CH. Ill] SUMMARY FOR SMALL CURRENT LIGHTS 



97 



148. Summary of Chapter III: 



Do 



1. Find out the kind of cur- 

 rent used in the house lighting 

 system and the voltage (alter- 

 nating or direct current; vol- 

 tage no or 220). 



2. Wire the small arc lamp 

 exactly as the large arc lamp is 

 wired (fig. 40). 



3. Always use a rheostat or 

 some other balancing device 

 with the arc lamp ( 129). 



4. Use small carbons for the 

 arc lamp on the house circuit 

 (131)- 



5. Make sure of the polarity 

 if direct current is used (701- 

 73)- 



6. Follow carefully the direc- 

 tions for lighting the arc lamp 

 ( J 32). 



7. Be very careful to turn off 

 the arc lamp by one of the safe 

 methods ( 133). 



8. Make the room darker for 

 the small arc lamp than for the 

 large one, and have a smaller 

 screen picture ( 139). 



Do NOT 



1. Do not try to use an arc 

 lamp on the house circuit with- 

 out knowing the kind of current 

 and the voltage. 



2 . Do not wire the small lamp 

 differently from the large lamp 

 except that smaller wire can be 

 used. 



3. Never use the arc lamp 

 without a proper balancing 

 device. 



4. Do not use large carbons 

 for the lamp on the house cir- 

 cuit, they would not heat 

 enough to give a good light. 



5. Do not worry about the 

 polarity if alternating current 

 is used. If direct current is 

 used the polarity must be 

 attended to so that the upper 

 carbon is positive. 



6. Do not have the carbons 

 in contact when turning on the 

 current. 



7. Do not turn off the arc 

 lamp by the socket switch. 



8. Do not expect so much of 

 the small as of the large current 

 arc lamp. Do not have the 

 room too light for the small 

 lamp. 



