Swiss silver watch with independent centre seconds Circa 1853

Silver key-wind cylinder pocket watch
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A fine Swiss and very rare key-wind silver open faced pocket watch with independent centre seconds, circa 1853. Accompanied by an Extract from the Archives. Made for Tiffany & Co., New York, sold on August 10th, 1853. Polished case, gold hinges, switch to start/stop seconds in the band, signed and numbered cuvette with outer guilloche, reverse engraved in worn script Thomas Porter.  White enamel dial secured by two blued steel screws, Roman numerals, outer minutes. Blued steel Breguet hands. Gilt brass movement, double barrel for the going and independent seconds, cylinder escapement, plain three-arm balance, blued steel balance spring with temperature compensation curve, index regulator. The cuvette is signed by the manufacturer and retailer.
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Diameter: 49 mm
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Signed: Patek, Philippe & Cie.  Genève
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The case is slightly worn.
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This pocket watch is one of the earliest examples of a Patek Philippe pocket watch with independent seconds, the rarity is further increased by the addition of the retailer, Tiffany & Co.