English 18K gold open faced lever pocket watch Circa 1850

Gold lever pocket watch
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A fine 18K gold English watch with quality movement, circa 1850. Early precision caliber with lever escapement, cut bimetallic compensation balance, key winding, with very unusual dust cover that opened by pushing the button near the balance.
White enamel dial, Roman numerals outer minute track, gilt spade hands. Back cover opened by pushing the button at the gold pendant.
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Diameter: 50 mm
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Weight: 94.5 g
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Signed: R. Roskell London
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Wear marks.
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Reference 0020000