of Chemical Equivalents. 
The next question that occurs relates to the composition 
of this crystallized carbonate of potash, which I am induced 
to call bi-carbonate of potash, for the purpose of marking 
more decidedly the distinction between this salt and that 
which is commonly called a subcarbonate,* and in order to 
refer at once to the double dose of carbonic acid contained in 
it. With reference to carbonate of lime also, I must neces- 
sarily consider it as a supercarbonate, for if I add a solution 
of this salt to a neutral solution of muriate of lime, a consi- 
derable effervescence takes place, from a redundance of car- 
bonic acid beyond what is necessary to saturate the lime. If 
I saturate 125,5 of this salt with nitric acid, taking due pre- 
cautions not to expel any of the fluid along with the gas which 
escapes, it loses about 55 of carbonic acid, which is the double 
27,5. But if, previous to the saturation, I heat the salt 
moderately red, it loses 38,8, consisting of 27,5 carbonic acid 
and 11,3 water, after which the addition of an acid expels only 
27 j 5. or a single dose of carbonic acid.'f 
I have in this experiment made use of nitric acid, in order 
that the resulting compound might guide me in the selection 
from among former estimates which are extremely discord- 
ant with regard to the equivalent of that acid. The proportion 
of nitrate of potash, which I have obtained by evaporating 
such a solution by a heat just sufficient to fuse the residuum, 
gave at the lowest in three experiments 1 26*, for the equiva- 
lent of nitrate of potash; from which, if we deduct 59,1 potash, 
* I avoid using the term carbonate of potash for either of these salts, because it 
has been applied to both, and consequently is liable to be misunderstood when stand* 
ing alone. 
f Phil, Trans. 1808, p. 97. 
Ca 
