Danish 18 carat gold keywind chronometer watch Circa 1855

Gold watch pivoted detent escapement 
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A very early, very rare pocket watch chronometer with key winding by Jules Jürgensen Copenhagen, circa 1855. An 18 K gold, engine turned, very early Jürgensen chronometer movement, unusual construction, pivoted detent escapement with gold mounted endstones, big ruby bearings, gold escape wheel, bimetallic compensation balance with blued arms, blued inside, blue hairspring, signature „Jules Jürgensen Copenhagen N° 8331“, signed enamel dial, blued Breguet steel hands, good condition, in working order, rare.
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Diameter: 49 mm
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Weight: 84 g
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Signed: Jules Jürgensen  Copenhagen
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Dial  fine hairline