Everest's three-foot theodolite made for the Survey of India, 1825-1830.
© Science Museum / Science & Society Picture Library
Elevation drawn in 1847-1874 of the theodolite made by Barrow at Troughton & Simms in 1825-1830. Like the Cary theodolite, this was extremely heavy. It was designed to the specification of Colonel Sir George Everest (1790-1866), Surveyor General of India, to be used with a similar theodolite made by Cary for the Great Trigonometrical Survey of India (1830-1843). Its extreme solidity ensured the highest accuracy of the readings. In 1849, survey officer James Nicolson also used this theodolite to establish that a peak on Mount Everest, then known as peak 'b', was the highest in the world. In 1865, the Royal Geographical Society named the mountain after Everest in tribute to his pioneering work in mapping India. Everest's own belief was that mountains should be known by their local names.