Mackintosh was soon absorbed in the question of the time; and in April 1791, after long meditation, he published his Vindiciae Gallicae, a reply to Burke's Reflections on the French Revolution.
By his Analysis of the Mind and' his Fragment on Mackintosh Mill acquired a position in the history of psychology and ethics.
In the midst of the attractions of London society and of his parliamentary avocations Mackintosh felt that the real work of his life was being neglected.
Mar never crossed the Forth, and the command of Mackintosh, who did, was captured, with his Northumbrian cavaliers, at Preston, on the very day (12th of November) when Argyll foiled Mar in the confused battle of Sheriffmuir.
In their anxiety to get back to the Cape Evans party, Mackintosh and Hayward attempted the journey on the sea-ice on May 8, but the ice was not strong enough and they were lost.