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Glossary

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Everest, Sir George (1790-1866):

Sir George Everest was a surveyor. He was in charge of The Great Trigonometrical Survey in 1823. He was later the Surveyor-General of India between 1830 and 1843. Everest was interested in measuring the curvature of the earth. He became famous for measuring the longest ever arc of the meridian. In 1865, a year before he died, ‘Mount Everest’ was officially accepted by The Royal Geographical Society as the name for the highest peak in the world.

Great theodolite:

The great theodolite was a geometric instrument used in of The Great Trigonometrical Survey of India in the nineteenth century. It was used to measure the angle between a base point and a higher vantage point. Through this measurement, the height of that vantage point could be calculated. The Great Theodolite was used to make the most accurate map of India of its generation. Using the instrument was far from easy because it weighed more than half a ton (508 kg) and needed 12 men to carry it!

Great Trigonometrical Survey:

The Great Trigonometrical Survey was started in 1800 by the surveyor William Lambton. It was an attempt to create the most accurate map possible of the Indian subcontinent by using geometric instruments such as the great theodolite. These measured the angle between an established base line and vantage points on mountain tops. With the help of these measurements, a unique picture of the topography of India was created. For the first time, the heights and positions of 79 peaks in the Himalaya were correctly measured. This Survey was a mammoth project, taking over 70 years and involving 2000 miles (3200 km) of travel. The geometric instruments were not easy to move either - the great theodolite weighed over half a ton (508 kg)! The surveyors also faced huge perils during the process of measurement, risking death on remote mountains and the many dangers of the disease-ridden jungles of India and their tigers. The Great Trigonometrical Survey was so successful that it was endorsed by the Indian government in 1818. Yet Lambton failed to see the completion of his great plan. After his death, George Everest became Surveyor-General of India and head of the mapping project. However, it was Sir Andrew Waugh who finally finished The Great Trigonometrical Survey.

Lambton, William (1753-1823):

William Lambton was a famous surveyor who helped to map the Indian subcontinent. He started The Great Trigonometrical Survey in 1800 and later became Surveyor-General of the British India Survey in 1808. However, Lambton never saw the completion of his project, dying in 1823.