Extra flat Danish/Swiss 18K gold precision watch Circa 1836

Gold open faced chronometer by Jules Jürgensen
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An extremely rare and extra flat Danish/Swiss 18 carat gold open faced precision watch, circa 1836. Bridge movement, key wind, a spring detent escapement according to Thomas Earnshaw, gold screw compensation balance and flat spherical balance spring. The cuvette is engraved with technical details. White enamel dial, an eccentrically placed chapter ring with Roman hours, outer minute divisions, unusually placed auxiliary seconds and heavy moon hands. An engine-turned case. Dial signed, case and cuvette numbered.
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Diameter: 45 mm
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Weight: 63 g
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Signed: Jules Jürgensen
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The present timepiece is illustrated in detail in ‘The Jürgensen Dynasty’ by John M.R. Knudsen, Copenhagen 2013. It was this watch that Jules Jürgensen presented to German-Danish astronomer and mathematician Prof. Heinrich Christian Schumacher (1780-1850), in Altona, 1836. Schumacher managed, with some difficulties, to sell it to the Admiral of the Russian Black Sea fleet, Alexey Greig. To Jules’ great annoyance and Schumacher’s embarrassment, the Admiral kept the watch 18 months for examination before he paid the 1000 francs, the price of the watch. Alexey Greig is considered a co-founder of the Pulkovo Observatory. From 1840 to 1845 he was President of the Imperial Free Economic Society of Saint Petersburg. Heinrich Christian Schumacher was adjunct professor of astronomy in Copenhagen from 1808. He directed the Mannheim Observatory from 1813 to 1815 and then in 1815 was appointed Professor of Astronomy in Copenhagen and Director of the Observatory.
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Jules Frédéric Jürgensen was born in 1808 and died in 1877. He was the son of Urban Jürgensen and a very eminent watchmaker himself. Jules was born in Le Locle, Switzerland but as a child moved to Denmark with his parents. In 1830, after his father’s death, the company was taken over by Jules and his brother Louis Urban. In 1833, Jules returned to Le Locle and built up a successful business. Jürgensen, who was watchmaker to the King of Denmark, was made a Knight of the Légion d’Honneur and Knight of the Royal Order of Dannebrog. Between 1870 and 1876 he was a member of the commission of surveillance of the Geneva School of Horology, along with Ekegren, Potter and others. He further was a member of many commissions in Switzerland judging horological contests. He stamped most of his watches on the pillar plate under the dial ‘Jules Jürgensen of Copenhagen’.

Jürgensen invented his bow-setting mechanism in 1867. He wanted to prevent any accidental changing of the watch setting. In his design, the cover had to be opened to turn the bow far enough to engage the setting pin. In some of his watches, he did not want the back cover, which was not spring-loaded, to be opened by the owner. Therefore, for his watches with an open face, he used a special case in which the front was designed with a bezel utilizing a lifting mechanism like that in a hunting case. The setting could be done safely, by first opening the front by pushing on the stem, turning the bow until it touched the crystal and then setting the watch. After his death, the business was continued by his brother and in 1886 it was sold to an employee, H. Kiens, whose sons Jules (1837-1894) and Jacques Alfred (1842-1912) continued the business, as did the House of Heuer afterwards.