(b. Upcott, near Chudleigh, Devon, England, 3 December 1742; d. London, England, 29 March 1830)
Rennell, the son of an artillery officer, entered the Royal Navy in 1756 and served in the East Indies from 1760 to 1763. During this period he prepared charts of several harbors, having learned surveying on the voyage out from England. He then left the navy and in 1764 was appointed surveyor by the East India Company, first making a survey of the Ganges and then a general survey of Bengal. In 1767 the company made him surveyor general. In 1777, suffering from ill health after wounds received in an affray with a band of fakirs, he returned to England with instructions to prepare a map of India from material at India House, London. He devoted the rest of his life to geographical research, maps, and memoirs.
Rennell was elected fellow of the Royal Society in 1781 and in 1791 was awarded its Copley Medal. He studied the works of classical geographers and wrote a commentary on Herodotus. He also acted as geographical adviser to the African Association, which was founded in 1788, and was rightly regarded as the most eminent British geographer of his period.
In addition to his regional work on Asia and North Africa, Rennell made several important contributions to physical geography. His detailed account of the Ganges, read to the Royal Society in 1781, was drawn on by James Hutton, John Playfair, and Lyell in their geological works. His work on ocean currents, which consisted of various papers from 1793 on and culminated in a posthumous book, An Investigation of the Currents of the Atlantic Ocean… (1832), was used by many subsequent writers. Humboldt visited Rennell in 1827 and consulted him on the subject of currents, and Rennell’s map of the currents of the Atlantic appeared in several well-known atlases.
I. Original Works. Rennell’s principal works are A Bengal Atlas (London, 1779); Memoir of a Map of Hindoostan (London, 1783; 2nd ed., 1792; 3rd ed., 1793), with a map of all India dated 1782 and published separately; The Geographical System of Herodotus Examined and Explained… (London, 1800); and An Investigation of the Currents of the Atlantic Ocean… (London, 1832).
II. Secondary Literture. A detailed account of Rennell and his work in India is R. H. Phillimore, Historical Records of the Survey of India, I, (Dehra Dun, India, 1945), 369–378. A well-documented assessment of his geographical work, with bibliographical details and corrections of the errors of earlier authors, is J. N. Baker’s “Major James Rennell, 1742–1830, and His Place in the History of Geography,” in The History of Geography (Oxford, 1963), 130–157.
Joan M. Eyles
James Rennell, 1742–1830, English cartographer, geographer, and oceanographer. He was surveyor general (1764–77) of Bengal and published A Bengal Atlas (1779). He constructed the first approximately correct map of India (1783). A specialist on the geography of W Asia and of North Africa, he wrote on the geographical knowledge of Herodotus (1800), on the topography of the plain of Troy (1814), and on Xenophon's retreat (1816). He was a pioneer in the scientific study of winds and of ocean currents.