206 ADULTERATION OF POTASSA BY SODA. 
test acid, to obtain immediately the indication in hundredths 
of the proportion of soda contained in potassa. 
A anhydrous carbonate of Contains the following num- 
potassa, 100 grains of bers of hundredths of an 
which require, for their hydrous carbonate of so- 
neutralisation, the follow- da : — 
ing quantities of dilute sul- 
phuric acid (of the specific 
gravity of 1.0687), 
Although such a Table may serve for determining with 
sufficient accuracy for the object in question, and very 
promptly, the proportion of soda which might be found in 
a pure carbonate of potassa, it is not, however, applicable 
to testing the various kinds of potassa of commerce, espe- 
cially because all, even without being adulterated, contain 
different accidental mixtures, such as chloride of sodium, 
chloride of potassium, sulphate of potassa, silica, &c, and 
because, so long as we are unacquainted with the quantity 
of all these substances united, and have not subtracted 
them from the weight of the dry potassa, the preceding 
Table cannot be made use of with clearness ; for, admitting 
that a potassa contains, for example, 80 per cent, of carbo- 
nate of potasoa, 6.7 per cent, of accidental impurities, and 
13.3 per cent, of anhydrous carbonate of soda, this potassa 
should, according to this Table, be regarded as pure and dry 
carbonate of potassa, for the 1 3.3 of anhydrous soda found in 
it would require for their neutralisation nearly as much alka- 
limetric test-acid as 20 of pure and dry carbonate of potassa. 
1000 
1025^ 
1051 
1102 
1127§ 
1255 
1382 
1510 

5 
10 
20 
25 
50 
75 
100 
