Troughton & Simms was a British scientific instrument firm. It was formed when Edward Troughton in his old age took on William Simms as a partner in 1826. It became a limited company in 1915 and in 1922 it merged with T. Cooke & Sons to form Cooke, Troughton & Simms. The firm had its origins in the instrument-making business begun in 1764 by John Troughton (1716-1788). This business was successively passed down first to nephews, John Troughton (1739-1807) and then to Edward Troughton (1756-1835). In 1826 Edward Troughton took on William Simms as partner. Origins In 1756, John Troughton Senior from Corney, Cumberland, set up business in London, having completed his apprenticeship with London instrument maker Thomas Heath. In 1769, his nephew John Troughton Junior, after completing his apprenticeship with his uncle, set up in business for himself. He took over the business of Benjamin Cole in 1782, a maker of orreries at a shop in Fleet Street called "At the Sign of The Orrery". His work at that time was mostly providing a service to other craftsmen in the difficult skill of dividing circles by hand for navigation, surveying and astronomical instruments. In 1789, he took his brother Edward Troughton into partnership. The Board of Longitude was wound up in 1828, but the Board of Ordnance (now Ordnance Survey) started work on the Triangulation of Britain in 1791. This was reflected in the change in Troughton's work away from astronomical and navigational towards terrestrial surveying. William Simms completed his goldsmithing apprenticeship in 1815 and set up business as a maker of marine compasses. In about 1825, he was asked to repair and re-divide an astronomical circle made by Troughton. Having completed this work, he wrote a paper for Edward Troughton describing his new method of dividing which was more accurate than an engine and quicker than using a roller. Edward Troughton took on William Simms as a partner in 1826. Notable Troughton instruments from this period include the Equatorial telescope at Armagh Observatory (1795), the Mural circle at Greenwich Royal Observatory (1812), and the Transit telescope at Greenwich Royal Observatory (1816). Troughton & Simms during the Industrial Revolution In 1828, George Everest returned from India and asked Simms to repair instruments used for the Survey of India. To try to make his theodolites less susceptible to field conditions Everest proposed a new pattern with a lower centre of