Franklin'. turn of mind was emloently practical. Ho said with truth, "I have always act a greater value on the character of a doer of good than on any other kiod of reputation." Not that ho joined in the vulgar prejudice of setting theory and practice in opposition, for he was bold, speculative, and inquiring In physical as well as iu metaphysical science. But science in his bands always bore fruit directly applicable to the usca of common life; and while ho never neglected his own affairs, industry and economy of time enabled him to originate, or take an active part in supporting, a variety of projects for the public good. Of these the chief were the first publio library, incorporated in 1742 by the name of "The Library Company of Philadelphia," hut which he act on foot and procured subscriptions for in 1732. In 1738 he established the first association for extin guishing fires; and, at a later period, the first Fire Insurance Company. In 1749 he raised subscriptions for the foundation of a public academy, the schools of Pennsylvania being few and bad. This was the origin of the present university of Pennsylvania. In 1752 he raised subscriptions and procured an auxiliary grant from the legis lature to establish the first hospital in Philadelphia ; a scheme eug ge•ted in the first instance by a physician of the city, who had not influence enough to work it out. In 1754 he proposed a plan for a union of the American provinces against invasion, in which a germ of the future Union may be found. It was kopt alive, he used to say, like all good notions, though not carried into effect at the time.' It was approved by a species of congress from six of the provinces, but rejected both by the colonial assemblies and the British government. He was also a zealous member of several societies; among them, of the Philadelphia Society for the Improvement of Prisons, and the Penney!. vanian Society for the Abolition of Slavery, both founded in 1787.
As a philosopher, his name is indissolubly linked with the history of electricity, in which he was one of the most active, patient, and successful experimentere; and his industry was rewarded by that brilliant discovery, the cornerstone of his scientific fame, of the identity of the electric fluid and lightning. His attention was first turned this way in 1745, the science being then in its infancy, by the transmission of an electrical apparatus to Philadelphia, for the purpose of having the experiments which had attracted so much notice iu Europe repeated in America. In 1747 he sent a series of letters to England, iu which he noted the power of sharp points both to attract and to give out electric matter; and explaiued his theory, that instead of the phenomena observed being produced by two different electric fluids, they arose from the effort made to restore an equi librium when one body was overcharged, and another undercharged, with electricity. A. body in the former state he called positively, in the latter state negatively electrified. This theory he used to explain the action of the Leyden jar ; and though not universally admitted, it at least furnishes a simple and satisfactory explanation of the phenomena of the science. In 1749 he had conjectured the
identity of lightning and electricity, and suggested the idea of pro tecting houses by pointed conductors, but did not prove it till 1752. He was waiting for the erection of some lofty building, upon which an iusulated lion rod might ba placed, in hope that on the passage of a thunder-cloud overhead, sparks might be taken from the rod, as from a charged conductor, when it occurred to him that by flying a kite, pointed with iron, during a thuuder-storm, the matter of ii.ffltuing might, if his views were correct, be drawn down the string. Ile tied a key to the end of tho hempen string, insulated the whole apparatus by adding a piece of silk to the end next the heed ; and the experiment succeeded. Sparks were taken from the key, a Leyden jar was charged, and the phenomena exhibited were identically the same as if an electrical machine had been used instead of the kite. lie varied the experiment by fixing an insulated iron rod at the top of his house ; and immediately proceeded to turn his discovery to account by publishing a plan for defending houses from lightning by the use of pointed couductors.
Ilia character, in reference to this branch of his pursuits, has been described in the following terms by Sir H. Davy : "A eiugular felicity for induction guided all his researches, and by very small means lie established very grand truths. The style and manner of his publi cation (on Electricity) are almost as worthy of admiration as the doetriue it coutaius. Ho has endeavoured to remove all mystery and obscurity from the subject. He has written equally for the un initiated and for the philosopher ; and he has rendered his details amusing as well as perspicuous', elegant as well as simple." (' Life,' by Dr. Davy.) To Franklin's other scientific labours we can only allude. They treat of many branches of meteorology, maritime phenomena, ship building and various subjects connected with navigatiou, as the Gulf Stream, and the effect of oil iu stilling waves; of the proper con 'erection of stoves and chimneys, which, to use a common phrase, seems to have been one of his hobbies; of the art of swimming, which, being himself an excellent swimmer, he was anxious to recotnuieud as a universal branch of education : subjects consonant to his practical character, and most of them directly applicable to the increase of human comforts. Papers on these matters nearly fill the second volume of his collected works; his electrical treatises and letters occupy the first volume; and his moral, historical, and political writings the third.
To return to Franklin's private history : the increasing estimation in which he was held, was manifested in his successive appointments to different offices. In 1736 he was made clerk to the General Assem bly of Pennsylvania; in 1737 postmaster of Philadelphia; in 1747 he was elected as one of the representatives of Philadelphia in the Assem bly ; in 1753 he was appointed deputy postmaster-general for the British colonies.