane surface of smoked glass. With this
apparatus I succeeded in producing very beautiful tracings of the
vibrations of the air for vowel sounds. Some of these tracings are shown
in Fig. 4. I was much struck with this improved form of apparatus, and
it occurred to me that there was a remarkable likeness between the
manner in which this piece of wood was vibrated by the membrane of the
phonautograph and the manner in which the _ossiculo_ [small bones] of
the human ear were moved by the tympanic membrane. I determined
therefore, to construct a phonautograph modelled still more closely
upon the mechanism of the human ear, and for this purpose I sought the
assistance of a distinguished aurist in Boston, Dr. Clarence J. Blake.
He suggested the use of the human ear itself as a phonautograph, instead
of making an artificial imitation of it. The idea was novel and struck
me accordingly, and I requested my friend to prepare a specimen for me,
which he did. The apparatus, as finally constructed, is shown in Fig. 5.
The _stapes_ [inmost of the three auditory ossicles] was removed and a
pointed piece of hay about an inch in length was attached to the end of
the incus [the middle of the three auditory ossicles]. Upon moistening
the membrana tympani [membrane of the ear drum] and the ossiculae with a
mixture of glycerine and water the necessary mobility of the parts was
obtained, and upon singing into the external artificial ear the piece of
hay was thrown into vibration, and tracings were obtained upon a plane
surface of smoked glass passed rapidly underneath. While engaged in
these experiments I was struck with the remarkable disproportion in
weight between the membrane and the bones that were vibrated by it. It
occurred to me that if a membrane as thin as tissue paper could control
the vibration of bones that were, compared to it, of immense size and
weight, why should not a larger and thicker membrane be able to vibrate
a piece of iron in front of an electro-magnet, in which case the
complication of steel rods shown in my first form of telephone, Fig. 3,
could be done away with, and a simple piece of iron attached to a
membrane be placed at either end of the telegraphic circuit.

Figure 6 shows the form of apparatus that I was then employing for
producing undulatory currents of electricity for the purpose of multiple
telegraphy. A steel reed, A, was clamped firmly by one extremity to the
uncovered leg _h_ of an electro-magnet E, and the free end of the reed
projected above the covered leg. When the reed A was vibrated in any
mechanical way the battery current was thrown into waves, and electrical
undulations traversed the circuit B E W E', throwing into vibration the
corresponding reed A' at the other end of the circuit. I immediately
proceeded to put my new idea to the test of practical experiment, and
for this purpose I attached the reed A (Fig. 7) loosely by one extremity
to the uncovered pole _h_ of the magnet, and fastened the other
extremity to the centre of a stretched membrane of goldbeaters' skin
_n_. I presumed that upon speaking in the neighbourhood of the membrane
_n_ it would be thrown into vibration and cause the steel reed A to move
in a similar manner, occasioning undulations in the electrical current
that would correspond to the changes in the density of the air during
the production of the sound; and I further thought that the change of
the density of the current at the receiving end would cause the magnet
there to attract the reed A' in such a manner that it should copy the
motion of the reed A, in which case its movements would occasion a sound
from the membrane _n'_ similar in _timbre_ to that which had occasioned
the original vibration.

[Illustration: Fig. 7]

[Illustration: Fig. 8]

The results, however, were unsatisfactory and discouraging. My friend,
Mr. Thomas A. Watson, who assisted me in this first experiment, declared
that he heard a faint sound proceed from the telephone at his end of the
circuit, but I was unable to verify his assertion. After many
experiments, attended by the same only partially successful results, I
determined to reduce the size and weight of the spring as much as
possible. For this purpose I glued a piece of clock spring about the
size and shape of my thumb nail, firmly to the centre of the diaphragm,
and had a similar instrument at the other end (Fig. 8); we were then
enabled to obtain distinctly audible effects. I remember an experiment
made with this telephone, which at the time gave me great satisfaction
and delight. One of the telephones was placed in my lecture room in the
Boston University, and the other in the basement of the adjoining
building. One of my students repaired to the distant telephone to
observe the effects of articulate speech, while I uttered the sentence,
"Do you understand what I say?" into the telephone placed in the lecture
hall. To my delight an answer was returned through the instrument
itself, articulate sounds proceeded from the steel spring attached to
the membrane, and I heard the sentence, "Yes, I understand you
perfectly." It is a mistake, however, to suppose that the articulation
was by any means perfect, and expectancy no doubt had a great deal to do
with my recognition of the sentence; still, the articulation was there,
and I recognized the fact that the indistinctness was entirely due to
the imperfection of the instrument. I will not trouble you by detailing
the various stages through which the apparatus passed, but shall merely
say that after a time I produced the form of instrument shown in Fig. 9,
which served very well as a receiving telephone. In this condition my
invention was, in 1876, exhibited at the Centennial Exhibition in
Philadelphia. The telephone shown in Fig. 8 was used as a transmitting
instrument, and that in Fig. 9 as a receiver, so that vocal
communication was only established in one direction....

[Illustration: Fig. 9]

The articulation produced from the instrument shown in Fig. 9 was
remarkably distinct, but its great defect consisted in the fact that it
could not be used as a transmitting instrument, and thus two telephones
were required at each station, one for transmitting and one for
receiving spoken messages.

[Illustration: Fig. 10]

It was determined to vary the construction of the telephone shown in
Fig. 8, and I sought, by changing the size and tension of the membrane,
the diameter and thickness of the steel spring, the size and power of
the magnet, and the coils of insulated wire around their poles, to
discover empirically the exact effect of each element of the
combination, and thus to deduce a more perfect form of apparatus. It was
found that a marked increase in the loudness of the sounds resulted from
shortening the length of the coils of wire, and by enlarging the iron
diaphragm which was glued to the membrane. In the latter case, also, the
distinctness of the articulation was improved. Finally, the membrane of
goldbeaters' skin was discarded entirely, and a simple iron plate was
used instead, and at once intelligible articulation was obtained. The
new form of instrument is that shown in Fig. 10, and, as had been long
anticipated, it was proved that the only use of the battery was to
magnetize the iron core, for the effects were equally audible when the
battery was omitted and a rod of magnetized steel substituted for the
iron core of the magnet.

[Illustration: Fig. 11]

It was my original intention, as shown in Fig. 3, and it was always
claimed by me, that the final form of telephone would be operated by
permanent magnets in place of batteries, and numerous experiments had
been carried on by Mr. Watson and myself privately for the purpose of
producing this effect.

At the time the instruments were first exhibited in public the results
obtained with permanent magnets were not nearly so striking as when a
voltaic battery was employed, wherefore we thought it best to exhibit
only the latter form of instrument.

The interest excited by the first published accounts of the operation of
the telephone led many persons to investigate the subject, and I doubt
not that numbers of experimenters have independently discovered that
permanent magnets might be employed instead of voltaic batteries.
Indeed, one gentleman, Professor Dolbear, of Tufts College, not only
claims to have discovered the magneto-electric telephone, but, I
understand, charges me with having obtained the idea from him through
the medium of a mutual friend.

A still more powerful form of apparatus was constructed by using a
powerful compound horseshoe magnet in place of the straight rod which
had been previously used (see Fig. 11). Indeed, the sounds produced by
means of this instrument were of sufficient loudness to be faintly
audible to a large audience, and in this condition the instrument was
exhibited in the Essex Institute, in Salem, Massachusetts, on the 12th
of February, 1877, on which occasion a short speech shouted into a
similar telephone in Boston sixteen miles away, was heard by the
audience in Salem. The tones of the speaker's voice were distinctly
audible to an audience of six hundred people, but the articulation was
only distinct at a distance of about six feet. On the same occasion,
also, a report of the lecture was transmitted by word of mouth from
Salem to Boston, and published in the papers the next morning.

From the form of telephone shown in Fig. 10 to the present form of the
instrument (Fig. 12) is but a step. It is, in fact, the arrangement of
Fig. 10 in a portable form, the magnet F. H. being placed inside the
handle and a more convenient form of mouthpiece provided....

It was always my belief that a certain ratio would be found between the
several parts of a telephone, and that the size of the instrument was
immaterial; but Professor Peirce was the first to demonstrate the
extreme smallness of the magnets which might be employed. And here, in
order to show the parallel lines in which we were working, I may mention
the fact that two or three days after I had constructed a telephone of
the portable form (Fig. 12), containing the magnet inside the handle,
Dr. Channing was kind enough to send me a pair of telephones of a
similar pattern, which had been invented by experimenters at Providence.
The convenient form of the mouthpiece shown in Fig. 12, now adopted by
me, was invented solely by my friend, Professor Peirce. I must also
express my obligations to my friend and associate, Mr. Thomas A. Watson,
of Salem, Massachusetts, who has for two years past given me his
personal assistance in carrying on my researches.

In pursuing my investigations I have ever had one end in view--the
practical improvement of electric telegraphy--but I have come across
many facts which, while having no direct bearing upon the subject of
telegraphy, may yet possess an interest for you.

For instance, I have found that a musical tone proceeds from a piece of
plumbago or retort carbon when an intermittent current of electricity is
passed through it, and I have observed the most curious audible effects
produced by the passage of reversed intermittent currents through the
human body. A breaker was placed in circuit with the primary wires of an
induction coil, and the fine wires were connected with two strips of
brass. One of these strips was held closely against the ear, and a loud
sound proceeded from it whenever the other slip was touched with the
other hand. The strips of brass were next held one in each hand. The
induced currents occasioned a muscular tremor in the fingers. Upon
placing my forefinger to my ear a loud crackling noise was audible,
seemingly proceeding from the finger itself. A friend who was present
placed my finger to his ear, but heard nothing. I requested him to hold
the strips himself. He was then distinctly conscious of a noise (which I
was unable to perceive) proceeding from his finger. In this case a
portion of the induced current passed through the head of the observer
when he placed his ear against his own finger, and it is possible that
the sound was occasioned by a vibration of the surfaces of the ear and
finger in contact.

When two persons receive a shock from a Ruhmkorff's coil by clasping
hands, each taking hold of one wire of the coil with the free hand, a
sound proceeds from the clasped hands. The effect is not produced when
the hands are moist. When either of the two touches the body of the
other a loud sound comes from the parts in contact. When the arm of one
is placed against the arm of the other, the noise produced can be heard
at a distance of several feet. In all these cases a slight shock is
experienced so long as the contact is preserved. The introduction of a
piece of paper between the parts in contact does not materially
interfere with the production of the sounds, but the unpleasant effects
of the shock are avoided.

[Illustration: Fig. 12]

When an intermittent current from a Ruhmkorff's coil is passed through
the arms a musical note can be perceived when the ear is closely applied
to the arm of the person experimented upon. The sound seems to proceed
from the muscles of the fore-arm and from the biceps muscle. Mr. Elisha
Gray has also produced audible effects by the passage of electricity
through the human body.

An extremely loud musical note is occasioned by the spark of a
Ruhmkorff's coil when the primary circuit is made and broken with
sufficient rapidity. When two breakers of different pitch are caused
simultaneously to open and close the primary circuit a double tone
proceeds from the spark.

A curious discovery, which may be of interest to you, has been made by
Professor Blake. He constructed a telephone in which a rod of soft iron,
about six feet in length, was used instead of a permanent magnet. A
friend sang a continuous musical tone into the mouthpiece of a
telephone, like that shown in Fig. 12, which was connected with the soft
iron instrument alluded to above. It was found that the loudness of the
sound produced in this telephone varied with the direction in which the
iron rod was held, and that the maximum effect was produced when the rod
was in the position of the dipping needle. This curious discovery of
Professor Blake has been verified by myself.

When a telephone is placed in circuit with a telegraph line the
telephone is found seemingly to emit sounds on its own account. The most
extraordinary noises are often produced, the causes of which are at
present very obscure. One class of sounds is produced by the inductive
influence of neighbouring wires and by leakage from them, the signals of
the Morse alphabet passing over neighbouring wires being audible in the
telephone, and another class can be traced to earth currents upon the
wire, a curious modification of this sound revealing the presence of
defective joints in the wire.

Professor Blake informs me that he has been able to use the railroad
track for conversational purposes in place of a telegraph wire, and he
further states that when only one telephone was connected with the track
the sounds of Morse operating were distinctly audible in the telephone,
although the nearest telegraph wires were at least fifty feet distant.

Professor Peirce has observed the most singular sounds produced from a
telephone in connection with a telegraph wire during the aurora
borealis, and I have just heard of a curious phenomenon lately observed
by Dr. Channing. In the city of Providence, Rhode Island, there is an
over-house wire about one mile in extent with a telephone at either end.
On one occasion the sound of music and singing was faintly audible in
one of the telephones. It seemed as if some one were practising vocal
music with a pianoforte accompaniment. The natural supposition was that
experiments were being made with the telephone at the other end of the
circuit, but upon inquiry this proved not to have been the case.
Attention having thus been directed to the phenomenon, a watch was kept
upon the instruments, and upon a subsequent occasion the same fact was
observed at both ends of the line by Dr. Channing and his friends. It
was proved that the sounds continued for about two hours, and usually
commenced about the same time. A searching examination of the line
disclosed nothing abnormal in its condition, and I am unable to give you
any explanation of this curious phenomenon. Dr. Channing has, however,
addressed a letter upon the subject to the editor of one of the
Providence papers, giving the names of such songs as were recognized,
and full details of the observations, in the hope that publicity may
lead to the discovery of the performer, and thus afford a solution of
the mystery.

My friend, Mr. Frederick A. Gower, communicated to me a curious
observation made by him regarding the slight earth connection required
to establish a circuit for the telephone, and together we carried on a
series of experiments with rather startling results. We took a couple of
telephones and an insulated wire about 100 yards in length into a
garden, and were enabled to carry on conversation with the greatest ease
when we held in our hands what should have been the earth wire, so that
the connection with the ground was formed at either end through our
bodies, our feet being clothed with cotton socks and leather boots. The
day was fine, and the grass upon which we stood was seemingly perfectly
dry. Upon standing upon a gravel walk the vocal sounds, though much
diminished, were still perfectly intelligible, and the same result
occurred when standing upon a brick wall one foot in height, but no
sound was audible when one of us stood upon a block of freestone.

One experiment which we made is so very interesting that I must speak of
it in detail. Mr. Gower made earth connection at his end of the line by
standing upon a grass plot, whilst at the other end of the line I stood
upon a wooden board. I requested Mr. Gower to sing a continuous musical
note, and to my surprise the sound was very distinctly audible from the
telephone in my hand. Upon examining my feet I discovered that a single
blade of grass was bent over the edge of the board, and that my foot
touched it. The removal of this blade of grass was followed by the
cessation of the sound from the telephone, and I found that the moment I
touched with the toe of my boot a blade of grass or the petal of a daisy
the sound was again audible.

The question will naturally arise, Through what length of wire can the
telephone be used? In reply to this I may say that the maximum amount of
resistance through which the undulatory current will pass, and yet
retain sufficient force to produce an audible sound at the distant end,
has yet to be determined; no difficulty has, however, been experienced
in laboratory experiments in conversing through a resistance of 60,000
ohms, which has been the maximum at my disposal. On one occasion, not
having a rheostat [for producing resistance] at hand, I passed the
current through the bodies of sixteen persons, who stood hand in hand.
The longest length of real telegraph line through which I have attempted
to converse has been about 250 miles. On this occasion no difficulty was
experienced so long as parallel lines were not in operation. Sunday was
chosen as the day on which it was probable other circuits would be at
rest. Conversation was carried on between myself, in New York, and Mr.
Thomas A. Watson, in Boston, until the opening of business upon the
other wires. When this happened the vocal sounds were very much
diminished, but still audible. It seemed, indeed, like talking through a
storm. Conversation, though possible, could be carried on with
difficulty, owing to the distracting nature of the interfering currents.

I am informed by my friend Mr. Preece that conversation has been
successfully carried on through a submarine cable, sixty miles in
length, extending from Dartmouth to the Island of Guernsey, by means of
hand telephones.




PHOTOGRAPHING THE UNSEEN: THE ROENTGEN RAY

H. J. W. DAM

     [By permission from _McClure's Magazine_, April, 1896, copyright by
     S. S. McClure, Limited.]


In all the history of scientific discovery there has never been,
perhaps, so general, rapid, and dramatic an effect wrought on the
scientific centres of Europe as has followed, in the past four weeks,
upon an announcement made to the Wuerzburg Physico-Medical Society, at
their December [1895] meeting, by Professor William Konrad Roentgen,
professor of physics at the Royal University of Wuerzburg. The first news
which reached London was by telegraph from Vienna to the effect that a
Professor Roentgen, until then the possessor of only a local fame in the
town mentioned, had discovered a new kind of light, which penetrated and
photographed through everything. This news was received with a mild
interest, some amusement, and much incredulity; and a week passed. Then,
by mail and telegraph, came daily clear indications of the stir which
the discovery was making in all the great line of universities between
Vienna and Berlin. Then Roentgen's own report arrived, so cool, so
business-like, and so truly scientific in character, that it left no
doubt either of the truth or of the great importance of the preceding
reports. To-day, four weeks after the announcement, Roentgen's name is
apparently in every scientific publication issued this week in Europe;
and accounts of his experiments, of the experiments of others following
his method, and of theories as to the strange new force which he has
been the first to observe, fill pages of every scientific journal that
comes to hand. And before the necessary time elapses for this article to
attain publication in America, it is in all ways probable that the
laboratories and lecture-rooms of the United States will also be giving
full evidence of this contagious arousal of interest over a discovery so
strange that its importance cannot yet be measured, its utility be even
prophesied, or its ultimate effect upon long established scientific
beliefs be even vaguely foretold.

The Roentgen rays are certain invisible rays resembling, in many
respects, rays of light, which are set free when a high-pressure
electric current is discharged through a vacuum tube. A vacuum tube is a
glass tube from which all the air, down to one-millionth of an
atmosphere, has been exhausted after the insertion of a platinum wire in
either end of the tube for connection with the two poles of a battery or
induction coil. When the discharge is sent through the tube, there
proceeds from the anode--that is, the wire which is connected with the
positive pole of the battery--certain bands of light, varying in colour
with the colour of the glass. But these are insignificant in comparison
with the brilliant glow which shoots from the cathode, or negative wire.
This glow excites brilliant phosphorescence in glass and many
substances, and these "cathode rays," as they are called, were observed
and studied by Hertz; and more deeply by his assistant, Professor
Lenard, Lenard having, in 1894, reported that the cathode rays would
penetrate thin films of aluminum, wood, and other substances, and
produce photographic results beyond. It was left, however, for Professor
Roentgen to discover that during the discharge quite other rays are set
free, which differ greatly from those described by Lenard as cathode
rays. The most marked difference between the two is the fact that
Roentgen rays are not deflected by a magnet, indicating a very essential
difference, while their range and penetrative power are incomparably
greater. In fact, all those qualities which have lent a sensational
character to the discovery of Roentgen's rays were mainly absent from
those of Lenard, to the end that, although Roentgen has not been working
in an entirely new field, he has by common accord been freely granted
all the honors of a great discovery.

Exactly what kind of a force Professor Roentgen has discovered he does
not know. As will be seen below, he declines to call it a new kind of
light, or a new form of electricity. He has given it the name of the X
rays. Others speak of it as the Roentgen rays. Thus far its results only,
and not its essence, are known. In the terminology of science it is
generally called "a new mode of motion," or, in other words, a new
force. As to whether it is or not actually a force new to science, or
one of the known forces masquerading under strange conditions, weighty
authorities are already arguing. More than one eminent scientist has
already affected to see in it a key to the great mystery of the law of
gravity. All who have expressed themselves in print have admitted, with
more or less frankness, that, in view of Roentgen's discovery, science
must forthwith revise, possibly to a revolutionary degree, the long
accepted theories concerning the phenomena of light and sound. That the
X rays, in their mode of action, combine a strange resemblance to both
sound and light vibrations, and are destined to materially affect, if
they do not greatly alter, our views of both phenomena, is already
certain; and beyond this is the opening into a new and unknown field of
physical knowledge, concerning which speculation is already eager, and
experimental investigation already in hand, in London, Paris, Berlin,
and, perhaps, to a greater or less extent, in every well-equipped
physical laboratory in Europe.

This is the present scientific aspect of the discovery. But, unlike most
epoch-making results from laboratories, this discovery is one which, to
a very unusual degree, is within the grasp of the popular and
non-technical imagination. Among the other kinds of matter which these
rays penetrate with ease is human flesh. That a new photography has
suddenly arisen which can photograph the bones, and, before long, the
organs of the human body; that a light has been found which can
penetrate, so as to make a photographic record, through everything from
a purse or a pocket to the walls of a room or a house, is news which
cannot fail to startle everybody. That the eye of the physician or
surgeon, long baffled by the skin, and vainly seeking to penetrate the
unfortunate darkness of the human body, is now to be supplemented by a
camera, making all the parts of the human body as visible, in a way, as
the exterior, appears certainly to be a greater blessing to humanity
than even the Listerian antiseptic system of surgery; and its benefits
must inevitably be greater than those conferred by Lister, great as the
latter have been. Already, in the few weeks since Roentgen's
announcement, the results of surgical operations under the new system
are growing voluminous. In Berlin, not only new bone fractures are being
immediately photographed, but joined fractures, as well, in order to
examine the results of recent surgical work. In Vienna, imbedded bullets
are being photographed, instead of being probed for, and extracted with
comparative ease. In London, a wounded sailor, completely paralyzed,
whose injury was a mystery, has been saved by the photographing of an
object imbedded in the spine, which, upon extraction, proved to be a
small knife-blade. Operations for malformations, hitherto obscure, but
now clearly revealed by the new photography, are already becoming
common, and are being reported from all directions. Professor Czermark
of Graz has photographed the living skull, denuded of flesh and hair,
and has begun the adaptation of the new photography to brain study. The
relation of the new rays to thought rays is being eagerly discussed in
what may be called the non-exact circles and journals; and all that
numerous group of inquirers into the occult, the believers in
clairvoyance, spiritualism, telepathy, and kindred orders of alleged
phenomena, are confident of finding in the new force long-sought facts
in proof of their claims. Professor Neusser in Vienna has photographed
gallstones in the liver of one patient (the stone showing snow-white in
the negative), and a stone in the bladder of another patient. His
results so far induce him to announce that all the organs of the human
body can, and will, shortly, be photographed. Lannelongue of Paris has
exhibited to the Academy of Science photographs of bones showing
inherited tuberculosis which had not otherwise revealed itself. Berlin
has already formed a society of forty for the immediate prosecution of
researches into both the character of the new force and its
physiological possibilities. In the next few weeks these strange
announcements will be trebled or quadrupled, giving the best evidence
from all quarters of the great future that awaits the Roentgen rays, and
the startling impetus to the universal search for knowledge that has
come at the close of the nineteenth century from the modest little
laboratory in the Pleicher Ring at Wuerzburg.

The Physical Institute, Professor Roentgen's particular domain, is a
modest building of two stories and basement, the upper story
constituting his private residence, and the remainder of the building
being given over to lecture rooms, laboratories, and their attendant
offices. At the door I was met by an old serving-man of the idolatrous
order, whose pain was apparent when I asked for "Professor" Roentgen, and
he gently corrected me with "Herr Doctor Roentgen." As it was evident,
however, that we referred to the same person, he conducted me along a
wide, bare hall, running the length of the building, with blackboards
and charts on the walls. At the end he showed me into a small room on
the right. This contained a large table desk, and a small table by the
window, covered by photographs, while the walls held rows of shelves
laden with laboratory and other records. An open door led into a
somewhat larger room, perhaps twenty feet by fifteen, and I found myself
gazing into a laboratory which was the scene of the discovery--a
laboratory which, though in all ways modest, is destined to be
enduringly historical.

There was a wide table shelf running along the farther side, in front of
the two windows, which were high, and gave plenty of light. In the
centre was a stove; on the left, a small cabinet whose shelves held the
small objects which the professor had been using. There was a table in
the left-hand corner; and another small table--the one on which living
bones were first photographed--was near the stove, and a Ruhmkorff coil
was on the right. The lesson of the laboratory was eloquent. Compared,
for instance, with the elaborate, expensive, and complete apparatus of,
say, the University of London, or of any of the great American
universities, it was bare and unassuming to a degree. It mutely said
that in the great march of science it is the genius of man, and not the
perfection of appliances, that breaks new ground in the great territory
of the unknown. It also caused one to wonder at and endeavour to imagine
the great things which are to be done through elaborate appliances with
the Roentgen rays--a field in which the United States, with its foremost
genius in invention, will very possibly, if not probably, take the
lead--when the discoverer himself had done so much with so little.
Already, in a few weeks, a skilled London operator, Mr. A. A. C.
Swinton, has reduced the necessary time of exposure for Roentgen
photographs from fifteen minutes to four. He used, however, a Tesla oil
coil, discharged by twelve half-gallon Leyden jars, with an alternating
current of twenty thousand volts' pressure. Here were no oil coils,
Leyden jars, or specially elaborate and expensive machines. There were
only a Ruhmkorff coil and Crookes (vacuum) tube and the man himself.

Professor Roentgen entered hurriedly, something like an amiable gust of
wind. He is a tall, slender, and loose-limbed man, whose whole
appearance bespeaks enthusiasm and energy. He wore a dark blue sack
suit, and his long, dark hair stood straight up from his forehead, as if
he were permanently electrified by his own enthusiasm. His voice is full
and deep, he speaks rapidly, and, altogether, he seems clearly a man
who, once upon the track of a mystery which appealed to him, would
pursue it with unremitting vigor. His eyes are kind, quick, and
penetrating; and there is no doubt that he much prefers gazing at a
Crookes tube to beholding a visitor, visitors at present robbing him of
much valued time. The meeting was by appointment, however, and his
greeting was cordial and hearty. In addition to his own language he
speaks French well and English scientifically, which is different from
speaking it popularly. These three tongues being more or less within the
equipment of his visitor, the conversation proceeded on an international
or polyglot basis, so to speak, varying at necessity's demand.

It transpired in the course of inquiry, that the professor is a married
man and fifty years of age, though his eyes have the enthusiasm of
twenty-five. He was born near Zurich, and educated there, and completed
his studies and took his degree at Utrecht. He has been at Wuerzburg
about seven years, and had made no discoveries which he considered of
great importance prior to the one under consideration. These details
were given under good-natured protest, he failing to understand why his
personality should interest the public. He declined to admire himself or
his results in any degree, and laughed at the idea of being famous. The
professor is too deeply interested in science to waste any time in
thinking about himself. His emperor had feasted, flattered, and
decorated him, and he was loyally grateful. It was evident, however,
that fame and applause had small attractions for him, compared to the
mysteries still hidden in the vacuum tubes of the other room.

"Now, then," said he, smiling, and with some impatience, when the
preliminary questions at which he chafed were over, "you have come to
see the invisible rays."

"Is the invisible visible?"

"Not to the eye; but its results are. Come in here."

[Illustration: BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH

From a photograph by A. A. C. Swinton, Victoria Street, London.
Exposure, fifty-five seconds]

He led the way to the other square room mentioned, and indicated the
induction coil with which his researches were made, an ordinary
Ruhmkorff coil, with a spark of from four to six inches, charged by a
current of twenty amperes. Two wires led from the coil, through an open
door, into a smaller room on the right. In this room was a small table
carrying a Crookes tube connected with the coil. The most striking
object in the room, however, was a huge and mysterious tin box about
seven feet high and four feet square. It stood on end, like a huge
packing case, its side being perhaps five inches from the Crookes tube.

The professor explained the mystery of the tin box, to the effect that
it was a device of his own for obtaining a portable dark-room. When he
began his investigations he used the whole room, as was shown by the
heavy blinds and curtains so arranged as to exclude the entrance of all
interfering light from the windows. In the side of the tin box, at the
point immediately against the tube, was a circular sheet of aluminum one
millimetre in thickness, and perhaps eighteen inches in diameter,
soldered to the surrounding tin. To study his rays the professor had
only to turn on the current, enter the box, close the door, and in
perfect darkness inspect only such light or light effects as he had a
right to consider his own, hiding his light, in fact, not under the
Biblical bushel, but in a more commodious box.

"Step inside," said he, opening the door, which was on the side of the
box farthest from the tube. I immediately did so, not altogether certain
whether my skeleton was to be photographed for general inspection, or my
secret thoughts held up to light on a glass plate. "You will find a
sheet of barium paper on the shelf," he added, and then went away to the
coil. The door was closed, and the interior of the box became black
darkness. The first thing I found was a wooden stool, on which I
resolved to sit. Then I found the shelf on the side next the tube, and
then the sheet of paper prepared with barium platinocyanide. I was thus
being shown the first phenomenon which attracted the discoverer's
attention and led to his discovery, namely, the passage of rays,
themselves wholly invisible, whose presence was only indicated by the
effect they produced on a piece of sensitized photographic paper.

A moment later, the black darkness was penetrated by the rapid snapping
sound of the high-pressure current in action, and I knew that the tube
outside was glowing. I held the sheet vertically on the shelf, perhaps
four inches from the plate. There was no change, however, and nothing
was visible.

"Do you see anything?" he called.

"No."

"The tension is not high enough;" and he proceeded to increase the
pressure by operating an apparatus of mercury in long vertical tubes
acted upon automatically by a weight lever which stood near the coil. In
a few moments the sound of the discharge again began, and then I made my
first acquaintance with the Roentgen rays.

The moment the current passed, the paper began to glow. A yellowish
green light spread all over its surface in clouds, waves and flashes.
The yellow-green luminescence, all the stranger and stronger in the
darkness, trembled, wavered, and floated over the paper, in rhythm with
the snapping of the discharge. Through the metal plate, the paper,
myself, and the tin box, the invisible rays were flying, with an effect
strange, interesting and uncanny. The metal plate seemed to offer no
appreciable resistance to the flying force, and the light was as rich
and full as if nothing lay between the paper and the tube.

"Put the book up," said the professor.

I felt upon the shelf, in the darkness, a heavy book, two inches in
thickness, and placed this against the plate. It made no difference. The
rays flew through the metal and the book as if neither had been there,
and the waves of light, rolling cloud-like over the paper, showed no
change in brightness. It was a clear, material illustration of the ease
with which paper and wood are penetrated. And then I laid book and paper
down, and put my eyes against the rays. All was blackness, and I neither
saw nor felt anything. The discharge was in full force, and the rays
were flying through my head, and, for all I knew, through the side of
the box behind me. But they were invisible and impalpable. They gave no
sensation whatever. Whatever the mysterious rays may be, they are not to
be seen, and are to be judged only by their works.

I was loath to leave this historical tin box, but time pressed. I
thanked the professor, who was happy in the reality of his discovery and
the music of his sparks. Then I said: "Where did you first photograph
living bones?"

"Here," he said, leading the way into the room where the coil stood. He
pointed to a table on which was another--the latter a small
short-legged wooden one with more the shape and size of a wooden seat.
It was two feet square and painted coal black. I viewed it with
interest. I would have bought it, for the little table on which light
was first sent through the human body will some day be a great
historical curiosity; but it was not for sale. A photograph of it would
have been a consolation, but for several reasons one was not to be had
at present. However, the historical table was there, and was duly
inspected.

"How did you take the first hand photograph?" I asked.

The professor went over to a shelf by the window, where lay a number of
prepared glass plates, closely wrapped in black paper. He put a Crookes
tube underneath the table, a few inches from the under side of its top.
Then he laid his hand flat on the top of the table, and placed the glass
plate loosely on his hand.

"You ought to have your portrait painted in that attitude," I suggested.

"No, that is nonsense," said he, smiling.

"Or be photographed." This suggestion was made with a deeply hidden
purpose.

The rays from the Roentgen eyes instantly penetrated the deeply hidden
purpose. "Oh, no," said he; "I can't let you make pictures of me. I am
too busy." Clearly the professor was entirely too modest to gratify the
wishes of the curious world.

"Now, Professor," said I, "will you tell me the history of the
discovery?"

"There is no history," he said. "I have been for a long time interested
in the problem of the cathode rays from a vacuum tube as studied by
Hertz and Lenard. I had followed their and other researches with great
interest, and determined, as soon as I had the time, to make some
researches of my own. This time I found at the close of last October. I
had been at work for some days when I discovered something new."

"What was the date?"

"The eighth of November."

"And what was the discovery?"

"I was working with a Crookes tube covered by a shield of black
cardboard. A piece of barium platinocyanide paper lay on the bench
there. I had been passing a current through the tube, and I noticed a
peculiar black line across the paper."

"What of that?"

"The effect was one which could only be produced, in ordinary parlance,
by the passage of light. No light could come from the tube, because the
shield which covered it was impervious to any light known, even that of
the electric arc."

"And what did you think?"

"I did not think; I investigated. I assumed that the effect must have
come from the tube, since its character indicated that it could come
from nowhere else. I tested it. In a few minutes there was no doubt
about it. Rays were coming from the tube which had a luminescent effect
upon the paper. I tried it successfully at greater and greater
distances, even at two metres. It seemed at first a new kind of
invisible light. It was clearly something new, something unrecorded."

"Is it light?"

"No."

"Is it electricity?"

"Not in any known form."

"What is it?"

"I don't know."

And the discoverer of the X rays thus stated as calmly his ignorance of
their essence as has everybody else who has written on the phenomena
thus far.

"Having discovered the existence of a new kind of rays, I of course
began to investigate what they would do." He took up a series of
cabinet-sized photographs. "It soon appeared from tests that the rays
had penetrative powers to a degree hitherto unknown. They penetrated
paper, wood, and cloth with ease; and the thickness of the substance
made no perceptible difference, within reasonable limits." He showed
photographs of a box of laboratory weights of platinum, aluminum, and
brass, they and the brass hinges all having been photographed from a
closed box, without any indication of the box. Also a photograph of a
coil of fine wire, wound on a wooden spool, the wire having been
photographed, and the wood omitted. "The rays," he continued, "passed
through all the metals tested, with a facility varying, roughly
speaking, with the density of the metal. These phenomena I have
discussed carefully in my report to the Wuerzburg society, and you will
find all the technical results therein stated." He showed a photograph
of a small sheet of zinc. This was composed of smaller plates soldered
laterally with solders of different metallic proportions. The differing
lines of shadow, caused by the difference in the solders, were visible
evidence that a new means of detecting flaws and chemical variations in
metals had been found. A photograph of a compass showed the needle and
dial taken through the closed brass cover. The markings of the dial were
in red metallic paint, and thus interfered with the rays, and were
reproduced. "Since the rays had this great penetrative power, it seemed
natural that they should penetrate flesh, and so it proved in
photographing the hand, as I showed you."

A detailed discussion of the characteristics of his rays the professor
considered unprofitable and unnecessary. He believes, though, that these
mysterious radiations are not light, because their behaviour is
essentially different from that of light rays, even those light rays
which are themselves invisible. The Roentgen rays cannot be reflected by
reflecting surfaces, concentrated by lenses, or refracted or diffracted.
They produce photographic action on a sensitive film, but their action
is weak as yet, and herein lies the first important field of their
development. The professor's exposures were comparatively long--an
average of fifteen minutes in easily penetrable media, and half an hour
or more in photographing the bones of the hand. Concerning vacuum tubes,
he said that he preferred the Hittorf, because it had the most perfect
vacuum, the highest degree of air exhaustion being the consummation most
desirable. In answer to a question, "What of the future?" he said:

"I am not a prophet, and I am opposed to prophesying. I am pursuing my
investigations, and as fast as my results are verified I shall make them
public."

"Do you think the rays can be so modified as to photograph the organs of
the human body?"

In answer he took up the photograph of the box of weights. "Here are
already modifications," he said, indicating the various degrees of
shadow produced by the aluminum, platinum, and brass weights, the brass
hinges, and even the metallic stamped lettering on the cover of the box,
which was faintly perceptible.

"But Professor Neusser has already announced that the photographing of
the various organs is possible."

"We shall see what we shall see," he said. "We have the start now; the
development will follow in time."

"You know the apparatus for introducing the electric light into the
stomach?"

"Yes."

"Do you think that this electric light will become a vacuum tube for
photographing, from the stomach, any part of the abdomen or thorax?"

The idea of swallowing a Crookes tube, and sending a high frequency
current down into one's stomach, seemed to him exceedingly funny. "When
I have done it, I will tell you," he said, smiling, resolute in abiding
by results.

"There is much to do, and I am busy, very busy," he said in conclusion.
He extended his hand in farewell, his eyes already wandering toward his
work in the inside room. And his visitor promptly left him; the words,
"I am busy," said in all sincerity, seeming to describe in a single
phrase the essence of his character and the watchword of a very unusual
man.

Returning by way of Berlin, I called upon Herr Spies of the Urania,
whose photographs after the Roentgen method were the first made public,
and have been the best seen thus far. In speaking of the discovery he
said:

"I applied it, as soon as the penetration of flesh was apparent, to the
photograph of a man's hand. Something in it had pained him for years,
and the photograph at once exhibited a small foreign object, as you can
see;" and he exhibited a copy of the photograph in question. "The speck
there is a small piece of glass, which was immediately extracted, and
which, in all probability, would have otherwise remained in the man's
hand to the end of his days." All of which indicates that the needle
which has pursued its travels in so many persons, through so many years,
will be suppressed by the camera.

"My next object is to photograph the bones of the entire leg," continued
Herr Spies. "I anticipate no difficulty, though it requires some thought
in manipulation."

It will be seen that the Roentgen rays and their marvellous practical
possibilities are still in their infancy. The first successful
modification of the action of the rays so that the varying densities of
bodily organs will enable them to be photographed will bring all such
morbid growths as tumours and cancers into the photographic field, to
say nothing of vital organs which may be abnormally developed or
degenerate. How much this means to medical and surgical practice it
requires little imagination to conceive. Diagnosis, long a painfully
uncertain science, has received an unexpected and wonderful assistant;
and how greatly the world will benefit thereby, how much pain will be
saved, only the future can determine. In science a new door has been
opened where none was known to exist, and a side-light on phenomena has
appeared, of which the results may prove as penetrating and astonishing
as the Roentgen rays themselves. The most agreeable feature of the
discovery is the opportunity it gives for other hands to help; and the
work of these hands will add many new words to the dictionaries, many
new facts to science, and, in the years long ahead of us, fill many more
volumes than there are paragraphs in this brief and imperfect account.




THE WIRELESS TELEGRAPH

GEORGE ILES

     [From "Flame, Electricity and the Camera," copyright by Doubleday,
     Page & Co., New York.]


In a series of experiments interesting enough but barren of utility, the
water of a canal, river, or bay has often served as a conductor for the
telegraph. Among the electricians who have thus impressed water into
their service was Professor Morse. In 1842 he sent a few signals across
the channel from Castle Garden, New York, to Governor's Island, a
distance of a mile. With much better results, he sent messages, later in
the same year, from one side of the canal at Washington to the other, a
distance of eighty feet, employing large copper plates at each terminal.
The enormous current required to overcome the resistance of water has
barred this method from practical adoption.

We pass, therefore, to electrical communication as effected by
induction--the influence which one conductor exerts on another through
an intervening insulator. At the outset we shall do well to bear in mind
that magnetic phenomena, which are so closely akin to electrical, are
always inductive. To observe a common example of magnetic induction, we
have only to move a horseshoe magnet in the vicinity of a compass
needle, which will instantly sway about as if blown hither and thither
by a sharp draught of air. This action takes place if a slate, a pane of
glass, or a shingle is interposed between the needle and its perturber.
There is no known insulator for magnetism, and an induction of this kind
exerts itself perceptibly for many yards when large masses of iron are
polarised, so that the derangement of compasses at sea from moving iron
objects aboard ship, or from ferric ores underlying a sea-coast, is a
constant peril to the mariner.

Electrical conductors behave much like magnetic masses. A current
conveyed by a conductor induces a counter-current in all surrounding
bodies, and in a degree proportioned to their conductive power. This
effect is, of course, greatest upon the bodies nearest at hand, and we
have already remarked its serious retarding effect in ocean telegraphy.
When the original current is of high intensity, it can induce a
perceptible current in another wire at a distance of several miles. In
1842 Henry remarked that electric waves had this quality, but in that
early day of electrical interpretation the full significance of the fact
eluded him. In the top room of his house he produced a spark an inch
long, which induced currents in wires stretched in his cellar, through
two thick floors and two rooms which came between. Induction of this
sort causes the annoyance, familiar in single telephonic circuits, of
being obliged to overhear other subscribers, whose wires are often far
away from our own.

The first practical use of induced currents in telegraphy was when Mr.
Edison, in 1885, enabled the trains on a line of the Staten Island
Railroad to be kept in constant communication with a telegraphic wire,
suspended in the ordinary way beside the track. The roof of a car was of
insulated metal, and every tap of an operator's key within the walls
electrified the roof just long enough to induce a brief pulse through
the telegraphic circuit. In sending a message to the car this wire was,
moment by moment, electrified, inducing a response first in the car
roof, and next in the "sounder" beneath it. This remarkable apparatus,
afterward used on the Lehigh Valley Railroad, was discontinued from lack
of commercial support, although it would seem to be advantageous to
maintain such a service on other than commercial grounds. In case of
chance obstructions on the track, or other peril, to be able to
communicate at any moment with a train as it speeds along might mean
safety instead of disaster. The chief item in the cost of this system is
the large outlay for a special telegraphic wire.

The next electrician to employ induced currents in telegraphy was Mr.
(now Sir) William H. Preece, the engineer then at the head of the
British telegraph system. Let one example of his work be cited. In 1896
a cable was laid between Lavernock, near Cardiff, on the Bristol
Channel, and Flat Holme, an island three and a third miles off. As the
channel at this point is a much-frequented route and anchor ground, the
cable was broken again and again. As a substitute for it Mr. Preece, in
1898, strung wires along the opposite shores, and found that an electric
pulse sent through one wire instantly made itself heard in a telephone
connected with the other. It would seem that in this etheric form of
telegraphy the two opposite lines of wire must be each as long as the
distance which separates them; therefore, to communicate across the
English Channel from Dover to Calais would require a line along each
coast at least twenty miles in length. Where such lines exist for
ordinary telegraphy, they might easily lend themselves to the Preece
system of signalling in case a submarine cable were to part.

Marconi, adopting electrostatic instead of electro-magnetic waves, has
won striking results. Let us note the chief of his forerunners, as they
prepared the way for him. In 1864 Maxwell observed that electricity and
light have the same velocity, 186,400 miles a second, and he formulated
the theory that electricity propagates itself in waves which differ from
those of light only in being longer. This was proved to be true by
Hertz, who in 1888 showed that where alternating currents of very high
frequency were set up in an open circuit, the energy might be conveyed
entirely away from the circuit into the surrounding space as electric
waves. His detector was a nearly closed circle of wire, the ends being
soldered to metal balls almost in contact. With this simple apparatus he
demonstrated that electric waves move with the speed of light, and that
they can be reflected and refracted precisely as if they formed a
visible beam. At a certain intensity of strain the air insulation broke
down, and the air became a conductor. This phenomenon of passing quite
suddenly from a non-conductive to a conductive state is, as we shall
duly see, also to be noted when air or other gases are exposed to the X
ray.

Now for the effect of electric waves such as Hertz produced, when they
impinge upon substances reduced to powder or filings. Conductors, such
as the metals, are of inestimable service to the electrician; of equal
value are non-conductors, such as glass and gutta-percha, as they
strictly fence in an electric stream. A third and remarkable vista opens
to experiment when it deals with substances which, in their normal
state, are non-conductive, but which, agitated by an electric wave,
instantly become conductive in a high degree. As long ago as 1866 Mr. S.
A. Varley noticed that black lead, reduced to a loose dust, effectually
intercepted a current from fifty Daniell cells, although the battery
poles were very near each other. When he increased the electric tension
four- to six-fold, the black-lead particles at once compacted themselves
so as to form a bridge of excellent conductivity. On this principle he
invented a lightning-protector for electrical instruments, the incoming
flash causing a tiny heap of carbon dust to provide it with a path
through which it could safely pass to the earth. Professor Temistocle
Calzecchi Onesti of Fermo, in 1885, in an independent series of
researches, discovered that a mass of powdered copper is a non-conductor
until an electric wave beats upon it; then, in an instant, the mass
resolves itself into a conductor almost as efficient as if it were a
stout, unbroken wire. Professor Edouard Branly of Paris, in 1891, on
this principle devised a coherer, which passed from resistance to
invitation when subjected to an electric impulse from afar. He enhanced
the value of his device by the vital discovery that the conductivity
bestowed upon filings by electric discharges could be destroyed by
simply shaking or tapping them apart.

In a homely way the principle of the coherer is often illustrated in
ordinary telegraphic practice. An operator notices that his instrument
is not working well, and he suspects that at some point in his circuit
there is a defective contact. A little dirt, or oxide, or dampness, has
come in between two metallic surfaces; to be sure, they still touch each
other, but not in the firm and perfect way demanded for his work.
Accordingly he sends a powerful current abruptly into the line, which
clears its path thoroughly, brushes aside dirt, oxide, or moisture, and
the circuit once more is as it should be. In all likelihood, the coherer
is acted upon in the same way. Among the physicists who studied it in
its original form was Dr. Oliver J. Lodge. He improved it so much that,
in 1894, at the Royal Institution in London, he was able to show it as
an electric eye that registered the impact of invisible rays at a
distance of more than forty yards. He made bold to say that this
distance might be raised to half a mile.

As early as 1879 Professor D. E. Hughes began a series of experiments in
wireless telegraphy, on much the lines which in other hands have now
reached commercial as well as scientific success. Professor Hughes was
the inventor of the microphone, and that instrument, he declared,
affords an unrivalled means of receiving wireless messages, since it
requires no tapping to restore its non-conductivity. In his researches
this investigator was convinced that his signals were propagated, not by
electro-magnetic induction, but by aerial electric waves spreading out
from an electric spark. Early in 1880 he showed his apparatus to
Professor Stokes, who observed its operation carefully. His dictum was
that he saw nothing which could not be explained by known
electro-magnetic effects. This erroneous judgment so discouraged
Professor Hughes that he desisted from following up his experiments, and
thus, in all probability, the birth of the wireless telegraph was for
several years delayed.[3]

[Illustration: Fig. 71.--Marconi coherer, enlarged view]

The coherer, as improved by Marconi, is a glass tube about one and
one-half inches long and about one-twelfth of an inch in internal
diameter. The electrodes are inserted in this tube so as almost to
touch; between them is about one-thirtieth of an inch filled with a
pinch of the responsive mixture which forms the pivot of the whole
contrivance. This mixture is 90 per cent. nickel filings, 10 per cent.
hard silver filings, and a mere trace of mercury; the tube is exhausted
of air to within one ten-thousandth part (Fig. 71). How does this trifle
of metallic dust manage loudly to utter its signals through a
telegraphic sounder, or forcibly indent them upon a moving strip of
paper? Not directly, but indirectly, as the very last refinement of
initiation. Let us imagine an ordinary telegraphic battery strong enough
loudly to tick out a message. Be it ever so strong it remains silent
until its circuit is completed, and for that completion the merest touch
suffices. Now the thread of dust in the coherer forms part of such a
telegraphic circuit: as loose dust it is an effectual bar and obstacle,
under the influence of electric waves from afar it changes instantly to
a coherent metallic link which at once completes the circuit and
delivers the message.

An electric impulse, almost too attenuated for computation, is here able
to effect such a change in a pinch of dust that it becomes a free avenue
instead of a barricade. Through that avenue a powerful blow from a local
store of energy makes itself heard and felt. No device of the trigger
class is comparable with this in delicacy. An instant after a signal has
taken its way through the coherer a small hammer strikes the tiny tube,
jarring its particles asunder, so that they resume their normal state of
high resistance. We may well be astonished at the sensitiveness of the
metallic filings to an electric wave originating many miles away, but
let us remember how clearly the eye can see a bright lamp at the same
distance as it sheds a sister beam. Thus far no substance has been
discovered with a mechanical responsiveness to so feeble a ray of light;
in the world of nature and art the coherer stands alone. The electric
waves employed by Marconi are about four feet long, or have a frequency
of about 250,000,000 per second. Such undulations pass readily through
brick or stone walls, through common roofs and floors--indeed, through
all substances which are non-conductive to electric waves of ordinary
length. Were the energy of a Marconi sending-instrument applied to an
arc-lamp, it would generate a beam of a thousand candle-power. We have
thus a means of comparing the sensitiveness of the retina to light with
the responsiveness of the Marconi coherer to electric waves, after both
radiations have undergone a journey of miles.

An essential feature of this method of etheric telegraphy, due to
Marconi himself, is the suspension of a perpendicular wire at each
terminus, its length twenty feet for stations a mile apart, forty feet
for four miles, and so on, the telegraphic distance increasing as the
square of the length of suspended wire. In the Kingstown regatta, July,
1898, Marconi sent from a yacht under full steam a report to the shore
without the loss of a moment from start to finish. This feat was
repeated during the protracted contest between the _Columbia_ and the
_Shamrock_ yachts in New York Bay, October, 1899. On March 28, 1899,
Marconi signals put Wimereux, two miles north of Boulogne, in
communication with the South Foreland Lighthouse, thirty-two miles
off.[4] In August, 1899, during the manoeuvres of the British navy,
similar messages were sent as far as eighty miles. It was clearly
demonstrated that a new power had been placed in the hands of a naval
commander. "A touch on a button in a flagship is all that is now needed
to initiate every tactical evolution in a fleet, and insure an almost
automatic precision in the resulting movements of the ships. The
flashing lantern is superseded at night, flags and the semaphore by day,
or, if these are retained, it is for services purely auxiliary. The
hideous and bewildering shrieks of the steam-siren need no longer be
heard in a fog, and the uncertain system of gun signals will soon become
a thing of the past." The interest of the naval and military strategist
in the Marconi apparatus extends far beyond its communication of
intelligence. Any electrical appliance whatever may be set in motion by
the same wave that actuates a telegraphic sounder. A fuse may be
ignited, or a motor started and directed, by apparatus connected with
the coherer, for all its minuteness. Mr. Walter Jamieson and Mr. John
Trotter have devised means for the direction of torpedoes by ether
waves, such as those set at work in the wireless telegraph. Two rods
projecting above the surface of the water receive the waves, and are in
circuit with a coherer and a relay. At the will of the distant operator
a hollow wire coil bearing a current draws in an iron core either to the
right or to the left, moving the helm accordingly.

As the news of the success of the Marconi telegraph made its way to the
London Stock Exchange there was a fall in the shares of cable companies.
The fear of rivalry from the new invention was baseless. As but fifteen
words a minute are transmissible by the Marconi system, it evidently
does not compete with a cable, such as that between France and England,
which can transmit 2,500 words a minute without difficulty. The Marconi
telegraph comes less as a competitor to old systems than as a mode of
communication which creates a field of its own. We have seen what it may
accomplish in war, far outdoing any feat possible to other apparatus,
acoustic, luminous, or electrical. In quite as striking fashion does it
break new ground in the service of commerce and trade. It enables
lighthouses continually to spell their names, so that receivers aboard
ship may give the steersmen their bearings even in storm and fog. In the
crowded condition of the steamship "lanes" which cross the Atlantic, a
priceless security against collision is afforded the man at the helm.
On November 15, 1899, Marconi telegraphed from the American liner _St.
Paul_ to the Needles, sixty-six nautical miles away. On December 11 and
12, 1901, he received wireless signals near St. John's, Newfoundland,
sent from Poldhu, Cornwall, England, or a distance of 1,800 miles,--a
feat which astonished the world. In many cases the telegraphic business
to an island is too small to warrant the laying of a cable; hence we
find that Trinidad and Tobago are to be joined by the wireless system,
as also five islands of the Hawaiian group, eight to sixty-one miles
apart.

A weak point in the first Marconi apparatus was that anybody within the
working radius of the sending-instrument could read its messages. To
modify this objection secret codes were at times employed, as in
commerce and diplomacy. A complete deliverance from this difficulty is
promised in attuning a transmitter and a receiver to the same note, so
that one receiver, and no other, shall respond to a particular frequency
of impulses. The experiments which indicate success in this vital
particular have been conducted by Professor Lodge.

When electricians, twenty years ago, committed energy to a wire and thus
enabled it to go round a corner, they felt that they had done well. The
Hertz waves sent abroad by Marconi ask no wire, as they find their way,
not round a corner, but through a corner. On May 1, 1899, a party of
French officers on board the _Ibis_ at Sangatte, near Calais, spoke to
Wimereux by means of a Marconi apparatus, with Cape Grisnez, a lofty
promontory, intervening. In ascertaining how much the earth and the sea
may obstruct the waves of Hertz there is a broad and fruitful field for
investigation. "It may be," says Professor John Trowbridge, "that such
long electrical waves roll around the surface of such obstructions very
much as waves of sound and of water would do."

[Illustration: Fig. 73--Discontinuous electric waves]

[Illustration: Fig. 74--Wehnelt interrupter]

It is singular how discoveries sometimes arrive abreast of each other so
as to render mutual aid, or supply a pressing want almost as soon as it
is felt. The coherer in its present form is actuated by waves of
comparatively low frequency, which rise from zero to full height in
extremely brief periods, and are separated by periods decidedly longer
(Fig. 73). What is needed is a plan by which the waves may flow either
continuously or so near together that they may lend themselves to
attuning. Dr. Wehnelt, by an extraordinary discovery, may, in all
likelihood, provide the lacking device in the form of his interrupter,
which breaks an electric circuit as often as two thousand times a
second. The means for this amazing performance are simplicity itself
(Fig. 74). A jar, _a_, containing a solution of sulphuric acid has two
electrodes immersed in it; one of them is a lead plate of large surface,
_b_; the other is a small platinum wire which protrudes from a glass
tube, _d_. A current passing through the cell between the two metals at
_c_ is interrupted, in ordinary cases five hundred times a second, and
in extreme cases four times as often, by bubbles of gas given off from
the wire instant by instant.


FOOTNOTES:

[3] "History of the Wireless Telegraph," by J. J. Fahie. Edinburgh and
London, William Blackwood & Sons; New York, Dodd, Mead & Co., 1899. This
work is full of interesting detail, well illustrated.

[4] The value of wireless telegraphy in relation to disasters at sea was
proved in a remarkable way yesterday morning. While the Channel was
enveloped in a dense fog, which had lasted throughout the greater part
of the night, the East Goodwin Lightship had a very narrow escape from
sinking at her moorings by being run into by the steamship _R. F.
Matthews_, 1,964 tons gross burden, of London, outward bound from the
Thames. The East Goodwin Lightship is one of four such vessels marking
the Goodwin Sands, and, curiously enough, it happens to be the one ship
which has been fitted out with Signor Marconi's installation for
wireless telegraphy. The vessel was moored about twelve miles to the
northeast of the South Foreland Lighthouse (where there is another
wireless-telegraphy installation), and she is about ten miles from the
shore, being directly opposite Deal. The information regarding the
collision was at once communicated by wireless telegraphy from the
disabled lightship to the South Foreland Lighthouse, where Mr. Bullock,
assistant to Signor Marconi, received the following message: "We have
just been run into by the steamer _R. F. Matthews_ of London. Steamship
is standing by us. Our bows very badly damaged." Mr. Bullock immediately
forwarded this information to the Trinity House authorities at
Ramsgate.--_Times_, April 29, 1899.




ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT

GEORGE ILES

     [From "Flame, Electricity and the Camera," copyright by Doubleday,
     Page & Co., New York.]


With the mastery of electricity man enters upon his first real
sovereignty of nature. As we hear the whirr of the dynamo or listen at
the telephone, as we turn the button of an incandescent lamp or travel
in an electromobile, we are partakers in a revolution more swift and
profound than has ever before been enacted upon earth. Until the
nineteenth century fire was justly accounted the most useful and
versatile servant of man. To-day electricity is doing all that fire ever
did, and doing it better, while it accomplishes uncounted tasks far
beyond the reach of flame, however ingeniously applied. We may thus
observe under our eyes just such an impetus to human intelligence and
power as when fire was first subdued to the purposes of man, with the
immense advantage that, whereas the subjugation of fire demanded ages of
weary and uncertain experiment, the mastery of electricity is, for the
most part, the assured work of the nineteenth century, and, in truth,
very largely of its last three decades. The triumphs of the electrician
are of absorbing interest in themselves, they bear a higher significance
to the student of man as a creature who has gradually come to be what he
is. In tracing the new horizons won by electric science and art, a beam
of light falls on the long and tortuous paths by which man rose to his
supremacy long before the drama of human life had been chronicled or
sung.

Of the strides taken by humanity on its way to the summit of terrestrial
life, there are but four worthy of mention as preparing the way for the
victories of the electrician--the attainment of the upright attitude,
the intentional kindling of fire, the maturing of emotional cries to
articulate speech, and the invention of written symbols for speech. As
we examine electricity in its fruitage we shall find that it bears the
unfailing mark of every other decisive factor of human advance: its
mastery is no mere addition to the resources of the race, but a
multiplier of them. The case is not as when an explorer discovers a
plant hitherto unknown, such as Indian corn, which takes its place
beside rice and wheat as a new food, and so measures a service which
ends there. Nor is it as when a prospector comes upon a new metal, such
as nickel, with the sole effect of increasing the variety of materials
from which a smith may fashion a hammer or a blade. Almost infinitely
higher is the benefit wrought when energy in its most useful phase is,
for the first time, subjected to the will of man, with dawning knowledge
of its unapproachable powers. It begins at once to marry the resources
of the mechanic and the chemist, the engineer and the artist, with issue
attested by all its own fertility, while its rays reveal province after
province undreamed of, and indeed unexisting, before its advent.

Every other primal gift of man rises to a new height at the bidding of
the electrician. All the deftness and skill that have followed from the
upright attitude, in its creation of the human hand, have been brought
to a new edge and a broader range through electric art. Between the uses
of flame and electricity have sprung up alliances which have created new
wealth for the miner and the metal-worker, the manufacturer and the
shipmaster, with new insights for the man of research. Articulate speech
borne on electric waves makes itself heard half-way across America, and
words reduced to the symbols of symbols--expressed in the perforations
of a strip of paper--take flight through a telegraph wire at twenty-fold
the pace of speech. Because the latest leap in knowledge and faculty has
been won by the electrician, he has widened the scientific outlook
vastly more than any explorer who went before. Beyond any predecessor,
he began with a better equipment and a larger capital to prove the
gainfulness which ever attends the exploiting a supreme agent of
discovery.

As we trace a few of the unending interlacements of electrical science
and art with other sciences and arts, and study their mutually
stimulating effects, we shall be reminded of a series of permutations
where the latest of the factors, because latest, multiplies all prior
factors in an unexampled degree.[5] We shall find reason to believe that
this is not merely a suggestive analogy, but really true as a tendency,
not only with regard to man's gains by the conquest of electricity, but
also with respect to every other signal victory which has brought him to
his present pinnacle of discernment and rule. If this permutative
principle in former advances lay undetected, it stands forth clearly in
that latest accession to skill and interpretation which has been ushered
in by Franklin and Volta, Faraday and Henry.

Although of much less moment than the triumphs of the electrician, the
discovery of photography ranks second in importance among the scientific
feats of the nineteenth century. The camera is an artificial eye with
almost every power of the human retina, and with many that are denied
to vision--however ingeniously fortified by the lens-maker. A brief
outline of photographic history will show a parallel to the permutative
impulse so conspicuous in the progress of electricity. At the points
where the electrician and the photographer collaborate we shall note
achievements such as only the loftiest primal powers may evoke.

A brief story of what electricity and its necessary precursor, fire,
have done and promise to do for civilization, may have attraction in
itself; so, also, may a review, though most cursory, of the work of the
camera and all that led up to it: for the provinces here are as wide as
art and science, and their bounds comprehend well-nigh the entirety of
human exploits. And between the lines of this story we may read
another--one which may tell us something of the earliest stumblings in
the dawn of human faculty. When we compare man and his next of kin, we
find between the two a great gulf, surely the widest betwixt any allied
families in nature. Can a being of intellect, conscience, and aspiration
have sprung at any time, however remote, from the same stock as the
orang and the chimpanzee? Since 1859, when Darwin published his "Origin
of Species," the theory of evolution has become so generally accepted
that to-day it is little more assailed than the doctrine of gravitation.
And yet, while the average man of intelligence bows to the formula that
all which now exists has come from the simplest conceivable state of
things,--a universal nebula, if you will,--in his secret soul he makes
one exception--himself. That there is a great deal more assent than
conviction in the world is a chiding which may come as justly from the
teacher's table as from the preacher's pulpit. Now, if we but catch the
meaning of man's mastery of electricity, we shall have light upon his
earlier steps as a fire-kindler, and as a graver of pictures and symbols
on bone and rock. As we thus recede from civilization to primeval
savagery, the process of the making of man may become so clear that the
arguments of Darwin shall be received with conviction, and not with
silent repulse.

As we proceed to recall, one by one, the salient chapters in the history
of fire, and of the arts of depiction that foreran the camera, we shall
perceive a truth of high significance. We shall see that, while every
new faculty has its roots deep in older powers, and while its growth may
have been going on for age after age, yet its flowering may be as the
event of a morning. Even as our gardens show us the century-plants, once
supposed to bloom only at the end of a hundred years, so history, in the
large, exhibits discoveries whose harvests are gathered only after the
lapse of aeons instead of years. The arts of fire were slowly elaborated
until man had produced the crucible and the still, through which his
labours culminated in metals purified, in acids vastly more corrosive
than those of vegetation, in glass and porcelain equally resistant to
flame and the electric wave. These were combined in an hour by Volta to
build his cell, and in that hour began a new era for human faculty and
insight.

It is commonly imagined that the progress of humanity has been at a
tolerably uniform pace. Our review of that progress will show that here
and there in its course have been _leaps_, as radically new forces have
been brought under the dominion of man. We of the electric revolution
are sharply marked off from our great-grandfathers, who looked upon the
cell of Volta as a curious toy. They, in their turn, were profoundly
differenced from the men of the seventeenth century, who had not learned
that flame could outvie the horse as a carrier, and grind wheat better
than the mill urged by the breeze. And nothing short of an abyss
stretches between these men and their remote ancestors, who had not
found a way to warm their frosted fingers or lengthen with lamp or
candle the short, dark days of winter.

Throughout the pages of this book there will be some recital of the
victories won by the fire-maker, the electrician, the photographer, and
many more in the peerage of experiment and research. Underlying the
sketch will appear the significant contrast betwixt accessions of minor
and of supreme dignity. The finding a new wood, such as that of the yew,
means better bows for the archer, stronger handles for the tool-maker;
the subjugation of a universal force such as fire, or electricity,
stands for the exaltation of power in every field of toil, for the
creation of a new earth for the worker, new heavens for the thinker. As
a corollary, we shall observe that an increasing width of gap marks off
the successive stages of human progress from each other, so that its
latest stride is much the longest and most decisive. And it will be
further evident that, while every new faculty is of age-long derivation
from older powers and ancient aptitudes, it nevertheless comes to the
birth in a moment, as it were, and puts a strain of probably fatal
severity on those contestants who miss the new gift by however little.
We shall, therefore, find that the principle of permutation, here merely
indicated, accounts in large measure for three cardinal facts in the
history of man: First, his leaps forward; second, the constant
accelerations in these leaps; and third, the gap in the record of the
tribes which, in the illimitable past, have succumbed as forces of a new
edge and sweep have become engaged in the fray.[6]

The interlacements of the arts of fire and of electricity are intimate
and pervasive. While many of the uses of flame date back to the dawn of
human skill, many more have become of new and higher value within the
last hundred years. Fire to-day yields motive power with tenfold the
economy of a hundred years ago, and motive power thus derived is the
main source of modern electric currents. In metallurgy there has long
been an unwitting preparation for the advent of the electrician, and
here the services of fire within the nineteenth century have won
triumphs upon which the later successes of electricity largely proceed.
In producing alloys, and in the singular use of heat to effect its own
banishment, novel and radical developments have been recorded within the
past decade or two. These, also, make easier and bolder the
electrician's tasks. The opening chapters of this book will, therefore,
bestow a glance at the principal uses of fire as these have been
revealed and applied. This glance will make clear how fire and
electricity supplement each other with new and remarkable gains, while
in other fields, not less important, electricity is nothing else than a
supplanter of the very force which made possible its own discovery and
impressment.

[Here follow chapters which outline the chief applications of flame and
of electricity.]

Let us compare electricity with its precursor, fire, and we shall
understand the revolution by which fire is now in so many tasks
supplanted by the electric pulse which, the while, creates for itself a
thousand fields denied to flame. Copper is an excellent thermal
conductor, and yet it transmits heat almost infinitely more slowly than
it conveys electricity. One end of a thick copper rod ten feet long may
be safely held in the hand while the other end is heated to redness,
yet one millionth part of this same energy, if in the form of
electricity, would traverse the rod in one 100,000,000th part of a
second. Compare next electricity with light, often the companion of
heat. Light travels in straight lines only; electricity can go round a
corner every inch for miles, and, none the worse, yield a brilliant beam
at the end of its journey. Indirectly, therefore, electricity enables us
to conduct either heat or light as if both were flexible pencils of
rays, and subject to but the smallest tolls in their travel.

We have remarked upon such methods as those of the electric welder which
summon intense heat without fire, and we have glanced at the electric
lamps which shine just because combustion is impossible through their
rigid exclusion of air. Then for a moment we paused to look at the
plating baths which have developed themselves into a commanding rivalry
with the blaze of the smelting furnace, with the flame which from time
immemorial has filled the ladle of the founder and moulder. Thus methods
that commenced in dismissing flame end boldly by dispossessing heat
itself. But, it may be said, this usurping electricity usually finds its
source, after all, in combustion under a steam-boiler. True, but mark
the harnessing of Niagara, of the Lachine Rapids near Montreal, of a
thousand streams elsewhere. In the near future motive power of Nature's
giving is to be wasted less and less, and perforce will more and more
exclude heat from the chain of transformations which issue in the
locomotive's flight, in the whirl of factory and mill. Thus in some
degree is allayed the fear, never well grounded, that when the coal
fields of the globe are spent civilization must collapse. As the
electrician hears this foreboding he recalls how much fuel is wasted in
converting heat into electricity. He looks beyond either turbine or
shaft turned by wind or tide, and, remembering that the metal dissolved
in his battery yields at his will its full content of energy, either as
heat or electricity, he asks, Why may not coal or forest tree, which are
but other kinds of fuel, be made to do the same?

One of the earliest uses of light was a means of communicating
intelligence, and to this day the signal lamp and the red fire of the
mariner are as useful as of old. But how much wider is the field of
electricity as it creates the telegraph and the telephone! In the
telegraph we have all that a pencil of light could be were it as long as
an equatorial girdle and as flexible as a silken thread. In the
telephone for nearly two thousand miles the pulsations of the speaker's
voice are not only audible, but retain their characteristic tones.

In the field of mechanics electricity is decidedly preferable to any
other agent. Heat may be transformed into motive power by a suitable
engine, but there its adaptability is at an end. An electric current
drives not only a motor, but every machine and tool attached to the
motor, the whole executing tasks of a delicacy and complication new to
industrial art. On an electric railroad an identical current propels the
train, directs it by telegraph, operates its signals, provides it with
light and heat, while it stands ready to give constant verbal
communication with any station on the line, if this be desired.

In the home electricity has equal versatility, at once promoting
healthfulness, refinement and safety. Its tiny button expels the
hazardous match as it lights a lamp which sends forth no baleful fumes.
An electric fan brings fresh air into the house--in summer as a grateful
breeze. Simple telephones, quite effective for their few yards of wire,
give a better because a more flexible service than speaking-tubes. Few
invalids are too feeble to whisper at the light, portable ear of metal.
Sewing-machines and the more exigent apparatus of the kitchen and
laundry transfer their demands from flagging human muscles to the
tireless sinews of electric motors--which ask no wages when they stand
unemployed. Similar motors already enjoy favour in working the elevators
of tall dwellings in cities. If a householder is timid about burglars,
the electrician offers him a sleepless watchman in the guise of an
automatic alarm; if he has a dread of fire, let him dispose on his walls
an array of thermometers that at the very inception of a blaze will
strike a gong at headquarters. But these, after all, are matters of
minor importance in comparison with the foundations upon which may be
reared, not a new piece of mechanism, but a new science or a new art.

In the recent swift subjugation of the territory open alike to the
chemist and the electrician, where each advances the quicker for the
other's company, we have fresh confirmation of an old truth--that the
boundary lines which mark off one field of science from another are
purely artificial, are set up only for temporary convenience. The
chemist has only to dig deep enough to find that the physicist and
himself occupy common ground. "Delve from the surface of your sphere to
its heart, and at once your radius joins every other." Even the briefest
glance at electro-chemistry should pause to acknowledge its profound
debt to the new theories as to the bonding of atoms to form molecules,
and of the continuity between solution and electrical dissociation.
However much these hypotheses may be modified as more light is shed on
the geometry and the journeyings of the molecule, they have for the time
being recommended themselves as finder-thoughts of golden value. These
speculations of the chemist carry him back perforce to the days of his
childhood. As he then joined together his black and white bricks he
found that he could build cubes of widely different patterns. It was in
propounding a theory of molecular architecture that Kekule gave an
impetus to a vast and growing branch of chemical industry--that of the
synthetic production of dyes and allied compounds.

It was in pure research, in paths undirected to the market-place, that
such theories have been thought out. Let us consider electricity as an
aid to investigation conducted for its own sake. The chief physical
generalization of our time, and of all time, the persistence of force,
emerged to view only with the dawn of electric art. When it was observed
that electricity might become heat, light, chemical action, or
mechanical motion, that in turn any of these might produce electricity,
it was at once indicated that all these phases of energy might differ
from each other only as the movements in circles, volutes, and spirals
of ordinary mechanism. The suggestion was confirmed when electrical
measurers were refined to the utmost precision, and a single quantum of
energy was revealed a very Proteus in its disguises, yet beneath these
disguises nothing but constancy itself.

"There is that scattereth, and yet increaseth; and there is that
withholdeth more than is meet, but it tendeth to poverty." Because the
geometers of old patiently explored the properties of the triangle, the
circle, and the ellipse, simply for pure love of truth, they laid the
corner-stones for the arts of the architect, the engineer, and the
navigator. In like manner it was the disinterested work of investigation
conducted by Ampere, Faraday, Henry and their compeers, in ascertaining
the laws of electricity which made possible the telegraph, the
telephone, the dynamo, and the electric furnace. The vital relations
between pure research and economic gain have at last worked themselves
clear. It is perfectly plain that a man who has it in him to discover
laws of matter and energy does incomparably more for his kind than if he
carried his talents to the mint for conversion into coin. The voyage of
a Columbus may not immediately bear as much fruit as the uncoverings of
a mine prospector, but in the long run a Columbus makes possible the
finding many mines which without him no prospector would ever see.
Therefore let the seed-corn of knowledge be planted rather than eaten.
But in choosing between one research and another it is impossible to
foretell which may prove the richer in its harvests; for instance, all
attempts thus far economically to oxidize carbon for the production of
electricity have failed, yet in observations that at first seemed
equally barren have lain the hints to which we owe the incandescent lamp
and the wireless telegraph.

Perhaps the most promising field of electrical research is that of
discharges at high pressures; here the leading American investigators
are Professor John Trowbridge and Professor Elihu Thomson. Employing a
tension estimated at one and a half millions volts, Professor Trowbridge
has produced flashes of lightning six feet in length in atmospheric air;
in a tube exhausted to one-seventh of atmospheric pressure the flashes
extended themselves to forty feet. According to this inquirer, the
familiar rending of trees by lightning is due to the intense heat
developed in an instant by the electric spark; the sudden expansion of
air or steam in the cavities of the wood causes an explosion. The
experiments of Professor Thomson confront him with some of the seeming
contradictions which ever await the explorer of new scientific
territory. In the atmosphere an electrical discharge is facilitated when
a metallic terminal (as a lightning rod) is shaped as a point; under oil
a point is the form least favourable to discharge. In the same line of
paradox it is observed that oil steadily improves in its insulating
effect the higher the electrical pressure committed to its keeping; with
air as an insulator the contrary is the fact. These and a goodly array
of similar puzzles will, without doubt, be cleared up as students in the
twentieth century pass from the twilight of anomaly to the sunshine of
ascertained law.

"Before there can be applied science there must be science to apply,"
and it is by enabling the investigator to know nature under a fresh
aspect that electricity rises to its highest office. The laboratory
routine of ascertaining the conductivity, polarisability, and other
electrical properties of matter is dull and exacting work, but it opens
to the student new windows through which to peer at the architecture of
matter. That architecture, as it rises to his view, discloses one law of
structure after another; what in a first and clouded glance seemed
anomaly is now resolved and reconciled; order displays itself where
once anarchy alone appeared. When the investigator now needs a substance
of peculiar properties he knows where to find it, or has a hint for its
creation--a creation perhaps new in the history of the world. As he
thinks of the wealth of qualities possessed by his store of alloys,
salts, acids, alkalies, new uses for them are borne into his mind. Yet
more--a new orchestration of inquiry is possible by means of the
instruments created for him by the electrician, through the advances in
method which these instruments effect. With a second and more intimate
point of view arrives a new trigonometry of the particle, a trigonometry
inconceivable in pre-electric days. Hence a surround is in progress
which early in the twentieth century may go full circle, making atom and
molecule as obedient to the chemist as brick and stone are to the
builder now.

The laboratory investigator and the commercial exploiter of his
discoveries have been by turns borrower and lender, to the great profit
of both. What Leyden jar could ever be constructed of the size and
revealing power of an Atlantic cable? And how many refinements of
measurement, of purification of metals, of precision in manufacture,
have been imposed by the colossal investments in deep-sea telegraphy
alone! When a current admitted to an ocean cable, such as that between
Brest and New York, can choose for its path either 3,540 miles of copper
wire or a quarter of an inch of gutta-percha, there is a dangerous
opportunity for escape into the sea, unless the current is of nicely
adjusted strength, and the insulator has been made and laid with the
best-informed skill, the most conscientious care. In the constant tests
required in laying the first cables Lord Kelvin (then Professor William
Thomson) felt the need for better designed and more sensitive
galvanometers or current measurers. His great skill both as a
mathematician and a mechanician created the existing instruments, which
seem beyond improvement. They serve not only in commerce and
manufacture, but in promoting the strictly scientific work of the
laboratory. Now that electricity purifies copper as fire cannot, the
mathematician is able to treat his problems of long-distance
transmission, of traction, of machine design, with an economy and
certainty impossible when his materials were not simply impure, but
impure in varying and indefinite degrees. The factory and the workshop
originally took their magneto-machines from the experimental laboratory;
they have returned them remodelled beyond recognition as dynamos and
motors of almost ideal effectiveness.

A galvanometer actuated by a thermo-electric pile furnishes much the
most sensitive means of detecting changes of temperature; hence
electricity enables the physicist to study the phenomena of heat with
new ease and precision. It was thus that Professor Tyndall conducted
the classical researches set forth in his "Heat as a Mode of Motion,"
ascertaining the singular power to absorb terrestrial heat which makes
the aqueous vapours of the atmosphere act as an indispensable blanket to
the earth.

And how vastly has electricity, whether in the workshop or laboratory,
enlarged our conceptions of the forces that thrill space, of the
substances, seemingly so simple, that surround us--substances that
propound questions of structure and behaviour that silence the acutest
investigator. "You ask me," said a great physicist, "if I have a theory
of the _universe_? Why, I haven't even a theory of _magnetism_!"

The conventional phrase "conducting a current" is now understood to be
mere figure of speech; it is thought that a wire does little else than
give direction to electric energy. Pulsations of high tension have been
proved to be mainly superficial in their journeys, so that they are best
conveyed (or convoyed) by conductors of tubular form. And what is it
that moves when we speak of conduction? It seems to be now the molecule
of atomic chemistry, and anon the same ether that undulates with light
or radiant heat. Indeed, the conquest of electricity means so much
because it impresses the molecule and the ether into service as its
vehicles of communication. Instead of the old-time masses of metal, or
bands of leather, which moved stiffly through ranges comparatively
short, there is to-day employed a medium which may traverse 186,400
miles in a second, and with resistances most trivial in contrast with
those of mechanical friction.

And what is friction in the last analysis but the production of motion
in undesired forms, the allowing valuable energy to do useless work? In
that amazing case of long distance transmission, common sunshine, a
solar beam arrives at the earth from the sun not one whit the weaker for
its excursion of 92,000,000 miles. It is highly probable that we are
surrounded by similar cases of the total absence of friction in the
phenomena of both physics and chemistry, and that art will come nearer
and nearer to nature in this immunity is assured when we see how many
steps in that direction have already been taken by the electrical
engineer. In a preceding page a brief account was given of the theory
that gases and vapours are in ceaseless motion. This motion suffers no
abatement from friction, and hence we may infer that the molecules
concerned are perfectly elastic. The opinion is gaining ground among
physicists that all the properties of matter, transparency, chemical
combinability, and the rest, are due to immanent motion in particular
orbits, with diverse velocities. If this be established, then these
motions also suffer no friction, and go on without resistance forever.

As the investigators in the vanguard of science discuss the constitution
of matter, and weave hypotheses more or less fruitful as to the
interplay of its forces, there is a growing faith that the day is at
hand when the tie between electricity and gravitation will be
unveiled--when the reason why matter has weight will cease to puzzle the
thinker. Who can tell what relief of man's estate may be bound up with
the ability to transform any phase of energy into any other without the
circuitous methods and serious losses of to-day! In the sphere of
economic progress one of the supreme advances was due to the invention
of money, the providing a medium for which any salable thing may be
exchanged, with which any purchasable thing may be bought. As soon as a
shell, or a hide, or a bit of metal was recognized as having universal
convertibility, all the delays and discounts of barter were at an end.
In the world of physics and chemistry the corresponding medium is
electricity; let it be produced as readily as it produces other modes of
motion, and human art will take a stride forward such as when Volta
disposed his zinc and silver discs together, or when Faraday set a
magnet moving around a copper wire.

For all that the electric current is not as yet produced as economically
as it should be, we do wrong if we regard it as an infant force. However
much new knowledge may do with electricity in the laboratory, in the
factory, or in the exchange, some of its best work is already done. It
is not likely ever to perform a greater feat than placing all mankind
within ear-shot of each other. Were electricity unmastered there could
be no democratic government of the United States. To-day the drama of
national affairs is more directly in view of every American citizen
than, a century ago, the public business of Delaware could be to the men
of that little State. And when on the broader stage of international
politics misunderstandings arise, let us note how the telegraph has
modified the hard-and-fast rules of old-time diplomacy. To-day, through
the columns of the press, the facts in controversy are instantly
published throughout the world, and thus so speedily give rise to
authoritative comment that a severe strain is put upon negotiators whose
tradition it is to be both secret and slow.

Railroads, with all they mean for civilization, could not have extended
themselves without the telegraph to control them. And railroads and
telegraphs are the sinews and nerves of national life, the prime
agencies in welding the diverse and widely separated States and
Territories of the Union. A Boston merchant builds a cotton-mill in
Georgia; a New York capitalist opens a copper-mine in Arizona. The
telegraph which informs them day by day how their investments prosper
tells idle men where they can find work, where work can seek idle men.
Chicago is laid in ashes, Charleston topples in earthquake, Johnstown is
whelmed in flood, and instantly a continent springs to their relief. And
what benefits issue in the strictly commercial uses of the telegraph!
At its click both locomotive and steamship speed to the relief of famine
in any quarter of the globe. In times of plenty or of dearth the markets
of the globe are merged and are brought to every man's door. Not less
striking is the neighbourhood guild of science, born, too, of the
telegraph. The day after Roentgen announced his X rays, physicists on
every continent were repeating his experiments--were applying his
discovery to the healing of the wounded and diseased. Let an anti-toxin
for diphtheria, consumption, or yellow fever be proposed, and a hundred
investigators the world over bend their skill to confirm or disprove, as
if the suggester dwelt next door.

On a stage less dramatic, or rather not dramatic at all, electricity
works equal good. Its motor freeing us from dependence on the horse is
spreading our towns and cities into their adjoining country. Field and
garden compete with airless streets. The sunny cottage is in active
rivalry with the odious tenement-house. It is found that transportation
within the gates of a metropolis has an importance second only to the
means of transit which links one city with another. The engineer is at
last filling the gap which too long existed between the traction of
horses and that of steam. In point of speed, cleanliness, and comfort
such an electric subway as that of South London leaves nothing to be
desired. Throughout America electric roads, at first suburban, are now
fast joining town to town and city to city, while, as auxiliaries to
steam railroads, they place sparsely settled communities in the arterial
current of the world, and build up a ready market for the dairyman and
the fruit-grower. In its saving of what Mr. Oscar T. Crosby has called
"man-hours" the third-rail system is beginning to oust steam as a motive
power from trunk-lines. Already shrewd railroad managers are granting
partnerships to the electricians who might otherwise encroach upon their
dividends. A service at first restricted to passengers has now extended
itself to the carriage of letters and parcels, and begins to reach out
for common freight. We may soon see the farmer's cry for good roads
satisfied by good electric lines that will take his crops to market much
more cheaply and quickly than horses and macadam ever did. In cities,
electromobile cabs and vans steadily increase in numbers, furthering the
quiet and cleanliness introduced by the trolley car.

A word has been said about the blessings which electricity promises to
country folk, yet greater are the boons it stands ready to bestow in the
hives of population. Until a few decades ago the water-supply of cities
was a matter not of municipal but of individual enterprise; water was
drawn in large part from wells here and there, from lines of piping laid
in favoured localities, and always insufficient. Many an epidemic of
typhoid fever was due to the contamination of a spring by a cesspool a
few yards away. To-day a supply such as that of New York is abundant
and cheap because it enters every house. Let a centralized electrical
service enjoy a like privilege, and it will offer a current which is
heat, light, chemical energy, or motive power, and all at a wage lower
than that of any other servant. Unwittingly, then, the electrical
engineer is a political reformer of high degree, for he puts a new
premium upon ability and justice at the City Hall. His sole condition is
that electricity shall be under control at once competent and honest.
Let us hope that his plea, joined to others as weighty, may quicken the
spirit of civic righteousness so that some of the richest fruits ever
borne in the garden of science and art may not be proffered in vain.
Flame, the old-time servant, is individual; electricity, its successor
and heir, is collective. Flame sits upon the hearth and draws a family
together; electricity, welling from a public source, may bind into a
unit all the families of a vast city, because it makes the benefit of
each the interest of all.

But not every promise brought forward in the name of the electrician has
his assent or sanction. So much has been done by electricity, and so
much more is plainly feasible, that a reflection of its triumphs has
gilded many a baseless dream. One of these is that the cheap electric
motor, by supply power at home, will break up the factory system, and
bring back the domestic manufacturing of old days. But if this power
cost nothing at all the gift would leave the factory unassailed; for we
must remember that power is being steadily reduced in cost from year to
year, so that in many industries it has but a minor place among the
expenses of production. The strength and profit of the factory system
lie in its assembling a wide variety of machines, the first delivering
its product to the second for another step toward completion, and so on
until a finished article is sent to the ware-room. It is this minute
subdivision of labour, together with the saving and efficiency that
inure to a business conducted on an immense scale under a single
manager, that bids us believe that the factory has come to stay. To be
sure, a weaver, a potter, or a lens-grinder of peculiar skill may thrive
at his loom or wheel at home; but such a man is far from typical in
modern manufacture. Besides, it is very questionable whether the
lamentations over the home industries of the past do not ignore evil
concomitants such as still linger in the home industries of the
present--those of the sweater's den, for example.

This rapid survey of what electricity has done and may yet do--futile
expectation dismissed--has shown it the creator of a thousand material
resources, the perfector of that communication of things, of power, of
thought, which in every prior stage of advancement has marked the
successive lifts of humanity. It was much when the savage loaded a pack
upon a horse or an ox instead of upon his own back; it was yet more when
he could make a beacon-flare give news or warning to a whole
country-side, instead of being limited to the messages which might be
read in his waving hands. All that the modern engineer was able to do
with steam for locomotion is raised to a higher plane by the advent of
his new power, while the long-distance transmission of electrical energy
is contracting the dimensions of the planet to a scale upon which its
cataracts in the wilderness drive the spindles and looms of the factory
town, or illuminate the thoroughfares of cities. Beyond and above all
such services as these, electricity is the corner-stone of physical
generalization, a revealer of truths impenetrable by any other ray.

The subjugation of fire has done much in giving man a new independence
of nature, a mighty armoury against evil. In curtailing the most arduous
and brutalizing forms of toil, electricity, that subtler kind of fire,
carries this emancipation a long step further, and, meanwhile, bestows
upon the poor many a luxury which but lately was the exclusive
possession of the rich. In more closely binding up the good of the bee
with the welfare of the hive, it is an educator and confirmer of every
social bond. In so far as it proffers new help in the war on pain and
disease it strengthens the confidence of man in an Order of Right and
Happiness which for so many dreary ages has been a matter rather of hope
than of vision. Are we not, then, justified in holding electricity to be
a multiplier of faculty and insight, a means of dignifying mind and
soul, unexampled since man first kindled fire and rejoiced?

We have traced how dexterity rose to fire-making, how fire-making led to
the subjugation of electricity. Much of the most telling work of fire
can be better done by its great successor, while electricity performs
many tasks possible only to itself. Unwitting truth there was in the
simple fable of the captive who let down a spider's film, that drew up a
thread, which in turn brought up a rope--and freedom. It was in 1800 on
the threshold of the nineteenth century, that Volta devised the first
electric battery. In a hundred years the force then liberated has
vitally interwoven itself with every art and science, bearing fruit not
to be imagined even by men of the stature of Watt, Lavoisier, or
Humboldt. Compare this rapid march of conquest with the slow adaptation,
through age after age, of fire to cooking, smelting, tempering. Yet it
was partly, perhaps mainly, because the use of fire had drawn out man's
intelligence and cultivated his skill that he was ready in the fulness
of time so quickly to seize upon electricity and subdue it.

Electricity is as legitimately the offspring of fire as fire of the
simple knack in which one savage in ten thousand was richer than his
fellows. The principle of permutation, suggested in both victories,
interprets not only how vast empire is won by a new weapon of prime
dignity; it explains why such empires are brought under rule with
ever-accelerated pace. Every talent only pioneers the way for the
richer talents which are born from it.


FOOTNOTES:

[5] Permutations are the various ways in which two or more different
things may be arranged in a row, all the things appearing in each row.
Permutations are readily illustrated with squares or cubes of different
colours, with numbers, or letters.

Permutations of two elements, 1 and 2, are (1 x 2) two; 1, 2; 2, 1; or
_a_, _b_; _b_, _a_. Of three elements the permutations are (1 x 2 x 3)
six; 1, 2, 3; 1, 3, 2; 2, 1, 3; 2, 3, 1; 3, 1, 2; 3, 2, 1; or _a_, _b_,
_c_; _a_, _c_, _b_; _b_, _a_, _c_; _b_, _c_, _a_; _c_, _a_, _b_; _c_,
_b_, _a_. Of four elements the permutations are (1 x 2 x 3 x 4)
twenty-four; of five elements, one hundred and twenty, and so on. A new
element or permutator multiplies by an increasing figure all the
permutations it finds.

[6] Some years ago I sent an outline of this argument to Herbert
Spencer, who replied: "I recognize a novelty and value in your inference
that the law implies an increasing width of gap between lower and higher
types as evolution advances."




COUNT RUMFORD IDENTIFIES HEAT WITH MOTION.

     [Benjamin Thompson, who received the title of Count Rumford from
     the Elector of Bavaria, was born in Woburn, Massachusetts, in 1753.
     When thirty-one years of age he settled in Munich, where he devoted
     his remarkable abilities to the public service. Twelve years
     afterward he removed to England; in 1800 he founded the Royal
     Institution of London, since famous as the theatre of the labours
     of Davy, Faraday, Tyndall, and Dewar. He bequeathed to Harvard
     University a fund to endow a professorship of the application of
     science to the art of living: he instituted a prize to be awarded
     by the American Academy of Sciences for the most important
     discoveries and improvements relating to heat and light. In 1804 he
     married the widow of the illustrious chemist Lavoisier: he died in
     1814. Count Rumford on January 25, 1798, read a paper before the
     Royal Society entitled "An Enquiry Concerning the Source of Heat
     Which Is Excited by Friction." The experiments therein detailed
     proved that heat is identical with motion, as against the notion
     that heat is matter. He thus laid the corner-stone of the modern
     theory that heat light, electricity, magnetism, chemical action,
     and all other forms of energy are in essence motion, are
     convertible into one another, and as motion are indestructible. The
     following abstract of Count Rumford's paper is taken from "Heat as
     a Mode of Motion," by Professor John Tyndall, published by D.
     Appleton & Co., New York. This work and "The Correlation and
     Conservation of Forces," edited by Dr. E. L. Youmans, published by
     the same house, will serve as a capital introduction to the modern
     theory that energy is motion which, however varied in its forms, is
     changeless in its quantity.]


Being engaged in superintending the boring of cannon in the workshops of
the military arsenal at Munich, Count Rumford was struck with the very
considerable degree of heat which a brass gun acquires, in a short time,
in being bored, and with the still more intense heat (much greater than
that of boiling water) of the metallic chips separated from it by the
borer, he proposed to himself the following questions:

"Whence comes the heat actually produced in the mechanical operations
above mentioned?

"Is it furnished by the metallic chips which are separated from the
metal?"

If this were the case, then the _capacity for heat_ of the parts of the
metal so reduced to chips ought not only to be changed, but the change
undergone by them should be sufficiently great to account for _all_ the
heat produced. No such change, however, had taken place, for the chips
were found to have the same capacity as slices of the same metal cut by
a fine saw, where heating was avoided. Hence, it is evident, that the
heat produced could not possibly have been furnished at the expense of
the latent heat of the metallic chips. Rumford describes these
experiments at length, and they are conclusive.

He then designed a cylinder for the express purpose of generating heat
by friction, by having a blunt borer forced against its solid bottom,
while the cylinder was turned around its axis by the force of horses. To
measure the heat developed, a small round hole was bored in the
cylinder for the purpose of introducing a small mercurial thermometer.
The weight of the cylinder was 113.13 pounds avoirdupois.

The borer was a flat piece of hardened steel, 0.63 of an inch thick,
four inches long, and nearly as wide as the cavity of the bore of the
cylinder, namely, three and one-half inches. The area of the surface by
which its end was in contact with the bottom of the bore was nearly two
and one-half inches. At the beginning of the experiment the temperature
of the air in the shade, and also that of the cylinder, was 60 deg. Fahr. At
the end of thirty minutes, and after the cylinder had made 960
revolutions round its axis, the temperature was found to be 130 deg..

Having taken away the borer, he now removed the metallic dust, or rather
scaly matter, which had been detached from the bottom of the cylinder by
the blunt steel borer, and found its weight to be 837 grains troy. "Is
it possible," he exclaims, "that the very considerable quantity of heat
produced in this experiment--a quantity which actually raised the
temperature of above 113 pounds of gun-metal at least 70 deg. of
Fahrenheit's thermometer--could have been furnished by so inconsiderable
a quantity of metallic dust and this merely in consequence of a _change_
in its capacity of heat?"

"But without insisting on the improbability of this supposition, we have
only to recollect that from the results of actual and decisive
experiments, made for the express purpose of ascertaining that fact,
the capacity for heat for the metal of which great guns are cast is _not
sensibly changed_ by being reduced to the form of metallic chips, and
there does not seem to be any reason to think that it can be much
changed, if it be changed at all, in being reduced to much smaller
pieces by a borer which is less sharp."

He next surrounded his cylinder by an oblong deal-box, in such a manner
that the cylinder could turn water-tight in the centre of the box, while
the borer was pressed against the bottom of the cylinder. The box was
filled with water until the entire cylinder was covered, and then the
apparatus was set in action. The temperature of the water on commencing
was 60 deg..

"The result of this beautiful experiment," writes Rumford, "was very
striking, and the pleasure it afforded me amply repaid me for all the
trouble I had had in contriving and arranging the complicated machinery
used in making it. The cylinder had been in motion but a short time,
when I perceived, by putting my hand into the water, and touching the
outside of the cylinder, that heat was generated.

"At the end of one hour the fluid, which weighed 18.77 pounds, or two
and one-half gallons, had its temperature raised forty-seven degrees,
being now 107 deg..

"In thirty minutes more, or one hour and thirty minutes after the
machinery had been set in motion, the heat of the water was 142 deg..

"At the end of two hours from the beginning, the temperature was 178 deg..

"At two hours and twenty minutes it was 200 deg., and at two hours and
thirty minutes it _actually boiled_!"

"It would be difficult to describe the surprise and astonishment
expressed in the countenances of the bystanders on seeing so large a
quantity of water heated, and actually made to boil, without any fire.
Though, there was nothing that could be considered very surprising in
this matter, yet I acknowledge fairly that it afforded me a degree of
childish pleasure which, were I ambitious of the reputation of a grave
philosopher, I ought most certainly rather to hide than to discover."

He then carefully estimates the quantity of heat possessed by each
portion of his apparatus at the conclusion of the experiment, and,
adding all together, finds a total sufficient to raise 26.58 pounds of
ice-cold water to its boiling point, or through 180 deg. Fahrenheit. By
careful calculation, he finds this heat equal to that given out by the
combustion of 2,303.8 grains (equal to four and eight-tenths ounces
troy) of wax.

He then determines the "_celerity_" with which the heat was generated,
summing up thus: "From the results of these computations, it appears
that the quantity of heat produced equably, or in a continuous stream,
if I may use the expression, by the friction of the blunt steel borer
against the bottom of the hollow metallic cylinder, was _greater_ than
that produced in the combustion of nine _wax-candles_, each
three-quarters of an inch in diameter, all burning together with clear
bright flames.

"One horse would have been equal to the work performed, though two were
actually employed. Heat may thus be produced merely by the strength of a
horse, and, in a case of necessity, this heat might be used in cooking
victuals. But no circumstances could be imagined in which this method of
procuring heat would be advantageous, for more heat might be obtained by
using the fodder necessary for the support of a horse as fuel."

[This is an extremely significant passage, intimating as it does, that
Rumford saw clearly that the force of animals was derived from the food;
_no creation of force_ taking place in the animal body.]

"By meditating on the results of all these experiments, we are naturally
brought to that great question which has so often been the subject of
speculation among philosophers, namely, What is heat--is there any such
thing as an _igneous fluid_? Is there anything that, with propriety, can
be called caloric?

"We have seen that a very considerable quantity of heat may be excited
by the friction of two metallic surfaces, and given off in a constant
stream or flux _in all directions_, without interruption or
intermission, and without any signs of _diminution_ or _exhaustion_. In
reasoning on this subject we must not forget _that most remarkable
circumstance_, that the source of the heat generated by friction in
these experiments appeared evidently to be _inexhaustible_. [The italics
are Rumford's.] It is hardly necessary to add, that anything which any
_insulated_ body or system of bodies can continue to furnish _without
limitation_ cannot possibly be a _material substance_; and it appears to
me to be extremely difficult, if not quite impossible, to form any
distinct idea of anything capable of being excited and communicated in
those experiments, except it be MOTION."

When the history of the dynamical theory of heat is written, the man
who, in opposition to the scientific belief of his time, could
experiment and reason upon experiment, as Rumford did in the
investigation here referred to, cannot be lightly passed over. Hardly
anything more powerful against the materiality of heat has been since
adduced, hardly anything more conclusive in the way of establishing that
heat is, what Rumford considered it to be, _Motion_.




VICTORY OF THE "ROCKET" LOCOMOTIVE.

     [Part of Chapter XII. Part II, of "The Life of George Stephenson
     and of His Son, Robert Stephenson," by Samuel Smiles New York,
     Harper & Brothers, 1868.]


The works of the Liverpool and Manchester Railway were now approaching
completion. But, strange to say, the directors had not yet decided as to
the tractive power to be employed in working the line when open for
traffic. The differences of opinion among them were so great as
apparently to be irreconcilable. It was necessary, however, that they
should, come to some decision without further loss of time, and many
board meetings were accordingly held to discuss the subject. The
old-fashioned and well-tried system of horse-haulage was not without its
advocates; but, looking at the large amount of traffic which there was
to be conveyed, and at the probable delay in the transit from station to
station if this method were adopted, the directors, after a visit made
by them to the Northumberland and Durham railways in 1828, came to the
conclusion that the employment of horse-power was inadmissible.

Fixed engines had many advocates; the locomotive very few: it stood as
yet almost in a minority of one--George Stephenson....

In the meantime the discussion proceeded as to the kind of power to be
permanently employed for the working of the railway. The directors were
inundated with schemes of all sorts for facilitating locomotion. The
projectors of England, France, and America seemed to be let loose upon
them. There were plans for working the waggons along the line by
water-power. Some proposed hydrogen, and others carbonic acid gas.
Atmospheric pressure had its eager advocates. And various kinds of fixed
and locomotive steam-power were suggested. Thomas Gray urged his plan of
a greased road with cog-rails; and Messrs. Vignolles and Ericsson
recommended the adoption of a central friction-rail, against which two
horizontal rollers under the locomotive, pressing upon the sides of this
rail, were to afford the means of ascending the inclined planes....

The two best practical engineers of the day concurred in reporting
substantially in favour of the employment of fixed engines. Not a single
professional man of eminence could be found to coincide with the
engineer of the railway in his preference for locomotive over fixed
engine power. He had scarcely a supporter, and the locomotive system
seemed on the eve of being abandoned. Still he did not despair. With the
profession against him, and public opinion against him--for the most
frightful stories went abroad respecting the dangers, the unsightliness,
and the nuisance which the locomotive would create--Stephenson held to
his purpose. Even in this, apparently the darkest hour of the
locomotive, he did not hesitate to declare that locomotive railroads
would, before many years had passed, be "the great highways of the
world."

He urged his views upon the directors in all ways, in season, and, as
some of them thought, out of season. He pointed out the greater
convenience of locomotive power for the purposes of a public highway,
likening it to a series of short unconnected chains, any one of which
could be removed and another substituted without interruption to the
traffic; whereas the fixed-engine system might be regarded in the light
of a continuous chain extending between the two termini, the failure of
any link of which would derange the whole. But the fixed engine party
was very strong at the board, and, led by Mr. Cropper, they urged the
propriety of forthwith adopting the report of Messrs. Walker and
Rastrick. Mr. Sandars and Mr. William Rathbone, on the other hand,
desired that a fair trial should be given to the locomotive; and they
with reason objected to the expenditure of the large capital necessary
to construct the proposed engine-houses, with their fixed engines,
ropes, and machinery, until they had tested the powers of the locomotive
as recommended by their own engineer. George Stephenson continued to
urge upon them that the locomotive was yet capable of great
improvements, if proper inducements were held out to inventors and
machinists to make them; and he pledged himself that, if time were
given him, he would construct an engine that should satisfy their
requirements, and prove itself capable of working heavy loads along the
railway with speed, regularity, and safety. At length, influenced by his
persistent earnestness not less than by his arguments, the directors, at
the suggestion of Mr. Harrison, determined to offer a prize of L500 for
the best locomotive engine, which, on a certain day, should be produced
on the railway, and perform certain specified conditions in the most
satisfactory manner.[7]

The requirements of the directors as to speed were not excessive. All
that they asked for was that ten miles an hour should be maintained.
Perhaps they had in mind the animadversions of the _Quarterly Review_ on
the absurdity of travelling at a greater velocity, and also the remarks
published by Mr. Nicholas Wood, whom they selected to be one of the
judges of the competition, in conjunction, with Mr. Rastrick, of
Stourbridge, and Mr. Kennedy, of Manchester.

It was now felt that the fate of railways in a great measure depended
upon the issue of this appeal to the mechanical genius of England. When
the advertisement of the prize for the best locomotive was published,
scientific men began more particularly to direct their attention to the
new power which was thus struggling into existence. In the meantime
public opinion on the subject of railway working remained suspended, and
the progress of the undertaking was watched with intense interest.

During the progress of this important controversy with reference to the
kind of power to be employed in working the railway, George Stephenson
was in constant communication with his son Robert, who made frequent
visits to Liverpool for the purpose of assisting his father in the
preparation of his reports to the board on the subject. Mr. Swanwick
remembers the vivid interest of the evening discussions which then took
place between father and son as to the best mode of increasing the
powers and perfecting the mechanism of the locomotive. He wondered at
their quick perception and rapid judgment on each other's suggestions;
at the mechanical difficulties which they anticipated and provided for
in the practical arrangement of the machine; and he speaks of these
evenings as most interesting displays of two actively ingenious and able
minds stimulating each other to feats of mechanical invention, by which
it was ordained that the locomotive engine should become what it now is.
These discussions became more frequent, and still more interesting,
after the public prize had been offered for the best locomotive by the
directors of the railway, and the working plans of the engine which they
proposed to construct had to be settled.

One of the most important considerations in the new engine was the
arrangement of the boiler, and the extension of its heating surface to
enable steam enough to be raised rapidly and continuously for the
purpose of maintaining high rates of speed--the effect of high pressure
engines being ascertained to depend mainly upon the quantity of steam
which the boiler can generate, and upon its degree of elasticity when
produced. The quantity of steam so generated, it will be obvious, must
chiefly depend upon the quantity of fuel consumed in the furnace, and,
by necessary consequence, upon the high rate of temperature maintained
there.

It will be remembered that in Stephenson's first Killingworth engines he
invited and applied the ingenious method of stimulating combustion in
the furnace by throwing the waste steam into the chimney after
performing its office in the cylinders, thereby accelerating the ascent
of the current of air, greatly increasing the draught, and consequently
the temperature of the fire. This plan was adopted by him, as we have
seen, as early as 1815, and it was so successful that he himself
attributed to it the greater economy of the locomotive as compared with
horse-power. Hence the continuance of its use upon the Killingworth
Railway.

Though the adoption of the steam blast greatly quickened combustion and
contributed to the rapid production of high-pressure steam, the limited
amount of heating surface presented to the fire was still felt to be an
obstacle to the complete success of the locomotive engine. Mr.
Stephenson endeavoured to overcome this by lengthening the boilers and
increasing the surface presented by the flue-tubes. The "Lancashire
Witch," which he built for the Bolton and Leigh Railway, and used in
forming the Liverpool and Manchester Railway embankments, was
constructed with a double tube, each of which contained a fire, and
passed longitudinally through the boiler. But this arrangement
necessarily led to a considerable increase in the weight of those
engines, which amounted to about twelve tons each; and as six tons was
the limit allowed for engines admitted to the Liverpool competition, it
was clear that the time was come when the Killingworth engine must
undergo a farther important modification.

For many years previous to this period, ingenious mechanics had been
engaged in attempting to solve the problem of the best and most
economical boiler for the production of high-pressure steam.

The use of tubes in boilers for increasing the heating surface had long
been known. As early as 1780, Matthew Boulton employed copper tubes
longitudinally in the boiler of the Wheal Busy engine in Cornwall--the
fire passing _through_ the tubes--and it was found that the production
of steam was thereby considerably increased. The use of tubular boilers
afterwards became common in Cornwall. In 1803, Woolf, the Cornish
engineer, patented a boiler with tubes, with the same object of
increasing the heating surface. The water was _inside_ the tubes, and
the fire of the boiler outside. Similar expedients were proposed by
other inventors. In 1815 Trevithick invented his light high-pressure
boiler for portable purposes, in which, to "expose a large surface to
the fire," he constructed the boiler of a number of small perpendicular
tubes "opening into a common reservoir at the top." In 1823 W. H. James
contrived a boiler composed of a series of annular wrought-iron tubes,
placed side by side and bolted together, so as to form by their union a
long cylindrical boiler, in the centre of which, at the end, the
fireplace was situated. The fire played round the tubes, which contained
the water. In 1826 James Neville took out a patent for a boiler with
vertical tubes surrounded by the water, through which the heated air of
the furnace passed, explaining also in his specification that the tubes
might be horizontal or inclined, according to circumstances. Mr.
Goldsworthy, the persevering adaptor of steam-carriages to travelling on
common roads, applied the tubular principle in the boiler of his engine,
in which the steam was generated _within_ the tubes; while the boiler
invented by Messrs. Summer and Ogle for their turnpike-road
steam-carriage consisted of a series of tubes placed vertically over the
furnace, through which the heated air passed before reaching the
chimney.

About the same time George Stephenson was trying the effect of
introducing small tubes in the boilers of his locomotives, with the
object of increasing their evaporative power. Thus, in 1829, he sent to
France two engines constructed at the Newcastle works for the Lyons and
St. Etienne Railway, in the boilers of which tubes were placed
containing water. The heating surface was thus considerably increased;
but the expedient was not successful, for the tubes, becoming furred
with deposit, shortly burned out and were removed. It was then that M.
Seguin, the engineer of the railway, pursuing the same idea, is said to
have adopted his plan of employing horizontal tubes through which the
heated air passed in streamlets, and for which he took out a French
patent.

In the meantime Mr. Henry Booth, secretary to the Liverpool and
Manchester Railway, whose attention had been directed to the subject on
the prize being offered for the best locomotive to work that line,
proposed the same method, which, unknown to him, Matthew Boulton had
employed but not patented, in 1780, and James Neville had patented, but
not employed, in 1826; and it was carried into effect by Robert
Stephenson in the construction of the "Rocket," which won the prize at
Rainhill in October, 1829. The following is Mr. Booth's account in a
letter to the author:

"I was in almost daily communication with Mr. Stephenson at the time,
and I was not aware that he had any intention of competing for the prize
till I communicated to him my scheme of a multitubular boiler. This new
plan of boiler comprised the introduction of numerous small tubes, two
or three inches in diameter, and less than one-eighth of an inch thick,
through which to carry the fire instead of a single tube or flue
eighteen inches in diameter, and about half an inch thick, by which
plan we not only obtain a very much larger heating surface, but the
heating surface is much more effective, as there intervenes between the
fire and the water only a thin sheet of copper or brass, not an eighth
of an inch thick, instead of a plate of iron of four times the
substance, as well as an inferior conductor of heat.

"When the conditions of trial were published, I communicated my
multitubular plan to Mr. Stephenson, and proposed to him that we should
jointly construct an engine and compete for the prize. Mr. Stephenson
approved the plan, and agreed to my proposal. He settled the mode in
which the fire-box and tubes were to be mutually arranged and connected,
and the engine was constructed at the works of Messrs. Robert Stephenson
& Co., Newcastle-on-Tyne.

"I am ignorant of M. Seguin's proceedings in France, but I claim to be
the inventor in England, and feel warranted in stating, without
reservation, that until I named my plan to Mr. Stephenson, with a view
to compete for the prize at Rainhill, it had not been tried, and was not
known in this country."

From the well-known high character of Mr. Booth, we believe his
statement to be made in perfect good faith, and that he was as much in
ignorance of the plan patented by Neville as he was of that of Seguin.
As we have seen, from the many plans of tubular boilers invented during
the preceding thirty years, the idea was not by any means new; and we
believe Mr. Booth to be entitled to the merit of inventing the method by
which the multitubular principle was so effectually applied in the
construction of the famous "Rocket" engine.

The principal circumstances connected with the construction of the
"Rocket," as described by Robert Stephenson to the author, may be
briefly stated. The tubular principle was adopted in a more complete
manner than had yet been attempted. Twenty-five copper tubes, each three
inches in diameter, extended from one end of the boiler to the other,
the heated air passing through them on its way to the chimney; and the
tubes being surrounded by the water of the boiler, it will be obvious
that a large extension of the heating surface was thus effectually
secured. The principal difficulty was in fitting the copper tubes in the
boiler ends so as to prevent leakage. They were manufactured by a
Newcastle coppersmith, and soldered to brass screws which were screwed
into the boiler ends, standing out in great knobs. When the tubes were
thus fitted, and the boiler was filled with water, hydraulic pressure
was applied; but the water squirted out at every joint, and the factory
floor was soon flooded. Robert went home in despair; and in the first
moment of grief he wrote to his father that the whole thing was a
failure. By return of post came a letter from his father, telling him
that despair was not to be thought of--that he must "try again;" and he
suggested a mode of overcoming the difficulty, which his son had
already anticipated and proceeded to adopt. It was, to bore clean holes
in the boiler ends, fit in the smooth copper tubes as tightly as
possible, solder up, and then raise the steam. This plan succeeded
perfectly, the expansion of the copper tubes completely filling up all
interstices, and producing a perfectly water-tight boiler, capable of
withstanding extreme external pressure.

The mode of employing the steam-blast for the purpose of increasing the
draught in the chimney was also the subject of numerous experiments.
When the engine was first tried, it was thought that the blast in the
chimney was not sufficiently strong for the purpose of keeping up the
intensity of fire in the furnace, so as to produce high-pressure steam
with the required velocity. The expedient was therefore adopted of
hammering the copper tubes at the point at which they entered the
chimney, whereby the blast was considerably sharpened; and on a farther
trial it was found that the draught was increased to such an extent as
to enable abundance of steam to be raised. The rationale of the blast
may be simply explained by referring to the effect of contracting the
pipe of a water-hose, by which the force of the jet of water is
proportionately increased. Widen the nozzle of the pipe, and the jet is
in like manner diminished. So it is with the steam-blast in the chimney
of the locomotive.

Doubts were, however, expressed whether the greater draught obtained by
the contraction of the blast-pipe was not counterbalanced in some degree
by the negative pressure upon the piston. Hence a series of experiments
was made with pipes of different diameters, and their efficiency was
tested by the amount of vacuum that was produced in the smoke-box. The
degree of rarefaction was determined by a glass tube fixed to the bottom
of the smoke-box and descending into a bucket of water, the tube being
open at both ends. As the rarefaction took place, the water would, of
course, rise in the tube, and the height to which it rose above the
surface of the water in the bucket was made the measure of the amount of
rarefaction. These experiments proved that a considerable increase of
draught was obtained by the contraction of the orifice; accordingly, the
two blast-pipes opening from the cylinders into either side of the
"Rocket" chimney, and turned up within it, were contracted slightly
below the area of the steam-ports, and before the engine left the
factory, the water rose in the glass tube three inches above the water
in the bucket.

The other arrangements of the "Rocket" were briefly these: the boiler
was cylindrical, with flat ends, six feet in length, and three feet four
inches in diameter. The upper half of the boiler was used as a reservoir
for the steam, the lower half being filled with water. Through the lower
part the copper tubes extended, being open to the fire-box at one end,
and to the chimney at the other. The fire-box, or furnace, two feet wide
and three feet high, was attached immediately behind the boiler, and was
also surrounded with water. The cylinders of the engine were placed on
each side of the boiler, in an oblique position, one end being nearly
level with the top of the boiler at its after end, and the other
pointing toward the centre of the foremost or driving pair of wheels,
with which the connection was directly made from the piston-rod to a pin
on the outside of the wheel. The engine, together with its load of
water, weighed only four tons and a quarter; and it was supported on
four wheels, not coupled. The tender was four-wheeled, and similar in
shape to a waggon--the foremost part holding the fuel, and the hind part
a water cask.

When the "Rocket" was finished it was placed upon the Killingworth
Railway for the purpose of experiment. The new boiler arrangement was
found perfectly successful. The steam was raised rapidly and
continuously, and in a quantity which then appeared marvellous. The same
evening Robert despatched a letter to his father at Liverpool, informing
him, to his great joy, that the "Rocket" was "all right," and would be
in complete working trim by the day of trial. The engine was shortly
after sent by waggon to Carlisle, and thence shipped for Liverpool.

The time so much longed for by George Stephenson had now arrived, when
the merits of the passenger locomotive were about to be put to the
test. He had fought the battle for it until now almost single-handed.
Engrossed by his daily labours and anxieties, and harassed by
difficulties and discouragements which would have crushed the spirit of
a less resolute man, he had held firmly to his purpose through good and
through evil report. The hostility which he experienced from some of the
directors opposed to the adoption of the locomotive was the circumstance
that caused him the greatest grief of all; for where he had looked for
encouragement, he found only carping and opposition. But his pluck never
failed him; and now the "Rocket" was upon the ground to prove, to use
his own words, "whether he was a man of his word or not."

On the day appointed for the great competition of locomotives at
Rainhill the following engines were entered for the prize:

1. Messrs. Braithwaite and Ericsson's "Novelty."

2. Mr. Timothy Hackworth's "Sanspareil."

3. Messrs. R. Stephenson & Co.'s "Rocket."

4. Mr. Burstall's "Perseverance."

The ground on which the engines were to be tried was a level piece of
railroad, about two miles in length. Each was required to make twenty
trips, or equal to a journey of seventy miles, in the course of the day,
and the average rate of travelling was to be not under ten miles an
hour. It was determined that, to avoid confusion, each engine should be
tried separately, and on different days.

The day fixed for the competition was the 1st of October, but, to allow
sufficient time to get the locomotives into good working order, the
directors extended it to the 6th. It was quite characteristic of the
Stephensons that, although their engine did not stand first on the list
for trial, it was the first that was ready, and it was accordingly
ordered out by the judges for an experimental trip. Yet the "Rocket" was
by no means the "favourite" with either the judges or the spectators.
Nicholas Wood has since stated that the majority of the judges were
strongly predisposed in favour of the "Novelty," and that "nine-tenths,
if not ten-tenths, of the persons present were against the "Rocket"
because of its appearance." Nearly every person favoured some other
engine, so that there was nothing for the "Rocket" but the practical
test. The first trip made by it was quite successful. It ran about
twelve miles, without interruption, in about fifty-three minutes.

The "Novelty" was next called out. It was a light engine, very compact
in appearance, carrying the water and fuel upon the same wheels as the
engine. The weight of the whole was only three tons and one
hundred-weight. A peculiarity of this engine was that the air was driven
or _forced_ through the fire by means of bellows. The day being now far
advanced, and some dispute having arisen as to the method of assigning
the proper load for the "Novelty," no particular experiment was made
further than that the engine traversed the line by way of exhibition,
occasionally moving at the rate of twenty-four miles an hour. The
"Sanspareil," constructed by Mr. Timothy Hackworth, was next exhibited,
but no particular experiment was made with it on this day. This engine
differed but little in its construction from the locomotive last
supplied by the Stephensons to the Stockton and Darlington Railway, of
which Mr. Hackworth was the locomotive foreman.

The contest was postponed until the following day; but, before the
judges arrived on the ground, the bellows for creating the blast in the
"Novelty" gave way, and it was found incapable of going through its
performance. A defect was also detected in the boiler of the
"Sanspareil," and some further time was allowed to get it repaired. The
large number of spectators who had assembled to witness the contest were
greatly disappointed at this postponement; but, to lessen it, Stephenson
again brought out the "Rocket," and, attaching it to a coach containing
thirty persons, he ran them along the line at a rate of from twenty-four
to thirty miles an hour, much to their gratification and amazement.
Before separating, the judges ordered the engine to be in readiness by
eight o'clock on the following morning, to go through its definite trial
according to the prescribed conditions.

On the morning of the 8th of October the "Rocket" was again ready for
the contest. The engine was taken to the extremity of the stage, the
fire-box was filled with coke, the fire lighted, and the steam raised
until it lifted the safety-valve loaded to a pressure of fifty pounds to
the square inch. This proceeding occupied fifty-seven minutes. The
engine then started on its journey, dragging after it about thirteen
tons' weight in waggons, and made the first ten trips backward and
forward along two miles of road, running the thirty-five miles,
including stoppages, in an hour and forty-eight minutes. The second ten
trips were in like manner performed in two hours and three minutes. The
maximum velocity attained during the trial trip was twenty-nine miles an
hour, or about three times the speed that one of the judges of the
competition had declared to be the limit of possibility. The average
speed at which the whole of the journeys was performed was fifteen miles
an hour, or five miles beyond the rate specified in the conditions
published by the company. The entire performance excited the greatest
astonishment among the assembled spectators; the directors felt
confident that their enterprise was now on the eve of success; and
George Stephenson rejoiced to think that, in spite of all false prophets
and fickle counsellors, the locomotive system was now safe. When the
"Rocket," having performed all the conditions of the contest, arrived at
the "grand stand" at the close of its day's successful run, Mr.
Cropper--one of the directors favourable to the fixed engine
system--lifted up his hands, and exclaimed, "Now has George Stephenson
at last delivered himself...."

The "Rocket" had eclipsed the performance of all locomotive engines that
had yet been constructed, and outstripped even the sanguine expectations
of its constructors. It satisfactorily answered the report of Messrs.
Walker and Rastrick, and established the efficiency of the locomotive
for working the Liverpool and Manchester Railway, and, indeed, all
future railways. The "Rocket" showed that a new power had been born into
the world, full of activity and strength, with boundless capability of
work. It was the simple but admirable contrivance of the steam-blast,
and its combination with the multitubular boiler, that at once gave
locomotion a vigorous life, and secured the triumph of the railway
system.[8]

[Illustration: The "Rocket"]


FOOTNOTES:

[7] The conditions were these:

1. The engine must effectually consume its own smoke.

2. The engine, if of six tons' weight, must be able to draw after it,
day by day, twenty tons' weight (including the tender and water-tank) at
_ten miles_ an hour, with a pressure of steam on the boiler not
exceeding fifty pounds to the square inch.

3. The boiler must have two safety-valves, neither of which must be
fastened down, and one of them be completely out of the control of the
engine-man.

4. The engine and boiler must be supported on springs, and rest on six
wheels, the height of the whole not exceeding fifteen feet to the top of
the chimney.

5. The engine, with water, must not weigh more than six tons; but an
engine of less weight would be preferred on its drawing a proportionate
load behind it; if of only four and a half tons, then it might be put on
only four wheels. The company will be at liberty to test the boiler,
etc., by a pressure of one hundred and fifty pounds to the square inch.

6. A mercurial gauge must be affixed to the machine, showing the steam
pressure above forty-five pounds per square inch.

7. The engine must be delivered, complete and ready for trial, at the
Liverpool end of the railway, not later than the 1st of October, 1829.

8. The price of the engine must not exceed L550.

Many persons of influence declared the conditions published by the
directors of the railway chimerical in the extreme. One gentleman of
some eminence in Liverpool, Mr. P. Ewart, who afterward filled the
office of Government Inspector of Post-office Steam Packets, declared
that only a parcel of charlatans would ever have issued such a set of
conditions; that it had been _proved_ to be impossible to make a
locomotive engine go at ten miles an hour; but if it ever was done, he
would undertake to eat a stewed engine-wheel for his breakfast.

[8] When heavier and more powerful engines were brought upon the road,
the old "Rocket," becoming regarded as a thing of no value, was sold in
1837. It has since been transferred to the Museum of Patents at South
Kensington, London, where it is still to be seen.


Transcriber's Notes:

Page 30--imployed changed to employed.

Page 31--subsequenty changed to subsequently.

Page 47--build changed to building.

Page 147--suggestor changed to suggester.

Page 166--supgestion changed to suggestion.

Footnote 7--Changed question mark for a period.

Inconsistencies in hyphenated words have been made consistent.

Obvious printer errors, including punctuation, have been corrected
without note.





End of Project Gutenberg's Little Masterpieces of Science:, by Various

*** 