Striking calendar with painted horn gilt outer case Circa 1799

An unusual and rare English 18 carat gold and gilt pair cased key wind striking calendar with painted horn gilt outer case, circa 1799. Gilt movement with large aperture for repeater bell, form of dead beat escapement with twin escape wheels with inter spaced cranked teeth, repeating on a bell. White enamel dial, black Arabic numerals, black outer minute divisions, oval inner calendar markers and gilt leaf form hands. Polished inner case with engraving to back, outer gilt with under painted horn pastoral scene.
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Diameter: 52 mm
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Signed: No name
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The unusual and very rare crank tooth twin escape wheel escapement looks to be that which Charles Gros in Echappements d’Horloges et de Montres, 1914, credits to Pierre Le Roy in 1742. With kind assistance from David Penney.