132 DEPOSIT OF RADIUM IX AX ELECTRIC FIELD. HEXDERSON. 



one hesitate to conclude that all the rest-atoms could be 

 collected on the cathode with a sufficiently high potential- 

 gradient However, it seems unnatural to suggest any limit 

 other than 100 for the percentage cathode acti\at3'', especially 

 in \dew of the fact that with the highest voltages the per- 

 centage was still increasing. Therefore, in the absence of 

 contradictory evidence, it seems reasonable to conclude 

 that in sulphur dioxide and in carbon dioxide all the rest- 

 atoms of radium are initially positively charged. 



1\. COXCLUSIOXS. 



In atmospheres of air, hydrogen, carbon dioxide, etc., 

 all the rest-atoms of radium appear to be initially positively 

 charged. 



So far no gas or vapor has been discovered in which the 

 radium rest-atoms are not all similarly charged. In this 

 respect the behavior of the rest-atoms of radium is the same 

 as that of the rest-atoms of thorium. The slight differences 

 in this respect which do exist are differences of degree and 

 not of kind. 



In a future paper the writer hopes to give some discussion 

 and explanation of these experimental results. 



I msh to express my gratitude to Dr. H. L. Bronson for 

 his continual inspiration and advice throughout this inves- 

 tigation. 



