MANUFACTURE OF RADIUM MATIGNON 



227 



gram of the chloride is supposed to be taken containing 100 milli- 

 grams of radium. 



Each circle represents the composition of a portion before crystal- 

 lization; the figures above give the weight of the crystals, the 

 figures below the concentration in radium referred to 1 kilogram 

 of the salt. Each figure at the side gives the quantity of radium 

 in the portion. 



After the first fractionation, the kilogram of salt is divided into 

 two parts, A and B, each weighing 500 grams and having concentra- 



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\Si6m 



l^anej 



Fig. 1. — The fractional crystallization of radium chloride 



tions of 160 and 40, respectively. The portions A and B give 

 further the fractions A^ A^ and B^ Bg characterized by the follow- 

 ing figures : 



Note that the portions A2 and B^ have the same concentration in 

 radium. The portions are combined so that there remains three 

 parts : A^ Ao+B^ B.. 



Similarly the mother liquors from the treatment A^ are added to 

 the crystals from the treatment of A^+Bi while the mother liquors 

 of the last fraction go to the crystals obtained from the fraction Bo. 



