By “useful,” in the patent law, is meant not an invention in all cases superior to the modes now in use for the same purposes, but “useful,” in contradis-tlnction to frivolous and mischievous, inven-tion. Lowell v. Lewis, 1 Mason, 182, 186, Fed. Cas. No. 8,568
Source: Black’s Law Dictionary 2nd Ed (1910)
