EXPERIMENTS ON CHRONOMETERS. 49 



the watch green retarded its rate." If we carry our obferva- 

 tions farther, we find, that, in their fublequent ti ial which 

 took place at Mr. Dutton's, (the watches having had nothing 

 <ione to them,) they both retarded their rates throughout. 

 I will endeavour to (hew why thefe vratches did accelerate 

 and retard their rates in this manner. 



The errors of oppofite tendency that did esifl: in thefe ma- Great difficulty- 

 chines were fo fmall, and I may add, were fuch a length oi^^^^^^^^l^^^^^ 

 time in generating, that it became very difficult for Mr. Mudge error in Mudge'* 



to afcertain their caufe. Where was he to look for them? .t^^-P'^?^^' '^ 



in the tram. 

 It was not to the 'fcapement only his fearch was to be con- 

 fined, but he had alfo to traverfe through the whole train of 

 wheels: For though he had applied his Remonloires beyond 

 the traiiT, yet the lad wheel (if there was any inequality in 

 the power derived from the main fpring or train) would prefs 

 fometimes ftronger, and at others weaker upon the pallets of 

 the Remontoires ; which pallets the balance in its vibrations 

 (by means of the pins in the crank affixed to it) had alternately 

 to unlock, before it could be impelled by the unbending of 

 the Remontoire fprings — therefore, as he fuppofed the caufes 

 were not determined to the 'fcapement, he knew not where 

 to fix them *. 



It was an opinion (in writing) of Mr. Mudge's, " that the Opinions of me- 

 fimple principles of all watches are the fame and perfed, ^^^ Mudge, that 

 errors found in them are therefore not errors arifing from the time-pieces err 

 principles, but from imperfections, infeparable from all nie- "|p|g '^"l^^Pf'^J' 

 chanic operations." perfea: execu- 



The late Mr. Arnold aflerted before a Committee of the ^'°"*, ,, , 



.... z- yirnold : that 



Houfe of Commons, that, though he put no oil to his 'fcape- his 'fcapement 



ment, yet it wore lefs than any other part that was uibied to ^°^^ ^^^^ ^^^"' 



•' J r J other parts. 



wear. 



Mr. Emery told the fame Committee, that the Tcapement j^^f^^f/^^.f g' 

 which he made for his Excellency the Count de Bruhl, after ment would not 

 a model of Mr. Mudge's, was very difficult to execute, but ^^^*'y ^^*'^' 

 when made, it would not eafily wear out. It is a known 

 fa6t, that this watch went with an unufual degree of ex- 

 cellence. 



* For drawings and defcriptions of Mr. Mudge's 'fcapement, 

 the detached 'fcapement now in general ufe, and feveral others, fee 

 Philof. Journal, quarto feries II. p. 49. 



Vol. VIII.—May, 1804.. E And 



