I^g SIMPLE RBI^BAtiVG WORK. 



New and ftmpfe moved round whenever the axis i«? moved by means of tli^ 

 grating mo- pendant. The firft d ferves to drive the work for ftriking the 

 hour, and the latter / the work for the quarters. The firfl: of 

 thefe apparatufes confifts of e the hour-locking fnail (fee alfo 

 Fig. 2.) which is fitted on the axis by a round focket or pipe, 

 upon which focket alfo is fixed (fteadily) the hour repeating 

 wheel g [Fi'g- 1 and 2,) and (on a round part) the ratchet 

 wheel h, which laft is drawn by a fpiral fpring ^ ^ in the di- 

 reftion oppofite to that which is produced by the pallet d {Fig, 

 1 and 2) * is the hammer urged by its fpring t? outwards, and 

 the defigncT has, I am forry to perceive, omitted to make a 

 Iraall tail from the center pin near k towards g the hourrepeat-^ 

 ing wheel. Now the a6tion of ftriking is firaply this ; when 

 ' by turning the pendant exacts upon the fmall pin in e, the wheel 

 g with its ratchet wheel A are carried round, and the teeth of 

 g a6t on the tail of the hammer, and give more or fewer ftrokes, 

 according to the number that pafs. 



The number is regulated thus, a {Fig. 4.) is the flar-wheel 

 as ufual, and b the hour fnail fcrewed on the fame ; c is the 

 click with its back fpring, and n 2 is the hour-locking lever, 

 which terminates in an hook at z that maybe feen in Fig» 2. 

 bearing againft the hour-locking fnail e. This hook will evi- 

 dently be nearer to or farther from the axis of the locking-fnail 

 e, according to the portion of the other end of the lever which 

 bears again (1 the hour fnail b, and will confequently flop the 

 pendant in its motion fooner or later by its oppofition to one of 

 the flops of the fnail e. As the ftar wheel a is carried regu- 

 larly round by the canon pinion as ufual, its fituation will de* 

 termine the number of ftrokes. 



The inftant the pendant is let go, the fpring k a6ls upon the 

 ratchet wheel, and reftores the original iituation ready fof 

 iiriking again. 



After this account of the hours, the ftriking of the quarters 

 will require little explanation, I [Fig. 1 and 5.) is the pallet 

 or arm ading (by a reverfe motion of the pendant,) on the 

 locking fnail in, which carries the contrate wheel p, for ftriking 

 the quarters by its action, upon another tail r of tiie hammer ; 

 and the original fituation is reftored by a ratchet wheel O and 

 its fpring, {fee Fig. 6.) 



In Fig. 4-. is feen the quarter fnail ^ with its leVCr hk, who(e 

 hook for regulating the number, may be feen at D in Fig. 5< 

 and the fnail is prevented from going back by a fixed hook. 



3 SCIENTIFIC 



