VOLTAIC ARC LA MIS. 



177 



Carre's Lamp. Carre's Lamp, which received a gold 

 medal at the Exposition of 1878, and is represented in Fig. 

 45, is only an ingenious 

 improvement on Ar- 

 chereau's and Gaiffe's 

 regulators. As in those, 

 the electro-magnetic ac- 

 tion is founded on the 

 attractive effects of sole 

 noids, but these effects 

 are by an ingenious ar- 

 rangement very much 

 magnified, and the me- 

 chanical action is pro 

 duced, as in the regula- 

 tors of Serrin, Foucault, 

 c., by clockwork acting 

 on two racks D, E, fixed 

 to the carbon-holders, 

 and controlled by a 

 detent brought in action 

 by the electro-magnetic 

 system. 



This system is formed 

 of two coils B, B', having 

 their axes slightly curved, 

 and into these pass the 

 ends of a soft iron core 

 A A bent into an S shape, 

 and turning at its middle 

 part about the centre c. 

 A double set of antago- 

 nistic springs ;-, ;-', regu- FlG ^ 

 lated by a system de- 

 pending upon the adjusting screw v, allows the force op- 

 posing the attraction of the coils to be suitably adjusted, and 



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