130 Geological Society. — 



5 

 Pentane, y = 281 (#— *138), and x— tr~ = *417, 



C.P. = 117. 



In the same way the C.P. of all hydrocarbons up to carbon 

 density 6 can be obtained from the scheme. How far they 

 will prove to be accurate remains to be seen. It must be 

 remembered that the number for benzene is a most important 

 element, and that it depends only on the mean of two mixtures, 

 neither of which contained much more than 3 per cent, of 

 benzene. 



No doubt the process could be carried further, but more 

 experimental evidence would be desirable first. So far I 

 have taken no account of the presence of mere diluents, such 

 as nitrogen or carbonic acid or oxide. 



Experimental determinations of propylene and its homo- 

 logues, and of the paraffins, or of mixtures of these substances 

 with marsh-gas or disilluminated gas, are commended to those 

 who possess experimental facilities in connexion with the 

 subject. Also more determinations of benzene mixtures are 

 wanted. 



I hope shortly to return to the question of diluents, so far 

 as the available material will permit. 



XIV. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from vol. xxxiii. p. 540.] 



February 10, 1892.— Sir Archibald Geikie, D.Sc, LLD., F.U.S., 

 President, in the Chair. 



rpHE following communications were read : — 

 -*- 1. " The Raised Beaches, and 'Head' or Hubble Drift of the 

 South of England : their relation to the Yalley Drifts and to the 

 Glacial Period ; and on a late Post-Glacial Submergence. — Part I." 

 By Joseph Prestwich, D.C.L., F.R.S., F.G.S. 



The author remarks that, besides the subaerial, fluviatile and 

 marine Drifts of the South of England, there is another Drift 

 which is yet unplaced. This he considers to be connected with 

 the ' Head ' overlying the Raised Beaches. Of these he describes 

 the distribution, characters, and relations along the South Coast. 

 The ' Head ' overlies the beaches, and frequently overlaps them. 

 In the beaches large boulders are found, and marine shells, of which 

 lists for the various localities are given. The ' Head ' frequently 

 shows rough stratification of finer and coarser materials. It contains 



