Everest's three-foot theodolite made by Troughton & Simms, 1874.
© Science Museum / Science & Society Picture Library
Elevation (showing the face of the vertical circle) and plan of the theodolite made by Cary and revised by Barrow. Weighing over 1000 pounds, it was taken to India by Captain Lambton in 1802 and later used by Colonel Sir George Everest (1790-1866), Surveyor General of India, in 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.