DRUMMOND, THOMAS (1797-1840), British inventor and administrator, was born at Edinburgh, on Oct. io, 1797, and was educated at the high school there. He was appointed to a cadetship at the Royal Military Academy, Woolwich, in 1813 ; and in 1815 he entered the Royal Engineers. In 1820 he received an appointment on the trigonometrical survey of Great Britain. In 1825, when he was assisting T. F. Colby in the Irish survey, his lime-light apparatus ("Drummond light") enabled observations to be completed between Divis mountain, near Belfast, and Slieve Snaght, a distance of 67 miles. About the same time he also de vised an improved heliostat, and in 1829 he was employed in adapting his light for lighthouse purposes. In 1835 he was made under-secretary of State for Ireland, where he proved himself a most successful administrator. It was he who in 1838 told the Irish landlords that "property has its duties as well as its rights." In 1836 he proposed the appointment of a commission on railways in Ireland, and took a large share in its work. Drummond died at Dublin on April 15, 1840.
See J. F. M'Lennan, Life of Thomas Drummond (1867) ; R. Barry O'Brien, Life and Letters of Thomas Drummond (1889).