Highly important Swiss gold grande complication watch Circa 1873

Gold grande complication pocket watch
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Highly important, unique and exceptional, Swiss 18K pink gold, grande complications, keyless pocket watch, circa 1873. Double perpetual calendar for Julian and Gregorian calendars, minute repeating, two-time zone, antimagnetic. With a chronograph, central progressive 60-minute register, moon phase, the lunar calendar and reference d’heure world-time calculation chart. Accompanied by the original G. Aspe receipt of sale, fitted box with initials PH. Retailed by G. Aspe, Paris. Started in April 1873, finished circa 1880, and sold by Aspe, Paris, to Monsieur P. Hebert on June 23, 1896, for 3240 Francs.
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A polished case, the bezel engraved around Fugit Irreparabile Tempus (Time Past is Irretrievable), pushers in the band for hand-setting of each dial, the back cover decorated in relief with the Gallic cockerel, its wings outstretched and holding a banner engraved with the motto Nunquam Quies (Never Rest). Hinged gold cuvette engraved with a reference d’heure – the names of 26 world cities with Paris as the meridian, each city engraved with its respective time difference from Paris. White enamel dial, two symmetrical mean time dials with radial Roman numerals, outer minute track, concentric inner date dials with hands on the same axis, one for Julian calendar, the other for Gregorian, subsidiary dials for the months of the 4-year cycle, days of the week concentric with seconds with hands on the same axis, aperture for the moon phases with the lunar calendar at the edge, outer seconds and fifths of a seconds track with Arabic five-second numerals for the chronograph and central 60-minute register. Pink gold spade hands.
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A bridge calibre movement, matte gilt, 40 jewels, counterpoised and calibrated straight-line lever escapement, cut bimetallic compensation balance with gold meantime and temperature compensation screws, special alloy antimagnetic Breguet balance spring, index regulator, repeating with two polished steel hammers on two gongs activated by a slide on the band. Dial signed Aspe à Paris, case numbered 12199.
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Diameter: 60,5 mm
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Signed: No Name  (Retailed by G. Aspe, Paris)
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This extraordinary and unique watch with a double perpetual calendar can be considered as the successor to the famous Louis Audemars watch La Russe built between 1860 and 1870. La Russe has the complications of two time zones and Julian and Gregorian calendars but is not a perpetual calendar. It is likely therefore that the present watch, started in 1873, was intended to surpass La Russe in terms of sophistication and dial design. The present watch was constructed by some of the greatest watchmakers of the 19th century over a period of about 7 to 10 years. La Russe, as the name suggests, was made for the Russian Imperial Court and the present watch was, at the time of conception, intended for the same market. Until 1918, the Julian calendar was still used in Russia and by the end of the 19th century, it was 12/13 days behind the Gregorian calendar which had been adopted by the rest of Europe after 1582.
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This watch has a perpetual calendar working simultaneously for both Julian and Gregorian calendars an extraordinary horological rarity. This is combined with minute repeating, two time zones and a chronograph with a central 60-minute register, the days of the week and the seconds’ hands are from the same axis as the moon phase. The cuvette is engraved with a reference d’heure world time calculation chart to allow the wearer to set the second time zone dial accurately for another city. This system allowed travellers to know exactly the time in the city they were in, and to calculate the time of the city where they were going. Despite all these complexities, the dial is designed to be elegant and clear.