DESCRIPTION OF A SECRET LOCK. 217 



have fuccefsfully employed themfelves upon them, to the pro- 

 duction of fecret locks, exhibiting different degrees of inge- 

 nuity. 



But it is not fufficient that this inftrument fhould contain a ought not to ad-" 1 

 fecret difficult to be developed by the lkilful method of con- in their f ecret . 

 cealment. The proprietor of this lock muft always have, as 

 partakers with him, not only the maker, but alfo fiis friends, 

 his domeftics, and generally every perfon who pofleffes a lock 

 conflrucled on iimilar principles. The queftion to be folved 

 remained as follows : 



To invent a lock which cannot be opened but by the pro- Enunciation of 

 prietor, of which the conftruaion mall be fxmple and eafy, ^ p . r ° blem ° f * 

 defended againft all internal derangements, and, laftly, ca- 

 pable of being readily opened by the proprietor. 



By reflecting on the conditions which a perfecl lock, ought Condition that 

 to include, I was naturally led fome years ago to this refult; ^ e v ^{ e ^. ould 

 namely, That the fecret of the lock ought to be variable at pieafure. 

 pleafure *, or at leaft that the fecrets mould be fo multiplied, 

 that it mould be morally impoflible for the workman who con* 

 flructed the lock, or any other perfon, to conjecture which 

 among them all the proprietor might have chofen at the time. 

 I foon afterwards contrived feveral kinds of locks founded on 

 this general principle. 



By continuing to attend to this objea, I foon found that Others as welt 

 others before me had arrived at the fame refill t, and had pub- ™ zd urfued ^ 

 liflied locks formed on the theory of combinations. object. 



As fimplicity is one of the moft effential conditions of this Simplicity an 

 purfuit, and there are thoufands of ways of applying the prin- g t g" U re(1U1 " 

 ciples of combinations to the conftruaion of locks, I thought it 

 would not be without utility to explain the different refults I 

 have obtained. For it will not be till after having compofed 

 the moft happy combinations, that we can hope to arrive at 

 that fimplicity, without which a lock of this kind would be 

 more curious than ufeful. 



I (hall firft defcribe the lock which appears to me to be the The author's 

 beft among thofe I have thought of. I mall afterwards com- p^^^" 

 pare it with that invented in 1777, by Cit. Reguier, and de, f Reguier. 



* This principle, which is appplied in the well-known lock of 

 Braviali, was explained to me in converfation, much at large, by 

 him, in 1797. 



fcribed 



