of British and Foreign Salt . 117 
lime, the presence of alkaline sulphates was investigated in 
the following manner. The salt was dissolved in water, and 
the solution was divided into two equal portions. To the one 
muriate of barytes was added, and to the other, the compound 
precipitant of carbonate of ammonia, and phosphate of soda. 
If the sulphate of barytes, thus produced, bore to the amrao- 
niaco-magnesian phosphate, the proportion of 112 to 90, it 
was concluded that no other sulphate had been decomposed, 
but that with base of magnesia. 
(H.) At one time, I expected to have ascertained the quan- 
tity of sulphate of soda, in an artificial mixture of that salt 
with sulphate of magnesia and muriate of soda, by the fol- 
lowing formula. To a solution of the three salts, heated to a 
boiling temperature, I added sub-carbonate of ammonia, which 
decomposes the sulphate of magnesia only. I had then a so- 
lution containing muriate and sulphate of soda, with sulphate 
of ammonia, and some carbonate of ammonia. This solution 
was evaporated to dryness, and the mass was sufficiently 
heated to expel the ammoniacal salts. I found, however, that 
at this temperature, the sulphate of ammonia acted upon the 
muriate of soda, and produced an additional, and not inconsi- 
derable quantity of sulphate of soda. 
Having determined, by the foregoing processes, the quan- 
tity and kind of the earthy muriates, the amount of the inso- 
luble matter, and the proportion of sulphates, the weights of 
all these different impurities were added together, and the sum 
being deducted from the weight of the salt submitted to ex- 
periment, the remainder was assumed as the amount of the 
pure muriate of soda in the specimen under examination.* 
# I have deemed it unnecessary to state, in the. table, the quantities of acid and 
