HOROLOGY. 



125 



lUorv- 



Ma - 



150 times in a minute. In the 'scapement of Mudge's 

 marine timekeepers, what may be called the remontoir 

 was bent up 300 times in a minute ; the 'scapement 

 here, became in same degree wholly the remontoir. A 

 variety of 'scapements may be seen in TMout, and in 

 some of the modern periodical works; yet, for the pur- 

 pose of common or ordinary sort of clocks, they are 

 r*>**^ dried* to those ofthe dead beat and the recoil 

 Where accurate performance is expected, some may have 

 seeourss to 'scapements of a different description. 

 About the year 1753, Le Roy, Lepente, and other 

 in Paris, were much engaged in making 



_!.__ t . . , 



(.*.- 1 ; :kiT - 



clocks having only one wheel; and some had not 

 even a single wheel in the movement. They were, 

 however, more expensive in making, and performed 

 much worse than those which were constructed in 

 the ordinary war. Simplititv in the machinery seem* 

 to have been their chief object. It requires, how- 

 ever, experience to know what simplicity in machi- 

 bnuficity nery is ; although apparently more simple, a clock 

 having two wheel* in it, will not be equal to that ha- 

 ving three or four; yet it does not follow, that, by having 

 ' , the clock will be proportionally better : it 

 sd that there are bound* which 

 be overstepped with impunity. This subject 



V 



; be better exemplified than by making a compa- 

 i of one of Hindley's clocks, having two wheels, 

 and giving thirty vibrations in a minute, with a clock 

 giving the same number of rftntions in th* smme time 

 and with three wheel*. The first or great wheel, in 

 one of Hindley's, had ISO teeth, the second or swing 

 wheel ISO, and the pinion 8. The number of these 



teeth, and of the pinion leaves, amounts to. 108. In the 

 ther, th* wheeU were 48, 4O. and SO, and two pinions 

 tf: the sum of these u 13: thedifieranc* ia 174. be. 



is 174, be. 

 in the one than in the 

 of the teeth in the 



tin- -..111 of thr^-I, I .V; 



number of teeth m 



and snore than the 

 three wheeled dock. 



shall now proceed to gfr* a abort account of such 

 watch 'scapements as have been thought worthy of no- 

 tice, from th* old crown wheel and verge to th* mo- 

 dern free or detached scapement ; but, in order that the 



mwslA*. nadir may be able to 



U-* given fron, Herthoud a view of an 

 and pinions, to 



uVWBwni* ,. ' 



r , ATr o< a watch or a small dock. They are contained in a 

 frame made tor th* purpose of allowing th*m to be 



F*. i. more readily seen. t>E is the pflaw pL*. or pillar 

 frame plate ; OF th* for* frame plate. A is the ba- 

 lance ; the arbor or axis on which it is fixed is the 

 verge, whose two pallets , p, scape with the teeth of 

 the crown wheel C The pivots of the balance turn or 

 nth* frame; those of the crown wheel C, and of 

 iu pmione*, run m the potence I, and m the counter po. 

 tone* H, both of which are screwed en the iueide of the 

 pular pUte, the arbor of the pinion bring at right 

 s^toth*axi.ofth*bJcnML Th. cottrut* wheel K 

 and its pinion C turn aUo in the frame; the teeth of the 



i) wheel 

 rheel I., 



el pitch into the contme wheel pinion, and 

 The centre or second wheel M and its 

 bv* long arbor going beyond the outside 

 HS. The rrond wheel M pitchr* with thr 

 Jfaird wheel pinion*, which it UkewieVcm turn. N is 

 the first or great wheel, pitching with the second 

 ifjion.. X is th* ratchet,, th* dick, and nits 

 On the arbor of U* jr.* wh*ol U* ratchet 



rontrate wheel pilch into the helanc* (or crown) wr 

 pinion, and cm tarn or drive h ; the third wheel 

 and ittvpmion . run hi the frame ; the teeth of 

 AM wheel nitch into taw mt*. _k~l ~ 



turn it, 



is fixed; and, on winding up the main spring, the 



ratchet and arbor turn freely in the hole at the centre 



of the ^reat wheel, which keeps its place during the 



time ot winding. OP is the main spring deprived of 



its barrel ; the inner end of it hooks on to ttie lower 



part of the great wheel arbor, and the outer end is movement. 



hooked to the rim ofthe barrel, but is here fixed to a Hi- TK 



temporary stud. The force of the main spring, 



watch 



after V.'' U j' 

 being wound up, sets all the wheels and pinions in '*>' 



motion, and would oblige the ratchet and arbor to tuni 

 round independent of the great wheel ; by this the 

 main spring would be instantly unbent, but is prevent- 

 ed from this, by the click m being forced by its 

 spring M to fall into the teeth of the ratchet, applying 

 its end to the face of the ratchet teeth ; by this means 

 the main spring must unbend itself very slowly, the 

 motion of the wheels being checked by the 'scaping of 

 the verge with the crown wheel teeth. Q is the can- 

 non pinion, put spring tight on the arbor of the second 

 wheel, whose socket or cannon goes outside or beyond 

 the dial where it is squared for the purpose -of the 

 minute hand being put on H. T is the minute wheel, 

 g its pinion ; the cannon pinion pitches into or leads 

 the minute wheel ; the hour wheel V having a hollow 

 arbor or socket /, is put on the cannon pinion, and is i< .1 

 by the minute pinion which pitches into its teeth. It is 

 on the socket of the hour wheel which comes a little 

 above the dial, that the hour hand is put. When a 

 wheel pitches with a pinion and turns it, the pinion -is 

 said to be driven by the wheel ; if the pinion turn* the 

 wheel, the wheel is then said to be led by the pinion. The 

 pendulum or balanc* spring t * has its inner end fixed 

 to a collet, which goes spring tight on the artrar of the 

 tiM ; th* outer end is fixed or pinned to a stud 

 fixed on the inside ofthe fore plate. la the action of 

 the crown whed teeth on the pallets, the balance ^ 

 it either bent up or unbending ; it U by the small force 

 that th* balance is made to give twice the num. 

 her of vibrations that it would give without it. It 

 should have been ubaened, that, by putting a key on 

 the square of the cannon pinion, and turning it about, 

 this will not only more the minute hand about, but 

 will oblige the hour hand to follow slowly, in the ratio 

 of one turn to -twelve of the minate- haud. 



The first watches may readily be supposed to hare 

 been of rod* execution. Having no pendulum spring. 

 and only an hour hand, and being wound up twice a 

 day, they could not be expected to keep tun* nearer than 

 15 or SO minutes in the twelve hours. After the appli- 

 cation of the pendulum spring, they would no doubt go 

 considerably better, and may now lie mad* to keep time 

 suoViently correct for the ordinary purposes of 

 Inslisrt. when the crown wheel and verge 'scapement 

 h eMCUtud with cure, it will do uncommonly well. 

 Let the angle of the verge be 99 or 95 degrees, th* Crown 

 teeth of the crown wheel undercut to an angle ofwfcsstand 

 99 or SO dtgreai, and scaped as near to the body of "TO* 

 the verge as just to beTlear of it, (it is to be under- J?J*! 

 stood here that the verge holes are jewelled.) To carry , ',' 

 the matter still farther, the body may so far be takeii 

 away as to admit the teeth near to the centre, which ,; "- 

 will tend to allow the vibration* ofthe balance to i 

 more freely and independently ; but this require* such 

 nice execution hert, and in other parts of the 'scape- 

 ment, that from not having encouragement, few are fit 

 to execute it, and therefore it may in general U *afor not 

 to bring the wheel teeth so near to the verge. Care mutt 

 also be taken to have the balance of a proper diameter 

 nd weight, which has of late been much neglected 



