'Spherometre' a type of sperometer used to measure the convex and concave shape of spectacle ophthalmic lenses, signed 'G. L.', French, 1900-1920. Dial scale graduated in dioptres (dioptrice) & inches (pouce) and marked as patented (Brevete S.G.D.G.). Spectacle lens measuring instrument 1900-1920
Spherometer (1-inch radius) with case, made by A. Hilger, London, England, 1891. Spherometer (1-inch radius) with case 1891