English pair cased watch with Tortoiseshell case Circa 1740

Rare verge pocket watch by Nicolaus Jansen
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A rare pair cased English verge pocket watch, circa 1740.
Two cases: a brass outer case with red tortoiseshell decoration and large lateral hinge; and a silver polished inner case with case maker’s punch mark “CIW”. Enamel dial with radial Roman hours, Arabic minutes and blued steel “Poker & Beetle” hands. Fine full plate movement, keywind, firegilt and signed, with applied florally engraved and pierced silver ornaments, chain/fusee, extremely decorative conical movement pillars, three-arm steel balance and an engraved and florally pierced silver balance cock with mascaron.
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Diameter: 53 mm
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Weight: 126 g
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Signed: Nicolaus Jansen, London