Mr. Peter Collinson, the London agent of the library that Franklin had founded in Philadelphia in 1732, was accustomed to send over with the annual parcel of books any work or curious object that chanced to be in vogue in London at the time. In 1746 he sent one of the new electrical tubes with a paper of directions for using it. The tubes then commonly used were two feet and a half long, and as thick as a man could conveniently grasp. They were rubbed with a piece of cloth or buckskin, and held in contact with the object to be charged. Franklin had already seen one of these tubes in Boston, and had been astonished by its properties. No sooner, therefore, was it unpacked at the Library, than he repeated the experiments he had seen in Boston, as well as those described by Collinson. The subject completely fascinated him. He gave himself up to it. Procuring other tubes, he distributed them among his friends and set them all rubbing. "I never," he writes in 1747, "was before engaged in any study that so totally engrossed my attention and my time as this has done; for what with making experiments when I can be alone, and repeating to my friends and acquaintances, 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." Franklin claimed no credit for what he achieved in electricity. During the winter of 1746-7 he and his friends experimented frequently, and observed electrical attraction and repulsion with care. That electricity was not created, but only collected by friction, was one of their first conjectures, the correctness of which they soon demonstrated by a number of experiments. Before having heard of the Leyden jar coated with tin-foil, these Philadelphia experimenters substituted granulated lead for the water employed by Professor Maschenbroeck. They fired spirits and lighted candles with the electric spark. They performed rare tricks with a spider made of burnt cork. Philip Syng mounted one of the tubes upon a crank and employed a cannon-ball as a prime conductor, thus obtaining the same result without much tedious rubbing of the tube. The summer of 1747 was devoted to preparing the province for defence. But during the following winter the Philadelphians resumed their experiments. The wondrous Leyden jar was the object of Franklin's constant observation. His method of work is well shown in his own account of an experiment during this winter. The jar used was Maschenbroeck's original device of a bottle of water with a wire running through the cork.