on the Atomic Weights of Bodies. 269 



constituting the base of these saline bodies loses one half 

 of its heat when it unites with the acid. The quantity of 

 heat instead of being six times as great as in a simple atom 

 is only five times as great. At the same time, it must be 

 acknowledged, that the specific heats of these bodies are so 

 imperfectly determined that it may be too small in them 

 all, except sulphate of soda which seems to contain six 

 atoms each furnished with its normal cmantity of heat. 



The eight carbonates and magnetic iron ore at the end 

 of table seven are septenary compounds, or contain seven 

 simple atoms united together. Now, the mean number 

 which they give is 2-077. And 0-375 x 6 = 2-250. It 

 would appear from this, that binary bases lose half their 

 heat when they combine with acids ; while the acids part 

 with none of their heat. 



Table eight exhibits the products of the atomic weights 

 of five octenary compounds multiplied respectively into 

 their specific heats. The mean product is 2-977. Now, 

 0-375 x 8 = 3-500. Hence, it would appear, that all the 

 atoms entering into these compounds retain the heat with 

 which they were furnished when in an uncombined state. 



Our knowledge of the composition of the eight substances 

 constituting the ninth table is too imperfect to permit us to 

 pursue the investigation. I have added a fourth column, 

 shewing what multiples of 0-375 are obtained when we 

 multiply the atomic weight of each into its specific heat. It 

 might lead to some important conclusions respecting the 

 true constitution of these minerals. But as it would not 

 throw any additional light on the atomic weights of simple 

 bodies, I shall here terminate this paper, which has been 

 drawn out to a much greater length than I contemplated 

 at first. 



Article III. 

 Notice of the Parr. By Sir William Jardine, Bart.* 



The fishes inhabiting the rivers of Berwickshire are com- 

 paratively limited in the numbers of their species, but some 

 of them are of so much importance and value, while others, 

 as the little fish we are now about to notice, although 

 * Proceedings of thn Berwickshire Naturalists' Club, p. 82. 



