English silver chronometer pocket watch Circa 1800

Silver spring detent escapement according to John Arnold and ZO balance
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An important pocket chronometer with spring detent escapement according to John Arnold and ZO balance, circa 1800. Sterling silver consular case, case maker punch mark “TH” (Thomas Hardy), smooth, à goutte, large lateral hinge. Dial is enamel, radial Roman numerals, auxiliary seconds, numbered, signed, blued spade hands. Full plate movement, frosted, gilt, chain/fusee, round pillars, keywind, signed, spring detent escapement, ZO-balance with 2 weights and 2 screws, blued helical freesprung balance spring with both sides passing terminal curves, very fine florally engraved balance cock, chatoned seconds wheel, chatoned ruby endstone on escape wheel, chatoned diamond endstone on balance.
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Diameter: 64 mm
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Weight: 194 g
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Signed: John Roger Arnold London