EXPERIMENTS ON CHRONOMETERS. 5S 



The mode of operation by which fridion isfaid to accelerate Whether gain 

 the rate of machines, is thus pointed out by the trade in ge- /ho^tened"vibra* 

 neral, viz. that whenever it takes place by the action of the tions. 

 wheel upon the pallet or pallets, (in watches or clocks con* 

 flrucled with one or two pallets), or in the verge holes by the 

 a6lion of pivols therein, it impedes the motion of the balance 

 or pendulum, ftiortens its vibrations, and in confequence the 

 machine goes fafter : hovv does this agree with M*. Harrifon's 

 opinion ? wiiich was, that large arcs are naturally performed in 

 lefstime than fmall ones. Mr. Gumming, in the work of his 

 before alluded to, has intimated, that nothing concliifive can 

 be drawn from different arcs, becaufe they are effects and not 

 c^ufes of error. 



In the Repertory of Arts and Manufadiures, No. 33, In the An efcapemoct 

 year 1796 or 7, there is a defcription of a Remontoire 'fcape- ^^^^^^^^^ ^^' 

 ment, which Is completely detached from the train of wheels. 

 The errors of this machine muft be determined to the 'fcape- 

 ment alone, becaufe no errors in the going can poffibly arife 

 in any other part of the watch. For if any additional power, 

 however great, be applied to the train, the arcs of the balance 

 will not be in the leaft affeded by It : in the opinion of all or 

 moft who'underftood its principles, its going muft be more per- 

 fect than that of any machine before Invented. 



In the following remarks upon that Tcapement, I fliail call. In this theweaf 

 what is in the before-mentioned defcription of It termed a ""^ateVbeclufe'* 

 fnail pallet, a locking pallet. In the commonly termed de- the aftion is on 

 tached 'fcapement, every tooth In the wheel is locked in fuc-* ^"^le "«. 

 ceffion upon the jewel 6f the detent, and the effe<5l arifing 

 from wearing of the teeth does not very foon Ihew itfelf, there 

 being 12,15 or more (at pleafure) in number, but in this re- 

 montoire Tcapement before every impulfe there is only this in- 

 dividual locking pallet to fupply the place of a wheel, (if I 

 may fo exprefs it) the wear therefore muft be 12 or 15 times as 

 great, and its effeftmuft maniteft Itfelf very foon. 



In the years 98 and 9, I executed four or five of thefe Account of the 



'fcapements, and tried the going of each. They all went in the ""^'•"^Jon »^i 



' . . , ^ ® •' early perrorm- 



lame manner, viz. for the firft twenty-four or thirty hours the ance of feveral 



machine would vary nothing; the day following it would gain ®^ *^^^^* 

 one or two feconds, the next day feven or eight, and on the 

 fourth or fifth day it would gain 30 or 40. I obferved, the 

 more the machine gained, the larger were the arcs of the ba- 

 lance ; 

 2 



