The remains of a pocket chronometer from the 1845 British Northwest Passage Expedition led by Sir John Franklin. The chronometer is in a silver case with an enamelled dial. The glass and hands are missing. It was issued to HMS Terror in 1845 along with eight others (see Chronometer Receipt ADL/D/19 for the full list). It is inscribed 'No 2020 Arnold Jn R. Arnold, London Invt et Fecit'. Lieutenant John Irving wrote to his sister Kate on 10 July 1845 'I have charge of our chronometers, which are little clocks. I have to wind them up and compare them, and write an account of their goings on - there are ten of them in each ship'.

The chronometer was one of two found by Lieutenant William R. Hobson's sledge team on 24 May 1859 at a place where a ship's boat was discovered on the coast of Erebus Bay, King William Island, as part of the search expedition led by Captain F. L. McClintock. Hobson described finding a lot of material in the boat, including 'two chronometers...' [Stenton, 'Arctic' v.69, No. 4, p. 518]. McClintock also records in his narrative '...one of the pocket chronometers found in the boat was marked "Parkinson and Frodsham 980" and the other "Arnold 2020"...', although in his appendix he refers to 'five watches', combining the two chronometers with the three watches found in the boat. [McClintock, Voyage of the Fox (1859), pages 297 and 367].

The Arnold 2020 chronometer was displayed at the Royal Naval Museum, Greenwich, Case 17, No. 7 and 11. 'Chronometers from H.M. Ships "Erebus" and "Terror" '. The item is shown in 'Stereoscopic slides of the relics of Sir John Franklin's Expedition' photographed by Lieutenant Cheyne RN, at the United Services Museum, Whitehall, No. 8 (top, left on top of the certificate of receipt signed by Lt. Irving).