One day Eli said: "I could make as good ones if I had tools, and I could make the tools if I had common tools to begin with;" his mother laughed at him. But it so happened soon afterward that one of the knives was broken, and he made one exactly like it in every respect, except the stamp of the blade. When he was fifteen or sixteen years of age, he suggested to his father an enterprise which clearly showed his capacity for important work. The time being the Revolutionary War, nails were in great demand and at high prices. They were made chiefly by hand. Whitney proposed to his father to get him a few tools and allow him to set up the manufacture of nails. His father consented, and the work was begun. By extraordinary diligence he found time to make tools for his own use and to put in knife-blades, repair farm machinery, and perform other little jobs beyond the skill of the country workman. At this occupation the enterprising boy worked, alone with great success and with large profit to his father for two winters, going on with the ordinary work of the farm during the summer. He devised a plan for enlarging the business, and managed to obtain help from a fellow-laborer whom he picked up when on a short journey of forty miles, in the course of which he tells us that he called at every workshop on the way and gleaned all the information as to tools and methods that he could. At the close of the war the business of making nails was no longer profitable; but the fashion prevailing among the ladies of fastening on their bonnets with long pins having appeared, he contrived to make these pins with such skill that he nearly monopolized the business, though he devoted to it only such leisure as he could redeem from the occupations of the farm. He also made excellent walking-canes. At the age of nineteen Whitney conceived the idea of getting a liberal education; and partly by the results of his mechanical industries, and partly by teaching the village school, he was enabled so far to surmount the difficulties in his way as to prepare himself for the Freshman Class in Yale College, which he entered in 1789. At college his mechanical propensity frequently showed itself. He successfully undertook, on one occasion, the repairing of some of the philosophical apparatus. Soon after taking his degree, in the autumn of 1792, he engaged with a Georgia family as private teacher, and through his engagement he made the acquaintance of a certain General Greene, of Savannah, who took a deep interest in him, and with whom he began the study of law. While living with the Greenes he noticed an embroidery-frame used by Mrs. Greene, and about which she complained, observing that it tore the delicate threads of her work. Young Whitney, eager to oblige his hostess, went to work and speedily produced a frame on an entirely new plan. The family were much delighted with it, and considered it a wonderful piece of ingenuity. [Illustration: Whitney Watching the Cotton-Gin.]