English rare precision watch with lever escapement Circa 1823

Silver open faced pocket watch by Thomas Earnshaw
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A rare English precision pocket watch with English lever escapement, circa 1823. This watch features a silver engine-turned case with a reeded band; a case maker punch mark BN, and a movement protection cap. The enamel dial is signed and numbered, showcasing radial Roman numerals, an auxiliary seconds display, and elegant blued Fleur-de-Lys hands. The movement of the watch is a full plate design, keywind, frosted and gilt, with ten jewels, a chain/fusee, an English lever escapement, and a bimetallic Z chronometer balance with two screws and two movable trapezoid weights. It also includes a florally engraved balance cock and a set diamond endstone on the balance.
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Diameter: 54 mm
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Weight: 149 g
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Signed: Thomas Earnshaw, London