50 Method of putting music on organ barrels, [Jan. 



Spiral groves from one another is sufficient to enable the bar- 

 rel during one revolution, to shift horizontally as much as is 

 necessary to present a fresh surface for another spiral row of 

 pins, which are to act on the keys of the organ during the < 

 succeeding revolution ; — of course these groves in both cases 

 produce an action on the barrel when fixed to the plate, 

 exactly equal to and corresponding with the action produced 

 by the mechanism and snail wheel (7) page 346 last volume. 



9. — In fig.. 3, is shown the dividing plate with the barrel 

 affixed to it ; the plate is represented at the left hand of the 

 figure, and the axis of the barrel enters the perforated end 

 of the dividing plate axis, and is held fast by the screws, 

 which are represented more distinctly by h, h, in fig. 2. 

 This figure 3, speaks for itself, it shows the barrel, the key 

 frame above it, the dividing plate, and the piece of music 

 which is to be transferred to the barrel ; and the method of 

 transferring it is as follows. 



10. — The barrel, made perfectly true and prepared to re- 

 ceive the music, is first put into the organ, and when placed 

 correctly and the snail wheel is properly adjusted, the keys of 

 the key-frame, N, fig. 1, of the plate in the last volume, are 

 pressed down upon the barrel, and a line of marks from the 

 points of the keys is made along its whole length ; so that 

 each mark represents the proper position of its own respec- 

 tive key. The barrel is then taken from the organ, and so is 

 the key-frame, and both are placed in a suitable stand with 

 four legs, of which an imperfect section only, is shown in 

 fig. 3. 



11. —The point, f, fig. 1, is now fixed so as to correspond 

 with the circle of divisions required by the music ; and the 

 piece, e, carrying the point, and the stop, g, are broughtinto 

 a proper position, which is shown in the perspective sketch 

 fig. 4, where g, represents the stop resting on the edge of the 

 front rail of the stand, to which the barrel and key-frame are 

 now supposed to be attached, and e,f } the point and the car- 

 rying piece, which together with the stop g } are exhibited in 

 their proper respective places. The point is supposed to be 

 placed at b, fig. I, that is at the commencement of the line of 

 divisions required ; and the plate is supposed to be turned 



