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Theodolite

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probably made in London

Theodolite
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A theodolite is a surveying instrument for measuring horizontal and vertical angles. This example is known as an 'Everest' theodolite after its designer, Sir George Everest (1790-1866). It was made around 1860, probably by Troughton and Simms, scientific instrument makers based in London.

The instrument is a bold attempt to model a radically new theodolite, on the best principles of contemporary astronomical instruments, and some of its best features were adopted as standard in theodolites.

Everest (after whom the mountain is named) was head of the Great Trigonometrical Survey of India from 1823. In 1825 he went back to England on sick leave, and it was apparently during this period that he devised a small five-inch theodolite which was manufactured and tested during 1829. So successful did this model prove that it was still in production in the 1880s.

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