348 Description of a .^eif perfonnin gharrcJ organ. [Oct. 



but more to the left ; and thrrc uill be a space between 

 the end of the screw, f, and the brass, n, about equal to 

 the distance of c, d, in figure .3. In this supposed po- 

 sition then, the key frame N, N* is lifted up and sus- 

 tained while the barrel INI (figures 1, 5, or 0) is 

 shifting. But as soon as it shifts, the piece of brass, n, 

 comes in contact with the screw, f, and drives away the 

 top of the spring, d, from underneath, h, and places it in 

 the position represented in the sketch. — At the same 

 instant the projecting piece, m, is received by and rests 

 upon the brass, n, which is an incbned plane fixed on 

 the end of the barrel ]\I,as shown in the end section." 

 This projecting piece, m, slides down the inclined plane, 

 n, and lets the key frame down easily to its proper bear- 

 ing and prevents its falling with a jerk, which might in- 

 jure it, and which would be bad and inconvenient in prac- 

 tice. Observe, the piece, M, projects downwards below 

 the top of the barrel when the key frame is down; and just 

 level with the surface of the barrel when the key frame 

 is up; — The sketch supposes the barrel to have shifted, 

 and the key frame to be down, and that the lower por- 

 tion of, m, has slidden down the inclined plane, n, and is 

 concealed behind it. The barrel now commences play- 

 ing, finishes the piece of music, the key frame rises, the 

 barrel shifts, commences playing again, and so continues 

 to act until the weight F figure 1, descends to the 

 bottom. 



9. — All self-performing organs which I have seen, and 

 that act in the foregoing manner, have been so con- 

 structed that they could not play and repeat single tunes, 

 as songs, airs, waltzes, quadrilles, &c. unless indeed the 

 tune was set as many times over on the barrel, as the 

 barrel made revolutions before it shifted. But they 

 played one long, or 3 or 4 shorter pieces, and then re- 

 peated them. It occurred to me that by a very simple 

 contrivance, single tunes, dances^ songs, waltzes, &c. 



