Rare Swiss 18K gold jump hour open faced watch Circa 1830

Gold jump hour pocket watch 
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A very rare Swiss 18 carat gold jump hour open faced pocket watch, circa 1830. Jewelled cylinder bar movement with 3-arm balance.
Silvered dial with outer engraved minute chapter with Arabic numerals, rotating polished silver central disc with fixed pink gold hand around Arabic jumping hour. Foliate engraved case with engraved soldier in the centre, movement and cuvette signed.
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Diameter: 50 mm
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Signed: Bachelard & fils