English silver early 2nd quality chronometer watch Circa 1783

Important chronometer in a case hinged on both sides.
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An important early 2^nd quality chronometer, assembled by John Arnold in London, England, circa 1783. The case of this watch was crafted from silver by William West, has London Hallmarks 1783 and is hinged on both sides. The enamel dial has Roman hour numerals, a subsidiary dial at 6 o’clock and steel hands. The numbered movement is fitted with an early John Arnold chronometer escapement, a balance spring and a diamond end stone.
The movement is signed.
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Diameter: 54.5 mm
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Weight: 133 g
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Signed: Jn Arnold, London
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This early John Arnold chronometer of the so called 2^nd quality is a museum rarity and according to Staeger, probably original in all parts. The watch is documented in detail in ‘100 Jahre Präzisionsuhren von John Arnold bis Arnold & Frodsham 1763-1862’ by Hans Staeger and is described and illustrated in great detail on pages 163/164 with the author’s note that this chronometer belongs to a certain early series of the 2^nd quality, which were all provided with unsigned dials. It is extremely rare today to find such an early John Arnold chronometer that is original in all parts.