Ionization of Hydrogen by X-Rays 

 Table I. 



645 



Authority. 

 Perrin 1 



Type of Rays 

 used. 



Ionization of H 2 

 Ionization of Air 



Soft rays 

 Soft rays 

 Hard rays 

 Hard rays 



0-026 



05 



0-33 



0-114 



0-105 



0-177 



042 



Rutherford 12 



Thomson 3 



Strutt 4 



McClung 5 



Eve 6 





1 Ann. de Chimie de Physique, 



[7] xi. p. 496 (1897). 



2 Phil. Mag. [5J xliii. p. 241 (1897). 



3 Proc. Camb. Phil. Soc. x. p. 10 (1897) 



4 Proc. Roy. Soc. Ixxii. p. 209 (1903). 



5 Phil. Mag. [6] viii. p. 357 (1904). 



6 Phil. Mag. [6] viii. p. 610 (1904;. 



case of hydrogen the net gain is a much larger proportion of 

 the whole ionization than in the case of air, so that it seems 

 probable that the variations in the above table are due not 

 merely to the different types of rays employed, but, to a 

 much greater extent, to the type of ionization chamber used 

 in the investigation. 



Crowther* made a more systematic series of measurements, 

 using rays of various penetrating powers. His results are 

 given in Table II. 



Table II. 



Equivalent Spark- 

 gap in mm. 



Ionization of H 2 

 Ionization of Air 



8 



0010 



12 



0013 



14 



0-021 



16 



0-068 



18 



0-107 



20 



0-135 



24 



0152 



28 



0-180 



* Proc. Roy. Soc. Ixxxii. p. 103 (1909). 



