German silver and tortoiseshell verge with calendar Circa 1810

Silver and tortoiseshell pair-cased verge by Tiedmann
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A German silver and tortoiseshell pair-cased verge pocket watch with calendar, circa 1810. Gilt-brass full plate movement, conical pillars, fuse and chain, verge escapement with micrometric potence adjustment, three-arm brass balance, flat balance spring, continental balance cock with polished steel endplate, silver regulator scale. White enamel dial with Breguet numerals, outer minute track, inner calendar ring with corresponding hand, gold arrow and partially replaced Breguet hands. The outer case overlaid with tortoiseshell with pique decoration, the inner case polished. Movement signed.
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Diameter: 63 mm
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Signed: J.C. Tiedmann Hamburg