554 



CANDLE-POWER OF ARC LAMPS 



[Cn. XIII 



m 



/< 



- 





V? 









X 



IS 



FIG. 302. VARIATION IN INTENSITY OF LIGHT FROM PROJECTION ARC LAMPS 

 WITH DIRECT AND WITH ALTERNATING CURRENT. 



x Right-angle arc. 



o Inclined carbon arc. 



The small dotted curve is for small currents with the right-angle arc burn- 

 ing 6mm. carbons. 



As shown by these curves, the right-angle arc lamp gives a greater candle- 

 power for the same current than does the inclined carbon arc lamp, with both 

 direct and alternating current. Also that direct current gives about four times 

 the light that the same number of amperes of alternating current gives. 



