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Rights. An addition of some useful thing to a machine, manufacture or composition of matter.

The patent law of July 4, 1836, authorizes the granting of a patent for any new and useful improvement on any art, machine manufacture or composition of matter. Sect. 6. It is often very difficult to say what is a new and useful improvement, the cases often approach very near to each other. In the present improved state of machinery, it is almost impracticable not to employ the same elements of motion, and in some particulars, the same manner of operation, to produce any new effect. 1 Gallis. 478; 2 Gallis. 51. See 4 B. & Ald. 540; 2 Kent, Com. 370.