Swiss 18 Carat yellow gold extra lever pocket watch Circa 1918

Gold watch accompanied by Observatory register
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An extremely fine and rare Swiss 18 Carat yellow gold keyless pocket watch, circa 1918. Accompanied by the extract from the Geneva Observatory register. Geneva Observatory tested and Honorable Mention was obtained in 1930 with 698 points, adjusted for trial by Henri Wehrli. A polished case concealed hinge with a hinged gold cuvette. White enamel dial with Paris numerals, outer minute track, subsidiary seconds and blued steel Breguet hands.
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A rhodium plated movement, Geneva striping decoration, 23 jewels, adjusted extra, punched twice with the seal of Geneva quality mark, straight line calibrated equidistant lever escapement, Anibal brass Guillaume compensation balance with poising wings on the balance arm, gold temperature adjustment screws, adjusted to heat, cold, isochronism and five positions, blued steel Breguet balance spring with an outer terminal curve, swan neck micrometric regulator, wolf’s tooth winding, special mainspring ratchet wheel click preventing over winding and Maltese Cross stop work. Dial, case, cuvette and movement signed.
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Diameter: 50 mm
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Signed: Patek, Philippe & Cie  Geneva
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A rare example of a gold cased Observatory trial watch. The movement has the unusual winding click and Maltese cross stop work to prevent overwinding found on very few Patek Philippe watches and seemingly only those for Observatory testing. When destined for Observatory Timing Contests, the movements of Patek Philippe watches, like those of other makers, were double engraved with the movement serial numbers. The inscription “Extra” on the bridge of the movement refers to the high finishing of all the parts of the movement.