INCANDESCENT LAMPS. 



197 



When all the carbons of one lamp were consumed, the 

 cap, by meeting with a copper rod, continued the circuit ; so 



FIG. 50. 



that, if there were several lamps included in the same circuit, 



the extinction of one of them did not involve that of the others. 



According to the experiments made at Florent's, at St. 



