136 Geological Society : — 



generally, n 6*25, and m is greater than n, taking m=xn and s=the 

 specific heat of a nitrate, we have 



Q=am 6*25 ; 

 but 2s=rc6'25; 



. • . Q = ;T25, 



and _S_ 2 = I 



Q cells <cs' 

 the expression for chemical activity in terms of specific heat. Compa- 

 ring the coefficients (a, a') for any two nitrates, the following relations 

 are obtained: — 



a m! S x's 

 a' m S'~~ xs ' 

 and it is shown that these formulae agree sufficiently well with expe- 

 riment. Where m=m f and x—x\ we have the simple expression 



a _Z__J_ 



a'~~2' s' 

 The values of Q are strictly equivalent to each other in point of 

 activity. The author believes that a is commensurate with the elec- 

 tive function of chemical attraction, first discovered by Bergman. 

 He terminates the memoir with a reference to some well-known in- 

 stances of chemical action (such as that of argentic nitrate on a 

 mixture of aqueous potassic chloride, bromide, and iodide) as serving 

 to bestow a presumptive generality on his principal conclusions. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 76.] 



January 12th, 1870.— Prof. Huxley, LL.D., F.R.S., President, 



in the Chair. 



The following communications were read : — 



1. "On the Geological Position and Geographical Distribution of 

 the Reptilian or Dolomitic Conglomerate of the Bristol Area." By 

 R. Etheridge, Esq., F.G.S., Palaeontologist to the Geological Survey 

 of Great Britain. 



The author noticed the history of our knowledge of the Dolomitic 

 Conglomerates of the Bristol area from which the remains of Dino- 

 saurian Reptiles have been obtained, and then described their mode 

 of occurrence and distribution over the district near Bristol. He 

 regarded these deposits as due to the action of the sea -waves 

 of the later or Middle Triassic periods upon the rocks of older 

 Triassic (Bunter) or Permian age during the gradual elevation of 

 the land, and as the probable representatives in point of time of the 

 Muschelkalk, otherwise deficient in Britain. The author then 

 noticed the influence of the conglomerate upon the production of 

 certain minerals, such as calamine and hsematitic iron-ores, and 

 discussed at some length the probable course of the phenomena of 



