CH. I] 



MAGIC LANTERN WITH DIRECT CURRENT 



FIG. 3. ARC LAMP FOR PROJECTION, WITH WIRING, SWITCHES 

 AND FUSES 



Supply Wires The conductors from the supply to the outlet box. 



Outlet Box. An iron box receiving the supply wires at one end and giving 

 exit to them from the other. 



Fuses & Switch Two cartridge fuses in the circuit and a double-pole knife 

 switch beyond the fuses. The fuses are present to avoid accident in case of a 

 short circuit and the switch to turn the current on or off as desired. 



P W R Polarized wall receptacle. This is composed of two parts as 

 shown, the part on the wall to receive the supply wires from the outlet box, 

 and the cap to connect with the table switch. The metal connections of the 

 cap with the receptacle arc in planes at right angles so that the cap can be put 

 in place only in one way, hence the polarity is always the same. 



Arc Supply The wires connecting the cap of the wall receptacle and the 

 table switch. 



Switch The double-pole, knife switch for turning the current on and off the 

 arc lamp. 



Wi The wire extending from the switch to the upper carbon of the arc 

 lamp. 



W2 The wire extending from the switch to the rheostat. 



If j The wire extending from the rheostat to the lower carbon of the arc 

 lamp. 



