UKM()\T0]1{, 



the wheel, but tlie pcrtdulum unbends it into a flute of teii- 

 fion, to rcfutne its ojnTation ; thcit is, the pendulum raifes 

 the fprinjT, tliat the fpiiiig may drive (he pendulum back 

 a^raiu ; and thus the vibrations are niaintaim-d without the 

 aid, and confequently without the iieceility, ot either amain- 

 taininir power or traui ; and what is equally extraordinary, 

 the impelling ipring locks the vshcel by its rcfijlnnce, near 

 the perpendicular line (within tlie fpace ot one tooth), 

 where it luui almolt the Imallelt force, or nearly the fame 

 Imall force that it has when it vnlachs tlie detfiit. According 

 to this account, even iuppoiing- the action of the wheel on 

 the remontoir pallet to be onutltd, the pendulum is under the 

 influence of the impelling pallet dunng nearly the wliole of 

 one excuriion, and tree from it in the other. The model, 

 however, is faid to be preferved in the fociety's room, and 

 will explain itfelf. 



G. Pfici's improved. — Mr. George Prior, jun. again prc- 

 fents an improved remontoir efcapement for a clock to the 

 focicty we have repeatedly had occalion to name in this arti- 

 cle, in the year 1811 (vol. xxix.), and again receives a re- 

 ward at their hands, of twenty guineas, for his improvement. 

 The defcriptioii given of this efcapement, and of its aftion, 

 is fufliciently clear, and the alteration made in the conilruc- 

 tion is in many refpetls an improvement, though we fliall 

 take occalion to fliew, in our remarks on it, that it is ftill 

 liable to objections. In the plate laft referred to, Ji^. 8. 

 contains the original ^/j-. 1, which will explain the account 

 with fufficient pveafion. " The fwing-whcel A," fays the 

 author, " has thirty teeth cut in its periphery, and is con- 

 llantly urged forwards by the maintaining power ; C, D, are 

 two fpring-detents, cat(;hing the teeth of the wheel alter- 

 nately ; thefe are, at the proper intervals, unlocked by the 

 parts marked 2 and 3 upon the pendulum-rod H, intercept- 

 ing fmall pins a, b, projecting from the detents, as it vi- 

 brates towards the one or the other ; E is the renovating or 

 remontoir-fpring, fixed to the fame ilud, F, as the detents ; 

 it is wound up by the highell tooth of the wheel, its poli- 

 tion, when unwound, being fliewn by the perpendicular dot- 

 ted line. This being the cafe, luppofe a tooth of the wheel 

 caught by the detent D, which prevents the wheel from 

 moving any further, and keeps the renovating Ipring from 

 pfcaping olf the point of the tooth ; in this pohtion the pen- 

 dulum is quite detached from the wheel : now it the pendu- 

 lum be caufed to vibrate towards G, the part of it marked 

 2 comes againft the pin b, projefting from the renovating 

 fpring E, and puflies this fpring from the point of the 

 wlieel's tooth ; on vibrating a little further, it removes the 

 detent D, which detained the wheel, by the part 3 ilriking 

 the pin a, which projefts from the detent ; the maintaining 

 power of the clock makes the wheel, thus unlocked, to ad- 

 vance, until it is detained by a tooth refting upon the end 

 of the detent C, on the oppofite tide ; by this means the re- 

 novating fpring will be clear of the tooth of the wheel as it 

 returns with the pendulum, and gives it an impulfe by its 

 pin h prefling againlt the part 2 of the pendulum, until 

 the fpring comes to the pofition fhewn by the dotted line, 

 in which poiition it is unwound, and relts againft a pin fixed 

 iti the crofs-bar of tlie plate ; the pendulum continues vi- 

 brating towards I, nearly to the extent of its vibration, 

 when the part 1 meets the pin in the detent C, and removes 

 it from the wheel and unlocks it ; the maintaining power now 

 carries it forward, puOiingthe renovating fpring E before it, 

 until another tooth is caught by the detent D, which de- 

 tains the wheel in the pofition firft defcribed." Agreeably 

 to this defcription,t!ie pendulum is oppofed in its afcent, and 

 accelerated in its defcent, in one of its excurfions from the 

 centre, or perpendicular line, by both the impelling fpring 



E, and detent D, alter it is unlocked, though ;.ot tiif 

 whole di (lance ; but is alternately accelerated and I'etarded 

 in the other excurfion by the detent C alone, and only af- 

 ter the unlocking ; thele unequal checks, given at different 

 parts of the arc of vibration, we apprehend, are by no 

 mean:, favourable to the natural ilochronifm of the pen- 

 dulum. 



Hardy\t. — Mr. Hardy, chronometer-maker, of Ccppic*'- 

 row, Cierkenwell, I^ondon, whofe ingenious improvements 

 in cluck and watch-making have placed him high in public 

 cllimation, on contemplating Mr. C. Haley's failure ia 

 the locking of his remaiitoir detent, contrived a remedy 

 which fully anfwers its purpofe, and which, on that ac- 

 count, merits our particular notice. 



Fig-I- of Plalc XiA. of Horology, reprefents the plan 

 of Hardy's new remontoir efcapement, which, though it 

 appears to differ coiifiderably in conllruClion from Haley's, 

 yet refembles it fo much in its aftion, as well as principle, 

 that we will put the fame letters of reference to the fame 

 correfponding parts, in order that the reader who has pe- 

 rufed our defcription of Haley's remontoir with attention, 

 may the more clearly comprehend our defcription of Hardy's, 

 and perceive in what the improvement confills. -^s in Ha- 

 ley's conftruC^ion, T T reprefents the balance, or rather the 

 place of the balance not feen ; E the etcapemcnt, or balance- 

 wheel ; P the pivot of the verge ; .S tire b;dance-lpring, 

 fufpended as ufual ; K the impelled pallet ; I the unlocking 

 pallet of the remontoir ; N the remontoir detent, or locking 

 pallet, on the fame axis with a, the arm of the flender or 

 unlocking fpring, Tvhich lies parallel with it ; n the cock, 

 taking the pivot of the remontoir detent's arbor, and alfo 

 the upper end of its fpiral fpring ; c the head of the banking 

 fcrew, audi its Ilud ; H the cock that takes the pivot of the 

 remontoir, or cylindrical fpring at W, and alfo one end of 

 the faid fpring, reprefented by the fmall circle at R ; L ia 

 the impelling lever or pallet, for giving motion to the paUet 

 K of the balance ; M is a lever, inllead of the notch i.n 

 Haley's large circular pallet, by means of which the wheel 

 winds up the fpring R of the remontoir ; O is a lever, in 

 place of the fmall ruby unlocking pallet of Haley, fixed to the 

 fnail ; d is the fpring-detent of the wheel, and j- its ruby, or 

 fapphire pallet, on which the wheel is locked,_/and^ being 

 the banking fcrew and its ftud, and y the place where it ia 

 fixed by a fcrew on the potance plate ; and lallly, the fec- 

 toral piece Q, in which the improvement chiefly confifts, is 

 the addition introduced for rendering the locking of the 

 rcmointoir-fpring, when wound up, both certain and feciu-e. 

 The acting faces of the pallets s, M, K, N, and of the cir- 

 cular portion of Q, are of ruby, or other precious flone 

 nicely polifhed, and are properly (haped for their refpective 

 offices. From this defcription of the mechanifm before us, 

 it will be perceived that the double Ipring a, and the detent 

 with a claw pallet at N, are both faft to the arbor 

 of the fpiral fpring, which gently prefl'es the detent 

 at all times down upon the fedtoral piece Q, thereby pre- 

 venting its being thrown back from its pofition for locking, as 

 was the cafe with Haley's remontoir detent. It will alfo 

 be feen that the arbor W, of the remontoir-fpring R, has 

 the faid fedtoral piece, the impelling lever L, the lever M 

 impelled by the wheel, and the difcharging lever O, all faft to 

 it at different heights, the two firft being above, and the two 

 laft below, fo that when one of thefe four pieces is moved 

 out of its firll fituation by any external force, they all move 

 together, as do alfo the remontoir detent N and its fpring 

 a on their common arbor, and as do likewife the pallets K 

 and I on tlie verge of the balance. Thefe particulars being 

 underftood, and that levers in Hardy'e conftruAion are 



ufed 



