342 



DRAWING WITH HOUSE CURRENT 



[Cn. X 



will wander but little, if at all, and the light will be more con- 

 stant. 



491. Feeding the carbons together. If one has an alternat- 

 ing current to work with, the small arc lamp will burn about 10 

 minutes with 8 mm. carbons before going out. With the right- 

 angle position the carbon giving the light remains constantly in 

 the axis. With inclined carbons, it rises constantly above the axis. 

 The carbons with the right-angle arc should be fed about every 

 five to seven minutes to insure the best light. 



FIG. 190. SIDE AND FRONT VIEW OF SMALL CARBONS WITH FIVE 

 AMPERES OF DIRECT CURRENT (Natural Size). Compare fig. 191. 



FIG. 191. SIDE AND FRONT VIEW OF SMALL CARBONS WITH FIVE AMPERES 

 OF ALTERNATING CURRENT (Natural Size). 



The crater is much smaller than with direct current (fig. 190). 



