Lieutenant-Colonel William Lambton, FRS was a British soldier, surveyor, and geographer who began a triangulation survey in 1800-1802 that was later called the Great Trigonometrical Survey of India. After triangulating across the peninsula, he continued surveys northwards for more than twenty years and he died during the course of the surveys in central India and is buried at Hinganghat in Wardha district of Maharashtra. He was succeeded by his assistant George Everest, Lambton was born around 1753 at Crosby Grange, near Northallerton, in North Yorkshire, the son of a farmer. He was extremely reserved about the details of his family, even the year of birth is speculated on the basis of an incident he recounted of a dinner in Madikeri in 1803 hosted by Veer Rajender Wadeer, the ruler of the province of Coorg. The Coorg Raja made all present declare their age and Lambton is said to have mentioned his as fifty, for many years he spent a substantial portion of his salary to support his parents from which it has been suggested that he came from humble origins. He often mentioned a mathematics teacher at school by the name of Emerson and his skill in mathematics earned him a place in a grammar school at Northallerton, and he studied under Dr. Charles Hutton. On 28 March 1781, Lambton was appointed ensign in Lord Fauconbergs regiment of foot and he was commissioned in the 33rd Regiment, and his ability at surveying led to work on measuring land for settlers in America. He spent most of his earning to support his parents, with his regiment he took part in the American War of Independence and was taken prisoner at Yorktown. Observing a solar eclipse through the telescope of a theodolite without darkened glasses led to the burning of the retina of his left eye. After this accident he obtained with the help of his friends, especially Sir Brook Watson, an appointment as barrack-master in New Brunswick with a salary of 400 pounds per year. He had considerable leisure during which he was able to lay, in his words. the foundation of that knowledge and he was appointed barrack master in Nova Scotia and he spent many years studying mathematics on his own. In 1795 the Duke of York ordered that all civilian officers should be struck off from the regiments, Lambton then joined the 33rd at Calcutta after 13 years away from regimental duties. The 33rd Regiment was commanded by Sir Arthur Wellesley at Calcutta, in 1796, he was promoted to Lieutenant and posted with his regiment to India, under the leadership of Colonel Arthur Wellesley. He took part in the Fourth Anglo-Mysore War in 1799 and he was a brigade major during the Siege of Seringapatam where he led the left column after the fall of his superiors. After the capture of Mysore Lambton proposed to Wellesley that the territory be surveyed, Lambtons proposal to conduct the survey was nearly shot down by Major James Rennel who declared that it was not needed since Colonel Colin Mackenzie was already undertaking a similar survey. The proposal was examined by Nevil Maskelyne, Astronomer Royal. Maskelyne saw the value of the survey and pointed out to Rennel that he had been misinformed. Just around the time that Lambton got his survey approved by Lord Clive, a set of instruments along with Dr Dinwiddie had been sent to China but the Chinese Emperor had not shown interest and the equipment was returned
Lambton in 1822, based on an oil painting by William Havell now in the Royal Asiatic Society
Great Theodolite by Jesse Ramsden, similar to the one made by William Cary that was used by Lambton in the early surveys.