Prior Scientific Instruments Ltd was established in London in 1919 as a manufacturer of optical microscopes. It is the last traditional microscope manufacturer of makers such as Vickers, W.Watson and Son, Baker, Charles Perry, Cooke, Troughton & Simms and many others who have ceased to produce microscopes. History Early history W. R. Prior & Co. Ltd. was founded by Walter Robert Prior in 1919. The Blitz in 1941 destroyed the factory building, so the company moved to their new facility in Bishop Stortford in 1942. Many records and a collection of microscopes from the early days of the company were lost in a fire in 1988, but some illustrated catalogs have survived which give an indication of the range of instruments produced by W. R. Prior over the years. W. R. Prior & Co. Ltd's offices were originally located at 9,10,11 Eagle Street, Holborn, London and later at 28a Devonshire Street, London W.1. Little is known about the Company during this time, and no records or catalogues exist as to when and why they began to produce microscopes under the Prior name. A W. R. Prior to catalogue of microscopes and accessories dated February 1950 gives the location of the office as Devonshire Street and the factory as Bishop's Stortford, Herts. England (13 Northgate End) where manufacturing was carried out from 1942-1957. Wartime The Eagle Street factory was destroyed during the London Blitz and the company relocated to 13 Northgate End, Bishop Stortford. Herts. The building was a garage and work began producing optical gun sights, tank periscopes, and range finders for the Ministry of Defence. No microscopes were produced during the war. The first post-war abridged catalogue includes a wood block illustration of a student “C” limb microscope, with the limb engraved with the Eagle Street address. Post-war On 10 January 1947 Walter Robert Prior died at the age of 55. 1953 brought the start of manufacturing micromanipulators for Prior, and later the micropositioner was developed. Both of these are still made. The company relocated to a new factory at London Road, Bishop Stortford in 1956 and continued to produce and develop microscopes. Because of the need for new universities and colleges during the post-war period, there was a demand for microscopes and accessories and Prior developed instruments for this market. The Science Master Microscope, introduced in 1957, was used in schools. The established Prior Monocular Dissecting Microscope was