JOHN POOLE ROSEWOOD 2-DAY MARINE CHRONOMETER WITH POOLE'S AUXILLIARY COMPENSATION BALANCE, NO. 2972, CIRCA 1860
the 3½in. silvered dial signed John Poole, Maker To The Admiralty, 57 Fenchurch St., London, 2972, champlevé Roman numerals, subsidiary seconds and up-and-down dials, gold hour and minute hands, movement punch-numbered on the pillar plate, fusee and chain, Harrison's maintaining power, Earnshaw-type footed spring detent escapement, bimetallic compensation balance with cylindrical temperature weights and meantime adjustment nuts, Poole's auxiliary compensation, diamond endstone, free-sprung blued-steel helical balance spring, punch-numbered gimbal-mounted brass bowl in three-tier brass-bound rosewood box with bone signature plaque also inscribed sold by B.R. Hennessy, 5, Wind St., Swansea -- 6½ x 7in. (16.5cm x 18cm.) square approx.
John Poole (1818-1867): Poole worked in premises at 57 Fenchurch Street between 1858 and 1885, he was one of the great makers who established himself as a chronometer maker in 1840. He is perhaps most famous for his auxiliary compensation which was first applied in 1850, of which the present chronometer is a fine example. Poole's auxiliary was commercially successful being easy to make, it acts only in the cold (the reverse of Molyneux's).
++In going order, just needs general cleaning, a nice chronometer in good original condition. Later key.