HOROLOGY. 



(ee Fig. 5.) or they may be made so short, as to allow 

 the wheel teeth to pass them altogether, without giving 

 any impulse at all to them. It is true, that there would 

 be no 'scapement here ; only it shows that the flinch of 

 the pallets may be made to give any angle of 'scape- 

 ment, from a few minutes to two or three degrees. 

 Whatever the angle of the flanches may be taken at, all 

 is requisite, is, to make the wheel 'scape so, that 

 the tooth, when it drops on the pallet, shall fall just 

 beyond the corner of the Ranch, on the circular or re- 

 coiling part of the pallet. 



Harmon's clock pallets ( which are sometimes made 

 Vck p*Uc*< to act b- means of very delicate springs, and sometimes 

 by their own gravity), have a very considerable recoil, 

 which was a most ingenious contrivance, to do away 

 the necessity of having oil put to them The construc- 

 tion of them seems to be nut little known ; and they 

 have very rarely been adopted in practice. Indeed, it 

 i. a 'acaperoent of such a nature, that very few would 

 be competent to execute it pro;>erly. The circum- 

 stance* which led to the invention of them, were men- 

 tioned by Mr Harrison himself to the late 1'rofessor 



ITC 



ion. Having been sent for to look at a turret 

 dock which had stopt, be went to it, though it was at 

 a considerable distance from his home, and found that 

 the pallets were very much hi want of oil, which be 

 then applied to them. On his returning, and rumi- 

 nating by the way on the indifferent sort of treatment 

 which he thought be bad met with, after having cone 

 w far, he wt him-elf to work, to contrive such a 

 sexperrcnt, as should not give to others that trouble to 

 which he had been put in consequence of this turret 

 clock Hence the origin of his pallets. A drawing and 

 description of them will be given in a future part of 

 this arti. 



The jii-tly celebrated Mr Mudjre. in a small tract, 

 published in June 17 i. relative to the best means of 

 improving marine tinw- keepers, suggested, as a great 

 advantage, that of making the moving power bend up 

 at every vibration of the balance, a snail ayring whose 

 ning force should be exerted in maintaining the 

 motion of the balance, (we Fig. 9 ) The first essay of 

 most ingeniou* contrivance was a small packet 

 watch, executed by himself, nearly about this period ; 

 ami this i the sssne principle which, some years after- 

 adopted and practised in those tune-keepers 

 he made. 



A!. ait two or three years or so after the publication 

 of this tract, Mr fuming contrived a clock 'sfapcment, 

 nearly on the sane principle a* that of Madge's, where 

 the notion of the pendulum was maintained by the force 

 of gravity of two small balls, which acted upon it during 

 the time of the descent In Uus'scapsnint, tbaceatre of 

 motion of the pallets is independent of that ofthe pen- 

 dulum and verge, although the same, and concentric 

 with them ; two detents were applied for locking the 

 swing wheel teeth, one for each pallet ; from each of 

 the pallet arbors a wire projected in an horizontal poi- 

 tion. and on the end of these wires the balls were fixed, 

 which were alternately raised up at every vibration of 

 the pendulum, by means of the action of the swing 

 wheel teeth on the pallets. In a periodical philoso- 

 phical journal, k is insinuated that Mudge bad bar- 

 rowed the idea of the 'scapnueiit, which be u. 

 his time- keepers, from this of Cuming's. That Mudge's 



'scaprroent was his own invention, M dearly evident 

 from the historical facts which have been stated. And 

 although there is an apparent similarity between 

 Cuming's and it, yet we are not inclined to be of 



opinion, that Nfr Cuming borrowed his from Mudge's. 

 The 'scapement of the clock made by Cuming for his 



v the kinj; in the year 170'3, "is of the free or 

 detached kind, a name which was not then known. 

 The improvement which he himself made upon it 

 two or three years after, was to keep up the motion 

 of the pendulum by the gravity of two small balls, 

 independent of the motive force through the wheels 

 of the movement. In this 'scapement, he insist* on 

 the adjustment between the pendulum screws and 

 crutch being made so as just to unlock the swing v. heel 

 and no more. This can then be only unlocked at die 

 time, when the force of the pendulum in its ascent is 

 nearly gone, and that the pendulum should not then 

 meet with the arm of the ball, but to receive it, as it 

 were, just before the descent of the pendulum has 

 commenced. In that part of Mr M ml m '-, each pallet and 



were formed in one, and tin- unlocking takes 

 place a considerable while before the i ml of the vibra- 

 tion. Thus, the springs which maintain the motion of 

 the balance are bent up, not only by means of the ac- 

 tion of the swing or balance wheel teeth on the palleU 

 at every vilir.itioti till the wheel teeth art- locked, hut 

 are still a little more l-t-nt up when unlocking by the 



n or momentum of the balance, or pendulum it- 

 self, previous to the vil>rations being nearly finished ; 

 and this i> one of the greatest properties of this 'scape- 

 roent, whether it i- applied to the balance and spring, 

 or to the pendulum. So 'capement appears to be better 

 calculated than this is, to keep the pendulum or balance 

 constantly up to the same arc of vibration, notwithstand- 



luting what some have been pleased to call a 

 offiof in the recoiling one, that of opposing the balance 

 or pendulum in its ascent, and promoting its descent. 

 In the spring pallet Vapement, as in the recoiling one, 

 the pendulum is opposed in its ascent, and has its descent 

 equally promoted ; Imt there is still a difference be- 

 tween them, notwithstanding this kimilarity. In the 

 spring pallet 'scapement, no retrograde motion is ^n en 

 to the wheels, pinions, and pivots, which produces that 

 early wearing on them, and where the seconds' hand 

 partakes also of this retrograde motion as in the 

 mon recoiling 'scapement. These are circumstances 

 which have no place in that of the other. In 

 'scapemcnts M those now mentioned of Mudge's or 

 Cuming's, it has been said by some, that it matters not 

 what sort of work the clock movement is, or how . , r 

 ill it may be execute- tlic motion of the pendu- 



lum i* kept up by a force, which, in some degree, is in- 

 dependent of the motive force produced through the 

 wheels in the movement. This may be so far true, yet 

 there is no 'ecapesnrnt, where any irregularity in the 

 pitching*, pinions, ftc. of the movement will be more 

 readily discovered than in Uii, during the going of the 

 dock, which will be very perceptible to the ear at the 

 time of raiting up the balls, or that of bending up the 

 springs. We would therefore by no means advise, that 

 this sort of 'scaperaent should be put to a movement of 

 indifferent execution : on the contrary, it seems to re- 

 quire one finished in the best possible manner. The 

 motive force put to it requires to be greater than that 

 which is usually put to clocks having the dead beat 

 'scapement. It may be asked, whether weights or 

 springs are the best for these sorts of 'scapemcnU, 

 which is perhaps a question not easy to be rcsolvej. 

 We confer that springs appear to be preferable ; they 

 seem to have, as it were, an alertness or quickness of 

 action, when compared to the apparent heavy dull 

 motion of gravity in the balls. Ihe pivots which are 



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