370 Boltwood — Note on a Nor L'nlio- Active Elena nf. 



Art. XXXIY. — Note on a New Radio- Active Element; 

 by Bertram B. Boltwood. 



Ix an earlier paper* the results of some experiments were 

 described which indicated the separation of the parent of 

 radium from a solution of a uranium mineral. Some pure 

 thorium nitrate was added to a solution obtained by treating a 

 kilogram of carnotite ore with dilute hydrochloric acid and, 

 after the removal of the substances precipitated by hydrogen 

 sulphide, the thorium was precipitated as oxalate. The oxa- 

 lates were converted into nitrates, the precipitation with oxalic 

 acid was repeated and the substances were converted into 

 chlorides. Measurements of the amount of radium emanation 

 produced by the solution of these chlorides showed that in a 

 period of 193 days the amount of radium present had more 

 than doubled, and it was therefore evident that the process 

 described had separated the immediate parent of radium from 

 the uranium mineral. 



From a number of earlier experiments I had found that 

 after this treatment the thorium salt contains a radio-active 

 body which retains its activity without apparent alteration in 

 the course of several years. As it was easily proved that this 

 substance was not radium, uranium or polonium, it was there- 

 fore assumed to be actinium, Debiernef having stated that 

 the chemical properties of actinium are similar to those of 

 thorium. Moreover, it had been found that small amounts of 

 an emanation which completely lost its activity in less than 

 half a minute were evolved from the oxides of the thorium 

 treated in this manner. I therefore suggested that actinium 

 was the parent of radium and the intermediate product between 

 uranium and radium. 



Rutherford, using a commercial preparation of actinium, 

 has recently obtained results;}: which prove that the immediate 

 parent of radium is distinct from actinium itself although it 

 is present in his actinium preparation. He states that the 

 parent substance can be separated from actinium by precipita- 

 tion with ammonium sulphide. 



For the past ten months I have been continuing my exper- 

 iments with the object of determining definitely the radio-active 

 properties and chemical behavior of the radium parent. As 

 sources of material I have used carnotite, Joachimsthal pitch- 

 blende, gammite, uranophane and a specimen of very pure 

 uraninite from JSTorth Carolina. 



In confirmation of Rutherford's statement it has been found 



*This Journal, xxii, 537, 1906. {Nature, i xxv i ) 126, 1907. 



fC. E., exxx, 906, 1900. 



