Catalogue Number: 1949
Orthops Slide Rule
Sub-Category: Dispensing tool
Year Of Publication/Manufacture: 1930s
Time Period: 1900 to 1939
Description Of Item: Shaped wooden rule with metal slide and various scales on both sides. Marked ' ORTHOPS SLIDE RULE' on one side.
Historical Significance: Various rules for the measurement of facial and spectacle frame dimensions were devised in the 1930s. This reflected the desire of early 20th C optometrists and opticans to be as precise as possible in fitting spectacles. The British Optical Association Museum has two paper items that give a description of this rule and its use. See Cat No 1940 for instructions for its use. See Cat No 1931 for another later version of this rule made with plastic rather than wood, The book L S Sasieni Spectacle fitting and optical dispensing 1950 (Cat nos 776 )2243) has an informative chapter (ch 2) on frame rules and one (ch 5) on devices for face measurements.
How Acquired: Donated by Pamela Sutton honorary archivist. Purchased from British Optical Association Museum
Date Acquired: July 2011
Location: Archive office. East wall shelves unit 3. Drawer 5