(Charles) Auguste BERTHOUD (1798-1876) CHRONOMETRE DE MARINE, No. 296. 8-day power reserve. Case: gimbaled brass in mahogany case, brass handles, with key. Sliding back for assembly (with key). Dial:silvered, two off-center auxiliary dials, for hours and minutes on the left and small seconds on the right, sector at noon for power reserve, blued steel "Breguet" hands. Signed and numbered. Movement:Full brass plate, detent escapement, compensated 3-arm balance with screwed weights, blued steel balance spring, spindle with steel chain and pillars. Case dimensions:Height 19 cm - width:18 cm and depth:18 cm. With case key, winding key, vintage card from Auguste Berthoud. (Operation not guaranteed). Charles-Auguste Berthoud, son of Louis Berthoud, himself a nephew and pupil of Ferdinand Berthoud, born in Argenteuil in 1798, Gold Medalist in 1849. As mentioned on the card found inside the box: "Auguste Berthoud, 1844 exhibition, teacher at the Ecole d'Horlogerie de précision, Argenteuil. Silver medal in 1823 and 1827. Gold medal in 1834. Suspension chronometers guaranteeing longitude to within half a degree after two months' navigation. Price:1200 F". The marine chronometer was developed during competitions for the construction of a reliable measuring instrument to solve the problem of precise geographical determination of position at sea: the "Longitude Act", after the maritime disaster of 1707 when 2,000 soldiers perished at sea. For this project, SC E & S Portier is assisted by expert Géraldine Richard.