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.