Large Swiss silver open faced lever with moon phases Circa 1890

Silver watch with triple date and calendar
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A fine and very rare Swiss, large, silver, 8 day going pocket watch, circa 1890. With unusual mainspring housing incorporating keyless winding to Swiss patent, triple date calendar and moon phases. A polished case, white enamel dial with bold radial Roman numerals, outer minute track, subsidiary dials for the date, days of the week, the months and the seconds, and aperture for the moon phases. Blued steel poire hands.
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Matte gilt, full plate movement, large glazed and ratcheted housing for the visible mainspring with folding winding flange mounted on the backplate, jewelled straight line lever escapement, cut bi metallic compensation balance, blued steel Breguet balance spring, index regulator protruding under the bezel.
The movement was signed beneath the calendar plate and punched with the patent number.
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Diameter: 66 mm
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Signed: Jacot & Bovy  Swiss