THORIUM IN AN ELECTRIC FIELD. — HENDERSON. 13 



It was found by Wollisch^ that in an atmosphere of 8 cm. 

 of ether vapor all the radium rest atoms were uncharged. 

 The effect of adding ether vapor to the air was found to be 

 very marked in the case of thorium. The apparatus was 

 placed under a bell jar from which the air was then exhausted. 

 Ether vapor in different quantities was added, air was then 

 allowed to enter till atmospheric pressure was reached. The 

 results obtained are shown in table 3 and graphically in fig. 5. 

 The potential employed was 40 volts and old type vessels 

 were used. 



Table 3. 



Ether added in 

 cm. mercury. 



Percentage 

 cathode activity. 







96.5 



3.8 



83.8 



9.9 



68.0 



15.7 



60.6 



37.2- 



54.5 



The effect of different potentials in the case of ether vapor 

 is shown in table 4. The ether vapor was saturated at room 

 temperatures and the results therefore are not strictly com- 

 parable. The general effect however is seen. Old type ves- 

 sels were used. 



Table 4. 



Volts. 



Percentage 

 cathode activity. 



13.9 

 40.0 



292.0 



51.1 

 54.5 

 62.3 



1. Wollisch, Phil. Mag, Oct. 1914. 



2. Estimated, air saturated. 



