THE DYNAMO. 73 



netic circuit as shown in Fig. 63. This figure shows one end 

 of a machine with three distinct armatures, each having its own 

 positive and negative brushes. One armature is the solid 

 cylinder A, the second armature is a cylindrical metal shell 2, 

 2 insulated from A, and the third armature is an insulated 

 cylindrical metal shell 3, 3. To connect these three armatures 

 in series so that their electromotive forces may be added, the 

 positive brushes of No. I are connected to the negative 

 brushes of No. 2, the positive brushes of No. 2 to the negative 

 brushes of No. 3 and so on, exactly as in the series connections 

 of voltaic cells. 



Fig. 62 shows that each set of brushes consists of a number 

 of individual blocks of metal or carbon arranged symmetrically 

 around the periphery of the rotating armature. 



