A Victorian small two-day marine chronometer, Parkinson and Frodsham, London, circa 1840 The four pillar full-plate single chain fusee movement with Harrison's maintaining power, split bimetallic balance with keystone-shaped compensation weights, helical balance spring and faceted diamond endstone, the spotted backplate signed Parkinson & Frodsham, Change Alley, London and with brass bayonet fitting dust cover, the 3.25 inch circular silvered Roman numeral dial with blued steel hands, subsidiary seconds and power reserve dials, and inscribed Parkinson & Frodsham, Change Alley, London 2276 to centre, set in a lacquered brass bowl with screw-down bezel mounted within pivoted gimbals with locking screw, the mahogany three-tier case with push button clasp for the top tier above inset ivory panel inscribed PARKINSON & FRODSHAM, LONDON to the middle tier with brass key escutcheon over blank circular inset ivory name plate beneath, the sides with brass carrying handles, 16cm (6.25ins) wide. William Parkinson and William James Frodsham founded the highly regarded firm of Parkinson & Frodsham in 1801 at 4 Change Alley, Cornhill, London. William Parkinson died in 1842 and William Frodsham in 1850. Initially the firm specialised in marine and pocket chronometers. It had an extensive export business, and supplied the Admiralty and numerous shipping companies. After the founders’ deaths the business was continued by Frodsham’s elder sons and grandson until 1912, when the name and business were sold to the foreman, William Harris. Harris and his son Geoffrey ran the business successfully until 1944 when the firm’s premises in Budge Row were bombed.