ON SULPHATE OF POTASH. 
29 
nearly all dissolved, the further additions of distilled water 
were made very gradually, and care was taken to preserve 
the temperature precisely at 60°. The solution being 
completed, the vial with its contents was weighed, and it 
was found that 69S grains of water had been added to the 
salt. 
Exp. 2. — A similar quantity (60 grains) of the same 
specimen of sulphate of potash, was put into ano-ther vial, 
together with thirty grains of sesquicarbonate of soda. 
The solution of these salts was effected in the same man- 
ner as in the previous case ; and it was found that 528 
grains only of water was required for the solution. 
Exp. 3. — Into another vial was put 60 grains of sulphate 
of potash and 30 grains of bicarbonate of potash; and, the 
solution being effected as before, 805 grains of water was 
found to have been required for that purpose. 
Exp. 4. — On dissolving 30 grains of the specimen of ses- 
quicarbonate of soda, used as above, it was found to re- 
quire 352 grains of water for its solution; and the same 
quantity of the bicarbonate of potash took 105 grains of 
water for its solution. 
In all these cases a period of six hours was occupied in 
effecting the solution. 
Thus, then, it, appears, that in operating as described 
above, one part of sulphate of potash requires 11.63 parts 
of water for its solution at 60° ; whereas, one part of sul- 
phate of potash, mixed with half its weight of sesquicar- 
bonate of soda, is soluble in 8.74 parts of water at the 
same temperature. It appears also that whilst the presence 
of sesquicarbonate of soda increases the solubility of sul- 
phate of potash, a contrary effect is produced by the 
presence of bicarbonate of potash, the same amount of 
water being necessary in the latter case, as the two salts 
would require for their solution separately. 
3* 
