Very rare English 20K gold and enamel verge watch Circa 1680

Early balance spring verge with Barlow regulator by Jacob
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A very rare English 20 carat gold and enamel early balance spring verge watch with Barlow regulator, circa 1680. Gilt finished verge movement, chain fusée, engraved and pierced balance cock revealing the plain three-armed steel balance and early balance spring, Barlow worm screwed regulator and scale, spiral-shaped pillars. White enamel dial with Roman numerals, the centre decorated with a painted polychrome enamel scene depicting Aurora and Cephalus, single brass hand of a spiral design, hinged within a circular case, split bezel, the band decorated with four painted polychrome enamel pastoral scenes with laurel surround and separated by floral decoration, one small cartouche signed Bulet pinxit, one with the title Aurora Cephalum rapiens, a painted polychrome enamel lakeside scene to the inside, the reverse with a painted polychrome enamel scene depicting the rapt of Cephalus by Aurora and two putti. movement signed Jacob on an applied silver cartouche, case signed Bulet pinxit.
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Diameter: 39 mm
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Signed: Jacob – Bulet pinxit