Dictionary of National Biography, 1885-1900/Duff, James (1752-1839)
DUFF, Sir JAMES (1752–1839), general, only son of Alexander Duff of Kinstoun, N.B., entered the army as an ensign in the 1st or Grenadier guards on 18 April 1769. He was promoted lieutenant and captain on 26 April 1775, and made adjutant of his battalion in 1777, and on 30 April 1779 he was knighted as proxy for the celebrated diplomatist Sir James Harris, afterwards first earl of Malmesbury, at his installation as a knight of the Bath. He was promoted captain and lieutenant-colonel on 18 July 1780, colonel on 18 Nov. 1790, and major-general on 3 Oct. 1794, and in 1797 received the command of the Limerick district. While there he rendered important services during the insurrection of 1798, and managed to keep his district quiet in spite of the state of affairs elsewhere. He was promoted lieutenant-general on 1 Jan. 1801, and general on 25 Oct. 1809, and at the time of his death, at Funtington, near Chichester, on 5 Dec. 1839, he was senior general in the British army, and was one of the few officers who held a commission for over seventy years. It is noteworthy that he had as aides-de-camp during his Limerick command two famous officers, William Napier [q. v.] and James Dawes Douglas [q. v.] There are numerous allusions to him in the 'Life of Sir William Napier.'
[Royal Military Calendar; Gent. Mag. March 1840; Life of Sir William Napier.]