Plan of the three-foot theodolite designed by Everest, 1825-1830.
© Science Museum / Science & Society Picture Library
Plan of the lower frame and stand, drawn in 1847-1874, of the immense theodolite made by Barrow at Troughton & Simms' London workshop in 1825-1830. It was designed to the specification of Colonel Sir George Everest (1790-1866), Surveyor General of India, and 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.