Steel oval shaped spectacles fitted with Franklin type bifocal lenses

Catalogue Number: 1698
Steel oval shaped spectacles fitted with Franklin type bifocal lenses
Category: Spectacles and lenses
Sub-Category: Spectacles (with lenses)
Year Of Publication/Manufacture: Late 19th C
Time Period: 19th C
Description Of Item: Light weight steel oval shaped spectacle frame 145 x 30 mm fitted with Franklin style bifocal lenses. Unsold stock. Each lens has an original sticker 70 on distance portion, 22 on the near portion indicating the powers of the sements in focal length in inches. This makes Rx approx. R&L +0.50 / add +1.50
Historical Significance: Benjamin Franklin is generally credited with the invention of bifocals in 1784. Serious historians have from time to time produced evidence to suggest that others may have preceded him in the invention; however, a correspondence between George Whatley and John Fenno, editor of The Gazette of the United States, suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought. Since many inventions are developed independently by more than one person, it is possible that the invention of bifocals may have been such a case. Nonetheless, Benjamin Franklin is certainly among the first to wear bifocal lenses, and Franklin's letters of correspondence suggest that he invented them independently, regardless of whether or not he was the first to invent them. John Isaac Hawkins, the inventor of trifocal lenses, coined the term bifocals in 1824 and credited Dr. Franklin. The invention of bifocals has been reviewed in great detail by Dr. John R. Levene in Chapter 6 of his book Clinical Refraction and Visual Science, Butterworth's, 1977. (Book held in Nathan Library)
Condition: Lenses fine, metal rim of frame rusting
Location: Archive Office. Spectacles cabinet Drawer 11

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