Major James Rennell (3 December 1742 – 29 March 1830) was an English geographer, historian and a pioneer of oceanography. Rennell produced some of the first accurate maps of Bengal at one inch to five miles as well as accurate outlines of India and served as Surveyor General of Bengal. Rennell has been called the Father of Oceanography. In 1830, he was one of the founders of the Royal Geographical Society in London.
Early life
Rennell was born at Upcot near Chudleigh in Devon. His father, John Rennell, an officer in the Royal Artillery, was killed in action in the Low Countries in July 1747 during the War of the Austrian Succession. The ancient paternal Devonshire family name was formerly spelt Reynell and was of French origin.
Rennell entered the Royal Navy as a midshipman at the age of fourteen<!--NB Born in December 1742, I have the same problem--> under Captain Hyde Parker, who was in the process of commissioning the frigate (launched in October 1757) at the beginning of the Seven Years' War.
In 1763, at the end of the Seven Years' War, seeing no chance of promotion, Rennell entered the service of the East India Company's sea service. He at once received command of a vessel of two hundred tons; but it was destroyed by a hurricane in Madras Roads in March 1763. Fortunately, his captain was on shore, and he was at once appointed to command a small yacht called the Neptune, in which he executed surveys of what is now called the Palk Strait and the Pamban Channel. Rennell became a good friend of the Governor of Madras, Robert Palk, who also came from Devon. His next cruise was to Bengal, and he arrived at Calcutta at a time when Governor Vansittart was anxious to initiate a survey of the British territory. Owing to the friendship of an old messmate Mr Topham, who had become the governor's secretary, he was chosen for survey duties and was initially commissioned as an ensign in the Bengal Engineers, dated 9 April 1764.
Survey work in India
thumb|upright=1.3|left|Map of Hindoostan, 1782
Rennell initially surveyed the Ganges river starting in the autumn of 1764, encountering in 1766 the mountains that he called the Tartarian mountains (the Himalayas). The main purpose of the survey was to find a navigable waterway from Calcutta to the northern regions. In the same year Captain Rennell was nearly killed when the party of surveyors were attacked by sanyasis on the Bhutan border. Injured badly in the shoulder blade, he was taken by boat to Dacca, a journey that took six days. He was treated by Dr Francis Russell and was fortunate to recover although he never gained full function of his right arm. On return Rennell's work was much appreciated and he was recommended for a handsome salary of £1000 a year. Rennell immediately sent money home to his mother and sister while also showing gratitude by sending gifts to Rev. Burrington's children. In 1767 Lord Robert Clive, the then Governor of Bengal and Bihar, appointed him as surveyor-general of the East India Company's dominions in Bengal. After this Rennell was always accompanied by a company of Sepoys. Economic pressures further forced a reduction in pay and there was dissatisfaction among the native ranks on the question of double batta (part payment). The surveys were sometimes dangerous, a party of his men were attacked by a leopard and Rennell had to use his bayonet to save his men. Malaria was common and in 1771 he was briefly diverted to military duties in an expedition against a band of raiders. The mapping project was originally a general survey of newly acquired lands, but the job soon gained a wider scope under Warren Hastings, who was appointed as Governor-General in 1773. One of Hastings' first projects was to begin a Domesday-style reckoning of property, land, people, and culture for taxation of revenue. As for Rennell's part in this, his project was carried out much like a military survey, searching for safe passage through territory, with information gathering a secondary object. Rennell received the rank of major of Bengal engineers on 5 April 1776, and retired from active service in 1777. The government of Warren Hastings granted him a pension of £600 per annum, which the East India Company somewhat tardily confirmed..
The remaining fifty-three years of his life were spent in London, and were devoted to geographical research chiefly among the materials in the East India House. He took up his residence in Suffolk Street, near Portland Place, where his house became a place of meeting for travellers from all parts of the world. the Comparative Geography of Western Asia (1831), and important studies on the geography of northern Africa—apparent in introductions to the Travels of Mungo Park and Hornemann. He also contributed papers to Archaeologia on the site of Babylon, the island of St Paul's shipwreck, and the landing-place of Caesar in Britain. Rennell published a book titled Memoir of a map of Hindoostan (1788) and dedicated to Sir Joseph Banks.
left|thumb|380px|Map of the currents in Atlantic and Indian Ocean around Africa, created by James Rennell in 1799. Amazing is the accuracy of the marine currents and winds in contrast to the nearly fantasy-like depiction of the inner parts of Africa (unknown to the Europeans until 1877).
Beside his geographical and historical works, James Rennell is known today for his hydrographical works on the currents in the Atlantic and Indian oceans. He started his research on these topics when he was travelling by a sailing ship with his family from India to Britain after his retirement in 1777. During the extraordinary prolonged voyage around the Cape of Good Hope he mapped "the banks and currents at the Lagullas" and published in 1778 the work on what is today called the Agulhas Current. This was one of the first contributions to the science of Oceanography. He was the first to explain the causes of the occasional northern current found to the south of the Isles of Scilly, which has since been called as Rennell's Current.
He was elected a fellow of the Royal Society in 1781; and he received the Copley Medal of the Royal Society in 1791, and the gold medal of the Royal Society of Literature in 1825. and for his pioneering work on oceanography as the Father of Oceanography.
In later life Rennell suffered from gout and in 1829 he fell from a chair and broke his thigh. He died on 29 March 1830 at his home on Suffolk Street. He was interred in the nave of Westminster Abbey, and there is a tablet to his memory, with a bronze bust by Ludwig Hagbold, near the western door. The year of his death saw the foundation of the Royal Geographical Society.
In 1851, botanist Pieter Willem Korthals published Rennellia, a genus of flowering plants from Indo-China and western Malesia, belonging to the family Rubiaceae and it was named in James Rennell's honour.
Controversy
James Rennell is credited with the original mapping of the Mountains of Kong, supposedly located in the western part of Africa, based on information supplied by explorer Mungo Park. This range was intended to support his own theory on the course of the Niger River, and eventually led to a major impact on the mapping industry to include the mountains. In 1802, Aaron Arrowsmith released a map that included the Mountains of Kong as a main physical geographic feature of western Africa, which encouraged other publishers to update their maps to match.
Debate surrounding the existence of the mountain range occurred frequently, however, it was French officer and explorer Louis-Gustave Binger officially reported that the Mountains of Kong did not exist during an expedition in 1887-1888.
While at Dacca, Rennell became a close friend of John Cartier. It was in Cartier's home that he met Jane Thackeray (d. 1810), daughter of Dr Thomas Thackeray, headmaster of Harrow, and a great-aunt of the novelist William Makepeace Thackeray and he married her in 1772. Their older son Thomas (born 1779) died unmarried in 1846, while the second son William (born 1781) worked in the Bengal civil service and died in 1819 without leaving any children. One daughter named Jane (born 1773) died young and was buried in Dhaka, whilst another daughter, also Jane, born in 1777 on St Helena where he had stopped on his way to England married Admiral Sir John Tremayne Rodd, KCB in 1809. Lady Rodd devoted several years publishing her father's current charts and revising new editions of his principal works. She died in December 1863.