4 PROFESSOR WILLIAM RAMSAY. 



presence of a yellow line apparently identical in position 

 with the line D3, noticed in 1868 by Lockyer in the spec- 

 tram of the chromosphere. Lockyer attributed this line to 

 the presence of an element then unknown on the earth, 

 and which he termed "heliam." 



The same gaseous element has now been obtained from 

 several other rare minerals containing uranium, yttrium, 

 and thorium. Professor Ramsay finds that the density of 

 helium compared with hydrogen is about 2*13, and that the 

 ratio of the specific heats has the theoretical value for a 

 monatomic gas ; the atomic weight therefore appears to be 

 about 4, and we have therefore now an element between 

 hydrogen (atomic weight = 1) and lithium (atomic weight — 

 7). Heliam, like argon, is characterised by its remarkable 

 inertness. The value of Professor Ramsay's researches, 

 chiefly those on argon and helium which have excited the 

 greatest interest, has been widely recognised both in this 

 country and abroad, and he has been elected a correspond- 

 ing member of the Institute of France (Academie des 

 Sciences), and a Foreign Member of the " Societe Holland- 

 aise des Sciences " (Ley den), of the " Societe d'Histoire 

 Naturelle " of Greneva, and of the Bohemian Academy of 

 Sciences. He has also received the Barnard Medal of the 

 Colombia College, New York, awarded by the American 

 Academy of Sciences ; the Davy Medal of the Royal 

 Society; the Leblanc Medal of the French Chemical Society, 

 and jointly with Lord Rayleigh he has received the 

 Hodgkins Prize of $10,000 awarded by the Smithsonian 

 Institute, Washington, and a prize of 25,000 francs awarded 

 by the French Academy. Professor Ramsay is the author 

 of several well-known text-books of chemistry. 



Professor Ramsay has read the following papers at meet- 

 ings of the Bristol Naturalists' Society : — 



