THE MANUFACTURE OF RADIUM ' 



By Prof. Camille Matignon, 

 College de France 



[With 4 plates] 

 HISTORICAL 



Mme Curie announced before the Academy of Sciences at Paris 

 on the 12th of April, 1898, that two uraniferous minerals, pitch- 

 blende and chalcolite, showed more intense radioactive properties 

 than should be due to the uranium they contained. This remarkable 

 fact, she added, led to the belief that these minerals should contain 

 an element more radioactive than uranium. 



M and Mme. Curie— at times in collaboration with M. Bemont— 

 by the chemical analysis of pitchblende, showed successively the ex- 

 istence of two new radioactive elements-polonium, which toUows 

 bismuth in the course of analytical processes, and radium, the ele- 

 ment next to barium. 



Radioactivitv, discovered by Henri Becquerel, thus proves to be a 

 direct method of chemical analysis of hitherto unexpected sensitive- 

 ness for indicating the existence of radioactive elements and serving 

 as a guide in their separation. 



The treatment of a ton of the residues of pitchblende, under the 

 chemical supervision of M. Debierne, enabled M. and Mme. Curie to 

 isolate a small quantity of radioactive matter associated with barium^ 

 This, by successive separations from the barium, became enriched 

 little by little, so that the spectroscope showed clearly the elementary 

 character of radium. In 1902 they obtained a strictly pure chloride 



of radium. 



During the progress of this work of separation, M. and Mme. 

 Curie dSnonstrated the curious and novel properties of this new 

 element— its radioactivity, induced radioactivity, physiological ac- 

 tions, etc. 



Pitchblende, an uranium and radium ore, is found in a well-known 

 mine of Joachimstahl, in Bohemia, where it is regularly treated for 

 the extraction of the uranium. The small amount of uranium salts 

 used throughout the world comes fr om there. During this extrac- 



' Translated by permission from Revue Sclentifique, Aug. 3, 1925. pp. 524-532. 



221 



