Danish 60 hour power reserve chronometer Circa 1850

Deck chronometer by Louis Urban Jürgensen
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A rare and fine Danish 60 hour power reserve deck chronometer in a mahogany box, circa 1850. Brass movement, ∅ 70 mm, chain and fusee, inner brass case, a double wheel chronometer escapement, gold helical balance spring and bi metallic chronometer balance with two screws and 12 weights. Silvered dial with Roman hours, an outer minute track, subsidiary seconds at 6 o’clock, a power reserve indicator at 12 o’clock and spade hands.
Dial signed, case numbered.
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Dimensions: 155 x 155 x 155 mm
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Signed: Louis Urban Jürgensen
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Deck chronometers from the Jürgensen watchmaking dynasty are rare objects. Around 1822, Urban Jürgensen developed the double wheel spring detent escapement, which was also used by his son Louis Urban Jürgensen (1806-1867) for the present, small chronometer. However, as a mixture of spring and duplex escapement, it could not establish itself because of the complicated manufacturing of the two escapement wheels. A peculiarity of the cases, which are often elaborately crafted with ivory and brass inlays, can also be found here: A thermometer is installed under the brass framed glass.