French 18 carat gold Seconde Morte pocket watch Circa 1830

Gold pocket watch with open face
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A very fine, large, heavy French open faced pocket watch with Seconde Morte, circa 1830.
Plain polished 18K gold case, guilloché middle part, case hallmark AP & Cie. Enamel dial with Breguet-style radial hours, red 24-hour numerals, outer minutes/seconds track, centre seconds, and blued steel Breguet-style hands. Early cylinder movement with two barrels for the movement and the independent jumping second.
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Diameter: 54 mm
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Weight: 110 g
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Unsigned
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Seconde morte, Dead seconds.
A hand that jumps forward when the second has elapsed. Breguet used the expression seconde d’un coup or sudden second. Generally, the jump of a hand is a distinctive feature of a quartz watch. In mechanical watchmaking, this function is a technical feat.