time prior to the introduction of coal, had to be brought such a long
distance that it was becoming very expensive. Franklin refused to take
out a patent for his invention; for he was on principle opposed to
patents, and said that as we enjoyed great advantages from the
inventions of others, we should be willing to serve them by inventions
of our own. He afterwards learned that a London ironmonger made a few
changes in the "Pennsylvania Fireplace" and sold it as his own, gaining
a small fortune.
Franklin's invention was undoubtedly an improvement on the old methods
of heating and ventilation; but he was not, as has been absurdly
claimed, the founder of the "American stove system," for that system
very soon departed from his lines and went back to the air-tight stoves
of Germany and Holland.
It was not until 1746 or 1747, after he had been making original
researches in science for about five years, that he took up the subject
of electricity, and he was then forty-one years old. It appears that Mr.
Peter Collinson, of London, who was interested in botany and other
sciences, and corresponded largely on such subjects, had presented to
the Philadelphia Library one of the glass tubes which were used at that
time for producing electricity by rubbing them with silk or skin.
Franklin began experimenting with this tube, and seems to have been
fascinated by the new subject. On March 28, 1747, he wrote to Mr.
Collinson thanking him for the tube, and saying that they had observed
with its aid some phenomena which they thought to be new.
"For my own part, I never was before engaged in any study that
so totally engrossed my attention and my time as this has lately
done; for what with making experiments when I can be alone, and
repeating them to my friends and acquaintance, who from the
novelty of the thing, come continually in crowds to see them, I
have, during some months past, had little leisure for anything
else."
It will be observed that he speaks of crowds coming to see the
experiments, and this confirms what I have already shown of the strong
interest in science which prevailed at that time in Pennsylvania, and
which had evidently first aroused Franklin. In fact, a renewed interest
in science had been recently stirred up all over the world, and people
who had never before thought much of such things became investigators.
Voltaire, who resembled Franklin in many ways, had turned aside from
literature, and at forty-one, the same age at which Franklin began the
study of electricity, had become a man of science, and for four years
devoted himself to experiments.
Franklin was by no means alone in his studies. Besides the crowds who
were interested from mere curiosity, there were three men--Ebenezer
Kinnersley, Thomas Hopkinson, and Philip Syng--who experimented with
him, and it was no mere amateurish work in which these men were engaged.
Franklin was their spokesman and reported the results of his and their
labor by means of letters to Mr. Peter Collinson. Within six months
Hopkinson had observed the power of points to throw off electricity, or
electrical fire, as he called it, and Franklin had discovered and
described what is now known as positive and negative electricity. Within
the same time Syng had invented an electrical machine, consisting of a
sphere revolved on an axis with a handle, which was better adapted for
producing the electrical spark than the tube-rubbing practised in
Europe.
The experiments and the letters to Collinson describing them continued,
and about this time we find Franklin writing a long and apparently the
first intelligent explanation of the action of the Leyden jar. Then
followed attempts to explain thunder and lightning as phenomena of
electricity, and on July 29, 1750, Franklin sent to Collinson a paper
announcing the invention of the lightning-rod, together with an
explanation of its action.
In these papers he also suggested an experiment which would prove
positively that lightning was a form of electricity. The two phenomena
were alike as regarded light, color, crooked direction, noise, swift
motion, being conducted by metals, subsisting in water or ice, rending
bodies, killing animals, melting metals, and setting fire to various
substances. It remained to demonstrate with absolute certainty that
lightning resembled electricity in being attracted by points; and for
this purpose Franklin proposed that a man stand in a sort of sentry-box
on the top of some high tower or steeple and with a pointed rod draw
electricity from passing thunder-clouds.
This suggestion was successfully carried out in France, in the presence
of the king, at the county-seat of the Duke D'Ayen; and afterwards
Buffon, D'Alibard, and Du Lor confirmed it by experiments of their own.
But they did not use steeples; they erected lofty iron rods, in one
instance ninety-nine feet high. Nevertheless, it was in effect the same
method that Franklin had suggested. The experiment was repeated in
various forms in England, and the Philadelphia philosopher, postmaster,
and author of "Poor Richard" became instantly famous as the discoverer
of the identity of lightning with electricity.
Two years before these experiments were inaugurated he had retired from
business for various reasons, chief among which was his strong desire to
devote more time to science. His letters continue to be filled with
closely reasoned details of all sorts of experiments. So earnest were
these Philadelphia investigators, that when Kinnersley wrote complaining
that in travelling to Boston he found difficulty in keeping up his
experiments, Franklin, in reply, suggested a portable electrical
apparatus which would not break on a journey.
In a letter written to Collinson on October 19, 1752, Franklin says he
had heard of the success in France of the experiment he had suggested
for drawing the lightning from clouds by means of an elevated metal rod;
but in the mean time he had contrived another method for accomplishing
the same result without the aid of a steeple or lofty iron rod. This was
the kite experiment of which we have heard so much, and he goes on to
describe it:
"Make a small cross of two light strips of cedar, the arms so
long as to reach to the four corners of a large thin silk
handkerchief when extended; tie the corners of the handkerchief
to the extremities of the cross, so you have the body of a kite;
which being properly accommodated with a tail, loop, and string,
will rise in the air, like those made of paper; but this being
of silk is fitter to bear the wet and wind of a thunder gust
without tearing. To the top of the upright stick of the cross is
to be fixed a very sharp pointed wire, rising a foot or more
above the wood. To the end of the twine, next the hand, is to be
tied a silk ribbon, and where the silk and twine join, a key may
be fastened. This kite is to be raised when a thunder-gust
appears to be coming on, and the person who holds the string
must stand within a door or window, or under some cover, so that
the silk ribbon may not be wet; and care must be taken that the
twine does not touch the frame of the door or window. As soon as
any of the thunder clouds come over the kite, the pointed wire
will draw the electric fire from them, and the kite, with all
the twine, will be electrified, and the loose filaments of the
twine, will stand out every way, and be attracted by an
approaching finger. And when the rain has wetted the kite and
twine, so that it can conduct the electric fire freely, you will
find it stream out plentifully from the key on the approach of
your knuckle. At this key the phial may be charged: and from
electric fire thus obtained, spirits may be kindled, and all the
other electric experiments be performed, which are usually done
by the help of a rubbed glass globe or tube, and thereby the
sameness of the electric matter with that of lightning
completely demonstrated."
This is the only description by Franklin of the experiment which added
so much to his reputation. Franklin and the kite became a story for
school-books; innumerable pictures of him and his son drawing the
lightning down the string were made and reproduced for a century or more
in every conceivable form, and even engraved on some of our national
currency.
The experiment was made in June, 1752; in the following October the
above letter was written, and the news it contained appears to have
rushed over the world without any effort on his part to spread it. He
never wrote anything more concerning this experiment than the very
simple and unaffected letter to Mr. Collinson. But people, of course,
asked him about it, and from the details which they professed to have
obtained grand statements have been built up describing his conduct and
emotions on that memorable June afternoon on the outskirts of
Philadelphia, probably somewhere in the neighborhood of the present Vine
Street, near Fourth; how his heart stood still with anxiety lest the
trial should fail; how with trembling hand he applied his knuckles to
the key, and the wild exultation with which he saw success crown his
efforts.
But it is safe to say that there were none of these theatrical
exhibitions, and that he made the experiment in that matter-of-fact and
probably half-humorous way in which he did everything. Nothing important
depended on it, for he had already proved conclusively, not only by
reasoning but by his suggested experiments which had been tried in
Europe, that thunder and lightning were phenomena of electricity. The
kite was used because there were in Philadelphia no high steeples on
which he could try the experiment that had proved his discovery in
France.
But it was Franklin's good fortune on a number of occasions to be placed
in picturesque and striking situations, which greatly increased his
fame. He did not foresee that kite-flying would be one of these, and as
it was not essential to his discovery of the nature of lightning, he was
disinclined at first to think much of it, and did not even report it to
Mr. Collinson until after several months had elapsed. But the world
fixed upon it instantly as something easy to remember. To this day it is
the popular way of illustrating Franklin's discovery, and is all that
most people know of his contributions to science.
He went on steadily reporting his experiments to Collinson, and in 1753
was at work on the mistaken hypothesis of the sea being the grand source
of lightning, but at the same time making the discovery of the negative
and sometimes positive electricity of the clouds. He had a rod erected
on his house to draw down into it the mystical fire of any passing
clouds, with bells arranged to warn him when his apparatus was working;
and it was about this time that he was struck senseless and almost
killed while trying the effect of an electrical shock on a turkey.
Collinson kept his letters, and in May, 1751, had them published in a
pamphlet called "New Experiments and Observations in Electricity made at
Philadelphia in America." It had immediately, like all of Franklin's
writings, a vast success, at first in France, and afterwards in England
and other countries. Franklin was, strange to say, always more popular
in France than in either America or England. In England his experiments
in electricity were at first laughed at, and the Royal Society refused
to publish his letters in their proceedings. But after Collinson had
secured their publication in a pamphlet, they were translated into
German, Italian, and Latin, as well as into French, and were greatly
admired not only for the discoveries and knowledge they revealed, but
for their fascinating style and noble candor tinged occasionally with
the most telling and homely humor.
It has been repeatedly charged that Franklin was indebted to his
fellow-worker, Kinnersley, for his discoveries in electricity. The
charge is so vaguely made that it is impossible to ascertain which of
them are supposed to have been stolen. In Franklin's letters on
electricity there are frequent footnotes giving credit to Hopkinson and
Syng for their original work, and there are also in his published works
letters to and from Kinnersley. He and Kinnersley seem to have been
always fast friends, and, so far as I can discover, the latter never
accused Franklin of stealing from him.
After he had proved in such a brilliant manner that lightning was merely
one of the forms or phenomena of that mysterious fire which appears when
we rub a glass tube with buckskin, Franklin made no more discoveries in
science; but his interest and patience of research were unabated. He
cannot be ranked among the great men of science, the Newtons and
Keplers, or the Humboldts, Huxleys, or Darwins. He belongs rather in the
second class, among the minor discoverers. But his discovery of the
nature of lightning was so striking and so capable of arousing the
wonder of the masses of mankind, and his invention of the lightning-rod
was regarded as so universally valuable, that he has received more
popular applause than men whose achievements were greater and more
important.
During the rest of his life his work in science was principally in the
way of encouraging its study. He was always observing, collecting facts,
and writing out his conclusions. The public business in which he was
soon constantly employed, and the long years of his diplomatic service
in England and France, were serious interruptions, and during the last
part of his life it was not often that he could steal time for that
loving investigation of nature which after his thirtieth year became the
great passion of his life.
His command of language had seldom been put to better use than in
explaining the rather subtle ideas and conceptions in the early
development of electricity. Even now after the lapse of one hundred and
fifty years we seem to gain a fresher understanding of that subject by
reading his homely and beautiful explanations; and modern students would
have an easier time if Franklin were still here to write their
text-books. His subsequent letters and essays were many of them even
more happily expressed than the famous letters on electricity.
In old editions of his works all his writings on science were collected
in one place, so that they could be read consecutively, which was rather
better than the modern strictly chronological plan by which they are
scattered throughout eight or ten large volumes. As we look over one of
the old editions we feel almost compelled to begin original research at
once,--it seems so easy and pretty. There are long investigations about
water-spouts and whirlwinds,--whether a water-spout ever actually
touches the surface of the sea, and whether its action is downward from
the sky or upward from the water. He interviewed sea-captains and
received letters from people in the West Indies to help him, and those
who had once come within the circle of his fascination were never weary
of giving aid.
He investigated what he called the light in sea-water, now called
phosphorescence. The cause of the saltness of the sea and the existence
of masses of salt or salt-mines in the earth he explained by the theory
that all the water of the world had once been salt, for sea-shells and
the bones of fishes were found, he said, on high land; upheavals had
isolated parts of the original water, which on evaporation had left the
salt, and this being covered with earth, became a salt-mine. This
explanation was given in a letter to his brother Peter, and is really a
little essay on geology, which was then not known by that or any other
name, but consisted merely of a few scattered observations.
Many of his most interesting explanations of phenomena appear in letters
to the young women with whom he was on such friendly terms. Indeed, it
has been said that he was never at his best except when writing to
women. People believe, he tells Miss Stevenson, that all rivers run
into the sea, and he goes on to show in his most clever way that some
rivers do not. The waters of the Delaware, for example, and the waters
of the rivers that flow into Chesapeake Bay, probably never reach the
ocean. The salt water backing up against them twice a day acts as a dam,
and their fresh water is dissipated by evaporation. Only a few, like the
Amazon and the Orinoco, are known to force their fresh water far out on
the surface of the sea. In this same letter he describes the experiments
he made to prove that dark colors absorb more of the sun's rays, and are
therefore warmer than white.
While representing Pennsylvania in England, and living with Mrs.
Stevenson, in Craven Street, London, he made an experiment to prove that
vessels move faster in deep than in shallow water. This was generally
believed by seafaring men; but Franklin had a wooden trough made with a
false bottom by which he could regulate the depth of water, and he put
in it a little boat drawn by a string which ran over a pulley at the end
of the trough, with a shilling attached for a weight. In this way he
succeeded in demonstrating a natural law which, though known to
practical men, had never been described in books of science.
He took much pains to collect information about the Gulf Stream. This
wonderful river in the ocean has been long known, but the first people
to observe it closely were the Nantucket whalemen, who found that their
game was numerous on the edges of it, but was never seen within its
warm waters. In consequence of their more exact knowledge they were
able to make faster voyages than other seamen. Franklin learned about it
from them, and on his numerous voyages made many observations, which he
carefully recorded. He obtained a map of it from one of the whalemen,
which he caused to be engraved for the general benefit of navigation on
the old London chart then universally used by sailors. But the British
captains slighted it, and this, like his other efforts in science, was
first appreciated in France.
He has been called the discoverer of the temperature of the Gulf Stream;
but this statement is somewhat misleading. That the stream was warmer
than the surrounding ocean seems to have been long known; but Franklin
was the first to take its temperature at different points with a
thermometer. He did this most systematically on several of his voyages,
even when suffering severely from sea-sickness, and thus suggested the
use of the thermometer in investigating ocean currents. He first took
these temperatures in 1775, and the next year Dr. Charles Blagden, of
the British army, took them while on the voyage to America with troops
to suppress the Revolution. He and Franklin are ranked together as the
first to show the value of an instrument which is now universally used
in ocean experiments as well as in the practical navigation of
ships.[19]
In the same careful manner he collected all that was known of the effect
of oil in stilling waves by making the surface so smooth and slippery
that the wind cannot act on it. So fascinated was he with this
investigation that he had a cane made with a little receptacle for oil
in the head of it, and when walking in the country in England
experimented on every pond he passed. But it would be long to tell of
all he wrote on light and heat, the _vis inertiæ_ of matter, magnetism,
rainfall, evaporation, and the aurora borealis.
One of the discomforts of colonial times, when large open fireplaces
were so common, was a smoky chimney. Franklin's attention was drawn to
this question about the time that he invented the Pennsylvania
fireplaces, and he made an exhaustive study of the nature of smoke and
heated air. He became very skilful in correcting defects in the chimneys
of his friends' houses, and while he was in England noblemen and
distinguished people often sought his aid. It was not, however, until
1785, near the close of his life, that he put his knowledge in writing
in a letter to Dr. Ingenhausz, physician to the Emperor of Austria. The
letter was published and extensively circulated as the best summary of
all that was known on this important question. It is as fresh and
interesting to-day as when it was written, and well worth reading,
because it explains so charmingly the philosophy of some phenomena of
common occurrence which modern books of science are not at much pains to
make clear.
His enemies, of course, ridiculed him as a chimney doctor, and his
friends have gone to the other extreme in implying that he was the only
man in the world who understood the action of heat and smoke, and that,
alone and unaided, he delivered mankind from a great destroyer of their
domestic comfort. But his letter shows that most of his knowledge and
remedies were drawn from the French and Germans. In this, as in many
other similar services, he was merely an excellent collector of
scattered material, which he summarized so well that it was more
available than before. He was by no means the only person in the world
who could doctor a chimney; but there were few, if any, who could
describe in such beautiful language the way in which it was done.
He invented a stove that would consume its own smoke, taking the
principle from a Frenchman who had shown how the flame of a burning
substance could be made to draw downward through the fuel, so that the
smoke was burnt with the fuel. But the way in which this invention is
usually described would lead one to suppose that it was entirely
original with Franklin.
He was much interested in agriculture, and was an earnest advocate of
mineral manures, encouraged grape culture, and helped to introduce the
basket willow and broom-corn into the United States. He at one time
owned a farm of three hundred acres near Burlington, New Jersey, where
he tried agricultural experiments. He dabbled in medicine, as has been
shown, and also wasted time over that ancient delusion, phonetic
spelling.
Knowing, as we do, Franklin's versatility, it is nevertheless somewhat
of a surprise to find him venturing into the sphere of music. He is said
to have been able to play on the harp, the guitar, and the violin, but
probably only in a philosopher's way and not well on any of them. Some
people in England had succeeded in constructing a musical instrument
made of glasses, the idea being taken from the pleasant sound produced
by passing a wet finger round the brim of a drinking-glass. When in
England Franklin was so delighted with these instruments that he set
about improving them. He had glasses specially moulded of a bell-like
shape and ground with great care until each had its proper note. They
were placed in a frame in such a way that they could all be set
revolving at once by means of a treadle worked by the foot, and as they
revolved they were played by the wet fingers pressed on their brims. He
gave the name "Armonica" to his instrument, and describes its tones as
"incomparably sweet beyond those of any other." It is said to have been
used in public concerts, and it was one of the curiosities at his famous
Craven Street lodging-house in London, where he also had a fine
electrical apparatus, and took pleasure in showing his English friends
the American experiments of which they had heard so much.
He seems to have studied music with great care as a science, just as he
studied the whirlwinds, the smoke, and the lightning; but he was
unalterably opposed to the so-called modern music then becoming
fashionable, and which is still to a great extent the music of our time.
The pleasure derived from it was, he said, not the natural pleasure
caused by harmony of sounds, but rather that felt on seeing the
surprising feats of tumblers and rope-dancers.
"Many pieces of it are mere compositions of tricks. I have
sometimes, at a concert, attended by a common audience, placed
myself so as to see all their faces, and observed no signs of
pleasure in them during the performance of a great part that was
admired by the performers themselves; while a plain old Scotch
tune, which they disdained, and could scarcely be prevailed upon
to play, gave manifest and general delight."
In a letter to Lord Kames which has been often quoted he explained at
length, and for the most part in very technical language, the reasons
for the superiority of the Scotch tunes.