Accompanied by a gold ratchet key.
John Roger Arnold (1769-1843) was the son of John Arnold, one of the most famous British watch and clock makers.
In 1783, John Roger started working with his father before moving to Paris as an apprentice to Abraham-Louis Breguet in 1792. He was admitted as a member of the Clockmaker's Company in 1796 and became Master in 1817.
After the death of John Arnold senior, John Roger continued on his own, maintaining his father's reputation of one of the leading watch and clock makers of his epoch. In 1830 he moved to 84 Strand and started a flourishing ten years partnership with E. J. Dent, during which the two associates were undertaking various experiments, especially in regard to the influence of magnetism on chronometers.
When Dent left in 1840, Arnold continued on his own until his death in February 1843 after which Charles Frodsham immediately purchased the commerce which prospered until 1858 under the name of Arnold and Frodsham.
Arnold's inventions comprise the helical balance spring for chronometers and a detent escapement similar to the modern chronometer escapement. To this day he is considered the principal chronometer maker.