Troughton & Simms began in business in London in 1826. Edward Troughton (1756-1835) had learned the trade from his father, John Troughton, a leading instrument maker in London; he also worked with his equally talented brother, also named John. William Simms (1793-1860) had a less distinguished pedigree, but proved to be an excellent craftsman and businessman. Under his leadership, Troughton & Simms manufactured mathematical instruments both large and small, and attracted customers around the world.
The 20th century brought important changes to Troughton & Simms. The firm became Troughton & Simms, Ltd. in 1916. A 1922 merger with T. Cooke & Sons, Ltd. led to the formation of Cooke, Troughton & Simms. This, in turn, became Vickers Instruments, Ltd, in business from 1963 to 1988.
Ref: Anita McConnell, Instrument Makers to the World. A History of Cooke, Troughton & Simms (York, England, 1992).