English silver experimental escapement chronometer Circa 1780

Technically highly interesting chronometer
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A technically highly interesting chronometer with experimental escapement, made by Josiah Jessop in London, England, circa 1780. This pair case watch, which was crafted from silver, has an enamel dial with decentralised time display with Arabic five minute- and Roman hour numerals, center seconds with Arabic five second numerals and black hands. The movement has an extremely rare chronometer escapement in a very special and probably unique construction, with a special rocker and a large diamond end stone.
Dome numbered and the dial, dome and movement are signed.
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Diameter: 60 mm
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Weight: 184 g
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Signed: Jessop, Southampton street, Strand, London
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The watch is an absolute rarity for chronometer collectors. It is one of the earliest English chronometer deck watches with an experimental escapement. It is known that Earnshaw also supplied movements to Jessop in his early years, which were signed Jessop on the movement and dial.
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Jessop
Josiah Jessop worked in London around 1780-1794, as the records show; his workshop was at 38 Southampton Street, Covent Garden. Museums now keep some of his pieces: there is a center second watch in the British Museum that was formerly part of the Ilbert collection, a gold enamel watch that was part of the Sternberger collection and a third watch held by the Metropolitan Museum of Art.