Onésime Dumas, 1824-1889, had an illustrious horological background. The Nephew of Henri Motel he was apprenticed first to Louis Frédérique Perrelet, (1781-1854), then to Charles Auguste Berthoud, (1798-1826). Having gone back to work with his uncle for a few years he succeeded Victor Gannery who had himself been apprenticed to Perrelet and soon afterwards set up at Saint Nicholas d'Aliermont near Dieppe. By this time Saint Nicholas had undergone an horological revolution under Honoré Pons - (see lot 31) - so that when Gannery died prematurely at the age of 32 Dumas came into possession of a thriving business in 1851. He exhibited precision horology at Rouen in 1856 and chronometers at Paris in 1857. He was also attributed as being the first to produce chronometers in the English calibre.
The present chronometer was on trial at the Depot de la Marine Chronometer Trials, 1 December 1864 to 1 March 1865.