MITCHELL, Sin. THOMAS LIVINGSTONE (1792-1855), Australian explorer, was a son of Mitchell of Craigend, Stirlingshire, where he was born, June 16, 1792. From 1808 to the end of the Peninsular War he served in Wellington's army, and for his services received the medal and five clasps, and was raised to the rank of • major. He was appointed to survey the battlefields of the Peninsula, and his map of the Lower Pyrenees is still admired. .In 1827 he was appointed deputy surveyor-general, and afterwards surveyor-general, of New South Wales. He devoted himself to the exploration of Australia, making four expeditions for that purpose between 1831 and 1846. During these expeditions he discovered the Peel, the Namoi, the Gwyder, and other rivers, traced the course of the Darling and Glenelg, and was the first to penetrate into that portion of the country which he named Australia Felix. His last expedition was mainly devoted to the discovery of a route between Sydney and the Gulf of Carpentaria, and during the journey he explored the Fitzroy Downs, and discovered the Balonne, Victoria, Warrego, and other streams. In 1838, while in England, Mitchell published the narrative of his first three journeys, Three Expeditions into the Interior of East Australia (2 vols.). In 1839 he was knighted and made a D.C.L. of Oxford. During this visit he took with him some of the first specimens of gold and the first diamond found in the country. In 1848 the narrative of his second expedition was published in London, .Journal of an Erpedition into the Interior of Tropical Australia. In 1851 he was sent to report on the Bathurst gold-fields, and in 1853 he again visited England and patented his boomerang propeller for steamers. He died at his residence at Darling Point, Sydney, October 5, 1855.

Besides the above works, Mitchell wrote a book on Geographical and Military Surveying (1827), an Australian Geography, and a translation of the Lashed of Camoens.