When only fifteen years old, and apprenticed in the printing-office of his brother in Boston, in the year 1721, he became a vegetarian. A book written by one of the people who have for many centuries been advocating that plan of living fell in his way and converted him. It appealed to his natural economy and to his desire for spare money with which to buy books. He learned from the book the various ways of cooking vegetables, and told his brother that if he would give him half the money paid for his board he would board himself. He found very soon that he could pay for his vegetable diet and still save half the money allowed him, and that he could also very quickly eat his rice, potatoes, and pudding at the printing-office and have most of the dinner-hour for reading the books his spare money procured. This was calculating very closely for a boy of fifteen, and shows unusual ability as well as willingness to observe and master small details. Such ability usually comes later in life with strengthened intellect, but Franklin seems to have had this sort of mature strength very early. He did not remain an entire convert to the vegetarians, but he often practised their methods and apparently found no inconvenience in it. He could eat almost anything, and change from one diet to another without difficulty. Two years after his first experiment with vegetarianism he ran away from his brother at Boston, and found work at Philadelphia with a rough, ignorant old printer named Keimer, who wanted, among other projects, to form a religious sect, and to have Franklin help him. Franklin played with his ideas for a while, and finally said that he would agree to wear a long beard and observe Saturday instead of Sunday, like Keimer, if Keimer would join him in a vegetable diet. He found a woman in the neighborhood to cook for them, and taught her how to prepare forty kinds of vegetable food, which reduced their cost of living to eighteen pence a week for each. But Keimer, who was a heavy meat-eater, could stand it only three months, and then ordered a roast-pig dinner, to be enjoyed by the two vegetarians and a couple of women. Keimer, however, arrived first at the feast, and before any of his guests appeared had eaten the whole pig. While working in the printing-office in London, Franklin drank water, to the great astonishment and disgust of the beer-guzzling Englishmen who were his fellow-laborers. They could not understand how the water-American, as they called him, could go without strength-giving beer and yet be able to carry a large form of letters in each hand up and down stairs, while they could carry only one with both hands.