wounded before Dunkirk. As senior lieutenant he commanded a company nearly all through the campaign of that year. His excellence as an officer became known to Thomas Graham of Balgowan, afterwards General Lord Lynedoch, who asked for his services when he was raising the Perthshire Light Infantry, better known as the 90th regiment. On 13 May 1794 Mackenzie was gazetted both captain and major into the newly formed regiment. With two such men as Graham and Hill as colonel and lieutenant-colonel, the 90th was soon fit for service, and was in the end of 1794 sent on foreign service, first to the Ile Dieu and then to Gibraltar. In 1796 it was chosen as one of the regiments to accompany Sir Charles Stuart to Portugal, and Mackenzie was made a local lieutenant-colonel and appointed to command all the flank companies of the various regiments as a battalion of light infantry. Sir Charles Stuart [q. v.] superintended Mackenzie's system of training and manœuvring, and made his battalion a sort of school of instruction for all the officers present with the army in Portugal. When Sir Charles Stuart went to Minorca in 1798, he took Mackenzie with him as deputy adjutant-general, and he was promoted lieutenant-colonel for his services at the capture of that island on 19 Oct. 1798. When Sir Ralph Abercromby succeeded Sir Charles Stuart in the command in the Mediterranean, Mackenzie was acting adjutant-general in Minorca, but he at once threw up his staff appointment to accompany his regiment in the expedition to Egypt. In the battle of 13 March the 90th regiment was more hotly engaged than any other corps and lost two hundred men in killed and wounded, and as Colonel Hill himself was wounded Mackenzie as senior major took the regiment out of action. In the battle of 21 March the 90th was also hotly engaged under the command of Mackenzie, and in recognition of his services he was appointed lieutenant-colonel of the 44th regiment before Alexandria in the place of Lieutenant-colonel Ogilvie, killed in that battle. He commanded that regiment in Egypt and then at Gibraltar until 1804, when the government determined to train some regiments as light infantry and summoned him to take command of the 52nd in camp at Shorncliffe. Sir John Moore was the general commanding the camp, and it was there that the famous light division of Peninsular fame was trained and disciplined. It is said that the new system was really the work of Mackenzie (Moorsom, History of the 52nd Regiment), though the spirit inspired was undoubtedly that of Sir John Moore. While at Shorncliffe Mackenzie was thrown from his horse and received so severe a concussion of the brain that he was obliged to go on half-pay, and unable to accompany his regiment to the Peninsula. He was, however, promoted colonel on 25 April 1808, and was in that year considered to be sufficiently well to accompany his old friend Graham to Cadiz, where he commanded a brigade for a short time until he was again obliged to return to England on account of his health. On 4 June 1811 he was promoted major-general, and soon after appointed to command all the light troops in England with his headquarters in Kent. In 1813 he accompanied Sir Thomas Graham to the Netherlands, and acted as governor of Antwerp after the surrender of that city during the peace of 1814, and throughout the campaign of 1815. He then retired to Hythe, where he had married, while in camp at Shorncliffe, Rachel, the only daughter and heiress of Robert Andrews of that place, and where he took a keen interest in local affairs and became a jurat. Mackenzie was promoted lieutenant-general on 19 July 1821, and made colonel of the 58th regiment on 1 March 1828. He was created a baronet ‘of Glenbervie’ on 30 Sept. 1831, and took the name of Douglas instead of his own by royal license on 19 Oct. 1831. He died at Holles Street, Cavendish Square, on 22 Nov. 1833, and was buried at Hythe.
[Royal Military Calendar, 3rd ed. iii. 181–5; Moorsom's History of the 52nd Regiment; Wilson's History of the Expedition to Egypt; Gent. Mag. April 1834.]
DOUGLAS, Lady MARGARET, Countess of Lennox (1515–1578), mother of Lord Darnley, was the daughter of Margaret Tudor, daughter of Henry VII, and queen dowager of James IV, by her second marriage to Archibald, sixth earl of Angus [q. v.] She was born 8 Oct. 1515 at Harbottle Castle, Northumberland, then garrisoned by Lord Dacre, her mother being at the time in flight to England on account of the proscription of the Earl of Angus (Dacre and Magnus to Henry VIII, 18 Oct. 1515, in Cal. State Papers, Hen. VIII, vol. ii. pt. i. entry 1044; and in Ellis, Historical Letters, 2nd ser. i. 265–7). The next day she was christened by the name of Margaret, ‘with such provisions as couthe or mought be had in this baron and wyld country’ (ib.) In May she was brought by her mother to London and lodged in the palace of Greenwich, where the young Princess Mary, four months her junior, was also staying. In the following May she accompanied her mother to Scotland, but when her parents separated three years afterwards, Angus, recognising the importance of having a near heiress to both thrones under his own authority, took her