Provenance: Time Museum, Rockford, Illinois, inv. No. 1529. A very rare example of an English pivoted detent chronometer ? few have survived. At the beginnings of chronometry in England, both Earnshaw and Arnold used pivoted detents, which in most cases were later converted to spring detents. They abandoned the pivoted one in favor of the spring detent mostly because of the undesirable action of oil on the detent pivots. Emery, best known for his pioneering work with lever escapements in his early years, also used pivoted detents. Only two examples have survived; this one and the slightly earlier No. 781, dating from 1778, owned by the Dukes of Northumberland, and presently in the British Museum. Happily, the escapement of this watch has not been converted, as most have been. Later improvements were the change of the balance for Emery?s patented ?double S? and the balance spring from a flat one to a free-sprung helical one. At that point Emery?s compensation curb was abandoned so as not to interfere with the action of the bimetallic ?S? strips, and the cock was remade to accommodate the higher balance spring. The dust cap was also probably abandoned then. As was customary, this type of upgrading was most likely done by the maker himself. In 1782 Emery patented his ?double S? balance, a fact which he advertised widely. It does not seem unlikely that the owner of the watch, having heard of the new invention, may have requested that the maker adapt it to his recently-bought watch. Most of Emery?s ?double S? balances are found in his lever watches, which he started making in 1782, the year of the patent. He produced less than 40 of them, of which fewer than twelve are known to have survived, making the ?double S? balance even rarer. The watch exemplifies the earliest English attempts to produce reliable and affordable precision timekeepers. In their quest, they experimented first with pivoted detents, which in the case of Arnold and Earnshaw later resulted in the development of the spring detent, and in Emery?s, the development of the lever escapement. Josiah Emery (Geneva 1725 - London 1796). An eminent clockmaker, L. Berthoud said of Emery?s work that it was particularly good in its essential points, and not ?showy?. He made several watches with anchor escapements, of which the first dates from 1774. Emery submitted four chronometers to the ?Office of Longitude? between 1792 and 1796, but obtained no success with them. He studied and corrected the error of the escapement of the chronometer made by Genevan clockmakers Demole & Magnin. Emery settled in London and became a member of the Clockmakers? Company in 1781. He had a shop at 33 Cockspur St., Charing Cross. His workmanship is always superlative, equal to the best of his contemporaries, including Arnold. In 1781 his excellence was recognized by his peers, who elected him an Honorary Freeman of the Clockmaker?s Company, a distinction rarely given. He was succeeded by Recordon and Dupont in 1796.