Swiss gold hunting cased tourbillon chronometer Circa 1870

Gold chronometer with tourbillon by Girard-Perregaux
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A Swiss 18 carat gold hunting cased tourbillon pocket chronometer, circa 1870. Movement with a three bridges long pivoted detent escapement. White enamel dial with Roman hours, an outer minute track, Arabic five minute numerals, subsidiary seconds at 6 o’clock and Fleur-de-Lys hands. The heavy case is finely engraved. Dial, cuvette and movement signed, case numbered. Comes with a Girard-Perregaux 18 Carat gold watch chain and the original presentation box.
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Diameter: 56 mm
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Signed: Girard-Perregaux Chaud-de-Fonds
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It was in 1856 that Girard-Perregaux was born. The marriage of Constant Girard and Marie Perregaux formed this famous Swiss watchmaker who is today associated with quality and excellence. This piece pays tribute to Girard-Perregaux and two particular complications. The first, the three bridge tourbillon is now part of the firms’ genetic code and this particular complication is associated immediately with the brand. The tourbillon, or rotating escapement carriage was patented by A.L. Breguet in 1801. The purpose of the tourbillon is to eliminate errors in the balance by revolving the escapement continuously to produce a uniform average rate. The second, the spring detent escapement is to increase accuracy. In a lever escapement, the escape wheel teeth and palette fork generate a lot of friction between them. The detent was designed to eliminate the palette fork and alter the balance wheel so that it will only interact with the escapement once a second when changing direction. It is the detent that changes the direction of the balance wheel. Instead of a lever escapement that connects multiple times per second, the detent escapement only connects once per second, subsequently the friction of the parts was reduced.
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The three bridge configuration was patented by Girard-Perregaux in 1884 and is still the most iconic feature of the brand today.
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This three bridge tourbillon manufactured by Girard-Perregaux is a very well made watch. The long pivoted detent escapement was made by Ernest Guinand and can be distinguished by a typical A shaped frame. Guinand made tourbillon carriages for the greatest maker of the time. The pivoted detent escapement helped avoid errors of rate with the change of position of the watch.