Page:A Dissertation on the Construction of Locks (1785).pdf/57

 which the production of correſpondent keys is avoided, however great the number of Locks may be, that are manufactured on any given ſcale. And, The property of motion,—which, precludes all poſſible means of obtaining an impreſſion of their interior parts, for the purpoſe, of fabricating falſe keys. The former is capable of demonſtration: the latter is ſelf-evident.—The variations, by which the production of correſpondent keys is avoided, have two ſources; the one, ariſing from the changes, that may be made in the diſpoſition of the levers;—the other, from the number of points, contained on the projected ſurface of each lever, by which the poſition