1911 Encyclopædia Britannica/Troughton, Edward

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TROUGHTON, EDWARD (1753-1835), English instrument maker, was born in the parish of Corney in Cumberland in October 1753. He joined his elder brother John in carrying on the business of making mathematical instruments in Fleet Street, London, and continued it alone after his brother's death, until in 1826 he took W. Simms as a partner. He died in London on the 12th of June 1835.

Troughton was very successful in improving the mechanical part of most nautical, geodetic and astronomical instruments, but complete colour-blindness prevented him from attempting experiments in optics. The first modern transit circle was constructed by him in 1806 for Steven Groombridge; but Troughton was dissatisfied with this form of instrument, which a few years afterwards was brought to great perfection by G. von Reichenbach and J. G. Repsold, and designed the mural circle in its place. The first instrument of this kind erected in Greenwich in 1812, and ten or twelve others were subquently constructed for other observatories; but they were ultimately superceeded by Troughton's earlier design, the transit circle, by which the two co-ordinates of an object can be determined simultaneously. He also made transit instruments, equatorials, &c.; but his failure to construct an equatorial mounting of large dimensions, and the consequent lawsuit with Sir James South, embittered the last years of his life.