WATCH. 



Table continued. 

 15 Teeth in the Balance-Wheel. 



17 Teeth in the Balance-Wheel. 



Second Wheel 48 6 Third Wheel P.n. 

 Third Wheel 45 6 Contrate Pin. 

 Contrate Wheel 50 6 Balance Pin. 

 Beats 17000 in an Hour 



Se 



conds 60 in which the 4th Wheel revolves 



If we divide double the produft of all the four wheels by 

 the produft of all the three pinions, the quotient will be 

 the number of teats as given in any of the trains contained 

 in this table ;'alfo, if we take the fecond and third wheels 

 and their pinions refpeftively, as a compound fraAion of 

 an hour, they will give the feconds in which the contrate- 

 wheel, attached to the latter pinion, will revolve ; thus, 

 Tcr of 3V of 60"" = I™, or 60', which numbers are canfe- 

 quently proper for a watch that indicates feconds ; and if 

 the beats be 18000, or 14400, there will be five or four 

 beatj refpeftively in a fecond, which are the beft trains 

 for raeafuring fraftional parts of a feeond. 



French Repeater. — The mechaiiifm which confUtutes the 



repetition portion of 3 French, and alfo of a Swifs watch, 

 was originally employed by Tompion, Quare, and other 

 Englifh artifts, and is reprefenled by the various figures 

 contained in Plate XL V. of Horology ; it is eafier of con- 

 ftruftion than the repetition-motion of Stockten, which 

 follows, but is not confidered fo perfeft. We have put 

 the fame letters of reference to the detached parts, that 

 ftand near them in the larger figures, where they occupy 

 their refpeftive fituations ; and that the reader may be able 

 to accompany us through our defcription of the aftion of 

 the relative parts, we will explain previoufly the appella- 

 tions by which the workmen defignate thefe afting pieces. 

 In Jigs. 1. and 2. A denotes the pendant-bow, carried at 

 the end of a cylindrical piece, called the pendant, and the 

 hollow piece, into which it is occafionally pufhed, is the 

 pendant-focket ; BCD the triple lever is called the cre- 

 maiUdre ; E is a fixed pulley ; and F the hour-fnail, by 

 which the number of hours to be ftruck by the hour-ham- 

 mer is limited ; H is the ftar -wheel, to which the hour- 

 fnail F is fixed faft ; I K is the tout-ou-rien and G its 

 fpring lying on its plane ; L and N are the two fets of 

 teeth, that take hold of the hammer-tails, which ftrike 

 quarters by double blows ; O is one of the quarter ham- 

 mer- 



