INVENTION OF THE BALANCE SPRING, &C. 385 



ledged that the late Mr. Arnold, as well for his own inventions 

 as from his ability for improving whatever came before him, 

 deserved all the encouragement he met with from his private 

 business, and from the public rewards which he may from time 

 to time have obtained, if it was no more but for his exertions 

 in persevering and shewing a track which others m,ight follow ; 

 and this he did with an enterprizing and ingenious spirit, of 

 which few men were capable. All circumstances considered, 

 the business of making chi-onometers stands more indebted to 

 him than any other man since Dr. Hooke; with whose merits 

 IMr. Arnold was so well acquainted, and whom he thought so 

 much of, as to set him on a par, nay, even above the most cele- 

 ' brated Sir Isaac Newton. When Mr, Arnold began his career Arnold extend-. 



in life, he was the first who brought watch jeweUi'^g, and the ^^ f^^ Pf.^'^*^'^^ 



_ '^ . . or jewelling. 



apphcation of stone to the places of action, into more ge- 

 neral use than ever had been done before his time ; and, 

 although these may not have any thing of a mechanical prin- 

 ciple in them, yet they certainly render any principle con- 

 nected with the holes, &c. as, for example, the pitchings 

 and 'scapements are made more permanent than they would 

 otherwise be, by which our watches have acquired a stabi- 

 lity and character (from jewelled holes, &c,) that in all 

 probability they would not have had without them. I speak 

 from experience of the utility of these things ; the pallets of 

 my astronomical clock being of stone, and it has been going 

 with me for sixteen years, without the smallest application 

 of oil to them in any manner whatever. 



I am, Sir, 



With much respect, 



Yours, 



THOMAS REID, 

 Edinburgh, July 12, 1S05. 



P. S. — In the work published by M. Thiout, in 1741, there A detached es- 

 is a large collection of the various 'scapements then known ; xiJioITAlA^ri 

 and, among others, there is one which seems to have been in-priorto Le 

 vented by himself, and is a sort of free or detached one, the Sentially'^dif- 

 same in its principle as the one invented by M. Le Roy in ferent. 



Vol. XIV.-^SuppLEitfENT. Ddd 174S. 



