This chronometer was supplied by Greenwich Observatory on August 31st 1860 for the 'Zambesi Expedition' and was probably part of the resupplying of the expedition in 1861 when Livingstone returned to Tete and took delivery of its new boat the Pioneer. A group from the Oxford and Cambridge mission arrived with the boat. For the next three years the chronometer was used by Livingstone, it was carried by him on board H.M.S. Pioneer and, later, was one of the two that he took with him in Lady Nyassa when he sailed from Mozambique to Bombay on 16th April 1864. On his arrival at Bombay on 14th June 1864 he checked it against the '9 p.m. Gun'. It was landed at Sheerness Dockyard at the beginning of June 1866 and on 11th June was returned to the maker DENT & CO. for overhauling and re-rating.