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Adam Hilger, makers of optical instruments for control of industrial processes, of 75a Camden Road, London, NW1. (1922)
of 98 St. Pancras Way, Camden Road, London, NW1. Telephone: Gulliver 5571. Cables: "Sphericity London". (1947)
1897 Otto succeeded his brother in charge of the company
1898 Frank Twyman (1876-1959) joined the company
1902 Otto Hilger died; Frank Twyman took over as manager
1904 Company incorporated as a limited company
1906 Catalogue page from the Exhibition Catalogue of Fifty-first Annual Exhibition of the Royal Photographic Society of Great Britain showing address details for Adam Hilger Ltd. 
1910 A. Hilger Ltd exhibited at the Physical Society's Exhibition
Pre-war: Hilger's main products had been optical parts, sold mainly to rangefinder manufacturers Barr and Stroud, and specialized finished instruments, including spectrometers. Before the war Barr and Stroud started to make their own optical parts; Hilgers developed use for the large quartz spectrograph for metallurgical analysis; sold instruments to the American Brass Company.
Post-war: A significant holding in the company was sold to T. Cooke and Sons of York without knowing that Vickers held the majority of shares in Cooke's; the new parent company wished to bring Hilgers into line with the rest of its organization; Twyman did not believe this to be in the best interests of Hilgers and, in 1926, bought back the shares.
1922 Listed Exhibitor - British Industries Fair. Manufacturers of Optical and other Scientific Instruments for research and control of industrial processes; Polarimeters, Saccharimeters, Spectrometers, Spectrophotometers, Refractometers, Colorimeters, Interferometers. (Stand No. G.1)
and: Manufacturers of apparatus for determining the annealing temperature of glasses and for controlling the process of annealing; Apparatus for testing glassware for defective annealing. (Stand No. C.14) 
1946 E. R. Watts and Son acquired 78% of Adam Hilger
1947 Listed Exhibitor - British Industries Fair. Manufacturers of Optical Equipment for Research and industrial control of materials by observing emission of absorption spectra; by X-ray crystal analysis; by measuring colour, refraction, light absorption, polarisation and fluorescence optical gauging. (Olympia, Ground Floor, Stand No. A.1021)