F.J.3. 



F.y. k. 



Figure 53. — Gramme's ring armature, showing 

 the many coils (S) that were connected to 

 commutator plates (R). From S. P. Thomp- 

 son, Dynamo-Electric Machinery, ed. 2, London, 

 1886, p. 116. 



sufficient power to maintain an arc light, to the 

 great astonishment cf the spectators. The small 

 size of these generators provided a striking contrast 

 to the bulky magneto generators of the Holmes 

 and the Alliance systems that also were exhibited. 

 The Wilde machines were so promising that within 

 two years the Alliance company had purchased the 

 French patent; the Scottish commission for lighthouses 

 was trying them in an installation; and the Elkington 

 firm in England was using a number of them for 

 electroplating.*' 



However, by that time the ne.xt step — that of 

 self-excitadon — had been taken, and the machines 

 of 1867 already were potentially outmoded. Some 

 isolated efforts at self-excitation had been made by 

 S0ren Hjorth^^ of Denmark in 1851, by Wilhelm 

 Sinsteden ^"^ of Germany in 1861, and by Moses 



Figure 52. — Pacinotti's illustrations in the 

 original pamphlet describing his machine, as 

 reproduced in Electrical Engineer, September 

 21, 1892, vol. 14, p. 260. 



82 Les Mondes, 1867, vol. 14, pp. 161-165; 1869, vol. 21, pp. 

 152-154; 1871, vol. 26, pp. 94-96. 



*' British patent 2198 (provisional specification filed October 

 14, 1854); Sigurd Smith, S^ren Hjorlh, Inventor of the Dynamo- 

 Electric Principle, Copenhagen, 1912. 



*' Wilhelm Sinsteden, ''Ueber die .\nwendung eines mit 

 einer Drahtspirale armirten Stahlmagnets in der dynamo- 

 elektrischen Maschine," Annalen der Physik und Chemie, 1869, 

 vol. 137, pp. 289-296. 



376 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



