It is not very clear from the published correspondence of Franklin what his earliest views on the subject were, but there are many indications that he conceived for a while that the ‘electric fire’ might be employed in arts and manufactures. In his usual humorous style he spoke of these utilitarian aims of his in a letter to Mr. Peter Collinson, written in the early summer of 1747: ‘Chagrined a little that we have not been able to produce hitherto anything in the way of use to mankind,’ he wrote, ‘and the hot weather coming on, when electrical experiments are not so agreeable, it is proposed to put an end to them, for this season, in a party of pleasure on the banks of the Schuylkill. Spirits at this party are to be fired by a spark sent from side to side through the river, without any other conductor than the water: an experiment which we some time since performed, to the amazement of many. Then a turkey is to be killed for our dinner by the electrical shock, and roasted by the electrical jack, before a fire kindled by the electrified bottle, when the healths of all the famous electricians in England, Holland, France, and Germany are to be drunk in electrified bumpers, under the discharge of guns from the electrical battery.’
The longer he experimented, the more fascinated grew Benjamin Franklin with his study of the phenomena of electricity. In order to be able to devote himself completely to his darling science, he sold his printing and publishing business in the year 1748, and went to live in a suburb of Philadelphia, not far from the banks of the Delaware. At the same time he purchased a complete set of electrical apparatus, the best that had yet been manufactured, which had been brought over from Europe by the same Dr. Spence who had given him his first ideas about electricity at Boston. With these more perfect means he now continued his investigations, arriving before long at results that formed an epoch in the history of electricity.
The results achieved were wholly of a practical kind. With that strong common sense which formed the most marked feature of his character, Benjamin Franklin, at a very early period of his experiments, came to the conclusion that of the actual _nature_ of electricity we know nothing, and, in all probability, never can know anything, with our finite senses. But, never losing sight of this starting point, he treated electricity as astronomers do the movement of the heavenly bodies. Of the incomprehensible forces that keep countless worlds in their courses through measureless space, astronomers know no more than the most ignorant of mankind; still they are able to arrive at very accurate calculations concerning the directions followed by stars and planets, and the amount of time consumed in their wanderings through the inconceivable universe. To such astronomical endeavours Franklin limited all his researches, and it was precisely because he so limited them that he achieved greater successes than any other investigator of the phenomena of electricity.