40-Hour Deck Chronometer” Dumas

“40-Hour Deck Chronometer” Dumas, Depot De La Marine, No. 81. Made circa 1840 under the direction of Henri Motel. Very fine and rare, marine deck chronometer with spring footed-detent and 40-hour power reserve. Three-tier mahogany deck box, the upper section with a numbered bone plaque, brass case en forme de tabatière secured inside the mahogany box, screwed-down brass bezel. Matte silvered, radial Roman numerals, outer minute track, subsidiary seconds, power reserve sector below 12. Blued steel Breguet hands. Brass, three-quarter plate, “spotted” decoration, reverse fusee and chain, Harrison’s maintaining power, the barrel under a separate bridge, Earnshaw-type chronometer escapement , spring footed-detent, two-arm cut bimetallic compensation balance with sliding cylindrical temperature weights and meantime adjustment screws, free-sprung blued steel helical balance spring, diamond endstone. Dial and movement signed, case numbered. Dim. 11.5 x 9.8 x 6.2 cm. Property of an American Collector Notes This French deck chronometer made by a pupil of Auguste Louis Berthoud, Louis Berthoud’s grandson and nephew of Henri Motel. Onésime Dumas (1824-1889). Was Louis Berthoud’s grandson and the nephew of Henri Motel. He was placed by the Government, in 1837, as pupil to Louis- Frédéric Perrelet, then in charge of the Ecole des Horlogers de la Marine, since 1832. When Perrelet resigned in December 1839 for health reasons, and Charles-Auguste Berthoud was appointed as his successor