with Observations on the Anahjsh of Salt-brines. 2i 



remained, which, when evaporated, gave a deliquescent saline 

 mass: by slow evaporation 2'6 grains of muriate of soda were 

 obtained from it ; the remainder yielded muriate of magnesia 

 equal to 3 grains. 



I. The crystals of sulphate of magnesia obtained by the suc- 

 cessive evaporations, were not all equally well formed ; and after 

 thev had been left exposed to a dry air for some time, some of 

 them became quite efflorescent, while others did not. The 

 former were j)icked out, and each portion was redissolved in 

 ■water. By a new crystallization, there were thus obtained 72 

 grains of sulphate of magnesia, and ISo of sulpiiate of soda. 



K. The muriate of soda obtained in the preceding steps 

 amounted in all to 759'6 grains. After exposure to a rerl-heat, 

 it weighed 7J2'4 grains. It has already been stated, that it 

 was not perfectly pure ; its solution being rendered milky, both 

 l)y sui)-carbonate of soda and muriate of barvtes. The separa- 

 tion of the sulphate of magnesia, which this chiefly indicated, 

 was not to be completely looked for by solution and crystalliza- 

 tion. Subcarbonate of soda was therefore added to the solution 

 as long as any precipitation took place; the precipitate, heated 

 with a sufficient proportion of sulphuric acid to redness, gave 

 16'4 sulphate of magnesia, equivalent to 33-7 of the same salt 

 crystallized. The former quantity abstracted from the weight of 

 the muriate of soda, reduces it to 736 grains. 



This analysis, then, affords the following ingredients, and 

 their proportions in their real state : 



Muriate of soda, . . . . 



Muriate of magnesia, 



Sulphate of magnesia, . . 



Sulphate of soda. 



Sulphate of lime, 

 Or, reducing them to a pint of the water. 



Muriate of soda. 



Muriate of magnesia, 



Sulphate of uiagnesia, . . 



Sulphate of soda, 



Sulphate of lime, 



227-() 

 By the two modes of analysis now stated, different results have 

 been obtained. There are common to both as the principal 

 products, muriate of soda, and muriate of magnesia. But in the 

 one, sulphate of magnesia, with only a small |)roportion of sul- 

 phate of soda, is procured. In the other, sulpiiate of soda in 

 u much larger quantity, with only an inferior proportion of sul- 

 phate of magnesia, is obtained. Mow is this diversity of re- 

 sult to be accounted for ? 



B3 As 



