MUTUAL DECOMPOSITION. 
74 
Decomposi- 
tion of some 
invaluable 
salts by carbo- 
nates of 
alkali. 
Deduction. 
AH insoluble 
salts are so 
decomposable. 
Carbonate of 
potash decom- 
posed sulphate 
of barytes ; 
but the whole 
carbonate ; did 
not act. 
sons would be capable, of all the direct observations which would 
be requisite to ascertain them. The considerations which have 
led me to a solution of this problem, being a continuation of 
the theory of the decompositions of the insoluble salts by the 
soluble carbonates, I shall begin by submitting to the judgment 
of the Class, the results of my inquiries upon that subject. 
Concerning the action of the soluble Carbonates on the insoluble 
Salts. 
If we examine all the analyses which have been made during 
the last twenty years, it will be seen that a great number of 
insoluble salts have been decomposed, either by the carbonate 
of potash, or by the carbonate of soda. I myself have ascer- 
tained by direct experiments, the decomposition of a great 
number of those which had not been examined with that view 5 
and it may be, therefore, concluded from a well-founded 
analogy, that all the insoluble salts may be decomposed by the 
two carbonates I have, mentioned. Some chemists have named 
as exceptions to this rule, the phosphate of lime and the fluate 
of the same base ; but I am convinced that this latter when free 
from silex, is decomposed like all the others. And so likewise 
is the phosphate of lime : except that it offers a peculiarity 
which I shall notice, and which may have misled those who 
have denied the possibility of its being decomposed. But the 
soluble carbonates present, in their reaction on the insoluble 
salts, phenomena which belong to no other kind of salts, and 
have not yet been observed j these are the phenomena I intend 
to describe. 
Experiment A. A solution of 15 grammes of carbonate of 
potash in 500 grammes of water, together with 15 grammes of 
sulphate of barytes reduced to an impalpable powder, was kept 
boiling for several hours. It formed a certain quantity of 
carbonate of barytes $ and as the liquor when filtered still pro- 
duced a strong effervescence with the acids, it was boiled a 
second time with a fresh quantity of sulphate of barytes 5 but 
though the boiling was continued for a length of time, it did 
not form any more of the carbonate of barytes. 
The 
