BALANCED MAGNET CHRONOSCOPES 



447 



lamps are to be used in the two primary receptacles (the left- 

 hand ones in the cut) only. Obviously a two-receptacle lamp 

 board is all that is necessary, since the motor circuit is closed. 

 One receptacle is sufficient if a single lamp of appropriate wattage 

 fits the requirements, but two receptacles connected in parallel 

 is better, since it makes possible lamp combinations to fit all 

 cases. 



LAMP BOARD No. I 



CHRONOSCOPY 



A.C o I 

 IKHZOVHto- 1 



FIG. 2. CHEONOSCOPE OPERATED ON ALTERNATING CURRENT 



Set up with voice keys for association reaction, with battery for clutch con- 

 nections. 



Two 100 to 120 watt lamps (of the voltage of the circuit), or 

 one 100 to 120 watt lamp and one 50 to 60 watt lamp, will be 

 found satisfactory. There is considerable latitude in amount 

 of current permissible in any case, since the speed of the motor 

 is not dependent on the current, but on the frequency. Enough 



