Carl Zeiss vertometer
 Catalogue Number: 2110 Carl Zeiss vertometer Category: Equipment Sub-Category: Vertometer, lensometer, focimeter Corporation: Carl Zeiss Jena Year Of Publication/Manufacture: c 1931 Time Period: 1900 to 1939 Place Of Publication/Manufacture: Jena, Germany Publisher/Manufacturer: Carl Zeiss Jena Description Of Item: Focimeter (syn vertometer, lensometer, lensmeter) for the measurement of ophthalmic lens powers, black metal, round base with slender stem , focussing knob with dioptre scale, rotating axis scale, adjustable ledge to locate lens and retractable spring to hold lens in place, adjustable eyepiece with rotatable flange with lenses to view the cylindrical lens axis scale and the lens power scale, slide-on metal lamp housing with electric cord and plug. 290 mm high. Marked 'CARL ZEISS/JENA/NO 1880' Historical Significance: The principle of the optical design of an instrument for measuring lens power was established by Snellen in 1876 but he used it as a phakometer. Troppmann introduced the first focimeter in 1912 in which dioptric power could be read off a scale. Previously opticians had used the lens curvature measure (spherometer). Carl Zeiss produced its first focimeter in 1915. This instrument was donated by David Cockburn who entered optometry practice in 1950 and may have bought it second hand. It probably dates from about 1932. Cat No 1905 is a similar item. How Acquired: Donated by David Cockburn, honorary life member of the College Date Acquired: July 2008 Condition: Good but light housing missing Location: Archive room. East wall Unit 3 Cupboard |