Swiss gold perpetual calendar keyless pocket watch Circa 1850

Gold open faced lever pocket watch
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A yellow gold open faced centre seconds perpetual calendar keyless watch with moon phases, circa 1850. Jewelled manual winding lever movement, white dial, Roman numerals, outer minute track, subsidiary dials for day, date, month combined with leap year indication in Spanish, fan-form aperture for moon phases, 18k yellow gold circular case, hinged back, case and movement signed.
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Diameter: 53 mm
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Signed: Henri Grandjean & Cie  Swiss