Another experience, this time a more painful lesson in honesty, he relates in his Autobiography. Having one day stolen some stones from an unfinished house while the builders were away, he and his comrades built up a wharf where they might stand and fish for minnows in the mill-pond. They were discovered, complained of, and corrected by their fathers; "and though I demonstrated the utility of our work," says Franklin, "mine convinced me that that which was not honest could not be truly useful." It is interesting, too, to see the boy showing the same experimental aptitude which brought scientific renown to the man. Like all American boys living on the coast, he was strongly attracted to the water, and early learned to swim. But ordinary swimming was not enough for Benjamin: with some skill he made a pair of wooden paddles for his hands, which enabled him to move through the water very rapidly, although, as he says, they tired his wrists. Another time he combined the two joyful pursuits of swimming and kite-flying in such a manner perhaps as no boy before him had ever conceived. Lying on his back, he held in his hands the stick to which the kite-string was attached, and thus "was drawn along the surface of the water in a very agreeable manner." Later in life he said he thought it not impossible to cross in this manner from Dover to Calais. "But the packet-boat is still preferable," he added. We shall see how he managed to put even his knowledge of swimming to practical use; and kite-flying, every one knows, served him in his most notable electrical experiment. Certainly, if it could ever be said of any one, it might be said of him, "The child is father of the man." But swimming and boyish play formed a small, though it may be important, part of his education. He was from childhood up "passionately fond of reading," and he was moreover a wise reader, which is still better. Books were not so easy to get in those days; and the good libraries of the country were composed chiefly of great theological volumes in folio on the shelves of the clergymen's studies. But in one way and another Franklin contrived to lay hands on the food he most needed. All the money he could save he devoted to buying books, and he even had recourse to unusual methods of saving for this purpose. When sixteen he chanced to read a treatise commending a vegetable diet, and forthwith he put himself under this regimen, finding he could thus set aside half his board money to increase his library. He also made the acquaintance of the booksellers' apprentices from whom he could borrow books; and often he would read late into the night so as to return the purloined volume early the next morning.