COMPENSATION PENDULUM. 53 



a little on tlie strain, in opposition to each ptliei-'s exeTtion, 

 the point of rest of both springs will be destroyed. Thus 

 by producing this counteracting force in the two springs at 

 the lowest point of vibration, the accelerating effect of the 

 escape wheel upon the balance in the small arcs of vibra- 

 tion will be corrected, whereby the whole of them will vi- 

 brate in equal time. 



Extract of a Letter from Captain William Brown, addressed 

 to Mr. John Nichols, Millpond-bridge, Bermondsey. 



Respecting the chronometer which I purchased from Mr. Testimony of 

 William Hardy last year, the jolting of the coach in the ^n^J'^f^'J,™* 

 conveyance to Liverpool altered its rate of going to 34" slow, Hardy's chro» 

 which rate it continued so exactly, that in making Cape de "'*'"^*^'^- 

 Verd, on the coast of Africa, (the longitude of which has -^' 

 been correctly ascertained) in 24 days from Liverpool, and 

 carefully measuring my distance from the Cape, I could not 

 discover it to have deviated from the rate, say 34" slow, 

 one second in the whole time ; and I have every reason tp 

 believe that it continued the same rate, until ray niisfortune, 

 when it got imraerged in sea-water, having lost my ship on 

 a shoal five or six leagues from the Riopongas, this dange- Danfrerous 

 ous bank not being laid down correctly, or the latitude or * *** " 

 longitude given in order to avoid it. 



VIIL 



Description of a Compensation Pendulum for a Clock, or 

 Timepiece, with Experiments. By Mr. Henry Ward, 

 of Blandford, in Dorsetfhire*, 



SIR, 



H 



.EREWITH I send you a new compensation-pendu- New compen= 

 lum, which I beg you will lay before the Society of Arts for J^'J°" P'^"^"* 

 their inspection. I trust their liberality will be equal to the 

 advantages that may be seen to rgsult from it, together with 

 their consideration of the pains I have bestowed in making 



* Trans, of the Society of Aits, vol. XXV, p. 1 16. "^he silver medal 

 •f the Society was voted to Mr. Ward. 



