^3 



EFFECT OF ATTRACTION ON THE GOING OF CLOCKS. 



electrical effects ; which will give me an opportunity of examifi- 

 ing his system under a different point of view. 

 I have the honour to be. 

 Sir, 

 Your obedientj humble Servant, 



J. A. DE LUG. 

 Win dsor, August the 27th, 1812. 



n. 



Effect of the Attrnctinn letween the Weights and the Pendulum 

 on the goijjg of Clocks. In a Letter from Mr. Thomas 

 Keid. 



To W. Nicholson, Esq. 



Edhihurgh, ISth Aug. 1812. 



Sir, 



The goin 

 a time-piece 

 fected by 

 traction. 



^O 



A six-v/eeks 

 astronomical 

 filock. 



F late, having been much engaged with astronomical 

 clocks, which require a great deal of attention, to see that 

 they are fit to perform, and to keep as near to time as it is possi- 

 ble from the nature of things to bring them ; it will perhaps be 

 thought strange to say, that attraction comes in for a share in 

 those obstacles, v.'hich stand in the way of good timekeeping. 

 This is what has never been even hinted at before ; if it has, I 

 confess it is new to me. We have heard of clock pendulums 

 disturbing one another, where clocks were set agoing on the 

 same board, and where the pendulums were not sufficiently 

 fixed, but this arose from a very different cause. 



Having fitted up a clock in every respect particularly good, 

 and unexceptionable boih in the plan and the execution of it, 

 which, by express order, was made to go about one month or 

 six weeks, the scapement of it made after the principle sug- 

 gested by Mudge as far back as the year 1760, and which he 

 afterwards introduced or used in his timekeepers. This clock, 

 from the nature of the scapement, and from that of its pivots 

 being so independent of oil, at almost all of the holes, was, 

 from these circumstances, expected to keep the arc of the vibra- 

 tion of the pendulum as nearly constant »£ possible ; but after 



keeping 



