The History of the Challenger Expedition

In 1870, Charles Wyville Thomson (right), Professor of Natural History at Edinburgh University, persuaded the Royal Society of London to ask the British Government to furnish one of Her Majesty's ships for a prolonged voyage of exploration across the oceans of the globe. On the 7th December 1872, the expedition put to sea from Sheerness aboard the corvette H.M.S. Challenger.

The vessel was a three-masted square-rigged wooden ship of 2300 tons displacement and some 200 feet in length. She was essentially a sailing ship even though she possessed an engine of 1200 horsepower. It was planned that the ship would be under sail for most of the cruise, using the engine primarily for manoeuvring when conducting scientific observations and deploying heavy gear. All but two of the ship's 17 guns had been removed to make way for purpose-built scientific laboratories and workrooms designed specifically for biological, chemical and physical work. Storage space for all the trawls and dredges was also necessary, together with space for the anticipated sample collection.

The commanding officer was Captain George Nares (left), with approximately 20 naval officers (including surgeons and engineers) and 200 crew. There were six civilian staff and scientists under the direction of Wyville Thomson that included the naturalists John Murray and Henry N. Mosely, the chemist/physicist John Buchanan and the official artist J.J. Wild.

Between her departure in December 1872 and her return to Spithead on 24 May 1876, H.M.S. Challenger traversed 68,890 nautical miles, in the course of which she sampled in the North and South Atlantic and Pacific Oceans and travelled north of the limits of drift ice in the North Atlantic polar seas and south of the Antarctic Circle.

Wyville Thomson reported the Challenger to have made 362 sample/observation stations "at intervals as nearly uniform as possible". At each station, the following observations were made, as far as circumstances allowed:

• The exact depth was determined.
• A sample of the bottom averaging from 1 ounce to 1 pound in weight was recovered by means of the sounding instrument.
• A sample of bottom water was procured for chemical/physical examination.
• The bottom temperature was recorded by a registering thermometer.
• At most stations, a fair sample of the bottom fauna was procured by means of the dredge or trawl.
• At most stations, the fauna of the surface and of intermediate depths was examined by the use of tow nets variously adjusted.
• At most stations, a series of temperature observations was made at different depths from the surface to the bottom.
• At many stations, samples of sea-water were obtained from different depths.
• In all cases, atmospheric and other meteorological conditions were carefully observed and noted.
• The direction and rate of the surface current was determined.
• At a few stations, an attempt was made to ascertain the direction and rate of movement of the water at different depths.

Back at home, the scientific findings of the cruise were examined by over 100 scientists, primarily under the guidance of John Murray, who should receive the highest praise for the work's eventual publication The Report of the Scientific Results of the Exploring Voyage of H.M.S. Challenger during the years 1873-76 occupied 50 volumes, each measuring about 13 by 10 inches and as "thick as a family Bible". They appeared between 1885 and 1895. Scientists involved with collecting and publishing the data were awarded with a specially-minted medal, the original Challenger Medal.

At its completion, The Report discussed with full detail of text and illustrations the currents, temperatures, depths and constituents of the oceans, the topography of the sea bottom, the geology and biology of its covering and the animal life of the abyssal waters. The Challenger cruise had lain the cornerstone of scientific oceanography and begun its introduction to the wider scientific and lay community. The findings of the cruise were correctly described by John Murray in 1895 as "the greatest advance in the knowledge of our planet since the celebrated discoveries of the fifteenth and sixteenth centuries".