Unusual silver lever deck watch with power reserve Circa 1915

Silver open faced lever deck watch by Ulysse Nardin|
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An unusual Swiss silver open faced keyless lever deck watch with power reserve, circa 1915. Nickel finished jewelled movement, Earnshaw type spring detent escapement, bimetallic compensation balance with gold poising screws. Hinged cuvette. White enamel dial with large Roman numerals, blued steel spade hands, two subsidiary dials indicating 36 hours power reserve and constant seconds. Plain case, hinged back. Case, cuvette, dial and movement signed.
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Diameter: 64 mm
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Signed: Chronometre – Ulysse Nardin Locle & Geneve Suisse