Coupe verticale. 



Figure 44. — Details of tlie arrangement of tfie arc liglit in tlie lighthouse at Cap de la Heve. 

 From E. AUard, Phares et balises, vol. 5 of Les Travaux publics de la France, L. Raynaud, 

 ed., Paris, 1883, pp. no, in. 



an H cross-section.'' The wire was wound longi- 

 tudinally into the cavities in the armature and the 

 ends of the wire were led out to a commutator divided 



'» British patent 2107 (provisional specification filed Septem- 

 ber 10, 1856); Werner .Siemens, "Ueber eine neue Construction 

 magneto elektrischer Maschine," Annalen der Physik und Chemie, 

 1857, vol. 101, pp. 271-274. 



into two parts. The armature was spun on its long 

 axis between rounded-out cavities in the poles of the 

 field magnets (fig. 49). 



This shuttle-type armature was more efficient 

 mechanically than the disk armature. Because of 

 its more compact forin, the shuttle armature could be 

 driven with less power than could a disk armature of 



370 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



