Swiss grande/petite sonnerie repeating clockwatch Circa 1870

Important gold quarter repeating grande and petite sonnerie chronometer
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An extremely fine, important Swiss 18 carat gold open faced two train grande and petite sonnerie trip quarter repeating keyless clockwatch, circa 1870. Chronomètre Répétition Petite et Grande Sonnerie. Nickel plated movement, fausses côtes decoration, double train with differential tandem winding, 29 jewels, gold wheel train, pivoted detent chronometer escapement, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator, striking and repeating hours and quarters on two gongs activated by a trip slide on the band, Marche/Silence and Petite/Grande Sonnerie selection levers under the bezel. Gold hinged cuvette engraved with the technical details and with engineturned border. White enamel dial with Roman numerals, outer minute track and Arabic five minute numerals, subsidiary seconds and original gold Louis XV hands. Plain case. Cuvette and movement signed.
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Diameter: 51 mm
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Signed: Girard-Perregaux La Chaux-de-Fonds
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Any complication, such as a striking train, affects the timekeeping of a watch, so that watches with striking, repeating or chronographs were not usually regarded as precision watches. This watch is extremely rare because it has a detent chronometer escapement combined with grande and petite sonnerie striking and quarte repeating. The use of the chronometer escapement shows that Girard-Perregaux intended this watch to be a precision timekeeper and as such a great deal of skill would have been needed to make the movement and to incorporate all the functions, yet retain the timekeeping capabilities. In grande sonnerie striking, both the hours and the quarter hours are struck at each quarter. In petite sonnerie striking, ‘ting-tang’ quarter hours are struck at the quarters, but the hour is struck only at the hour.