OF SEA-WATER. 243 



to the end of it, and the muriate of soda would be depo- 

 sited in the same manner ; so that the proportion between the 

 two would continue nearly the same. But if the sulphate of 

 lime did not exist in solution, but derives its origin from the 

 action of sulphate of soda on muriate of lime, which these 

 brines contain, this action would take place, when a certain 

 degree of concentration of the liquor had been attained ; the 

 sulphate of lime would then be copiously deposited ; but as 

 the evaporation continued to proceed, its quantity would be di- 

 minished, as the quantity either of sulphate of soda, or of mu- 

 riate of lime, became less ; and its deposition would cease 

 when either of these salts was exhausted. 



This is placed in a still clearer light, by an analysis of these 

 brines, after evaporation, to a certain extent, compared with 

 their original composition. A brine from Northwich was 

 found by Dr Henry to afford, by evaporation, saline matter, 

 which, he inferred, contained in 1000 parts, muriate of lime 

 and muriate of magnesia in nearly equal proportions 5 parts, 

 sulphate of lime 19 parts, muriate of soda 974 parts. But the 

 brine remaining after the separation of all the common salt, 

 which it is thought worth while to extract, afforded saline mat- 

 ter by evaporation, which he found to contain, in 1000 parts, 

 muriate of magnesia 35, muriate of lime 32, sulphate of lime 6, 

 muriate of soda 927. Here, in the progress of the evapora- 

 tion, the quantity of sulphate of soda, which may be consider- 

 ed as an original ingredient of the brine, had been diminished 

 by the decomposition arising from its action on the muriate of 

 lime. The liquor, therefore, after this, afforded by farther 

 evaporation, along with a large quantity of muriate of lime, a 

 small quantity only of sulphate of lime ', while, if this sulphate 

 had been an original ingredient, it would have continued to be 

 afforded at least in equal proportion. 



H h 2 Something 



