1 6 An Analysis of Sea-water ; 



were perfectly pure. Their solutions became turbid on the ad- 

 dition of sub-carbonate of soda, and of muriate of barytes, indi- 

 cating the presence of sulphate of magnesia, or of muriate of 

 magnesia and sulphate of soda, and probably indeed of portions 

 of all these. The whole was submitted to the action of highly- 

 rectified alcohol for twelve hours, with repeated agitation ; the al- 

 cohol acquired a bitter taste ; being poured off, and distilled, it 

 afforded muriate of magnesia, which, heated with sulphuric acid, 

 gave a product equivalent to 6'2 of real muriate. The residual 

 salt still gave indications of the presence of sulphate of magnesia, 

 bv the tests of muriate of barytes and sub-carbonate of soda. 

 The difficulty is so great, of separating a small portion of a salt 

 from a large quantity of another, where the difference in their 

 solubility is not considerable, that instead of attempting to re- 

 move the sulphate of magnesia by further crystallizations, it was 

 decomposed by adding to the solution sub-carbonate of soda; 

 the precipitate was collected, and converted into sulphate of 

 magnesia by the addition of sulphuric acid. This, dried at a low 

 red-heat, weighed 16 grains, equivalent to 33 crystallized. The 

 salt had been previously exposed to a red- heat, when it weighed 

 744*5 grains. The above quantity of sulphate abstracted from 

 this, leaves as the real quantity of muriate of soda 728*5 grains. 



The powder G was soft, light, and tasteless. It weighed 

 when thoroughly dried 7*5 grains. It might be expected to be 

 similar to the powder A, and was therefore subjected to the same 

 treatment. Diluted alcohol, acidulated with muriatic acid, ex- 

 cited effervescence ; the liquor poured off afforded by evapora- 

 tion muriates equivalent to 2*8 of carbonate of magnesia, and 

 1 -3 of carbonate of lime. And the remaining sulphate of lime 

 dried, weighed 3 grains. 



By this analysis, then, the substances obtained from 4 pints 

 of sea-water, and their proportions, are as follow : 



Muriate of soda, .. .. 728*5 grains. 



Muriate of magnesia real, 83*5 



97 



6*2 



99*4 99-4 



Sulphate of magnesia crystallized, 6*3 



8*9 

 33 



48*2, or real, 23*5 

 Sulphate of soda crystallized, 18 



44-2 

 6 

 68-2, or real, 30*2 



Sulphate 



