Rare Swiss silver open faced key wind watch Circa 1840

Silver lever watch with thermometer and compass
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A fine and rare Swiss unusual silver open faced pocket watch with thermometer and compass, circa 1840. Gilt bar movement with a patented lever escapement and bimetallic balance wheel.
White enamel dial with Roman hour numerals, an outer minute track, subsidiary seconds at 8 o’clock, a thermometer with concentric compass at 4 and gilt moon hands. Both the front cover and reverse of the case are engraved.
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Diameter: 58 mm
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Signed: No name