By CHARLES CARLETON COFFIN.
The application of electricity for our convenience and comfort is one
of the marvels of the age. Never in the history of the world has there
been so rapid a development of an occult science. Prior to 1819 very
little was known in regard to magnetism and electricity. During that
year Oersted discovered that an electric current would deflect a
magnetic needle, thus showing that there was some relationship between
electric and magnetic force. A few months later, Arago and Sir Humphry
Davy, independently of each other, discovered that by coiling a wire
around a piece of iron, and passing an electric current through it,
the iron would possess for the time being all the properties of a
magnet. In 1825 William Sturgeon, of London, bent a piece of wire in
the form of the letter U, wound a second wire around it, and, upon
connecting it with a galvanic battery, discovered that the first wire
became magnetic, but lost its magnetic property the moment the battery
was disconnected. The idea of a telegraphic signal came to him, but
the electric impulse, through his rude apparatus, faded out at a
distance of fifty feet. In 1830 Prof. Joseph Henry, of this country,
constructed a line of wire, one and a half miles in length, and sent a
current of electricity through it, ringing a bell at the farther end.
The following year Professor Faraday discovered magnetic induction.
This, in brief, is the genesis of magnetic electricity, which is the
basis of all that has been accomplished in electrical science.
The first advance after these discoveries was in the development of
the electric telegraph--the discovery in 1837, by the philosopher
Steinhill, that the earth could serve as a conductor, thus requiring
but one wire in the employment of an electric current. Simultaneously
came Morse's invention of the mechanism for the telegraph in 1844,
foreshadowed by Henry in the ringing of bells, thus transmitting
intelligence by sound. Four years later, in 1848, Prof. M. G. Farmer,
still living in Eliot, Me., attached an electro-magnet to clockwork
for the striking of bells to give an alarm of fire. The same idea came
to William F. Channing. The mechanism, constructed simply to
illustrate the idea by Professor Farmer, was placed upon the roof of
the Court House in Boston, and connected with the telegraph wire
leading to New York, and an alarm rung by the operator in that city.
The application of electricity for giving definite information to
firemen was first made in Boston, and it was my privilege to give the
first alarm on the afternoon of April 12, 1852.
At the close of the last century, Benjamin Thompson, born in Woburn,
Mass., known to the world as Count Rumford, was in the workshop of the
military arsenal of the King of Bavaria in Munich, superintending the
boring of a cannon. The machinery was worked by two horses. He was
surprised at the amount of heat which was generated, for when he threw
the borings into a tumbler filled with cold water, it was set to
boiling, greatly to the astonishment of the workmen. Whence came the
heat? What was heat? The old philosopher said that it was an element.
By experiment he discovered that a horse working two hours and twenty
minutes with the boring machinery would heat nineteen pounds of water
to the boiling point. He traced the heat to the horse, but with all
his acumen he did not go on with the induction to the hay and oats, to
the earth, the sunshine and rain, and so get back to the sun. One
hundred years ago there was no chemical science worthy of the name, no
knowledge of the constitution of plants or the properties of light and
heat. The old philosophers considered light and heat to be fluids,
which passed out of substances when they were too full. Count Rumford
showed that motion was convertible into heat, but did not trace the
motion to its source, so far as we know, in the sun.
It is only forty-six years since Professor Joule first demonstrated
the mutual relations of all the manifestations of nature's energy.
Thirty-nine years only have passed since he announced the great law of
the convertibility of force. He constructed a miniature churn which
held one pound of water, and connected the revolving paddle of the
churn with a wheel moved by a pound weight, wound up the weight, and
set the paddle in motion. A thermometer detected the change of
temperature and a graduated scale marked the distance traversed by the
descending weight. Repeated experiments showed that a pound weight
falling 772 feet would raise the temperature of water one degree, and
that this was an unvarying law. This was transferring gravitation to
heat, and the law held good when applied to electricity, magnetism,
and chemical affinity, leading to the conclusion that they were
severally manifestations of one universal power.--_Congregationalist._
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