CH. XIII] 



INSTALLATION OF ARC LAMPS 



505 



FIG. 270. WIRING OF THE ARC LAMP FOR PROJECTION. 

 For full explanation, see fig. 3 and fig. 40. 



ing post of the rheostat a suitable wire is carried to the positive 

 binding post of the arc lamp, that is to the binding post for the 

 upper carbon. This puts the rheostat, or other balancing device 

 in one wire, or in series, not in parallel, or across both the wires of 

 the circuit. 



In securing the ends of the wires to the binding posts, scrape 

 them, and twist the strands, then make a loop and put under the 

 binding screw of the switch as described for the attachment cap. 

 Usually for the rheostat, and the arc lamp, the wires are twisted 

 and kept straight, then inserted into a hole, and a set screw turned 

 down upon them. 



If flexible cord or cables are used for these connections, the wires 

 on the end, after being scraped clean should be twisted and 

 soldered, then none of the strands will escape to lessen the carrying 

 capacity, or possibly to make a short circuit. 



