In May of 1876, a ship named the Challenger sailed into the harbor of Spithead, England, home from a voyage of three and a half years and 65,890 miles over the seven seas. Her voyage had been one of exploration, of the sea bottom.

the Challenger

The Challenger Expedition was organized by Charles Wyville Thomson. In 1868, he had undertaken a survey of the ocean bottom around the British Isles. The success of this expedition, as well as two subsequent ones, led him to approach the Admiralty with a much more ambitious project -- an investigation of the "conditions of the Deep Sea throughout all the Great Oceanic Basins." The naval authorities were impressed enough with Thomson's project to provide him with the services of the H.M.S. Challenger, which was fitted with auxiliary steam power in addition to her sails. A naval crew under Captain George S. Nares, who had already enjoyed a distinguished naval career, was assigned to the mission, and Thomson selected a staff of scientists and other civilians to assist him.

left: Charles Wyville Thomson
right: Captain George S. Nares

Challenger scientists and crew

Once the crew and staff had been assembled, they proceeded to adapt and/or make the necessary scientific equipment, and to fit out laboratories on the ship. To make room for the scientific gear, they removed all but two of the warship's 18 guns. Their equipment included instruments for taking soundings, bottom samples, and undersea temperatures; 144 miles of sounding rope and 12.5 miles of sounding wire; sinkers, nets, dredges, a small library, hundreds of miscellaneous scientific instruments, and "spirits of wine" for preserving specimens.

natural sciences laboratory aboard the Challenger

The Challenger sailed from Portsmouth, England, on December 21, 1872. The staff spent the first leg of the voyage, to Bermuda, in training and practice on their work -- sounding, dredging, trawling, and making measurement. Holding the ship steady, the crews took a standard series of observations: the total depth of water, the temperatures at various depths, atmospheric conditions, the direction and rate of the current on the ocean surface, and occasionally of the currents at different depths. They also dredged up samples of the bottom, including its plant and animal life, and dipped up samples of the water and of the sea life at various levels. By the time they had finished their voyage, they had made such observations at 360 stations scattered over 140 million square miles of ocean floor.

The routine was long and hard. In really deep water, it took more than an hour and a half to reach bottom, and much longer to haul the line back. Deepwater dredging, when repeated several hundred times, was regarded from two points of view: the one was the naval officer's, who had to stand for 10 or 12 hours at a stretch carrying on the work; the other was the naturalist's, to whom some new worm, coral, or echinoderm was a joy that would last forever.

Over the course of its voyage, the Challenger became the first steamship to cross the Antarctic Circle. On March 23, 1875, off the Mariana Islands, the explorers hit their deepest sounding -- 26,580 feet. The Challenger then zigzagged across the Pacific, stopping at the Hawaiian Islands and Tahiti, and then rounded South America through the Strait of Magellan. It swung north through the South and North Atlantic, and finally arrived back in England on May 24, 1876.

The voyage of the Challenger. Depths of more than 18,000 feet are in dark blue, and depths over 24,000 are numbered and named: 1) Kuril Trench, 2) Japan Trench, 3) Bonin Trench, 4) Mariana Trench, 5) Caroline Trench, 6) Mindanao Trench, 7) New Britain Trench, 8) Java Trench, 9) Tonga Trench, 10) Aleutian Trench, 11) South Sandwich Trench, 12) Puerto Rico Trench.

Of the Challenger's crew of about 240 men, seven died during the trip -- two by drowning, one of yellow fever, the others by accidents and miscellaneous causes. In addition, several crewmen left the ship in Australia.

The voyage of the Challenger resulted in proof that life existed at great depths in the sea. It also established the shapes of the ocean basins, and yielded the first knowledge of currents and temperatures in the oceans. The expedition made thousands of contributions to the fields of meteorology, hydrography, geology, petrology, botany, zoology, geography, and many others.

SOURCE
Our Wonderful World New York: Grolier Incorporated, 1965

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This page was last updated on 05/03/2017.