Page:A Dissertation on the Construction of Locks (1815).pdf/25

 wards, being fitted to the key-hole, and the shank of the key bored to a sufficient depth to receive the pin, nothing remains but to colour the bit with a preparation, which, by a gentle pressure against the introductory ward, may receive its impression, and thus furnish a certain direction for the application of the file. The block or bit being thus prepared to pass the first ward, gains admission to the second, and a repetition of the means by which the first impression was obtained, enables the workman to proceed, till by the dexterous use of his file he hath effected a free passage to the bolt. And in this operation he is directed by an infallible guide: for the pin being a fixed centre on which the key revolves without any variation, and the wards being fixed likewise, their position must be accurately described on the surface of the bit, which is prepared to receive their impression. The key, therefore, may be formed, and perfectly fitted to the Lock, without any extraordinary degree of genius, or mechanical skill. It is from hence evident, that endless variations in the disposition of, are not alone sufficient to the purpose of perfect security.

I do not mean to detract from the merit of such inventions, nor to dispute their utility and