170 SIR WILLIAM RAMSAY 



was not found possible for the former to comply with 

 the requirements of the latter. Negotiations therefore 

 fell through and the Institute got its radium from 

 Austria. 



A new mineral, having radio-active properties, had 

 been discovered in Ceylon in 1904. It contained a 

 large percentage of thorium oxide, and hence received 

 the name thorianite. On being heated or dissolved in 

 dilute sulphuric acid it gives off a considerable quantity 

 of gas consisting chiefly of helium. Ramsay secured 

 several hundred-weights of this mineral, and with the 

 aid of a chemical manufacturer proceeded to treat it 

 by the process used in the case of pitchblende for the 

 extraction of barium and radium. 



This part of the product was investigated in Ramsay's 

 laboratory by Otto Hahn. It was found that in separat- 

 ing the radium salt from the barium, the radio-activity 

 became concentrated on the one hand into the least 

 soluble portion containing radium, and on the other 

 into the most soluble portion which was found to con- 

 tain a hitherto unrecognised radio-element to which 

 Ramsay gave the name radiothorium. The facts were 

 published both by Ramsay and Hahn in 1905. Hahn 

 then left London and went to work with Rutherford in 

 xmtreal, having evidently taken some of the same 

 aterial with him. He soon discovered mesoihorium, 

 he parent of radiothorium, and published an account 

 its radio-active properties while keeping the methods 

 of preparation and the chemical properties secret. Meso- 



