Swiss silver deck watch with 52h power reserve Circa 1930

Large silver deck watch with power reserve by Paul Ditisheim
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Very fine, large Swiss silver (0.925) open faced keyless wind deck chronometer with 52 hour power reserve indication, circa 1930. Gilded brass 3/4 plate movement, going barrel, gold screwed chatons (setting), straight line lever escapement, annibal brass Guillaume balance with gold poising screws and blued steel hairspring with terminal curve, adjusted to nine positions and isochronism, inscribed: Paul Ditisheim la Chaux-de-Fonds Switzerland The Highest Records at Kew Teddington and Swiss Observatories. Dial with Roman numerals, subsidiary seconds at 6 and sector for power reserve indication at 12 o’clock. Plain case with ribbed band, screwed back. Case, dial and movement signed and numbered. Comes with original fitted box.
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Diameter: 65 mm
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Signed: Paul Ditisheim