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Imperial Gazetteer of India, v. 4, p. 482.

482 THE INDIAN EMPIRE [CHAP. rough coast charts. In this map he also incorporated the work of certain Lamas between China and Tibet and around the sources of the Ganges, as well as the information derived from early travels of the eighteenth century in those parts. Major James Rennell, who had served under Clive, made a further advance both by his personal exertions in surveying, continued until 1782, and by the publication of his Memoir of a Map of Hindoostan, which first appeared in I788. His Bengal Atlas, based on his own work, was published in I78S, on the scale of five miles to the inch, covering an area of about 27,000 square miles in Bengal, Bihar, and the Upper Provinces. The value of this map is now only historical, but his large-scale surveys of the Ganges and Brahmaputra are still of interest as showing the changes which have taken place in the courses of those rivers. The method of surveying adopted by Rennell was to fix the positions of a considerable number of stations by astronomical observations for latitude and longitude, and to measure the intervening distances with the chain or with the 'measuring- wheel.' The correct determination of longitudes was his chief difficulty and although he utilized the results of the work of several independent observers at Madras, Calcutta, and else- where, his maps, judged by later standards, can only be con- sidered as approximations to accurate cartography. Rennell was certainly the 'Father of Indian Geography,' and his Memoir is a laborious attempt to reconcile a vast array of conflicting geographical data. His field-work was continued in Madras, the Deccan, and Western India by his assistants and successors, Colonels Call, Pearse, Wood, and Reynolds. As materials accumulated, attempts were twice made to compile a general map of India. In 1787 Colonel Call of Madras had nearly completed such an atlas in twenty sheets, but returning home in 1788, he died soon after, and his map was lost. Colonel Reynolds of Bombay completed and sent home a Great MJap of India, in 1798. It was never published, and was, presum- ably, destroyed on the dissolution of the East India Company. The Great But at the end of the eighteenth century a man was found in Trigono- India destined to revolutionize the survey methods then in vogue metrical Survey, and to place them on a scientific basis. This was William Initiated Lambton-then Captain in the 33rd Regiment, commanded by Colonel Lambton. by Colonel Arthur Wellesley, afterwards Duke of Wellington -who had studied mathematics under Charles Hutton. To- wards the close of 1799, Lambton, with the approval of his commanding officer, submitted a project for a geographical survey of Southern India to the Governor of Madras. In the