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Title: Two "Franklin Split Bifocal" lenses: (1) Oval [Go to resource]
Description: Two "Franklin Split Bifocal" lenses: (1) Oval, consisting of two half lenses of foci, 40" and 41" respectively; (2) Round, consisting of two half lenses of foci 40" and 9" respetively License: http://creativecommons.org/licenses/by-nc-sa/2.5/ Source: Science Museum Identifier: 1933-148 Go to resource More Like this...
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