The Evolution of the Sciences 



millimetres of gas have to be manipulated with- 

 out loss for several months, requiring in the 

 operator an extreme degree of experimental 

 ability. We must not allow the extreme diffi- 

 culty of the task to incline us to scepticism ; those 

 who have seen Ramsay in his laboratory know 

 that no one could be better prepared for such an 

 arduous task. They know how conscientiously 

 and diffidently he advances on the path before him. 

 " During my last visit to Ramsay, over a 

 year ago/* writes the German chemist, Ostwald, 

 " he showed me, in the private laboratory which 

 he has had built in his house in Regent's Park, 

 some white crystals on a small watch glass. This 

 substance had been obtained by the action of the 

 emanation of radium on a solution of copper 

 sulphate. After eliminating the copper by 

 sulphuretted hydrogen the residue left by the 

 evaporation of the clear liquor shows distinctly 

 in the spectroscope the line of lithium, as I was 

 able to ascertain, thanks to Ramsay's kindness. 

 As this fact is absolute!}' extraordinary Ramsay 

 requested me not to publish it before it was 

 perfectly confirmed. This reserve is no longer 

 necessary, as a few days ago I received the proofs 



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