Swiss 18 carat gold open faced keyless pocket watch Circa 1910

Gold chronometer royal pocket watch
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A Swiss 18 carat yellow gold open faced keyless pocket watch by Vacheron Constantin, Geneva, circa 1910. A solid, open faced, engine turned case back. White enamel dial with Roman numerals, outer minute track, subsidiary seconds at 6 and gold hands. A gilded brass movement with going barrel, gold screwed chaton (setting) on the central wheel, straight line lever escapement, compensated balance with gold poising screws and blued steel hairspring with terminal curve, index regulator with swanneck spring and micrometric screw. Dial, Case and Movement are signed.
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Diameter: 57 mm
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Signed: Vacheron Constantin  Geneva