OF SEA-WATER. 



233 



According to the first analysis, 



Muriate of Soda, - 188.3 grains. 



Magnesia, 16 



Lime, - 5.8 



Sulphate of Magnesia, 18.4 



228.5 



According to the second analysis, 



Muriate of Soda, - 185.6 



Magnesia, 15.2 



Lime, - 5.9 



Sulphate of Magnesia, 20.9 



227.6 



But this view rests on no principle, and is, as I have stated, 

 less probable than the other *. 



Vol. VIII. P. I. G g The 



*There is sometimes obtained in the large way, from the products of the 

 evaporation of sea-water, a triple salt, which has not been noticed by che- 

 mists, but which appears to be of definite composition, and is distinguished 

 by peculiar properties, — a Sulphate of Magnesia and Soda. It is formed in pu- 

 rifying the sulphate of magnesia procured by the first evaporation from the 

 bittern of sea-salt. In this process the sulphate, which is impure, both from 

 the intermixture of muriate of soda and muriate of magnesia, and perhaps, 

 also, of sulphate of soda, is dissolved in water, and by evaporation and cool- 

 ing is obtained crystallised ; a fresh quantity of it is added to the residual li- 

 quor, and by the necessary evaporation and cooling, a new crystallization is 

 produced -, this is repeated for a third or fourth time ; and it is in these latter 

 crystallizations that this triple salt is formed, frequently in considerable quanti- 

 ty, and usually at a high temperature, being precipitated even in the boiler. It 

 crystallises in rhombs, at first irregular and semitransparent ; but by solution in 

 water, and a second crystallization, is obtained in more regular rhombs, trun- 

 cated on the acute angles, on the obtuse angles and edges, and on the terminal 



edges, 



