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Details
A rare and unusual 19th-Century optician's slide rule,
unsigned, with scales for Furthest Conc Nearest, Focus of Convex Nearest and Scale of Inches, with folding sights, single lens, two sliders and three oval apperture slides, contained in the original plush-lined morocco case -- 8in. (21.5cm.) long
See Illustration
unsigned, with scales for Furthest Conc Nearest, Focus of Convex Nearest and Scale of Inches, with folding sights, single lens, two sliders and three oval apperture slides, contained in the original plush-lined morocco case -- 8in. (21.5cm.) long
See Illustration