The ship sailed from Portsmouth on December 21, 1872 and, under the command of Captain George Nares and the scientific supervision of Thomson himself, travelled nearly 70,000 miles surveying and Report Of The Scientific Results of the Exploring Voyage of H.M.S. Challenger during the years 1873-76, which, among many other discoveries, catalogued 4,000 previously unknown species of animal. John Murray, who supervised the publication, described the report as "the greatest advance in the knowledge of our planet since the celebrated discoveries of the fifteenth and sixteenth centuries".