Disappearance of Gas in the Electric Discharge. 231 



The presence of such a grid does not change the main 

 characteristics. There is still a definite glow potential at 

 which an irreversible increase of current occurs ; but it now 

 depends on V as well on V. If i g and i e are measured 

 separately with V negative, curves are obtained of which 

 iig. 3 is typical. (The bulb used was not that of fig. 1 ; it 







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V (yolts) 



was that of vessel 2 in par. 7 ; but the arrangement of the 

 anode and cathode was the same). i e rises steadily from the 

 ionization to the glow potential, but i g is barely perceptible 

 until just before the glow potential. At the glow potential 



