Swiss silver cylinder watch glazed on both sides Circa 1885

Silver open faced watch by A.S. & F. 
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A rare Swiss silver gentleman’s pocket watch with hands moved by rotating glass discs, circa 1885. Silver decorated case and glazed on both sides. The dial features rotating glass discs with applied spade hands and radial Roman numerals. Crescent-shaped movement, frosted, gilt, H. R. Brevete, with cylinder escapement and ring balance.
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Diameter: 54 mm
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Weight: 84 g
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Signed: A.S. & F. Mystérieuse, Brevete S.G.D.G.
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Armand Schwob & Frère (AS & F.) were watch manufacturers based in La Chaux-de-Fonds in Switzerland. The company received two Swiss patents numbered 2445 and 2526 in 1881 and an English patent number 9865 in July 1888 for transparent watches.