HISTORY OF ELECTRICAL SCIENCE.
Electricity as a well-developed science is not old. Those of us who have
lived fifty years have seen nearly all its development so far as it has
been applied to useful purposes, and those who have lived over
twenty-five years have seen the major portion of its development.
Thales of Miletus, 600 B.C., discovered, or at least described, the
properties of amber when rubbed, showing that it had the power to
attract and repel light substances, such as straws, dry leaves, etc. And
from the Greek word for amber--elektron--came the name electricity,
denoting this peculiar property. Theophrastus and Pliny made the same
observations; the former about 321 B.C., and the latter about 70 A.D. It
is also said that the ancients had observed the effects of animal
electricity, such as that of the fish called the torpedo. Pliny and
Aristotle both speak of its power to paralyze the feet of men and
animals, and to first benumb the fish which it then preyed upon. It is
also recorded that a freed-man of Tiberius was cured of the gout by the
shocks of the torpedo. It is further recorded that Wolimer, the King of
the Goths, was able to emit sparks from his body.
Coming down to more modern times--A.D. 1600--we find Dr. Gilbert, an
Englishman, taking up the investigation of the electrical properties of
various substances when submitted to friction, and formulating them in
the order of their importance. In these experiments we have the
beginnings of what has since developed into a great science. He made the
discovery that when the air was dry he could soon electrify the
substances rubbed, but when it was damp it took much longer and
sometimes he failed altogether. In 1705 Francis Hawksbee, an
experimental philosopher, discovered that mercury could be rendered
luminous by agitating it in an exhausted receiver. (It is a question
whether this phenomenon should not be classed with that of
phosphorescence rather than electricity.) The number of investigators
was so great that all of them cannot be mentioned. It often happens that
those who do really most for a science are never known to fame. A number
of people will make small contributions till the structure has by
degrees assumed large proportions, when finally some one comes along and
puts a gilded dome on it and the whole structure takes his name. This is
eminently true of many of the more important developments in the
science and applications of electricity during the last twenty-five or
thirty years.
Following Hawksbee may be mentioned Stephen Gray, Sir Isaac Newton, Dr.
Wall, M. Dupay and others. Dupay discovered the two conditions of
electrical excitation known now as positive and negative conditions. In
1745 the Leyden jar was invented. It takes its name from the city of
Leyden, where its use was first discovered. It is a glass jar, coated
inside and out with tin-foil. The inside coating is connected with a
brass knob at the top, through which it can be charged with electricity.
The inner and outer coatings must not be continuous but insulated from
each other. The author's name is not known, but it is said that three
different persons invented it independently, to wit, a monk by the name
of Kleist, a man by the name of Cuneus, and Professor Muschenbroeck of
Leyden. This was an important invention, as it was the forerunner of our
own Franklin's discoveries and a necessary part of his outfit with which
he established the identity of lightning and electricity. Every American
schoolboy has heard, from Fourth of July orations, how "Franklin caught
the forked lightning from the clouds and tamed it and made it
subservient to the will of man." How my boyish soul used to be stirred
to its depths by this oratorical display of electrical fireworks!
Franklin had long entertained the idea that the lightning of the clouds
was identical with what is called frictional electricity, and he waited
long for a church spire to be erected in his adopted home, the Quaker
City, in order that he might make the test and settle the question. But
the Quakers did not believe in spires, and Franklin's patience had a
limit.
Franklin had the theory that most investigators had at that time, that
electricity was a fluid and that certain substances had the power to
hold it. There were two theories prevalent in those days--both fluid
theories. One theory was that there were two fluids, a positive and a
negative. Franklin held to the theory of a single fluid, and that the
phenomenon of electricity was present only when the balance or natural
amount of electricity was disturbed. According to this theory, a body
charged with positive electricity had an excessive amount, and, of
course, some other body somewhere else had less than nature had allotted
to it; hence it was charged with negative electricity. A Leyden jar, for
instance, having one of its coatings (say the inside) charged with
positive or + electricity, the other coating will be charged with
negative or - electricity. The former was only a name for an amount
above normal and the latter a name for a shortage or lack of the normal
amount.
As we have said, Franklin believed in the identity of lightning and
electricity, and he waited long for an opportunity to demonstrate his
theory. He had the Leyden jar, and now all he needed was to establish
some suitable connection between a thunder-cloud and the earth.
Previous to 1750 Franklin had written a paper in which he showed the
likeness between the lightning spark and that of frictional electricity.
He showed that both sparks move in crooked lines--as we see it in a
storm-cloud, that both strike the highest or nearest points, that both
inflame combustibles, fuse metals, render needles magnetic and destroy
animal life. All this did not definitely establish their identity in the
mind of Franklin, and he waited long for an opportunity, and finally,
finding that no one presented itself, he did what many men have had to
do in other matters; he made one.
In the month of June, 1752, tired of waiting for a steeple to be
erected, Franklin devised a plan that was much better and probably saved
the experiment from failure; for the steeple would probably not have
been high enough. He constructed a kite by making a cross of light cedar
rods, fastening the four ends to the four corners of a large silk
handkerchief. He fixed a loop to tie the kite string to and balanced it
with a tail, as boys do nowadays. He fixed a pointed wire to the upper
end of one of the cross sticks for a lightning-rod, and then waited for
a thunder-storm. When it came, with the help of his boy, he sent up the
kite. He tied a loop of silk ribbon on the end of the string next his
hand--as silk was known to be an insulator or non-conductor--and having
tied a key to the string he waited the result, standing within a door to
prevent the silk loop from getting wet and thus destroying its
insulating qualities. The cloud had nearly passed and he feared his long
waited for experiment had failed, when he noticed the loose fibers of
the string standing out in every direction, and saw that they were
attracted by the approach of his finger. The rain now wet the string and
made a better conductor of it. Soon he could draw sparks with his
knuckle from the key. He charged a Leyden jar with this electrical
current from the thunder-cloud, and performed all the experiments with
it that he had done with ordinary electricity, thus establishing the
identity of the two and confirming beyond a doubt what he had long
before believed was true. In after experiments Franklin found that
sometimes the electricity of the clouds was positive and at other times
negative. From this experiment Franklin conceived the idea of erecting
lightning-rods to protect buildings, which are used to this day.
The news spread all over Europe, not through the medium of electricity,
however, but as soon as sailing vessels and stage-coaches could carry
it. Many philosophers repeated the experiments and at least one man
sacrificed his life through his interest in the new discovery. In 1753
Professor Richman of St. Petersburg erected on his house a metal rod
which terminated in a Leyden jar in one of the rooms. On the 31st of May
he was attending a meeting of the Academy of Sciences. He heard a roll
of thunder and hurried home to watch his apparatus. He and one of the
assistants were watching the apparatus when a stroke of lightning came
down the rod and leaped to the professor's head. He was standing too
near it and was instantly killed.
Passing over many names of men who followed in the wake of Franklin we
come to the next era-making discovery, namely, that of galvanic
electricity. In the year 1790 an incident occurred in the household of
one Luigi Galvani, an Italian physician and anatomist, that led to a new
and important branch of electrical science. Galvani's wife was preparing
some frogs for soup, and having skinned them placed them on a table near
a newly charged electric machine. A scalpel was on the table and had
been in contact with the machine. She accidentally touched one of the
frogs to the point of the scalpel, when, lo! the frog kicked, and the
kick of that dead frog changed the whole face of electrical science. She
called her husband and he repeated the experiment, and also appropriated
the discovery as well, and he has had the credit of it ever since, when
really his wife made the discovery. Galvani supposed it to be animal
electricity and clung to that theory the rest of his life, making many
experiments and publishing their results; but the discovery led others
to solve the problem.
Alessandro Volta, a professor of natural philosophy at Pavia, Italy,
was, it must be said, the founder of the science of galvanic or voltaic
electricity. Stimulated by the discovery of Galvani he attributed the
action of the frog's muscles, not to animal electricity, but to some
chemical action between the metals that touched it. To prove his theory,
he constructed a pile made of alternate layers of zinc, copper, and a
cloth or pasteboard saturated in some saline solution. By repeating
these trios--copper, zinc, and the saturated cloth--he attained a pile
that would give a powerful shock. It is called the Voltaic Pile.
I have a clear idea of the construction of this form of pile, founded on
experience. It was my habit when a boy to make everything that I found
described, if it were possible. The bottom of my mother's wash-boiler
was copper, and just the thing to make the square plates of copper to
match the zinc ones, made from another piece of domestic furniture used
under the stove. I shocked my mother twice--first with the voltaic pile
that I had constructed, and again when she found out where the metal
plates came from. The sequel to all this was--but why dwell upon a
painful subject!
Galvanism and voltaic electricity are the same. Volta was the first to
construct what is termed the galvanic battery. The unit of electrical
pressure or electromotive force is called the volt, and takes its name
from Volta, the great founder of the science of galvanic or voltaic
electricity. From this pile constructed by Volta innumerable forms of
batteries have been devised. The evolution of the galvanic battery in
all its forms, from Volta to the present day, would fill a large volume
if all were described.
The discoveries of Michael Faraday (1791-1867), the distinguished
English chemist and physicist, led to another phase of the science that
has revolutionized modern life. Faraday made an experiment that contains
the germ of all forms of the modern dynamo, which is a machine of
comparatively recent development. He found that by winding a piece of
insulated wire around a piece of soft iron and bringing the two ends
(of the wire) very close together, and then placing the iron across the
poles of a permanent magnet and suddenly jerking it away, a spark would
pass between the two ends of the wire that was wound around the piece of
soft iron. Here was an incipient dynamo-electric machine--the germ of
that which plays such an important part in our modern civilization.
Having brought our history down to the present day, it would seem
scarcely necessary to recite that which everybody knows. It is well,
however, to call a halt once in a while and compare our present
conditions of civilization with those of the past. Our world is filled
with croakers who are always sighing for the good old days. But we can
easily imagine that if they could go back to those days their croaking
would be still louder than it is.
Before the advent of electricity many things were impossible that are
easy now. In the old days the world was very, very large; now, thanks to
electricity, it is knocking at the door of every man's house. The
lumbering stage-coach that was formerly our limited express--limited to
thirty or forty miles a day--has been supplanted by one that covers 1000
miles in the same time, and this high rate of speed is made possible
only by the use of the electric telegraph.
In the old days all Europe could be involved in a great war and the news
of it would be weeks in reaching our shores, but now the firing of the
first gun is heard at every fireside the world over, almost before the
smoke has cleared away. Our planet is threaded with iron nerves that run
over mountains and under seas, whose trembling atoms, thrilled with the
electric fire, speak to us daily and hourly of the great throbbing life
of the whole civilized world.
Electricity has given us a voice that can be heard a thousand miles, and
not only heard, but recognized. It has given us a pen that will write
our autograph in New York, although we are still in Chicago. It has
given us the best light, both from an optical and a sanitary standpoint,
that the world has ever seen. The old-fashioned, jogging horse-car has
been supplanted by the electric "trolley," and we no longer have our
feelings harrowed with pity for the poor old steeds that pulled those
lumbering coaches through the streets, with men and women crowded in and
hanging on to straps, while everybody trod on every other body's toes.
"In olden times we took a car
Drawn by a horse, if going far,
And felt that we were blest;
Now the conductor takes the fare
And puts a broomstick in the air--
And lightning does the rest.
"In other days, along the street,
A glimmering lantern led the feet,
When on a midnight stroll;
But now we catch, when night is nigh,
A piece of lightning from the sky
And stick it on a pole.
"Time was when one must hold his ear
Close to a whispering voice to hear,
Like deaf men--nigh and nigher;
But now from town to town he talks
And puts his nose into a box
And whispers through a wire."
So jogs the old world along. We sometimes think it is slow, but when we
look back a few years and see what has been accomplished it seems to
have had a marvelously rapid development.
Something like fifty years ago a professor of physics in one of our
colleges was giving his class a course in electricity. The electric
telegraph was too little known at that time to cut much of a figure in
the classroom, so the stock experiments were those made with the
frictional electric machine and the Leyden jar. One day the professor
had, in one hour's time, taken his class through a course of
electricity, and at the end he said: "Gentlemen, you were born too late
to witness the development of this great science." I often wonder if the
good professor is ever allowed to part the veil that separates us from
the great beyond and to look down upon this busy world of ours in which
electricity plays such an important part in our every-day life; and if
so, what he thinks of that little speech he made to the boys fifty years
or more ago.
If we make an analysis of the history of the science of electricity we
shall see that it has progressed in successive eras, shortening as they
approach our time. For a period of 2300 years, from Thales to Franklin,
but little or no progress was made beyond the further development of the
phenomena of frictional electricity--the most important invention being
that of the Leyden jar. From Franklin to Volta was forty-eight years,
and from Volta to Faraday about thirty-two years. From this time on the
development was very rapid as compared with the old days. Soon after
Faraday, Morse, Henry, Wheatstone, and others began experiments that
have grown, during fifty or sixty years, into a most colossal system of
electric telegraphs, telephones, electric lights and electric railroads.
In the latter days marvel has succeeded marvel with such rapid strides
that the ink is scarcely dry from the description of one before another
crowds itself upon our attention. Where it will all end no one knows,
but that it has ended no one believes. The human mind has become so
accustomed to these periodic revelations of the marvelous that it must
have the stimulus once in a while or it suffers as the toper does when
deprived of his cups. The commercial instinct of the news-vender is not
slow to see the situation, and if the development is too slow to suit
the public demand his fertile brain supplies the lack. So that every few
days we hear of some great discovery made by some one it may be unknown
to fame. It has served its purpose. The public mind has had its mental
toddy and has been saved from a fit of intellectual delirium tremens
that it was in danger of from lack of its accustomed stimulus.
Having given you a very limited outline of the history of electricity,
from ancient times down to the present, we will endeavor now to give you
an elementary notion of the science as it stands to-day. To the common
mind the science is a blank page. So little is known of it by the
ordinary reader, who is fairly intelligent in other matters, that to
account for anything that we do not understand it is only necessary to
say that it is an electrical phenomenon and he accepts it. Electricity
is a synonym for all that we cannot understand. Inasmuch as magnetism is
so closely related to electricity in its uses as related to every-day
life, we will carry the two subjects along together, as the one will to
a large extent help to explain the other. In our next chapter we will
look at the history of magnetism.