Although this effect jad been discovered by Lord Rayleigh in 1886 the use of lens coatings was not widely known. With war looming the firm began to work with Arthur Pollen on his 'Aim Correction' system for improving the accuracy of naval gunnery. Cooke & Sons supplied the optical components for the system which consisted of a gyroscopically stabilised rangefinder where successive readings of a moving target were mechanically integrated to give a prediction of range and bearing. In the event the British Admiralty for the most part chose the simpler and cheaper Dreyer predcictor. In 1914, a new factory was built in Bishophill. In 1915 Vickers acquired a controlling stake in the company. During World War I about half of the factory's capacity was turned over to contracts for large naval rangefinders from the main contractor, Barr & Stroud  In 1922 Vickers merged it with Troughton & Simms to form Cooke, Troughton & Simms. In 1924 the company became a wholly owned subsidiary of Vickers. In 1939 another factory was built on a larger site in Haxby Road and during the Second World War, the company employed 3,300 people. In 1963 the company was renamed Vickers Instruments. In 1989 the company was sold to Bio-Rad Micromeasurements, apart from the defence products, which were sold to British Aerospace. The Haxby Road site was demolished in 2008.