lS35.]^Description of a self performing barrel organ. 347 



the key frame N in figure 1, nearly touch the surface of 

 the barrel, and if the key frame was to remain in the same 

 position as it does while the music is playing, the keys 

 would stick among the pins and staples on the organ 

 barrel, and prevent its horizontal motion. To give the 

 barrel a clear and free movement it is necessary there- 

 fore that the key frame should be lifted up and sustain- 

 ed while the barrel is shifting, and that it should be re- 

 stored to its proper position as soon as the barrel has 

 effected its horizontal movement : — This is done as fol- 

 lows: 



8. — In figure 6 let, a, represent the left hand end of 

 the organ barrel and N the key frame ; — b, is a piece of 

 iron projecting from the key frame downwards level with 

 the top of the barrel ; c, is another piece fixed on the 

 surface of the barrel and acting as an inclined plane ; 

 these two pieces are so adjusted that when the barrel 

 has nearly completed the 10th revolution, and is on the 

 point of shifting, the inclined plane c, comes into con- 

 tact with b, and lifts the key frame clear of the pins on 

 the organ barrel. At the same time in order to sustain 

 the key frame in this position, a spring at the right hand 

 end of the barrel comes into play thus : — d, represents 

 this spring carrying on it the brass, e, and the screw, f, 

 when the key frame N, N* has been lifted as just ex- 

 plained, the iron elbow, h, [of which the elbow is at the 

 bottom and projects in front like the letter L] is lifted 

 above the top of the spring, d, so that the spring moves 

 towards, g, but is prevented from going too far by the 

 projection of the brass, e, striking against part of the 

 frame work, i, — Suppose now the key frame N* to be 

 lifted and sustained by the elbow, h, resting on the top 

 of the spring, d, and supposing the spring to be under- 

 neath, h, at g ; the projecting piece, m, will not then rest 

 on the brass, n, as shown in the figure, nor will the 

 brass, n, or the barrel, M, be in the position represented. 



