470 



place the values of Lp, A, and p found for neon (Rüttknaukr, 

 table 1 of his publication) in his table 4, we can write ^ = 5 for 

 neon, g being put at 2,0 for argon. Then we find : 



TABLE A. 



in other words the value of the "constant" is from 300 to 4007, 

 higher for argon and helium than for neon. This shows in our 

 opinion that it is injustifiable to put the pressure effects for different 

 gases comparable on such a basis. 



Conclusion. It is necessary to replace RtJTTENAUER's empirical 

 formula by the theoretical formula: 



Lp=f 



aVmi 



D' 



(p (g) resp. 



A \/Ml 



V 



D' 



in which (f {g) represents a function of the tension gradient, which 

 in definite regions can approximately assume the form hg, in which 

 h represents a constant the value of which is not the same for 

 different gases. 



^ 5. Region of validity. 



We pointed in our previous communication that the phenomena 

 in the path of the current are very complicated, and that our for- 

 mulae are drawn up for more or less idealized cases. What makes 

 A. Rüttenauer's determinations also so interesting is that they were 

 carried out with noble gases, in which the conditions in the path 

 of the current are naturally much less complicated than in the 

 multi-atomic not-noble gases. Besides this investigator used a very 

 long and wide positive pile, which brings out the influence of what 

 happens in the positive pile better. 



We mentioned already that in his second publication F. Skaupy 



then the ratio appears to agree with that which ensues from the values of the 

 potential gradient as they have been measured by A. Rüttenauer with the 

 positive pile. 



