Mechanics.
30 Strokes upon the Axis of the Balance, which wiiCall the Beats of the Balance; and therefore there willbe 2304 X 30 = 69120 Beats in one Turn of the Fuseeor Great-Wheel.
15. The Centre-Wheel is that which we must havethe principal Regard to in the Division of Tun: ; theWheels beyond this, towards the Balance, serving onlyto multiply the Strokes of the Balance,- and cause it tomove with an insensible Power, and be thereby subjectto a more perfect Regulation. But the Centre-Wheelis that upon which both the Hour and Minute-Hand ismoved or carried round upon t. e Face of the Watchto indicate the Time, viz. the Hour of the Day, orMinute of the Hour,
16. Since the Time of the Watch’s going is 30
Hours, and the Minute Hand, and consequently theCentre-Wheel, goes round once in an Hour, the saidCentre-Wheel will have 30 Turns in the Time of theWatch’s going; and because it has four Turns in Oneof the Fusee, therefore 4)3^ — — the Number of
Turns of the Fusee in winding up the Watch. Whence69x20 X 7,5 — 518400 — the Number of Beats duaring the whole Time of the Watcn’s going.
ij. if then we divide 518400 by 30, we shall havethe Quotient 17280 = Number of Beats in an Hour,which is call’d the Train of a Watch ; and it is saidto be a swifter or sower Train as the Number of Beatsin an Hour is greater or lesser. If we divide the Train17280 by 3600; the Seconds in an Hour, the Quotientwill be almost 5; that is, there will be near 5 Beats■per Second in such a Watch.
18. From this Analysts of a Watch, it will be easyto form an Idea cf the Manner of Calculation sot theNumbers of the Teeth and Leaves for the severalWheel's and Pinions throughout the Work ; and I shallendeavour to facilitate and illustrate this by an Exampleof the Numbers of a Watch whose ‘Train is 14400,and which therefore wiil beat Quarter-Seconds, be-cause such a one will be useful for many PhilosophicalPurposes, as well as the common Measure of Time.
19. The Time which this Watch shall go, may be32 Hours; then 14400 X 32 — 460800 — the Beat:;
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