1819.] and on some other Subjects of Chemical Theory. 293 
first part of this memoir, independent of the explanation of it 
from the formation of a super-muriate. A compound may be 
formed with less oxygen and hydrogen than what exist in 
muriatic acid, in combination with the metal acted on, and thus 
a portion of water may be liberated. Nor will it be easy to 
establish this by any difference in the product, as it can scarcel 
be submitted to any examination, but by processes whic 
change the result. The chloric acid which, according to Gay- 
Lussac, cannot exist insulated without water, may be in like 
manner a ternary compound of these elements in other propor- 
tions. Prosecuting the same analogy, the glacial, or fuming oil 
of vitriol may be, not what has lately been asserted, real sulphuric 
acid (for probably no such substance as that to which this term 
has been applied can be obtained insulated), but a compound of 
sulphur with oxygen and hydrogen, in proportions different from 
those which constitute common oil of vitriol. Nitrous acid, if 
it cannot be formed without water, may be a compound of 
nitrogen with a smaller proportion of oxygen and hydrogen than 
nitric acid. And some of the acids lately described, of which 
phosphorus is the base, may arise from variations of proportions 
of this kind. 
The view which I have now illustrated, I must add, is not to 
be regarded as mere speculation. The evidence in support of 
it is just as conclusive as that from which the opposite opinion is 
inferred. The obtaining water from a compound is no necessary 
proof that water pre-existed in it; and conversely, the causing 
water to enter into combination in a compound is no necessary 
proof that it remains in the state of water in the product. In 
many cases we draw the reverse conclusions, considering water 
as being formed where it is obtained, and as decomposed where 
it is communicated. And in the case of its relation to acids, it 
will be found that there is no strict evidence of its existing as 
water in combination with what is considered as the real acid ; 
and of course the conclusion is equally open to be drawn, that it 
exists in these combinations in the state of its elements, and 
that when obtained, it is a product of a change of composition. 
It is even more probable, a prior?, that the ultimate elements 
should act on each other where energetic affinities are evidently 
exerted, than the immediate principles, and the relations of 
these elements will determine the combinations and the propor- 
tions. And by admitting this view, we avoid the anomaly which 
is etal in ascribing to the agency of water effects so 
different from those to which it usually gives rise. In general, 
water operates on bodies simply as a solvent, overcoming cohe- 
sion in solids, diluting liquids, or absorbing gases, w'thout 
otherwise modifying their properties, or communicating to them 
any - rec chemical powers. - But in the particular cases 
now referred to, it is supposed to produce the effects of the 
most energetic chemical agent; it enters into combination in 
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