English gold cylinder watch with keyless winding Circa 1820

Gold ruby cylinder watch with early Prest patent keyless winding
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A rare English gold open-faced ruby cylinder watch with early Prest patent keyless winding, circa 1820, gilded full plate movement, ruby cylinder escapement, broad flat steel three-arm balance, ruby endstone, large blued steel regulation arm indicating on broad semi-circular scale engraved ongoing barrel bridge, signed Jno. R Arnold, London, and marked patent.
Gold dial, Roman numerals against a stippled ground, outer pearled minute ring, engine-turned center, gold hands, spade hour, the minute hand with pinhole to aid time setting.
Gold case, engine-turned back, milled band, case with maker’s mark TH in rectangular cameo for Thomas Hardy.
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Diameter: 42 mm
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Signed: Jno. R Arnold London
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Thomas Prest was John Roger Arnold’s foreman. Prest was granted patent no. 4501 for his keyless winding system on 20th October 1820. The present watch, numbered 3, has the London hallmark for 1819-1820 and may well be the earliest surviving watch with this keyless system.

Thomas Prest’s keyless system is discussed, together with an illustration of his patent drawings, in an article by Michael Gibbons for Antiquarian Horology: English Keyless Winding Watches. The patent only allowed for the winding of the watch and not the hand-setting – this watch is therefore fitted with an unusual minute hand that has a pinhole approximately 2/3 of the way down its length to aid adjustment with, presumably, a tool (quite possibly fitted to the top end of the original winding key) with a short protruding pin to avoid the risk of scratching the dial’s surface. The development of keyless winding was one of the greatest advances in mechanical horology and Prest’s system marked an important step in its evolution.