[Kennedy] 



ACTIVE DEPOSIT FROM ACTINIUM 



89 



in the charge acquired by the deposit particles in their passage, by dif- 

 fusion or otherwise, through the air. The phenomenon of recoil recently 

 noted by Otto Hahn ^ must also have been an important factor in con- 

 tributing to the deposit on both electrodes. 



VI. Activity of Deposits Obtained in Carbon Dioxide at 

 Different Pressures. 



In order to study how the deposits might be affected by a modifica- 

 tion in the conditions of diffusion a set of measurement?, similar 

 to those carried out with air, was made with carbon dioxide at pressures 

 varying from 750 mms. to 1 mm. of mercury, and the values of the 

 active deposits obtained are recorded in Table IV. From these results, 



TABLE IV 



Pressure 



Activity on the Cathode 



Activity on the Anode 





the curves shown in Figs. XI and XII have been drawn. It will be seen 

 that these curves also follow laws similar to those obtained with air, and 

 that the deposits on the two electrodes gradually increased as the pressure 

 was lowered. Both passed through a maximum and for still lower pres- 

 sures the active deposit on both plates decreased and approached equality 

 for the lowest pressures investigated. The maximum activity on the 

 negative electrode was obtained at a pressure of 60 mms., while the 



1 Deut. Phys. Ges. XI Jahr No. 3. 



