Proceedings and List of Papers read. 



329 



globe, where they are no longer exposed to such pressure, they have, 

 in consequence of the change, become endothermic ? The frequency 

 of the helium spectrum in the stars, and its presence in the sun, 

 makes it less improbable that some such explanation may lie not far 

 from the truth. 



There are at least two other minerals, gadolinite and aeschinite, 

 which exhibit endothermic properties. But these minerals, instead 

 of decreasing in density on ignition, increase. The following table 

 shows the gases evolved when they are heated, their densities before 

 and after heating, and the loss of weight which they suffer : — 



G-ases evolved. 



c.c. per gram. Density. 



( A ^ f A ^ Loss of 



H 2 . CO. C0 2 . He. Before. After, weight. 



Gadolinite .... 0-700 0-011 1-060 none 4-289 4-371 0'82 



^schinite 0'458 none 0*215 0*243 4-685 4*793 1-018 



It is to be noticed that only the seschinite contains helium, and that 

 in very small quantity. 



The fact that these minerals increase in density, and that only one 

 yields helium, places them in a different class from fergusonite. 

 Moreover, the rise of temperature is not to be compared to that seen 

 with fergusonite, for the glow is barely visible. 



January 27, 1898. 



The LORD LISTER, F.R.C.S., D.C.L., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The Right Hon. Sir Herbert Eustace Maxwell, a member of Her 

 Majesty's Most Honourable Privy Council, was balloted for and 

 elected a Fellow of the Society. 



The following Papers were read : — 



I. "Mathematical Contributions to the Theory of Evolution. On 

 the Law of Ancestral Heredity." By Karl Pearson, M.A., 

 E.R.S., University College, London. 



II. " On the Zoological Evidence for the former Connection of Lake 

 Tanganyika with the Sea." By J. E. S. Moore. Communi- 

 cated by Professor Lankester, F.R.S. 



