French 20K gold five-minute repeating pocket watch Circa 1799

Gold cylinder watch with jump hour
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An extremely fine and extremely rare 20K gold jump-hour, five-minute repeating à toc pocket watch with ruby cylinder escapement, circa 1799. An early type by Guillaume Mermillod (master mark), engine-turned, the back with central applied gold disc decorated with a blue enamel monogram, concealed hinge and gilt brass dust cover.
White enamel dial by F. Cave, Pl. Thionu, Breguet numerals, outer star minute indexes, lozenge quarter-hour indexes, secret signature. Blued steel Breguet hands.
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A gilt movement, Lépine calibre, standing barrel, overhanging ruby cylinder escapement, plain three-arm steel balance with a parachute on the top pivot, blued steel fl at balance spring, index regulator with bimetallic temperature compensation curb, all-or-nothing repeating with a single hammer on the side of the case activated by depressing the pendant. Dial and dust cover signed.
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Diameter: 56 mm
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Signed: Breguet  Paris
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In Breguet’s workbooks, escapements are rarely specified and the present watch is one of only a handful to be described as répétition garde-temps échappement isolé. Breguet must have considered this watch to have sufficient merit to be called garde-temps a description reserved only for the finest timekeepers. Later the term garde-temps applied only to watches with chronometer escapements and is usually only applicable to those. The movement of No. 23 is of the new calibre started in 1799 and is called the Lépine calibre after the famous Parisian watchmaker Jean- Antoine Lépine. This watch is illustrated in The Art of Breguet, George Daniels, 1975.