Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 132,775 pages of information and 210,006 images on early companies, their products and the people who designed and built them.
Foster Instrument Company, makers of measuring instruments, of Letchworth, Herts. Telephone: Letchworth 984 (3 lines). Cables: "Resilia, Letchworth"
1920 Jan. Physical and Optical Societies Exhibition. Exhibitor of testing machines.
1920 May. Issued catalogue on Pyrometer
1920 September. Exhibited at the Machine Tool and Engineering Exhibition at Olympia with radiation pyrometers
1937 Scientific instrument makers. "Resilia" Instruments.
1939 See Aircraft Industry Suppliers
1947 Listed Exhibitor - British Industries Fair. Manufacturers of Indicating, Recording, Controlling; also Optical and Radiation Pyrometers and Resistance Thermometers for every Industrial |Process. Photo-electric Recording Pyrometers for High Speed Temperature Measurement, Introscopes for Internal Inspection. (Olympia, Ground Floor, Stand No. A. 1074) 
1974 Taken over by the Swiss firm of Brown Boveri.