86 



ARC LAMPS WITH SMALL CURRENTS 



[CH. Ill 



Condenser 



FIG. 47. THE MAGIC LANTERN WITH A THREE-LENS CONDENSER AND A 

 WATER-CELL FOR USE ON THE HOUSE LIGHTING SYSTEM. 



This is the same as fig. 46 except that no double-pole knife switch is used, and 

 there is a triple-lens condenser and water-cell in place of a double-lens condenser. 



It is well also, when one has the lamp properly connected, to turn 

 off the current by opening the separable plug, and then paint the 

 positive wire red where it is inserted into the binding post for the 

 upper carbon. The negative wire can be painted black also. If 



HUBBEuOf 



FIG. 48. WALL RECEPTACLES WITH SEPARABLE CAP. 

 (Cuts loaned by II. Ilubbell, Inc.). 



A Wall receptacle with the connecting prongs polarized so that the cap 

 can be put on only one way, thus avoiding change of polarity with direct cur- 

 rent. 



B Wall receptacle in which the cap can be put in place either way around. 



Either form can be used with both direct and alternating current. 



