l8o ELECTRIC LIGHTING. 



arm fitted to the supporting column, and this last is arranged 

 in such a manner as to be capable of moving when the con- 

 sumption of the carbon requires ; for in this system it is only 

 the course of the upper carbon that is regulated electro- 

 magnetically, as in Archereau's original regulator. We must 

 add that the coil A is formed of two helices which may, by 

 means of a commutator shown at the top of the coil, be 

 arranged either for tension or for quantity, according to the 

 conditions of the experiment. 



The action of this apparatus will be readily understood: 

 when it is not working, the two carbons k k are in contact, 

 and the current can pass through them when the carbon- 

 holders are connected with the electric generator. Under 

 the influence of the current, then at its maximum intensity, 

 the magnetic core d is raised up, carrying with it, by its catch,, 

 the collar h ; the rod //is then raised, and the two carbons 

 separated ; the voltaic arc is produced, and, so long as the 

 electric action is kept within proper limits, the apparatus re- 

 mains in the condition brought about by the rise of the 

 core d i but when the consumption of the carbons becomes 

 sufficiently great to notably weaken the current, the core d 

 drops down again, and with it the iron rod // and the 

 collar h. If this descent is not complete, the carbons ap- 

 proach each other only by the distance the core has dropped ; 

 but should it be so great that the collar h presses on the 

 cross piece //, the rod // is liberated and falls by its own 

 weight until the approach of the carbons is sufficiently great 

 to bring about a fresh ascent of the core //. 



Ja spar's Lamp. Jaspar, of Liege, was one of the first 

 to turn his attention to electric lamps, and in the second 

 edition of our Expose des applications de r electricity published 

 in 1856, we have described the first system he sent to the 

 Exposition of 1855. Since that time he has paid little atten- 

 tion to the subject, and it was not until the Exposition of 

 1878 that he again entered the lists with other inventors of 



