All the phænomena of chemistry concur in proving, that the affinity of
one body, A, for another, B, is not destroyed by its combination with a
third, C, but only modified; either by condensation, or expansion, or
by the attraction of C for B.
On this principle, the attraction of compound bodies for each other
must be resolved into the reciprocal attractions of their constituents,
and consequently the changes produced in them by variations of
temperature explained, from the alterations produced in the attractions
of those constituents.
Thus in nitrate of ammoniac, four affinities may be supposed to exist: