1882 H. Watts II. 8 [quoting Laurent and Gerhardt] We designate as conjugate compounds all such as are formed by the direct union of two bodies, with elimination of water, and are capable of reproducing the original bodies by again taking up the elements of water.
1882 H. Watts II. 10 Another class of acids to which the term conjugate is still sometimes applied, includes those which result from a peculiar action of sulphuric acid..on certain organic bodies.