jf,Q, EXPERIMENTS ON CriRONOMET^R S. 



XII. 



Ohfcrvallons and Experiments tending to afcertain the Caufe$ of 

 tliofe Irregularities in Chronometers, which are generated 

 during confderable Intervals of Timet and have been afcribed 

 to external Caufes. By Mr. John Haley, J tin. 



To Mr. NICHOLSON. 

 SIR, 



IjLaVING feen in the lafl: number of your very ufeful 

 Journal fome remarks on chronometry, I have thought the 

 accompanying obfervations might not be unacceptable. If 

 you fliould confider them worthy of infertion, I fliall take 

 the liberty of communicating the refults of fome experiments 

 I am now making in the fame line. 

 I am. Sir, 



Your moil obedient and humble Servant, 

 JOHN HALEY. 

 March 29, 25, Cleveland Street, 



1 804-. Fitzroy Square. 



Latent caufes of MY defign in writing the following pages is to develope 

 enor in time- certain latent caufes of error, and their mode of operation, 

 which have been found in a greater or lefs degree to affcdl 

 every machine hitherto conflrudted for meafuring time. 

 If the errors of It is Certainly the part of a watch-maker to fearch for and 

 the machine be remove every mechanical caufe that may affedt the going of 

 foreien caufes, his machines, before he haftily concludes that the caufes of 

 jniprovements thofe errors which are generated in a length of time, (and 

 wi teae. vvhich have efcaped his notice,) arc foreign to its ftrudure ; 



fuch as the influence of the oil, the varyiiig different denfity 

 of the atmofphere in which the wheels move, &c. For 

 fuch opinions when once adopted, mufl greatly lend toflacken 

 his puifuit-s and put a flop to his hope of farther improve- 

 ment. 

 The foreign That thefe foreign caufes do in fa6t produce errors deferving 



caufes are of rauch notice in the beft adjufied time-keepers is probably an 

 little cffeft: For . -r -f r u ur c .-rr 



many machhies erroneous notion. for It lo, how could lo many of different 



have performed conflrucfions have been found to perform for very long periods 

 wiiiie^fLibica^to' ^^^ time, expofed to all thefe caufes, with a wonderful degree 



their aftiOu. cf 



