KXl'ERIMENTS ON CHRONOMETERS, ,57 



h'lgh, therefore there arofe in fome degree an impedimerit (o 

 (.he balance, which might occafion the arcs to be fhortened, 

 bccaufe, before the wheel was fetal liberty, or unlocked from 

 one pallet, in order to wind up (he other remont(jire fpring, 

 the balance (by means of the crank affixed to it) had alter- 

 nately to wind up each reinontoire fpring a little higher, and 

 in fhort, fo much higher than the wheel had before wound it, 

 as the momentain of the balance was equal to; therefore, as 

 I faid before, wiien the teeth of the wheel became Oiorter by 

 wear, they would not wind up the remontolre fprings quite fo — and the rc- 

 hijjh: in wh.ich cafe the crank would engage the pallets on the "^ontoire fpvings 



W /•! r.u . • • ,..T r u u- 1 would be lefs 



oppoute fide or the remontoire axis a little looner, by which wound up-. 



means the balance would receive a check in its vibrations, and whence the 

 the arcs would certainly fall oft'. Thefe, which I have men- j^^^g ^^^^ ^^ ^ 

 tioned, are the only reafons which have occurred to me to (lievv alone, 

 why the remontoire machine I made fliould have its arcs of 

 vibration increafed when the watch went fafter, and, on the 

 contrary, Mr. Mudge's (hould have its arcs fliortened when 

 ;'t went the fame way.* 



As to Mr. Madge's watches, o-reen and blue retarding their „i , . 



° _ ' ^ . ^ The retardation 



rates while under trial at Mr. Button's, after having gone of Mudgc'sother 

 through their public trials at the Royal Obfervatory, it Hiould timepieces af- 



t 1 . , , , , . 1 , ", . •, ^^'■'bed ro infpif- 



be remembered they had not been cleaned, and that the oil fation of the < il, 



being thicker, mufi; have had a [liai"e in producing that effect, 



and perhaps a principal one; for as to fridion in the impulfe 



or unlocking part, there was none, it was totally annihilated, 



by the verge and remontoire axis moving on the fame centre; 



if any wear could take place there, it muft be by percutTion and 



prefTure only : likewife it may beconfidered, that the teeth of 



the wheel (or locking part) having been blunted by wear with 



former going, would have larger furfaces to refift the wear 



and its accelerating effeft during this trial; befides, it will be 



readily believed by thofe acquainted with Mr. Mudge's fcape- 



ment, that the wearing of his wheel and its pernicious effe6l, 



cannot be io great as in that of the detached 'fcapemcnt. 



* It appears to me, that if the impelling pallet came to a flop 

 before the inftant of unlocking, no other than the lad efFeft, in 

 Mudge's machine, would take place ; except that the refiftance to 

 unlocking might become lefs. Would the crank and levers wear 

 iand diminifli the efFe61 of the acting pallet ? — N, , 



A Memoir 



