Figure 54. — Gramme's magneto with his ring 

 armature. Note the disk-shaped current 

 collectors. From Chronique de rindustrie, April 

 17, 1872, p. 84. 



Fie. J. 



Kie 3 



Figure 55. — A slightly later version of Gramme's magneto with ring armature, showing the 

 many-part commutator and the use of wire brushes as current collectors. From 

 Chronique de rindustrie. August 13, 1873, P- 223. 



PAPER 30: DEVELOPMENT OF ELECTRICAL TECHNOLOGY IN THE 19TH CENTURY: III 



377 



