24 



THE MECHANISM OF 



rnents of brass separated by hard-rubber insulation. This is 

 shown more plainly in the two views of the upper part of the 

 apparatus in Fig. 11, and is represented by S in the diagram (Fig. 

 2), to which future reference letters will apply. To each of the 

 brass segments an insulated co])per wire is connected, and passes 

 from thence down through a rubber tube, R, to the bottom of the 

 walnut base of the machine, where it is fastened to the screw of 

 one of the twenty-four binding-posts that are on the base at one 

 side of the apparatus. These can be seen in Fig. 10, and thirteen 

 of tiiem are represented at P in the diagram. Each segment and 



Fig. 11. 



each binding-post is stamped with a number from 1 to 24, and 

 the wire from any segment is connected with the binding-post of 

 the same number. 



Loose on the shaft which passes through the centre of the ring 

 is an iron collar carrying the double arm, B, outside the face of 

 the ring. The upper end of B is bent inward at a right angle, 

 and holds a laminated metallic brush in contact with the outside 

 of the segmented ring, while a second metallic brush is held in 

 contact with the iron collar by a stationary pin, K, projecting 

 from the side of the standard. An insulated copper wire con- 

 nected K with a separate binding-post, U, on the ba.se of the 

 machine. From the lower end of B a small projection or nipple 



