EXTRACTION OF RADIUM FROM THE OLARY ORES. 155 



usually present in radio-active minerals. In the course of 

 time, radium D produces radium P (polonium) and the ray 

 activity of the lead becomes about equal to that of uranium. " 



As stated previously, the radio lead separated on smelt- 

 ing the crude sulphide was about twice this activity. It 

 is possible that this is due to small amounts of radium 

 barium sulphate included in the lead. The lead accumul- 

 ated in the course of several years will ultimately form a 

 convenient source for the working up of polonium prepar- 

 ations. As the amount of polonium in equilibrium with a 

 mineral containing one grain of radium is only 0'19 milli- 

 gram, the direct recovery of polonium from the working 

 solution is obviously out of the question. 



It should be possible on the other hand to work up fairly 

 active ionium preparations from the rare earths without 

 much difficulty. 



While the chief technical problems in connection with 

 this ore may be regarded as solved, much work of a scientific 

 character remains to be done, aDd I hope to continue in- 

 vestigations on the three following lines : — 



1. To make a complete spectrographic examination of 



the ore and the various products separated out 

 during treatment. 



2. To investigate the radio-active properties of these 



products. 



3. To work up some kilos of the rare earths in order to 



examine them in detail. 



In conclusion I desire to thank Professor Pollock for his 

 kindness in testing various radium preparations from time 

 to time, and for the friendly interest he has taken in the 

 work throughout. 



