Technically interesting Swiss silver captain’s watch Circa 1883

Silver open faced key wind watch
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A technically interesting and very rare Swiss silver open faced lever captain’s watch with three time zones made by Henri Perregaux in Le Locle, Hallmarked for 1883. The key wind bridge movement with a lever escapement. White enamel dial with the indication of three time zones: Ship Time, East Time and West Time, an exceptionally large constant seconds display for observation purposes and blued steel hands. The plain case with a blank cartouche on the back. Case numbered, dial signed and numbered, movement signed. Comes with an old key.
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Diameter: 52.5 mm
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Weight: 100 g
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Signed: Henri Perregaux Locle
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The English dial lettering of this Swiss watch shows that the watch was intended for the English market and also explains the English silver case.
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The cuvette is missing.