Edison Effect in Glow Lamps. 59 



ordinates the current in milliamperes flowing through the 

 galvanometer connecting the positive electrode and the middle 

 plate. It is seen that corresponding to any working pressure 

 above 38 volts for this lamp, which is equivalent to 4*2 watts 

 per candle-power, there are two possible values of the effective 



Table No. 2.— Curve No. 2. 



32 34 36 38 40 42 44 

 Working Volts of Lamp. 



potential-difference between the middle plate and the positive 

 electrode. As the working voltage of the lamp is gradually 

 raised, the reading of the galvanometer inserted between the 

 middle plate and positive electrode is also increased, but there 

 is a great tendency to jump from a certain low value to a 



