Orthops Slide Rule
 Catalogue Number: 1949 Orthops Slide Rule Category: Equipment 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 Condition: Excellent Location: Archive office. East wall shelves unit 3. Drawer 5 |