CHAPTER VI 



WOKK ON RADIUM 



IN 1902 radium salts were isolated by Madame Curie, 

 and naturally the physical and chemical properties of 

 these remarkable substances attracted a large number 

 of investigators. Ramsay desired to examine the spec- 

 trum of the " emanation " which is evolved from radium, 

 and with the co-operation of Dr. Frederick Soddy, who 

 had come to work in his laboratory in the autumn of 

 1903, experiments were begun with this object. Ramsay 

 was a skilled manipulator of small quantities of gas, 

 having determined the physical properties of xenon with 

 less than 4 cubic centimetres, but in the case of the 

 emanation where it was a matter of cubic millimetres 

 special apparatus had to be devised. After some pre- 

 liminary attempts, vacuum tubes were made out of 

 thermometer tubing, and the emanation being admitted 

 the experimenters were surprised to find helium present. 

 Subsequently the volume of emanation evolved in a 

 given time from a given weight of radium bromide, 

 and the quantity of helium disengaged from a known 

 volume of emanation were approximately measured. 



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