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OF SEA-WATER. 293 
the evaporation be decomposed by the muriate of magnesia, 
and converted into the sulphate of magnesia; and hence, in. 
the subsequent solvent action of the alcohol, by which it is ob- 
tained, it must be re-formed. And, on the other hand, if -sul- 
phate of magnesiais the primary ingredient, and is obtained as 
such by the evaporation, it remains to be explained, how it is 
converted in the subsequent solution by the alcohol into sul- 
phate of soda. The whole question, therefore, resolves itself 
into the nature of the action of the alcohol, producing sul- 
phate of soda; and of this I perceive no other solution than. 
that which I have now to illustrate. 
The fact, however it is to be explained, or to be reconciled 
with the doctrine of chemical attraction giving rise to combi- 
nations or decompositions according to the strength with 
which it is exerted, seems to be established by an induction 
too strict and: extensive to admit of doubt, that these results. 
are often determined by the force of cohesion, in such a man- 
ner, that in principles acting on each other, those on which: 
this force operates most powerfully, in relation to the fluid 
which is the medium of action, are combined together. So. 
much is this the case, that, as Berruotter has justly remark- 
ed, we may, from a knowledge of the solubility of the com- 
pounds which substances form, predict what combinations 
will be established when they act on each other ; those always 
combining which form the least soluble compounds. | So far 
the influence of this has been illustrated by this able chemist. 
But it appears to me to admit of farther extension, so as to af- 
pre a solution of the present question. 
If the force of cohesion can so far modify heii attrac- 
tion, as to establish among compound salts dissolved i in any 
medium, those combinations whence the least soluble com- 
pounds are formed, we are entitled, I conceive, to conclude, 
that 
