Edward Troughton

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Born: Oct 1753 in Corney, Cumberland, England
Died: 12 June 1835 in London, England

Edward Troughton's father was a farmer and Edward worked for his father when he was young. He became an apprentice mathematical instrument maker in 1770, working for his brother John Troughton in London. In 1779 he became a partner with his brother and they bought The Sign of the Orrey at 136 Fleet Street, London.

Troughton soon established himself as the leading maker of instruments in England. Not only did he make great improvements in the design of existing instruments, but he also invented many new instruments. He began his instrument making career with instruments to aid navigation, for example, he designed the 'pillar' sextant, patented in 1788, the dip sector, the marine barometer and the reflecting circle built in 1796.

Other instruments which he designed were for use in surveying. He designed the pyrometer, the mountain barometer and the large theodolites which were used in the American Coast Survey of 1815, and base-line measuring apparatus. In fact these instruments were later used in surveys of Ireland and of India.

Troughton's most famous instruments were astronomical ones. He made the Groombridge Transit Circle in 1805 and a six foot Mural Transit Circle in 1810 which was erected at the Observatory in Greenwich in 1812. In 1816 he made a ten-foot Transit Circle. He never produced any telescopes, however, and the reason for this was that he suffered from colour-blindness which was a defect which ran in his family.

After his brother John died, Edward ran the business alone until, in 1826, because of failing health due to old age, he took on a new partner William Simms. Simms continued Troughton's internationally known business after Troughton died in 1835 at his home in Fleet Street.

One of Troughton's most important contributions was a method of dividing a circle. His paper on this, An account of the method of dividing astronomical and other instruments by ocular inspection in the Philosophical Transactions of the Royal Society in 1809 won him the Copley medal of the Royal Society.

Troughton was elected a Fellow of the Royal Society in 1810. He was also elected a Fellow of the Royal Society of Edinburgh in 1822. In 1822 he published another work A comparison of the repeating circle of Borda with the altitude and azimuth circle in the Memoirs of the Royal Astronomical Society.