We have seen in a previous chapter that a close approach to the interchangeable system was made in the Portsmouth block machinery of Bentham and Brunel. This was rather an application of modern manufacturing principles than a specific case of interchangeable manufacture. The interchangeability of product obtained was incidental to good manufacturing methods, not a distinct object aimed at, and there does not seem to have been any system of gauging during the processes of manufacture, to insure maintaining the various parts within specified limits of accuracy. In fact, the output itself did not require it, as ship’s blocks do not call for anything like the precision necessary in guns or the other typical products of the interchangeable system. We have seen, too, that John George Bodmer began about 1806 to manufacture guns at St. Blaise in the Black Forest, using special machinery for much of the work previously done by hand, especially for the parts of the lock, which “were shaped and prepared for immediate use, so as to insure perfect uniformity and economize labor.” In both of these instances, the Portsmouth block machinery and the St. Blaise factory, definite steps which form part of the interchangeable system were taken, but it does not seem probable that the system existed in anything like the completeness with which it was being developed at that time in America. In 1798 and 1799 two contracts were let by the United States Government for firearms, one to Eli Whitney in 1798, the other to Simeon North in 1799. These contracts are of the greatest importance. Whitney had invented the cotton gin in 1792. This invention, as is well known, had a profound economic effect on the whole civilized world, but the condition of the patent laws at that time and the very value of the invention itself made it impossible for him to defend his rights; and, although he had practically created a vast industry, he actually lost more money by the invention than he gained. By 1798 he made up his mind that he must turn to something else. He chose the manufacture of muskets, and addressed a letter to Oliver Wolcott, Secretary of the Treasury, in which he said: I should like to undertake the manufacture of ten to fifteen thousand stand of arms. I am persuaded that machinery moved by water, adapted to this business would greatly diminish the labor and greatly facilitate the manufacture of this article. Machines for forging, rolling, floating, boring, grinding, polishing, etc., may all be made use of to advantage.[152] [152] “New Haven Colony Historical Society Papers,” Vol. V, p. 117.