346 Dcscripiio?? of a self performing barrel orgmi. [Oct. 



times round to complete one revolution of the snail 

 ■which is fixed on the same axis as the SO teeth wheel. 

 But to describe the section figure 5. — M represents a 

 part of the organ barrel : 1.5 is the pin fixed to the 

 wheel 5 ; a, is the axle of the barrel entering the hollow- 

 axle of the wheel 5; b, is a polished circular rod of 

 steel moving freely in the bore of the axle, one end 

 touching the axle of the organ barrel, and the other end 

 bearing on the face edge of the snail wheel. This end 

 however is filed flat, and moves through a flat crevice or 

 guide attached to the frame work to prevent the rod from 

 turning round as the axle revolves. The upper side of 

 this flat part is in a line with the centre of the axle, and 

 of the snail, so that when the snail has made a complete 

 revolution the rod slips from the point c, to d, being pro- 

 pelled by the spring, e, at the left hand end of the organ 

 barrel, which consequently has a horizontal movement to 

 and ffo equal to the distance from c, to d, on the snail, 

 which distance is dependent upon and equal to the dis- 

 tance from one key to the next key on the key frame. 

 As the axle of the wheel 5 has to carry the weight of 

 the organ barrel, which is 2 ft. 10 in. long and 5 inches 

 in diameter, it (the axis) runs on a friction roller at f, 

 but it is not shown. This friction roller occasions the 

 axis to work smoothly and freely, which as it is made 

 of brass, and works in brass bearings, it would not 

 otherwise do. The point c, of the snail 12 is tipped 

 with hard steel to prevent it from wearing away. 



7. — From the foregoing description it is evident that 

 the barrel, while it revolves on its own axis will have a 

 continual slow horizontal motion towards the left hand 

 or spring end, and that when the snail has made a full 

 revolution, the barrel will suddenly shift to the right 

 hand by the flat end of the cylindrical rod, b, slipping 

 over the point c, of the snail wheel. Now the keys of 



