Early Swiss 18K gold open faced lever pocket watch Circa 1858

Gold ankerchronometer by Patek Philippe
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A very early Swiss 18 carat gold open faced ankerchronometer pocket watch, circa 1858. Delivered to Van Caulaert & Fils, Bruxelles. Very fine and early fire-gilt bridge movement, ankerchronometer, large bimetallic screwed balance, blued hairspring, fine adjusting device, balanced lever, wolf’s toothing, blued steel screws, a very early version with crown winding. Engine-turned cuvette signed Van Caulaert & Fils à Bruxelles – Patek, Philippe & Co à Genève. Screwed white enamel dial with black Roman numerals, outer minute divisions, subsidiary seconds, and blued Breguet hands. Engine-turned case, owner engraving Emile Wambacq. Case numbered, cuvette signed and numbered.
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Diameter: 46 mm
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Weight: 70 g
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Signed: Van Caulaert & Fils à Bruxelles – Patek, Philippe & Co à Genève