of these were undeveloped and compared to Arnold's were of little use, the balance especially having to be redesigned. Eventually, after much argument, the Board of Longitude granted Earnshaw and Arnold awards for their improvements to chronometers. Earnshaw received £2500 and John Arnold's son, John Roger Arnold, received £1672. The bimetallic compensation balance and the spring detent escapement in the forms designed by Earnshaw have been used essentially universally in marine chronometers since then. For this reason, Earnshaw is also generally regarded as one of the pioneers of chronometer development. However, because Arnold's balance spring patents were in force (each for 14 years), Earnshaw could not use the helical balance spring until the 1775 patent lapsed in 1789, and, in the case of the 1782 patent, 1796. Until around 1796, Earnshaw made watches with flat balance springs only, but post 1800, practically every marine chronometer, including those by Earnshaw, had a helical spring with terminal overcoils. Arnold was the first to produce marine and pocket chronometers in significant quantities at his factory at Well Hall, Eltham from around 1783. During the next 14 or 15 years, he produced hundreds before he had any kind of commercial competition. These indicate that authors such as Gould and Sobel are incorrect in their assertion that there was commercial rivalry between Arnold Sr. and Earnshaw. Arnold and Breguet The important French watchmaker Abraham-Louis Breguet became a great friend of Arnold. In 1792, the Duke of Orleans met Arnold in London and showed him one of Breguet's clocks. Arnold was so impressed that he immediately travelled to Paris and sought permission for Breguet to take on his son as his apprentice.<ref>David Salomons, Breguet 1747–1823, (London, 1921, privately published), p. 10</ref> Arnold appears to have given Breguet carte blanche to incorporate or develop any of Arnold's inventions and techniques into his own watches. These included his balance designs, helical springs made of steel or gold, the spring detent escapement, the overcoil balance spring, and even the layout of an Arnold dial design that Breguet incorporated into his own. These were made from engine-turned gold or silver—a pattern that became the classic and distinctive Breguet dial. Arnold's pattern first appeared in 1783, on the enamel dials Arnold designed for his small chronometers, and the proportions and layout of their figuring is identical to that of the classic "Breguet" type of engine-turned metal dials which appeared around 1800,