Trial Case (Bifocal Segments)

Catalogue Number: 2754
Trial Case (Bifocal Segments)
Category: Equipment
Sub-Category: Trial lens case
Designer/inventor: Frederick Goodell Blanchard
Year Of Publication/Manufacture: c1910
Time Period: 1900 to 1939
Place Of Publication/Manufacture: Southbridge Mass. USA
Publisher/Manufacturer: American Optical Company
Description Of Item: Small leatherette trial case with hinged lid & sliding catch. Purple velvet lining. Contains 12 pairs of round bifocal lenses (18 mm segment diameter) held by metal rim within full size (38mm) round trial lens rim. Add powers: +0.50 to +3.25. Purple ribbon inside lid printed in gold: 'PAT. FEB 15-1910 U.S.A./ PAT 2249-10 GT BRITAIN/ DRGM 444733'. Also loose in the case is an ivorine maker's plaque. Dimensions: L:12.5cm x D:10.0cm x H:5.0cm
Historical Significance: Patent referred to is US Patent No 949109, patented 15th February 1910. It was granted to Frederick Goodell Blanchard of Southbridge, Massachusetts for the American Optical Company. The patent shows 6 different designs for metal rims to hold a small round bifocal segment within an otherwise empty trial lens holder. This set uses the first of the 6 designs listed. Similar to Item 1993.
How Acquired: Donated by Alan Isaacs
Date Acquired: Sep 2015
Condition: Lenses: good, case:fair
Location: Archive office. East wall shelves unit 2

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