MR. REID ON TIME-KEE»ING MACHINES. O 



things for which premiums have been adjudged were not new, 

 perhaps ihey were neverthelefs Jb, to thofe to whom the pre- 

 miums were adjudged. 



Among Thiout's colleftion may be feen a 'fcapement, which ;^J"f ™*"g', 

 he gives to (he ingenious Dutertre, about the year 1724-. 

 Peler Le Roy gave into the Royal Academy of Arts and 

 Sciences in the year 1727, a defcription of the fame Tcape- 

 ment which Dutertre claimed, or pretended to fay was his 

 invention. The miftake lays with Thiout, for Dutertre's 

 'fcapement is an improvement of a very old one, ufed by the 

 Germans in large clocks, perhaps long before the year 1600, r' 



though neither the author of it, nor the time when, can now 

 be traced. 



However it was before Dr. Hook's time, who invented one 

 of the fame kind before 1658. I would not have entered fo 

 minutely into this difcuflion, but to fliow the progrefs of the 

 duplex, which in its prefent form, was firft made fo by Peter leading to the 

 Le Roy, who afterwards gave it up for a bad one; yet it ought ^'.^Jf^Jh^^^" 

 to be allowed that that of Dutertre's mutt have led him very was fi, ft made 

 eafily to it. So much for the duplex 'fcapement, f6 called by by Peter Le Roy. 

 the workmen, and now in fuch general ufe. A celebrated 

 Philofopher in the fupplement to the Edinburgh Encyclopedia, 

 under the article watch work, has given it a French furnarae^ 

 that of Dupleix, for what reafon, I know not. 



Thiout has given alfo among the number, a 'fcapement of The origin of 

 his own, a fort of detached one, and which may be conlider- (je^^ched 'fcape- 

 ed as the foundation of the detached one of the prefent day, ment afcribed to 

 now fo much improved, and of fuch general ule in all our 

 pocket and box chronometers: indeed it feems a fcapement 

 indifpenfably necetfary for thefe purpofes. Yet Berthoud in 

 his famous time-keeper. No. 8, ufed a very different one 

 from that of the detached fort. 



I am. 

 Sir, with much efteem, Your's, 



THOMAS REID. 



Edinburgh, 25th March, 1805, 



Thiout, 



An 



