Nine years afterwards he had an opportunity of presenting his brother-in-law Aulay Macaulay with the very pleasant living of Rothley.
Alexander, another son of John Macaulay, succeeded his father as minister of Cardross.

Colin went into the Indian army, and died a general.

He followed the example of the more ambitious among his brother officers, and exchanged military for civil duties.

In 1799 he acted as secretary to a political and diplomatic Commission which accompanied the force that marched under General Harris against Seringapatam.

The leading Commissioner was Colonel Wellesley, and to the end of General Macaulay's life the great Duke corresponded with him on terms of intimacy, and (so the family flattered themselves) even of friendship.
Soon after the commencement of the century Colin Macaulay was appointed Resident at the important native state of Travancore.