Rennell, James (1742-1830) geographer and marine engineer who made an exploration of the Bengal river basins and mapped them for the first time. Born in Devonshire, England, James Rennell joined the British navy in 1756. His father, John Rennell, was a captain in the artillery of the King's army. While in the navy Rennell received training in marine survey and engineering. Before he entered the service of the east india company in 1763, Rennell surveyed some harbours in the Philippines. To facilitate commercial navigation, henry vansittart, governor of the fort william, gave him a commission in Bengal Engineers of the company's army and entrusted him with the specific responsibility of making a survey of the major rivers of Bengal and their tributaries. After the company's acquisition of the diwani of Bengal, Bihar and Orissa (1765) the need for such a survey was more keenly felt. Governor robert clive thus established a regular survey department in 1767 with James Rennell as its Surveyor General.
By the time, of course, Rennell had largely completed his explorations of the Ganges, Brahmaputra and Meghna river-systems. Dhaka was his operational headquarters. Originally, Rennell was employed for only surveying the Ganges delta with the special objective of finding a shorter passage suitable for large vessels from the Ganges to Calcutta, than that through the sundarbans and the Meghna. His daily journal gives a detailed account of this voyage and of three subsequent expeditions, during which he surveyed greater part of northern and eastern Bengal, penetrating beyond Goalpara in Assam. It was while he was engaged on this duty on the frontier of Kuch Behar that he was attacked and severely wounded by a party of the rebellious followers of Fakir majnu shah. The incident possibly impelled Rennell to take a command of an expedition against the Fakir rebels in north Bengal in 1771.
Rennell records in his journal that in course of his explorations he was attacked by tigers, reptiles, dacoits and hostile people many times. Inadequately equipped though he was, he completed the survey within a span of three years with the help of only four assistants. His expeditions were so satisfactorily made that later the Survey of India found his identifications remarkably accurate. Rennell retired from the service with a pension in 1776 shortly after being promoted to the rank of Major in the Bengal Engineers. His Bengal Atlas, published in 1779, was a work of the highest importance from commercial, military and administrative points of view. To all users — academic, administrative and navigational, Rennell's Atlas was the dependable guide until professional maps were made available in mid 19th century. Rennell's second great work was the first approximately correct map of India. The map was accompanied by a Memoir (1783) containing a full account of the plan on which it was executed. He also constructed a map of northern Africa in 1790.
James Rennell was elected a Fellow of the Royal Society in 1781. In 1791 he received the Copley Medal of the Royal Society. Later he devoted all his time to the study of winds and ocean currents. Finally, he reduced all his observations and findings of his ocean studies into one general system which came to be known among the geographers as 'Rennell's Current'. He was made an Associate of the Institute of France in 1800, and in 1825 received the Gold Medal of the Royal Society of Literature. He died on the 29 March 1830, and was buried in the nave of the Westminster Abbey. [Sirajul Islam]