Page:A Dissertation on the Construction of Locks (1785).pdf/58

 poſition of its notch may, in the ſmalleſt degree, be varied.

The variations, produceable in the diſpoſition of ſix figures only, are 720; theſe, being progreſſively multiplied by additional figures; will increaſe, by aſtoniſhing degrees; and eventually ſhow, that a Lock, containing twelve levers, will admit of 479,001,500 changes; which, the addition of another lever will increaſe to 6,227,019,500.—Theſe, being again multiplied by the number of changes, which, the projected ſurface of the levers will admit, in the diſpoſition of the notches; their amount will exceed numeration; and, may, therefore, be properly ſaid to be infinite.—The ſlighteſt inſpection of theſe Locks, will, at once, evince, that I do not over-rate the effect of their property of motion; in aſſerting, that it precludes all poſſible means, of obtaining an impreſſion of their interior parts; which, is neceſſary to the fabrication of a falſe key: for, it will be