Editing Challenger expedition (section)

{{Short description|Oceanographic research expedition (1872–1876)}}
{{Use dmy dates|date=January 2019}}
{{DISPLAYTITLE:''Challenger'' expedition}}
[[File:HMS Challenger (1858).jpg|thumb|upright=1.3|{{HMS|Challenger|1858|6}} refitted at [[Sheerness]] in 1872, ''[[The Illustrated London News]]'']]

The '''''Challenger'' expedition''' of 1872–1876 was a scientific programme that made many discoveries to lay the foundation of [[oceanography]]. The expedition was named after the naval vessel that undertook the trip, {{HMS|Challenger|1858|6}}.
{{Multiple image|perrow=1| width             = 500| image1            =Thalassa; an essay on the depth, temperature, and currents of the ocean (1877) (14595726250).jpg| image2           =Thalassa; an essay on the depth, temperature, and currents of the ocean (1877) (14595927997).jpg| footer=            Maps of the ''Challenger''<nowiki>'</nowiki>s route.}}
The expedition, initiated by [[William Benjamin Carpenter]], was placed under the scientific supervision of Sir [[Charles Wyville Thomson]]—of the [[University of Edinburgh]] and [[Merchiston Castle School]]—assisted by five other scientists, including Sir [[John Murray (oceanographer)|John Murray]], a secretary-artist and a photographer.<ref name="Aitken_t1" /> The [[Royal Society of London]] obtained the use of ''Challenger'' from the [[Royal Navy]] and in 1872 modified the ship for scientific tasks at [[Sheerness]],<ref name="RMG">{{cite web |last1=Chamberlain |first1=Daisy |title=Telling the story of the Challenger Expedition, 1872–76 |url=https://www.rmg.co.uk/stories/blog/library-archive/telling-story-challenger-expedition-1872-76#:~:text=To%20prepare%20the%20ship%20for,HMS%20Challenger%2C%20by%20Alfred%20B. |website=Royal Museums Greenwich |access-date=15 August 2024 |date=26 March 2024 |quote=To prepare the ship for scientific work, HMS Challenger’s refit commenced at the Royal Navy’s Sheerness Dockyard in June 1872. The Admiralty estimated that repairs and modifications would require six months of planning and work.}}</ref> equipping it with separate laboratories for [[natural history]] and [[chemistry]]. The expedition, led by Captain [[George Nares]], sailed from [[Portsmouth, England]], on 21 December 1872.<ref name="Rice">{{cite book|last=Rice|first=A. L.|title=Understanding the Oceans: Marine Science in the Wake of HMS Challenger|publisher=Routledge|year=1999|pages=27–48|chapter=The Challenger Expedition|isbn=9781857287059|chapter-url=https://books.google.com/books?id=F5agn3NSzEoC&pg=PA27}}</ref> Other naval officers included Commander [[John Maclear]].<ref name="crew list">{{cite web|url=http://archimer.ifremer.fr/doc/1885/publication-4749.pdf|title=The Voyage of H.M.S. Challenger 1873–1876. Narrative Vol. I. First Part. Chapter I|archive-url=https://web.archive.org/web/20131014121006/http://archimer.ifremer.fr/doc/1885/publication-4749.pdf|archive-date=14 October 2013}} – pages 19 and 20 list the civilian staff and naval officers and crew, along with changes that took place during the voyage.</ref><ref name="Aitken_t1" />

Under the scientific supervision of Thomson himself, the ship traveled approximately 68,890 nautical miles (79,280 miles; 127,580 kilometres) surveying and exploring.<ref name=eis/> The result was the ''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 over 4,000&nbsp;previously unknown species. 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". The report is available online as the [https://books.google.com/books/about/A%20Summary%20of%20the%20Scientific%20Results%20Obta.html?id=EA1DAQAAIAAJ Report of the Voyage of HMS Challenger]. ''Challenger'' sailed close to [[Antarctica]], but not within sight of it.<ref name="aga">{{cite book|title=The Australian Geographic book of Antarctica|last=Scott|first=Keith|year=1993|publisher=Australian Geographic|location=Terrey Hills, New South Wales|isbn=978-1862760103|page=115}}</ref><ref name="Aitken_t1">{{cite book |last1=Aitken |first1=Frédéric |last2=Foulc |first2=Jean-Numa |title=From deep sea to laboratory. 1: the first explorations of the deep sea by H.M.S. Challenger (1872–1876) |date=2019 |publisher=Iste-Wiley |location=London, UK |isbn=9781786303745 |url=http://www.iste.co.uk/book.php?id=1474}}</ref> However, it was the first scientific expedition to take pictures of icebergs.<ref name="Aitken_t1" />

The expedition, which circumnavigated the Earth, collected data by lowering sounding lines to the bottom of the ocean floor to measure its depth and collect sediment samples, by collecting marine organisms by means of dredges lowered to the ocean floor and trawls lowered into the water at different depths, by measuring temperature at various depths and by collecting samples of seawater at standard depths for chemical analysis.<ref>{{cite web | url=https://salinometry.com/early-determination-of-salinity-from-ancient-concepts-to-challenger-results/4/ | title=Early Determination of Salinity: From Ancient Concepts to Challenger Results – Page 4 – Salinometry }}</ref> They collected plankton samples and recorded the speed and direction of ocean surface currents. Samples were preserved in brine or alcohol, or dried, then brought to Europe and distributed to various experts to analyze.