French gold quarter repeating pocket chronometer Circa 1793

Important rose gold open faced repeater by Louis Berthoud
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An important French 18 carat rose gold open faced quarter repeating pocket chronometer montre à toc, circa 1793. Plain case, casemaker’s punch mark Joly. White enamel dial with Arabic numerals, auxiliary second and opened Breguet hands. Gilt, frosted full plate movement, two hammers, chain/fusee, solid movement pillars, spring detent escapement according to Thomas Earnshaw, three armed brass balance, blued balance spring. Movement signed.
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Diameter: 53 mm
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Weight: 122 g
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Signed: Louis Berthoud à Paris
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One of earliest watches in France with pierced jewels.