Og2 DESCRIPTION Or A SECRET LOCK. 



Conftruftion of It would be fuperfluous to examine a greater number of 

 iffibfe on^to" f > ftems - l lhal1 conclude by one general obfervation. 

 the proprietor. All the compound locks that can poflibly be made, may be 

 divided into three fpecies. In the firfl, ltraight Or curve lines 

 are made to move ; in the fecond, plain or curved furfaces ; 

 in the third, folids. It is obvious that one (olid offers as many 

 arrangements or combinations as three lines together, and one 

 furface as many as two lines. 



Thefe lines, furfaces, and folids, form interior flops made 

 to receive motions (externally produced) in a flraight or in a 

 curve line. 



It is obvious from the application of thefe principles, an 

 almoft infinite variety of locks may be conflrucled. I fliall not 

 undertake to extend the variations, but (hall only fay, that I 

 think I am convinced that the bell: fyftem is that of moving 

 the circumferences of circles internally by circular motions 

 produced from without, 



CONCLUSION. 



I am fenfible that what I have faid concerning the looks, 

 which I confider as lefs perfect, is not fufficient to direct their 

 conflruclion ; but I have faid enough to make their fyftem 

 known to artifts, and to deter them from fruitlefs experiments. 

 It mull not be forgotten, that in this kind of machine nothing 

 good or ufeful (hall be done, uniefs fimplicity, convenience, 

 folidity, economy, and facility of execution, be combined. 



It is under thefe feveral points of view that the problem of 

 compound locks, which may be worthy of the attention of 

 artifts, ought to be confidered. I do not pretend to have dis- 

 covered the bed, but I dare aflferl, that the lock which I have 

 defcribed approaches fo near to perfection, as to entitle it to 

 the fuperiority over the common locks which are more or lefs 

 ingenious and complicated, and even to place it among the 

 locks of combination, as one of the moft fimple that has yet 

 appeared, or that I know of. 



Whether I fliall be allowed the fmall honour of having in- 

 vented this arrangement, or the merit .only of having brought 

 it to perfection, is not to me a matter of confequence. I fliall 

 be fatisfied if I have aflifted others in improving this fpecies of 

 machines, the utility of which need not be proved. In fact, 



the common locks which are brought to the greatefl perfec- 

 tion! 



