ADULTERATION OF POTASSA BY SODA. 
209 
After having determined these proportions, I endeavored to 
convert into bicarbonates, by carbonic acid, mixtures, ex- 
pressly prepared, of soda moistened with a solution of 
bicarbonate of soda ; but I found that not only was this 
object slowly attained, but that it could be only incom- 
pletely fulfilled in a simple manner. I could not satu- 
rate with carbonic acid a complete solution of these two 
mixtures in water, because it is necessary to drive off all the 
water of the solution in order to be able to separate from 
each other, by a concentrated solution of bicarbonate of 
soda, the crystallized salts obtained. 1 therefore tried, in 
order to avoid this inconvenience, to dissolve in a solution 
of bicarbonate of soda, saturated cold, new mixtures, (of 
100 grains) expressly prepared, of soda and potassa ; this 
operation likewise succeeded well, and nothing remained 
undissolved except the silica. 
I then passed for three days, a continued current of car- 
bonic acid into these solutions thus prepared, of mixtures of 
potassa and soda, to which I also joined a simple solution 
of potassa in the concentrated solution of bicarbonate of 
soda. 
The solution, which contained only potassa, presented, 
even at the end of several days' saturation by carbonic acid, 
no separation of bicarbonate of potassa or soda, and the li- 
quor had not undergone (at least in appearance) the slight- 
est change. 
A solution, which contained a mixture of 90 grains of 
potassa and 10 grains of anhydrous carbonate of soda, gave 
by a current of an excess of carbonate acid a crystalline 
precipitate of bicarbonate of soda, which collected on a fil- 
ter and pressed between folds of blotting paper, weighed, 
while damp, 19 grains; its weight was 14.6 grains after it 
had been completely dried at the ordinary temperature. 
A filtered solution of 80 grains of potassa and 20 grains 
of anhydrous carbonate of soda, treated in the same manner, 
gave 22.7 grains of bicarbonate of soda, pressed and still 
vol. x. — NO. III. 19 
