Part 13 (1/2)

The atmosphere of Boston was completely theological. There was no room, no opportunity, for science, and no inducement or even suggestion that would lead to it, still less to original research in it. We find Franklin in a state of rebellion against the prevailing tone of thought, writing against it in his brother's newspaper at the risk of imprisonment, and in a manner more bitter and violent than anything he afterwards composed. If he had remained in Boston it is not likely that he would ever have taken seriously to science, for all his energies would have been absorbed in fighting those intolerant conditions which smothered all scientific inquiries.

In Pennsylvania he found the conditions reversed. The Quakers and the German sects which made up the majority of the people of that province in colonial times had more advanced ideas of liberty and free thought than any of the other religious bodies in America, and in consequence science flourished in Pennsylvania long before it gained entrance into the other colonies. The first American medical college, the first hospital, and the first separate dispensary were established there.

Several citizens of Philadelphia who were contemporaries of Franklin achieved sufficient reputation in science to make their names well known in Europe.

David Rittenhouse invented the metallic thermometer, developed the construction of the compensation pendulum, and made valuable experiments on the compressibility of water. He became a famous astronomer, constructed an orrery to show the movements of the stars which was an improvement on all its predecessors, and conducted the observations of the transit of Venus in 1769. Pennsylvania was the only one of the colonies that took these observations, which in that year were taken by all the European governments in various parts of the world. The Legislature and public inst.i.tutions, together with a large number of individuals, a.s.sisted in the undertaking, showing what very favorable conditions for science prevailed in the province.[18]

These were the conditions which seem to have aroused Franklin. Without them his mind tended more naturally to literature, politics, and schemes of philanthropy and reform; but when his strong intellect was once directed towards science, he easily excelled in it. Some of the early questions discussed by the Junto, such as ”Is sound an ent.i.ty or body?”

and ”How may the phenomena of vapors be explained?” show an inclination towards scientific research; and it is very likely that he studied such subjects more or less during the ten years which followed his beginning business for himself.

In his _Gazette_ for December 15, 1737, there is an essay on the causes of earthquakes, summarizing the various explanations which had been given by learned men, and this essay is supposed to have been written by him. Six years afterwards he made what has been usually considered his first discovery,--namely, that the northeast storms of the Atlantic coast move against the wind; or, in other words, that instead of these storms coming from the northeast, whence the wind blows, they come from the southwest. He was led to this discovery by attempting to observe an eclipse of the moon which occurred on the evening of October 21, 1743; but he was prevented by a heavy northeaster which did great damage on the coast. He was surprised to find that it had not prevented the people of Boston from seeing the eclipse. The storm, though coming from the northeast, swept over Philadelphia before it reached Boston. For several years he carefully collected information about these storms, and found in every instance that they began to leeward and were often more violent there than farther to windward.

He seems to have been the first person to observe these facts, but he took no pains to make his observations public, except in conversation or in letters to prominent men like Jared Eliot, of Connecticut, and these letters were not published until long afterwards. This was his method in all his investigations. He never wrote a book on science; he merely reported his investigations and experiments by letter, usually to learned people in England or France. There were no scientific periodicals in those days. The men who were interested in such things kept in touch with one another by means of correspondence and an occasional pamphlet or book.

During the same period in which he was making observations on northeast storms he invented the ”Pennsylvania Fireplace,” as he called it, a new sort of stove which was a great improvement over the old methods of heating rooms. He published a complete description of this stove in 1745, and it is one of the most interesting essays he ever wrote. It is astonis.h.i.+ng with what pleasure one can still read the first half of this essay written one hundred and fifty years ago on the driest of dry subjects. The language is so clear and beautiful, and the homely personality of the writer so manifest, that one is inclined to lay down the principle that the test of literary genius is the ability to be fascinating about stoves.

He explained the laws of hot air and its movements; the Holland stove, which afforded but little ventilation; the German stove, which was simply an iron box fed from outside, with no ventilating properties; and the great open fireplace fed with huge logs, which required such a draft to prevent the smoke from coming back into the room that the outer door had to be left open,--and if the door was shut the draft would draw the outer air whistling and howling through the crevices of the windows.

His ”Pennsylvania Fireplace” was what we would now call an open-fireplace stove. It was intended to be less wasteful of fuel than the ordinary fireplace and to give ventilation, while combining the heating power of the German and Holland stoves. It continued in common use for nearly a century, and modified forms of it are still called the Franklin stoves.

One of its greatest advantages was that it saved wood, which, for some 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 gla.s.s 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 pa.s.sing 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 ident.i.ty 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 accomplis.h.i.+ng 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: