In 1747 Franklin made what is generally considered his chief contribution to science. One of his correspondents, Collinson (a Fellow of the Royal Society and a botanist interested in useful plants, through whom the vine was introduced into Virginia), had sent to the Library Company at Philadelphia one of the recently invented Leyden jars with instructions for its use. Franklin, who had already seen similar apparatus at Boston, and his friends, set to work experimenting. For months he had leisure for nothing else. In this sort of activity he had a spontaneous and irrepressible delight. By March, 1747, they felt that they had made discoveries, and in July, and subsequently, Franklin reported results to Collinson. He had observed that a pointed rod brought near the jar was much more efficacious than a blunt rod in drawing off the charge; also that if a pointed rod were attached to the jar, the charge would be thrown off, and accumulation of charge prevented. Franklin, moreover, found that the nature of the charges on the inside and on the outside of the glass was different. He spoke of one as plus and the other as minus. Again, “We say B (and bodies like-circumstanced) is electricized positively; A negatively.” Dufay had[Pg 124] recognized two sorts of electricity, obtained by rubbing a glass rod and a stick of resin, and had spoken of them as vitreous and resinous. For Franklin electricity was a single subtle fluid, and electrical manifestations were owing to the degree of its presence, to interruption or restoration of equilibrium.
His mind, however, was bent on the use, the applications, the inventions, to follow. He contrived an “electric jack driven by two Leyden jars and capable of carrying a large fowl with a motion fit for roasting before a fire.” He also succeeded in driving an “automatic” wheel by electricity, but he regretted not being able to turn his discoveries to greater account.
He thought later—in 1748—that there were many points of similarity between lightning and the spark from a Leyden jar, and suggested an experiment to test the identity of their natures. The suggestion was acted upon at Marly in France. An iron rod about forty feet long and sharp at the end was placed upright in the hope of drawing electricity from the storm-clouds. A man was instructed to watch for storm-clouds, and to touch a brass wire, attached to a glass bottle, to the rod. The conditions seemed favorable May 10, 1752; sparks between the wire and rod and a “sulphurous” odor were perceived (the manifestations of wrath!). Franklin’s well-known kite experiment followed. In 1753 he received from the Royal Society a medal for the identification and control of the forces of lightning; subsequently he was elected Fellow, became a member of the Académie des Sciences, and of other learned bodies. By 1782 there were as many as four[Pg 125] hundred lightning rods in use in Philadelphia alone, though some conservative people regarded their employment as impious. Franklin’s good-will, clearness of conception, and common sense triumphed everywhere.
One has only to recall that in 1753 he (along with Hunter) was in charge of the postal service of the colonies, that in 1754 as delegate to the Albany Convention he drew up the first plan for colonial union, and that in the following year he furnished Braddock with transportation for the expedition against Fort Duquesne, to realize the distractions amid which he pursued science. In 1748 he had sold his printing establishment with the purpose of devoting himself to physical experiment, but the conditions of the time saved him from specialization.
In 1749 he drew up proposals relating to the education of youth in Pennsylvania, which led, two years later, to the establishment of the first American Academy. His plan was so advanced, so democratic, springing as it did from his own experience, that no secondary school has yet taken full advantage of its wisdom. The school, chartered in 1753, grew ultimately into the University of Pennsylvania. Moreover, it became the prototype of thousands of schools, which departed from the Latin Grammar Schools and the Colleges by the introduction of the sciences and practical studies into the curriculum.
Franklin deserves mention not only in connection with economics, meteorology, practical ethics, electricity, and pedagogy; his biographer enumerates nineteen sciences to which he made original contributions or which he advanced by intelligent criti[Pg 126]cism. In medicine he invented bifocal lenses and founded the first American public hospital; in navigation he studied the Gulf Stream and waterspouts, and suggested the use of oil in storms and the construction of ships with water-tight compartments; in agriculture he experimented with plaster of Paris as a fertilizer and introduced in America the use of rhubarb; in chemistry he aided Priestley’s experiments by information in reference to marsh gas. He foresaw the employment of air craft in war. Thinking the English slow to take up the interest in balloons, he wrote that we should not suffer pride to prevent our progress in science. Pride that dines on vanity sups on contempt, as Poor Richard says. When it was mentioned in his presence that birds fly in inclined planes, he launched a half sheet of paper to indicate that his previous observations had prepared his mind to respond readily to the discovery. His quickness and versatility made him sought after by the best intellects of Europe.
I pass over his analysis of mesmerism, his conception of light as dependent (like lightning) on a subtle fluid, his experiments with colored cloths, his view of the nature of epidemic colds, interest in inoculation for smallpox, in ventilation, vegetarianism, a stove to consume its own smoke, the steamboat, and his own inventions (clock, harmonica, etc.), for which he refused to take out patents.
However, from the many examples of his scientific acumen I select one more. As early as 1747 he had been interested in geology and had seen specimens of the fossil remains of marine shells from the strata of the highest parts of the Alleghany Moun[Pg 127]tains. Later he stated that either the sea had once stood at a higher level, or that these strata had been raised by the force of earthquakes. Such convulsions of nature are not wholly injurious, since, by bringing a great number of strata of different kinds today, they have rendered the earth more fit for use, more capable of being to mankind a convenient and comfortable habitation. He thought it unlikely that a great bouleversement should happen if the earth were solid to the center. Rather the surface of the globe was a shell resting on a fluid of very great specific gravity, and was thus capable of being broken and disordered by violent movement. As late as 1788 Franklin wrote his queries and conjectures relating to magnetism and the theory of the earth. Did the earth become magnetic by the development of iron ore? Is not magnetism rather interplanetary and interstellar? May not the near passing of a comet of greater magnetic force than the earth have been a means of changing its poles and thereby wrecking and deranging its surface, and raising and depressing the sea level?
We are not here directly concerned with his political career, in his checking of governors and proprietaries, in his activities as the greatest of American diplomats, as the signer of the Declaration of Independence, of the Treaty of Versailles, and of the American Constitution, nor as the president of the Supreme Executive Council of Pennsylvania in his eightieth, eighty-first, and eighty-second years. When he was eighty-four, as president of the Society for Promoting the Abolition of Slavery, he signed a petition to Congress against that atrocious debase[Pg 128]ment of human nature, and six weeks later, within a few weeks of his death, defended the petition with his accustomed vigor, humor, wisdom, and ardent love of liberty. Turgot wittily summed up Franklin’s career by saying that he had snatched the lightning from the heavens and the scepter from the hands of tyrants (eripuit cɶlo fulmen sceptrumque tyrannis); for both his political and scientific activities sprang from the same impelling emotion—hatred of the exercise of arbitrary power and desire for human welfare. It is no wonder that the French National Assembly, promulgators of the Rights of Man, paused in their labors to pay homage to the simple citizen, who, representing America in Paris from his seventy-first till his eightieth year, had by his wisdom and urbanity illustrated the best fruits of an instructed democracy.
American Philosophical Society, Record of the Celebration of the Two Hundredth Anniversary of the Birth of Benjamin Franklin.
S. G. Fisher, The True Benjamin Franklin.
Paul L. Ford, Many-sided Franklin.
Benjamin Franklin, Complete Works, edited by A. H. Smyth, ten volumes, vol. X containing biography.
Gutenberg, An Introduction to the History of Science, by Walter Libby