Trial Case (Bifocal Segments)
 Catalogue Number: 1993 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'. One of the +0.50 Add lenses is a replacement of a different design. 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. How Acquired: Not known Condition: Lenses: good, case:fair Location: Archive office. East wall shelves unit 2 |