469 



2,01 C///V to 0,454 cni'^j shows the inaxiiriiim deviation of 0,7 . 10— 5. 



In opposition to the fact of such a maximum deviation of abont 

 30" J it maj be stated that the values of the tension gradient for 

 one and the same gas in Rüttenauer's observations inter se are to 

 each other as a maximum as 1 to 4. We therefore consider (see 

 also our calculation for nitrogen p. 472 footnote) the effect of g 

 exceeding the errors of observation to be present. 



We consider the fact of this theoretical and empirical determi- 

 nation of (he approximated propovtionality of the pressure ej^ect wiih 

 Ag, hence loith ike ddded energy, of great importance. It is in perfect 

 harmony with the proportionality of (he light emission of the pos. 

 pile with the added energy, which had been established by our 

 objective measuremen(s. We will presendy come back to this point 

 of simultaneous and quantitative parallelism. (See ^ 5). 



With respect to case c we already remarked that divergent values 

 should be expected for ag resp. b for different gases. This is opposed 

 to Rüttenauer's view; for this investigator thinks — with reference 

 to his empirical formule — to be allowed (o consider the pressure 

 effects comparable for different kinds of gases, and assumes ƒ to 

 have the same value foi' different gases. \n our opinion the way in 

 which RiJTTENAUEK introduced g into the empirical formula of the 

 pressure effect, cannot very well be accepted. He was in this 

 evidently led by (he results for argon and helium (table 4 of his 

 communication); in fact we find here only a maximum deviation 

 of about 157o ')• Besides on the ground of the theoretical expectation, 

 we have, however, reason to think here of chance, also on the 

 ground of what follows. In the absence of determinations of the 

 value 0Ï g, neon has not been taken for a comparison by Rüttknauer 

 in the corresponding calculated constants. F'or this purpose we can, 

 however, derive with amply sufficient accuracy from the determi- 

 nations of the terminal voltage communicated in our Thesis that 

 under comparable circumstances the potential gradient in neon 

 amounts to about 2^ times that in argon "). When we, therefore, 



M In Rüttenauer's tabel 4 we find for helium and argon for the same tube 



a maximum deviation in the "constant" — ; — rr^r^rr» which amounts to about 



Ag vMl 



4,6. 1Ü-5, of a value of 0,75 . 10-5 



(in which p varies from 0.618 to 0,776 m.m.) 



{ , A ^ „ 1.36 , 1.21 amp/c.m.«). 



2) In the derivation from the terminal voltage cathode- and anode gradient 



have been taken into account. That irregularities at the electrodes cannot play an 



important part in our case, appears among other things when also the ratio of 



the tension-gradients for argon and helium are derived from the terminal voltages; 



