WATCH. 



ulwaye puiiits upwards to the paffiiig hour, as reprefented in 

 fig. 18. 



Ill the work of which we have juft given the double title, 

 there are various devices for making balls defcend on fpiral 

 and Z'gzacc planes in a given time, which are again elevated 

 by a fpring, and which indicate the time by the number of 

 their defcents ; but thefe matters of curiofity are no longer 

 ufefnl as horological machines in the prcfent ftate of the 

 fcience of horology. 



Mufical Watch. — The works of a watch may be applied 

 moreover to give motion to various devices and piecei of 

 machinery, at the fame time that the watch performs its 

 own operations ; fuch as aiSuating the handle of a planeta- 

 rium, or orrery, exhibiting the motions of any of the ce- 

 leftial bodies by means of its dial-work, or urging the bar- 

 rel of fmall mufical chimes : but after the detailed accounts 

 we have given of Planetarv Machines, it will only be necef- 

 fary here to explain how a tune may be played by a mufical 

 watch, from which our reader will perceive that the appli- 

 cation of fimilar means to other amuling puipofes is equaUy 

 prafticable. In Plate XLII. of Horology, fig. 4. exhibits, 

 on an enlarged fcale, the internal difpoCtion of a watch- 

 movement, as feen on the pillar-plate from above, when the 

 other plate of the frame is removed, and the watch laid 

 down on its face ; the pillars being fuppofed to be at 

 the circles N, N, N, and N ; the box A contains the main- 

 fpring ; B is the fufee, with the chain or cord winding 

 round it, as it comes from the circumference of the faid 

 box ; D is the great wheel, and within it are the ratchet, 

 click, and fpring, as ufual ; E is the pinion of the centre 

 wheel, or hour-wheel, F, and is driven by the great 

 wheel as foon as the main-fpring is wound up ; G is the 

 pinion on the arbor of the fecond wheel, and is driven by F ; 

 and H, that revolves in the fame time with the pinion G, is 

 the third wheel, which wheel again actuates a pinion, I, on 

 the arbor of the fourth wheel, K ; which here is not a con- 

 trate-wheel, becaufe the balance-wheel I is made for the cy- 

 linder efcapemciit, which we defcribed under the article 

 Escapement, N'^ 8. The arbors of thefe wheels and 

 pinions pointing upwards to meet the eye, appear only in 

 plan ; and the dial-work, lying under the plate, is con- 

 cealed from view. The parts done only in outline exhibit 

 the calliper of the watch, independently of the mufical 

 train, barrel, fpring, and other appendages, which are 

 Jbaded, for the purpofe of diftinguilhing this portion from the 

 ordinary movement of the watch. In this figure, the calli- 

 per of the mufical train and fpring-barrel may be obferved 

 to lie on one fide of the frame ; but the mode of their aftion 

 will be better explained hy fig. 5, which is a feftion of the 

 frame, in which the calliper is io altered into a llraight line, 

 for the purpofe only of explanation, that the effeA to be 

 produced may be clearly comprehended. In botl; the figures, 

 4 and 5, the great wheel attached to the fpring-barrel is de- 

 noted by the unit i, and the wheels that follow, with 

 tlieir refpetlive pinions) in the mufical train, are denoted 

 by 2, 3, 4, and j, till we come to the regulating fly, 6, 

 placed on the arbor of tile lall pinion. This fly performs 

 the fame office as in the ilriking part of a clock, or re- 

 peating train of a watch ; that is, it regulates the velocity 

 with which ihe main-fpring fhall unbend itfelf, and give mo- 

 tion to the barrel in which it is contained ; fo that if a quick 

 motion be required, a few wheels and pinions only are iie- 

 cedary, and a liglit fly ; but when the motion is required to 

 be flow, there mull be a longer train, or a heavier fly, 

 proportioned to the ttrength of the main-fpring. The in- 

 terior end of the fpring is, as in the common main-fpring 

 boxes, hooked to a pin on the arbor </, and the exterior «id 



to the fide of the box, fo that turning the arb»r d round by 

 a key, coils the fpring into its ftate of greatefl tenfion, 

 which is adjufted by the notched piece, or ratchet, e, which 

 is held to its place by the click and fpring in the ufual way, 

 as reprefented m fig. 6. Upon the rim or cylindrical fide of 

 the box a, containing the main-fpring, are inferted various 

 pins in parallel lines, but at unequal diftances, according to 

 the frequency of the occurrence of the refpeftive notes to 

 be founded by the correfponding prongs of the forked piece 

 of fteel b c, in any given tune which is to be played ; and 

 the number of prongs muft be equal to the number of mufi- 

 cal tones and femi-tones to be produced. In the drawing 

 before us the fork has eight prongs, and the notes are pro- 

 duced by the catching of the pins, inferted into the revolv- 

 ing barrel, on the ends of the prongs, which are elaftic and 

 tapered, as well as tempered, to produce the requifite fuc- 

 ceflion of tones that are required in the tune to be per- 

 formed. 



The upper pivots of all the arbors of the mufical train 

 are callipered in the cock h h, while the lower pivots hate 

 their holes on the pillar-plate ; and upon this cock h h the 

 bent detent, or double lever/;, with a hook at e, is placed 

 fo as to be moveable round a fcrew at the angular point in 

 the middle : the hook of this detent is kept clofe to the re- 

 volving barrel by the prefiing fpring \, and when the tune il 

 finilhed, a hole is caught on the fide of the barrel, free from 

 the pins, by the hook e, which ftays the motion till the 

 button g, in the cafe of the watch, is puflied in againft the 

 tail-piece of the detent, and frees the hook again from its 

 hole, when the tune is repeated nearly in the fame manner 

 that chimes are ufually performed. (See Chimes.) The 

 parts drawn in perfpedive in _yf^. 6. reprefent a conftruftioa 

 in which the elaftic prongs of the mufical fork are bent into 

 a curve, fo as to occupy lefs fpacc than in figs. 4 and 5, or 

 to produce more powerful tones where the fpace will admit of 

 an enlargement of their dimenfions. But inftead of a barrel 

 containing the main-fpring, fometimes a cyhnder, A, revolv- 

 ing in the cocks and/, contains the pins, as is feen mfig. 7, 

 where a pinion on the projedling arbor of the cylinder is 

 actuated by the great wheel attached to the fpring-box ; and 

 this conftrnftion is beft calculated for a fork with more tones, 

 and confcquently for a tune of greater compafs. F\g. 8. 

 flievvs how tlie prong of the fork is caught by the pins in 

 fuccefiion, and/^. y. explains how a number of double- 

 pronged forks, b f, are feparately fcrewed into a frame, k, 

 where the dift^erence in the tones is produced by a correfpond- 

 ing difhTence in tliu dimenfions of the prongs. The hole in 

 which the hook e falls is here in the end of tlie cylinder, but 

 the motion is not ftayed thereby ; for tlie (lender fpring, 

 prelfing againft it, lays hold of the fly-pinion, when it fol- 

 lows the detent, and thus ftops the part that has the greateft 

 velocity, and leall power ; whereas confiderable ftr.-iiii takes 

 place on the barrel when its motion is flopped by the hook 

 of the detent, as ^nfiigs. 4 and 6. The arrangement in_y%. 4. 

 is beft fuited for a fmall watch, but does not produce the 

 moll audible tones ; and is that which is ufually concealed 

 ill tlie Swils mufical feals, that have been lately intro- 

 duced into England : but the cylinder in fig. 7. is that 

 wiiicli the mufical boxes contain, and which, from its length, 

 is capable of containinjj two tunes, as well as notes on both 

 the trci)le and bafs clefs. When the elaftic prongs are tem- 

 pered, they are brought to an exa6l mufical fcale by grind- 

 ing with oil-ftone dull, and the prongs that require to iiave 

 their tones much flattLued, are made more flender at the end 

 iiioft remote from the cylinder or barrel, where their rc- 

 fiftance to motion is diminiflied, fo that the vibrations arc 

 rendered lefs frequent, and the tones lefs acute. Wiicn a 



fecond 



