English early pocket watch chronometer Circa 1801/1811

Important open faced collector’s watch by Thomas Earnshaw
–
An important and very early English pocket watch chronometer with hallmarks London, circa 1801/1811.
Pair cases: 1st case with hallmarks London 1811, 2nd case with hallmarks London 1801, watchpaper and signed Earnshaw. Chronometer movement with Z balance, splendidly engraved bridge and diamond endstone. Signed and numbered enamel dial with subsidiary Arabic seconds, Roman hours and gold hands.
–
Diameter: 61 mm
–
Weight: 160 g
–
Signed: Thomas Earnshaw Invenit et fecit
–
It is one of the earliest Earnshaw pocket watch chronometers. Thomas Earnshaw (1749-1829) was trained as a watchmaker in 1763. From 1780 he completed movements for Brockbanks. In his own factory in London 1781, Earnshaw developed the spring detent escapement, which became common practice and binding for more than 150 years. Thomas Earnshaw took over 1794/1795 the business of William Hughes in the High Holborn 119. In chronometers, but especially in the further development of the detent escapement, Thomas Earnshaw is considered as one of the pioneers. About 3.000 pocket watches and about 1.500 marine deck watches and pocket watch chronometers of the highest quality were made in his workshop.