Heavy English 18K gold quarter repeating verge watch Circa 1830

Gold quarter repeater by Thomas Earnshaw
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A fine and heavy English 18 carat gold open faced quarter repeating verge pocket watch, circa 1830. Verge movement. A later white enamel dial with Roman hours, an outer minute track, sunk subsidiary seconds and later Fleur de Lys hands. An engraved case with London Hallmarks for 1830-1831, the pendant and bow decorated to match, plain bezels. Movement signed and numbered.
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Diameter: 52 mm
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Signed: Thos. Earnshaw High Holborn London
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Thomas Earnshaw was born on February 4th, 1749 in Ashton-under-Lyne and died on March 1st, 1829 in London. He was an English watchmaker who, following John Arnold’s earlier work, further simplified the process of marine chronometer production, making them available to the general public. Earnshaw is also known for his improvements to the transit clock at the Royal Greenwich Observatory in London, his invention of a chronometer escapement and a form of bimetallic compensation balance. In 1780, he devised a modification to the detached chronometer escapement, the detent being mounted on a spring instead of on pivots. This spring detent escapement was patented by Thomas Wright for whom he worked in 1783. Whilst initially the design was crude and unsuccessful, with modifications it later became the standard form in marine chronometers, following the invention of the detent escapement by Pierre Le Roy in 1748. John Arnold also invented a similar escapement in 1782. The bimetallic compensation balance and the spring detent escapement in the forms designed by Earnshaw have been used essentially universally in marine chronometers since then and for this reason, Earnshaw is generally regarded as one of the pioneers of chronometer development.