326 



Mr. R. Tc Beatty on the Production of Cathode 



magnitude is the same in each case. Hence we may assume 

 that in the case investigated a constant fraction of the homo- 

 geneous radiation is spent in producing cathode particles. 



Further, if the absorption by air of these radiations were 

 known, we could find this fraction numerically. 



In Table II., R is the distance which the cathode particles 

 travel in hydrogen at normal pressure and temperature before 

 becoming half absorbed, divided by the corresponding dis- 

 tance in air. 



The ratios increase as the particles become more pene- 

 trating. A similar change in R has been observed by 

 Lenard * over a much wider range of speeds of cathode 

 particles. 



N is the total number of ions produced by a given set of 

 cathode particles when totally absorbed in hydrogen, relative 

 to the number produced in air under the same conditions. 

 The ratio approaches very closely to unity. 



In Table III. are added some data previously found for 

 cathode particles by Lenard f and Seitz \. 



Table III. 



Energy of 

 corpuscles in volts. 



X for air. 



X for IT 2 . 



Eanjre in H„ 

 liange in air' 



Authority. 



4,000 

 20,000 

 30,000 



645 

 31 



3-8 



144 

 •47 



448 

 8-05 



Lenard 



Seitz 



Lenard 



It will be seen that the constants relating to the cathode 

 particles due to the Sn radiations are very close to those 

 found by Lenard for corpuscles possessing a velocity due to 

 a drop of potential of 30,000 volts. 



In fig. 8 (PI. V) the coefficients of absorption of the 

 cathode particles are plotted against the absorption by Al of 

 the exciting homogeneous radiations. The curves approach 

 a linear form. 



* Lenard, Ann. der Phys. xii. p. 732 (1903). 



f Lenard, ibid. 



X Seitz, Ann. der Phys. xii. p. 860 (1903). 



