18 
MUTUAL DECOMPOSITION'. 
Mutual dc- 
compu-siticns 
of tlie insolu- 
ble neutial 
salts, &CC. 
employed in experiment C. contained equal quantities of car- 
bonic acid, the ponderable masses of potash and of soda, which 
enter into the composition of those salts, were therefore in in- 
verse ratio to their capacity of saturation ; and, as these two 
alkalies were likewise in the same state of saturation, their 
I 
effect ought to be the same if the affinity was exactly propor- 
tioned to the capacity for saturation ; for, whatever may be, in 
this case, the circurfistances which modify the affinity, as they 
are perfectly identical as to both, the results ought to preserve 
their equality. Nevertheless, the quantities of the sulphate 
of barytes, which is decomposed, or, what is the same th ing, 
the quantities of sulphuric acid taken up by the potash or the 
soda, in this experiment, are nearly in the relation of 6 to 5.’ 
The experiment (E) also confirms this result. The quantities of 
potash and of soda are likewise found to be in the inverse 
ratio of the capacities for saturation. The circumstances were 
the same on both sides, and the ponderable masses of acid 
retained by those two alkalies, are likewise in the same pro- 
portion. If the analysis upon which the proportions depend, 
were perfectly accurate, we should be forced to admit, that the 
affinities of these two alkalies is not exactly proportioned to 
their capacity for saturation. 
The re-action of the soluble salts of potash and of soda upon 
the insoluble carbonates, considered as a general property that 
is applicable to all the salts which unite the condition already 
mentioned, will furnish, in several instances, much shorter, 
and more exact means of analysis, than those which result from 
the facts already known : but there may be deduced from the 
theory which I have explained, a more important application, 
which I shall only/point out at present, because it ought to form 
the subject of a second memoir. 
After having ascertained, by direct experiments, the recipro- 
cal decomposition of a great number of soluble and insoluble 
salts, I have sought for the explanation of this phenomenon, 
and the means of foreseeing the results. The analogy founded 
upon the corresponding phenomena which took place between 
the soluble salts, naturally led me to consider the various de- 
grees 
