vi WORK AT MANCHESTER i 45 



is a chemist." "What's that? what does he do?" 

 "Well, I will tell you: he has something in a big 

 bottle, then he pours it into a smaller one, and then 

 again into quite a tiny bottle." "Well, and what 

 then happens to it?" " Oh, then I throw it away." 



I think it may here be well to mention a few points 

 of scientific interest which attracted my attention during 

 my last few years in Manchester. I became possessed, 

 through a friend in South Africa, of a considerable 

 quantity of Kimberley diamonds. These all had 

 a yellowish tint, and it would be worth much if 

 this colour could be discharged and a diamond of pure 

 water obtained. I daresay that it is known to many 

 that if such yellow diamonds are immersed in pow- 

 dered charcoal and then heated to a white heat 

 and allowed to cool in absence of air, the yellow tint 

 disappears, but unfortunately on exposing them again 

 to light the yellow colour returns. I do not know any 

 explanation of this, and I doubt whether either Sir 

 William Crookes or M. Moissan can at present account 

 for it. 



The diamond which was burnt in a current of 

 oxygen by Dumas and Stas in 1841 was, I believe, a 

 Brazilian stone ; at any rate it was not South African ; 

 and it became a matter of interest to note whether 

 the South African diamond consisted of carbon giving 

 an atomic weight identical with that yielded by the 

 Brazilian stones. Strange things have occurred in 

 chemistry, and it would be possible, at any rate, that 

 the Kimberley diamond was something different from 

 those obtained from other sources, so I burnt a 

 quantity of the diamonds and obtained numbers 

 closely agreeing with those of Dumas and Stas. So 

 far so good. Still, we chemists know of elementary 

 bodies possessing identical or nearly identical atomic 



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