1 2 jin Analysis of Sea-water ; 



Lavoisier's analysis has been considered as incorrect in two 

 circumstances, — in the finding muriate of lime, and sulphate of 

 soda. Neither of these has been discovered by other chemists ; 

 and in a late analysis of sea-water by Vogel and Lagrange, one 

 of the objects of experiment was to detect their presence, and 

 the conclusions drawn were, " that sea-water contains no sul- 

 phate of soda," and " no muriate of lime." In this analysis 

 the saline ingredients found in sea-water were the same as those 

 assigned bv IBergman, with the addition of sulphate of magnesia. 

 In 1000 grammes there were found 25*10 grammes of muriate 

 of soda, 3*5 of muriate of magnesia, 5'78 of sulphate of mag- 

 nesia, 0*20 of carbonate of lime and magnesia, and 0*1 5 of sul- 

 phate of lime*. 



Some other recent analyses have been given ; that by Lich- 

 tenbergh is noticed by Vogel and Lagrange, from a German 

 journal, as approaching to their own ; and that of Pfaff, in which, 

 as in Lavoisier's analysis, there is foimd a portion of muriate of 

 lime. 



It is obvious, that there remains a degree of uncertainty with 

 regard to the ingredients of sea-water, sufficient to give interest 

 to a new analysis. The principle, too, which I have illustrated 

 in a preceding paper, on the Analysis of Mineral Waters, — that 

 the substances obtained are not always to be regarded as the 

 original ingredients, but freijuently as products of new combina- 

 tions established by the analytic operations, may contribute to 

 throw light on the conclusions to be drawn, and seemed to me 

 to admit of being applied to the explanation of some of the pre- 

 ceding results. This led to the experiments of which I now pro- 

 pose to give an account. 



The peciiliarity in the results of Lavoisier's analysis, and with 

 regard to which the others differ from him, is the obtaining, as 

 ingredients of sea-water, portions of sulphate of soda and muri- 

 ate of lime. Applying the principle now referred to, it is ob- 

 vious that, in an an-ilysis by evaporation, the composition of 

 these salts would be subverted by their reciprocal action ; neither 

 of them would be obtained ; but by mutual decomposition they 

 would be converted into muriate of soda, and sulphate of lime. 

 Sulphate of lime is accordingly obtained in all these analyses, 

 and probably has this origin. 



But, admitting this, how had muriate of lime, and sulphate of 



soda, been procured by Lavoisier ? This, supposing the result 



accurate, can only be ascribed to some peculiarity in his process, 



bv which their mutual action had been prevented, and their di- 



tinct exiijtence preserved. The method he employed was to 



* Thomson's Annals, vol. iv. p. 200. 



evaporate 



