The Experiments of Ramsay 



into the surrounding space, impregnating the 

 bodies it encounters and transferring to them the 

 activity derived from the radium. 



This explanation of induced radio-activity, 

 advanced by Rutherford, ceased to be a hypothe- 

 sis on the day that Ramsay and Soddy managed 

 to collect the " emanation " of radium and to 

 isolate and study it. The emanation is a true 

 gas which follows Boyle's law and liquifies when 

 cooled in contact with liquid air; it is char- 

 acterised by a bright spectrum, which recalls that 

 of the gases of the argon series ; on the other hand 

 its chemical inactivity appears absolute, in fact, 

 it may be heated without any alteration in 

 contact with the most energetic oxidisers and 

 reducers; for this reason Ramsay considers it a 

 simple gas, with atomic weight about 215, and 

 occupying in the periodic classification a place 

 below xenon. 



Here we have a fact which has no analogy in 

 chemistry. Radium, a body accurately defined 

 as an element by its spectrum and all its chemical 

 properties, decomposes spontaneously into 

 another body, which appears also to be simple, 

 and if the rate of transformation ascertained 



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