William Stroud was a Scottish professor of physics, instrumental with his business partner Archibald Barr in the development of rangefinders for the Royal Navy through their company Barr and Stroud, Ltd..
The two men met at Leeds. Stroud's talent for applying scientific theory to practical problems paired well with Barr's knack for mechanical design. In 1888 they collaborated on an improved optical rangefinder, which they patented that year. A version of the instrument was adopted by the Royal Navy in 1892, and in 1894 the professors set up a company, Barr and Stroud's Patents, to market the rangefinder and other inventions. In 1895 they established a small workshop in Glasgow to assemble and test rangefinders, expanding in 1904 into a large purpose-built factory at Anniesland on the outskirts of Glasgow. The firm supplied rangefinders to nearly all of the world's navies, and manufactured smaller, portable instruments which were adopted by the British, French, and other European armies. In 1912, Barr and Stroud became a private limited company.
Barr and Stroud remained the sole supplier of periscopes to the Royal Navy, and a leading supplier of optronics, including thermal imaging equipment, to the British army.
Moss, Michael; Russell, Iain (1988). Range and Vision: The First Hundred years of Barr & Stroud. Edinburgh: Mainstream Publishing. ISBN 1851581286.