336 Correspondence.— -Mr. G. H. Kinahan. 



motion within the shell." Mr. Mallet's mode of estimating the 

 amount of heat derivable from crushing a cubic foot of rock was 

 explained, and it was accepted as a postulate, that the heat de- 

 veloped by crushing one cubic foot of rock would be sufficient to 

 fuse O108 of a cubic foot of rock ; or, in other words, that it would 

 require nearly the heat developable by crushing ten volumes to fuse 

 one. Mr. Mallet considers that the heat so developed may be 

 localized. But Mr. Fisher inquires why, since the work is distri- 

 buted equally with the crushing, the heat should not be so also ; 

 and since no cause can be assigned why one portion of the crushed 

 portion of rock should be heated more than the rest, assumes 

 that all which is crushed must be heated equally. In short, he is 

 of opinion that if Mr. Mallet's theory were true, the cubes expe- 

 rimented upon ought to have been themselves fused. 



After paying a just tribute of admiration to Mr. Mallet's elaborate 

 and highly important experiments upon the fusion and subsequent 

 contraction of slags, the author remarked upon Mr. Mallet's estimate 

 of the probable contraction from cooling of the earth's dimensions, 

 showing that it had been based on untenable assumptions. (The 

 author of the paper, however, holds that the contraction of the 

 dimensions of the globe has been greater than mere cooling will 

 account for.) Upon the concluding portions of Mr. Mallet's paper, 

 in which he estimates that the amount of energy afforded by the 

 crushing of the solid crust would be sufficient to account for ter- 

 restrial vulcanicity, some strictures were made ; but it was held 

 that, if the main proposition had not been proved, these calculations 

 were not of essential importance. 



The Meeting was made special for the election of a Member of 

 Council and of a Vice-President in the room of the late Sir Charles 

 Lyell, Bart. W. Carruthers, Esq., F.B.S., F.G.S., was elected a 

 Member of Council, and Sir P. de M. Grey-Egerton, Bart., M.P., 

 F.B.S., F.G.S., a Vice-President of the Society. 



COEEESPO^DBITCE. 



DENUDATION OF THE WEALD. 

 Sir, — I regret much that the gallant author of " Bain and Bivers " 

 should think I had robbed him of one of his numerous honours ; but 

 at the same time I cannot feel that I am guilty. Messrs. Foster and 

 Topley are not referred to as the authors of the Subaerial Theory of 

 the Denudation of the Weald Valley, but as the authors of a memoir 

 containing the information I required. Moreover, it would ap- 

 pear superfluous to mention Col. Greenwood's name, as the few read- 

 ers I may have, must be fully acquainted with " Bain and Bivers." I 

 appear to have been unfortunate in my selection, as the Denudation 

 of the Weald seems to be an apple of discord, the gallant Colonel 

 being the third claimant who has called me to task for having 

 mentioned Messrs. Foster's and Topley's names. 

 The Author of "Valleys and their Belations to Faults," etc. 1 

 Wexford, June 4th, 1875. 



1 London, 1875, Triibner and Co., 8yo. pp. 240. 



