TJieory of Ionization by Collision. 137 



The values of log— are drawn with a as abscissae (fig. 6). 



One puts after a preliminary trial / = 0"05 cm., and draws 

 through the point c on the abscissae axis determined by 

 0c=/ a straight line cb which for small values of a 



Fig. 6. 



S % 























3 



c 

























> 





















■ y 



-f 

















































1? 

























:8 



=> 



















































o e 



-8 



1-0 



1-2C!tV 



JO&W 



agrees as closely as possible with the found values of log — , 



n . n o 



(For greater values of a, log— lies above the line cb on 



n 



account of the ionization caused by the positive ions of 

 which no account is taken.) From fig. 6 is obtained 



ya = 5*8. To / = O05 cm. corresponds y = ^.e l = 0'328, 



to which again according to the preceding table corresponds 



5'8 

 ry = 0'78. Consequently a =-— — = 744. From this is found 



by using equation (16') / = 0"046 cm., and as this value is 

 sufficiently near to the one previously assumed, namely 

 0*05 cm., there is no reason to make a new determination. 

 For the ionization voltage we now obtain, 



V = 0-046 x 350 = 16-1 volt. 



A further discussion of this problem is to be found in 

 a Danish paper *. 



Copenhagen, 



November 1919. 



* Dot K(jl. Danske Videnskabernes Selskab. Mathematisk-fysiske 

 Meddelelser, i. part 7 (1918). 



