HOROLOGY. 



167 



the upper one of which pitches with the first bevel- 

 led wheel ; the lower one, whose lower pivot or arbor 

 may be connected with that of another, which carries 

 bevelled wheel, turning four others, all of them in the 

 tame frame : The four wheels, if properly placed, will 

 turn the four minute arbors at the dials all in their pro- 

 per course or direction. This frame will require to be 

 placed a little below that of the main frame of the clock. 

 It is seldom that four dials are wanted, and in mot in- 

 stances the two opposite generally suffice. To lead the 

 snail wheel, or what is generally though improperly 

 called the hour wheel, let another' flat minute wheel of 

 the same number ef teeth and diameter as the fin* be 

 pitched with it, and whose arbor foes tbroagh the 

 main frame ; and near the edge of the going great 

 wheel, a little below, on the left hand side, COCK on 

 the fore bar receives the wheel pirot, and the arbor is 

 free on the fore bar : The other pirot, which M Ml 

 pretty thick, turn* in the back bar; on the end 

 of th'is pfrot, which is prolonged a Httte way beyond 

 the bar, is formed lanthom pinion of 4 or 6, or such 

 a number as may sntt the number of teeth in the snail 

 wheel ; or a pinion of a proper number having a prong 

 to it, aiav be twisted in a hole made in the arbor to m 

 and receive it A lanthom pinion of four will lead 

 about the snail wheel and mail, having a runnnaai 

 socket ; the wheel having 48 teeth and 7 inches in 

 diameter, and turning oaj a stud in the back bar ; the 

 rack is also on a stud here. The pivot required to 

 have a lanthom pinion formed on the end of it, for a 

 wheel of 48 teeth, and 7 inches diameter, would be 

 Other too thick ; so that by keeping the pirot of a 

 moderate site, or sufficiently thick to have a h*le hi 

 tt to receive the prong of a pinion of 6, and the snail 

 wheel 72, may be a better way than that which we 

 woposed. The boar lifting arm and the A tain 

 me may be formed or not from one and the 

 piece, and fixed on an arbor which He* above 

 > great wheel, whose pivot* matt run in corks *t- 

 "ied to the main frame ; cocks are also required for 

 hammer, the verge, and the pendulum The 

 Vngth of the penduhrtn which we have prupoxd for 

 lock, may be thought by some rather incrmve- 

 niently \crg, which in a matter that can very ctly be 

 eot the better of, by asaomrng any other length*, tay 

 , 7, or 8 feet : either of these length* will hav< 

 dominion enough over the dock ; but lhe*e 

 e other srts of number* for the second and third 

 *, allowing the pinion* to remain 10 each, and the 

 wrng whet- 1 to have 3O treth. The second wheel harm 

 th, the thinl wheel 1O, the pinion* 10 each, and 

 the wing wheel 3O. the vibration* in a mtmite are 45, 

 and length of pendulum required u 5 feet 



- third wheel of thi* *rt is marie 70, all other, re- 

 maining the same, the vibration* in a mrnnte will be 

 **. and the length of the penduhmi 6 feet 8 mehe.: 4O 

 wtaatiana in a minute would require the wheel* to be 

 h disproportionate in number*, ante** we were to 



ntalaorwofthepmiom 12 m place of 1O; the wheels 

 in tin* caw would be 75 and r>4. In the other they 

 would have been *0 and 50. Tl length of pemhshni 



>t 4.5 inche* ; the vibration* hi a minute 38 . the 

 piniflns 10 each, and the swing wheel 3O. The wheeh) 

 arc 75 and 64, the length of pendulum 8 feet. 

 iMBe*. Wheels 80, 7t, and 50, and pinion* of I*, wiQ 



i') vibrations in a minute. 



certainly not requisite to give any more exam- 

 ple* of coiwtnirtin^ turret clock*. The one which ha* 

 ten given is sufficient to enable any intelligent artist 



to proceed in this way, whether with clocks going 

 eight day*, or with those which require daily winding 

 up. There are often great objections made against the 

 trouble of daily winding up a turret clock, but when 

 this trouble can be submitted to, a clock of this sort is 

 decidedly preferable to those which go eight days. 

 Turret clocks which >trike quarters are sometimes 

 made, some of which are done by a quarter rack and 

 Mail, and other* by a count wheel. For the descrip- 

 tion of a thirty hour clock of this kind, put up in the 

 town-house of Paris in the year 17S2, we refer to Ber- 

 thoud*s Hittotre de la Menre du Tempt par les //Wo- 

 re*. This is perhaps one of the finest public clocks in 

 Europe. It was constructed with much care and ex- 

 pense, and i* the only one which has enamelled dials, 

 one of which is above 9 feet in diameter. 



Although not in it* proper place, we may here re- 

 nark, that where four *eta of dials and dial work are 

 required, it would hardly be safe to trust them to 

 a yowng tight collet behind the minute wheel. \Ve 

 would thuifoTu prop oat, that the pivot of the second 

 wheel pinion he squared down, and a little longer be- 

 yond the fore bar than what was proposed tor the 

 square of the spring ; this i for the particular reason 

 of getting easily at a bolt pin when at any time setting 

 the hand*. On thi* square of the pinion let the 

 squared socket of a plain wheel be \ cry well fitted, 

 wheel is- about 3.6 inches in diameter, and in 

 thickness about one-fourth of an inch. The minute 

 wheel must have a sink in it, so as to receive the plain 

 wheel, but the sink matt be mare extended in diame- 

 ter, to admit a skeleton sort of a rim of a wheel with 

 forty teeth cut inside of it. This rim mut fit well 

 the inde of the sink in the minute wheel, and be fixed 

 to it, ritrwT by soft solder, or *oiue other mean*. I he 

 minute wheel, in thi* ca*e of the *ink in it. will rr- 

 Mrire to be thicker than in the ca*e of the *pring collet. 

 A holt may be lodged under a dovetail slit mticle in the 

 plain wheel ; hi thi* ilit, and lying close to the sink, 

 the bolt can be made to move out or in to the in-ide 

 teeth on the minute whrel ; on the end opposite that 

 of the locking end of the bolt, i* fixed a stont round 

 pin or knob, for the finger to pull out when ri re mini 

 airy letting the hand* ; thi* pin erve also for a stout 

 pring to push the bolt into it* place between the in. 



In fitting up the dial work immediately behind the 

 dials, it may be recommended to adopt that which wa* 

 contrived and put in practice in the different dial- 

 work* of St Andrew'* church clock ; on the minute 

 arbor, just by the lower end of the hour wheel socket, 

 M a loose steel washer, which lies close to the fore- 

 pwx*j of the dial work frame; and should the wind 

 pres* the hoar hand and hour wheel socket down, it 

 affect* no other part, but only pruxs the washer against 

 the plate. In**de of the dial work frame, and on the 

 minute arbor, are washers to prevent any binding on 

 the end* of the hour- wheel socket. 



In the tow n dock at Paris, the revolution* of the fly 

 striking the hour, are eight for every blow of the ham. 

 mer; the fry of the quarter part mahtn four revo- 

 lution* for every quarter hammer blow, there being ten 

 lifting proa on each side of the great wheel, reakingfO 

 lifts, the amount of the quarter blows in an hour. The 

 whig* or vane* of the Hie* in thi* Hock are pretty broad 

 and long, and can be *et to take more or les* hold of 

 the air. The fly of Hindlry's clock in the Orphan 

 Hoepital make* 4.57 turn* for every blow of the ham. 

 mer; but, from the imperfect construction of the clock: 



