402 MOVING PICTURE APPARATUS [CH. XI 



inclined position as desired and each carbon holder can be turned so 

 that the upper carbon is inclined and the lower one is vertical 

 The right-angle arc can be used with the moving picture outfit if 

 desired, but it should not be used with currents much above 25 

 amperes Twenty-five amperes direct current will be found 

 sufficient for all but the largest rooms. 



Fic^222.. POWER'S CAMERAGRAPH No. 6, SHOWING THE LAMP-HOUSE 



IN POSITION 

 (Cut loaned by the Nicholas Power Co.). 



567. Lamp-house. The arc lamp is enclosed by a metal 

 house to protect the operator from being blinded by stray light and 

 to protect the arc from air currents which might blow it out or 

 otherwise interfere with its performance. The adjusting handles 

 of the lamp project so that the lamp can be adjusted from time .to 

 time without opening the doors of the lamp-house. 



The house should be provided with doors to enable the operator 

 to change the carbons and should have a window of dark glass so 



