172 



HOROLOGY. 



nd assumed ; all that is required is to proportion the 

 number of turns of the endless screw, and parts of 

 ""~ v ""' a turn, to the number of bars in the tune, and to the 

 notes in each bar, and to have the tunes to go nearly 

 round the barrel, so that a small part of a revolution 

 of it after the tune is played over, may be left for 

 what is called locking and running. If the dividing 

 wheel was taken at 128 teeth, and the tune being sup- 

 posed to have 20 bars, each bar having three crotchets, 

 as in the former example, 128 teeth divided by 60, the 

 number of crotchets, the quotient would be two, and 

 the remainder would be eight ; so that each crotchet 

 would require two teeth or turns of the endless screw, 

 a quaver one turn, and a semiquaver half a turn, and 

 the remaining eight teeth would serve for locking and 

 running. When the tunes are all marked on the barrel, 

 each mark must be drilled to obtain holes for the lifting 

 pins to be driven into them. Great care should be taken 

 to have a stiff and excellent drill, so as to run no risk of 

 breaking, which would occasion a great deal of trou- 

 ble ; and it should be of such a temper, and well and ju- 

 diciously whetted up, so that it may drill all the holes 

 without requiring to be once sharpened up : the ob- 

 ject here is to have all the holes of the same width, 

 so that the lifting pins may be all of the same diame- 

 ter. The holes being drilled, and the barrel polish- 

 ed, a number of pins should be prepared into lengths 

 of half an inch or so each, and a very little tapered at 

 one end. The stronger and harder the brass wire for 

 the pins is, so much the better ; some of the best kind 

 of pins used in the female dress are very fit for this 

 purpose. In placing the pins in the holes, if they should 

 be found too long for knocking in by the hammer, they 

 should be shortened by the cutting plyers before the 

 hammer is applied, which will prevent bending, and 

 allow the pins to have a more secure hold of the bar- 

 rel rim. After all the pins are put in, they must 

 now be shortened to an equal and proper length or 

 height. For this purpose prepare a hard cylindrical 

 steel collet, having a hole in its centre sufficiently 

 wide to allow it to be put readily on the pins ; the 

 lower end of it hollowed, the upper end rounded, and 

 the height of the collet about one-twentieth of an inch 

 or a little more ; the height depending on the size of 

 the barrel and the diameter of the pins. The collet being 

 placed on a pin, the cutting plyers are applied to cut 

 the pin just over by the rounded end; a small touch of 

 a file takes away the burr made by cutting, and as the 

 hardness of the collet prevents the file from taking 

 any more away from the height of one pin than from 

 another, they must be all of an equal height. This 

 operation being finished, the small burrs made on the 

 top of the pins by the file must be taken off; this is 

 done by a piece of steel wire, about six or seven inches 

 long. The end where it is twirled about by the fore 

 finger and thumb, should, for the length of an inch or 

 so, be made into an octangular form, for the more 

 readily turning it round back and forward. On the 

 face or point of the other end, two notches are made 

 across each other, which may be either angular or 

 round at bottom ; the latter may be the better of the 

 two, if rightly executed, and should be made with the 

 round edge of a flat file, whose thickness should not be 

 more than the diameter of the pins. The point where 

 the notches are cut should be hardened, and the inside 

 and bottom of the notches polished, so that a sharpness 

 may be given to take away the burrs easily from the 

 top of the pins. 



The shape of the hammer tail is such as is repre- 

 sented at Plate CCCVIII. Fig. 3, a form which makes 



the hammer easy enough to be drawn, and the tail Chimes aftfl 

 takes little or no room when falling; and should two l L 

 pins or notes succeed each other rather rapidly, the p^^T* 

 nib or point of the hammer tail will not be interrupted ccCVIir. 

 by the succeeding pin. In the first musical clocks, and Fig. 3. 

 even in those made long afterwards, the bells were all 

 placed on one strong iron bell stud, the opposite end of 

 which was supported by what may be called an auxilia- 

 ry stud, which occasioned a crampness that prevented 

 the bells, when they were struck by the hammers, from 

 vibrating, or giving out that full tone which they might 

 have otherwise been made to produce; and the improve- 

 ment made on this, as well as on the quarter bell studs 

 afterwards, was effected by placing each bell separate- 

 ly on its own bell stud, which was made of well ham- 

 mered brass, having some degree of elasticity. The 

 sweetness given to the tone of the bells by this method 

 was truly surprizing. The bells in this kind of music 

 may be sounding at the time that a succeeding note in 

 struck out and sounding too, which may not be so plea- 

 sant to a very nice ear. This can be prevented by having 

 a double set of hammers, and having every tune pinned 

 twice over on the barrel, one set of the hammers hav- 

 ing the heads of buff leather, or having a brass head 

 with a piece of cloth sewed over it. These, when they 

 strike the bell, will damp the sound of the note which 

 is last struck. The buff hammer should fall on the bell 

 to be damped, at the same instant that the brass ham- 

 mer strikes the succeeding note on its bell. This im- 

 provement, however, must greatly increase the expence 

 on such a clock ; but the effect of buff or cloth hammers 

 is so striking, that the additional price ought not to be 

 grudged. 



In Plate CCCVIII. Fig. S, A A is a circle representing PLATE . 

 an end view of a clock music barrel, and a few of the CCcVHi. 

 lifting pins. The dart shews the direction in which it '^' 

 turns. The letters a, a, a, a, a, represents a section or 

 end view of a brass piece thus shaped. The length 

 depends on that of the barrel, and the number of 

 hammers to be let into this brass piece, which is called 

 the hammer frame, the length of it being sometimes 

 three or four inches, sometimes ten or twelve. The 

 flat part of the hammer tails fills up the thick part of the 

 hammer frame, into which slits are made to receive the 

 hammers. Near to the outer and lower angular part at a 

 of the frame, a hole h is made through the whole length 

 of it, not drilled, but ploughed -as the workmen call it, 

 and this is done before any slits are made in it for the 

 hammers. A wire is put through this hole, and through 

 corresponding holes in the flat part of the hammer tails. 

 This wire is their centre of motion, and the holes in them 

 are made so as to have freedon) on it, and the flat part 

 of the hammer tails are also made to have freedom in 

 the slits made to receive them. On the under side of 

 the hammer frame at b, the hammer springs c, c are 

 screwed, one for each hammer, acting on that part of 

 the hammer tail just where it comes out of the thick 

 part of the hammer frame. When the pins in the bar- 

 rel raise up any hammer by the nib, and carrying 

 it away from the bell, at the instant the pin quits 

 the nib, the spring c,c, by its returning force, makes 

 the hammer head give a blow on the bell to elicit 

 the sound. To prevent any jarring in the bell by the 

 hammer head resting or touching it after having given 

 the blow, each hammer has a counter-spring acting 

 near the lower end of the shank, and inside of it. All 

 the counter-springs are made to project from one slip 

 of well-hammered brass, and screwed on the top of three 

 kneed brass cocks, fixed to the upper side of the brass 

 frame, d d is a view of the side of one of the cocks ; 



