Marking the 150th anniversary of a voyage that revolutionised our understanding of the oceans

It has been called the Apollo mission of the Victorian era.  In December 1872, exactly 150 years ago, the Royal Navy ship HMS Challenger set sail on an extraordinary four-year voyage around the world.  Her mission was to plumb the deepest, hitherto unexplored regions of the ocean.  On board she carried six scientists, 23 naval officers, about 240 crew, thousands of gallons of alcohol and one hundred miles of rope. 

From our 21st-century perspective, it is difficult to grasp the significance of Challenger’s quest.  She would take depth soundings, of course, and examine the temperature and composition of seawater from the surface to the seabed, and lots more besides, but there was a greater question attached to every single recording that was made in her laboratories. 

Just 13 years earlier, Charles Darwin’s controversial theories about evolution had shaken the very foundations of people’s religious beliefs.  Darwin believed, although many disagreed with him, that marine creatures preserved only as fossils on land might still be flourishing in the depths of the ocean.  By probing the abyss with dredging nets on their extraordinary lengths of rope, Challenger’s scientists therefore hoped to discover primitive organisms that offered clues to the origin of life on Earth.

The scale of the expedition was unprecedented, and it required a unique combination of persuasion, cooperation and funding in order to set it in motion.  The impetus came from two of the leading scientists of their day:  Linlithgow-born Charles Wyville Thomson, who had been educated at the University of Edinburgh and was now its Regius Professor of Natural History;  and William Benjamin Carpenter, Vice-President of The Royal Society, who had accompanied Thomson on a smaller-scale dredging survey in the North Atlantic in 1868. 


Charles Wyville Thomson

Thomson and Carpenter were highly fortunate in that Britain’s government saw the potential benefits of their expedition.  The first permanent telegraph cable had been laid across the Atlantic in 1866, and both Parliament and the British Admiralty understood the advantages of  expanding the telegraph network further.  A circumnavigation of the globe with the intention of mapping the sea bed was regarded as a valuable opportunity;  government funding was approved in April 1872, and by December of that year a Royal Navy ship, stripped of all but two of her guns and converted into a fully-functioning research vessel, was ready to depart, complete with a company of officers, crew and scientists. 

When Challenger slipped into the Solent on 21st December, Wyville Thomson was very conscious, as the expedition’s chief scientist, that a lot was resting on his shoulders.  Personally, he was drawn towards Darwin’s theory, but he was also aware of another, directly opposing idea proposed by Edward Forbes, an earlier Professor of Natural History at the University of Edinburgh.  Forbes believed that the diversity and abundance of marine life diminished with depth, partly as a result of the increasing pressure, and he claimed that no life could exist below 300 fathoms (1,800 feet).  In consequence, this region was called the azoic zone, from the Greek word meaning ‘with no signs of life’. 

But Wyville Thomson had good reason to doubt Forbes’ theory.  On voyages closer to home he had seen remnants of organic life emerge from depths of more than 600 fathoms, and he wanted to conduct a thorough scientific investigation of the deep sea, not just in British and European waters but around the world.  Despite his heartache at leaving his wife and young son behind, he was looking forward to seeing what Challenger’s nets brought to the surface.

Wyville Thomson’s scientists included John Murray, a Canadian-born scientist of Scottish descent who had interrupted his medical training at the University of Edinburgh with a spell as ship’s surgeon on an Arctic whaling cruise.  Murray had returned to Edinburgh to study geology under Sir Archibald Geikie, and he assisted Wyville Thomson in preparing scientific apparatus for Challenger before being confirmed as a member of the expedition team.  


John Murray

The others were Henry Nottidge Moseley, who had a first-class degree from Oxford’s Honour School of Natural Science;  a German scientist called Rudolf von Willemoes Suhm, who was an assistant in the zoological museum at the University of Munich;  John Young Buchanan, a Scot who had studied chemistry at Glasgow University and was assistant to Alexander Crum Brown at the University of Edinburgh;   and John James Wild, a Swiss-born linguist and illustrator who was appointed as Wyville Thomson’s secretary and the expedition’s official artist.

Commanding the ship was Captain George Nares, an experienced Royal Navy officer who had taken part in one of the many search missions for Sir John Franklin’s lost expedition in the Arctic.  Three of Nares’ officers - Herbert Swire, William Spry and George Campbell (the youngest son of the 8th Duke of Argyll) - wrote accounts of the voyage, and provided an entertaining and often irreverent counterpoint to the sober-minded observations of the scientific staff. 

Officers and scientists of Challenger.  Nares is seated, 3rd from right;  Spry seated, 4th from left;  Swire standing behind Nares and Spry, with Wild in white to his left;  Murray standing, 2nd from right;   Wyville Thomson seated in white, 3rd from left;   Buchanan standing 2nd from left with Willemoes Suhm behind him.


By the time Challenger had left Tenerife and started crossing the Atlantic, the naval officers and crew were in no doubt about what kind of activities they would be seeing on a regular basis.  Depth-sounding involved letting down a lump of lead on a length of rope and measuring, by the knots tied in the rope, how much was paid out before it reached the bottom.  Next a dredge was sent down, consisting of a net fitted to an iron frame which was allowed to drag across the sea bed while the ship drifted in the wind.  Then it was hauled back up. 


The contents of a dredge net are examined by Challenger scientists standing ready with sieves and jars


Commonly, what was deposited on deck was a type of soft mud known as ooze, which accumulates on the floor of the deep sea and contains the skeletal remains of dead micro-organisms.  Oozes are classified according to their constituents, and in particular the Challenger was repeatedly finding two kinds of calcareous ooze, which they named Pteropod ooze (consisting of tiny molluscs) and Globigerina ooze (containing a genus of marine plankton).  Both these substances held important new information about early life forms in the oceans, but they failed to impress Sub-lieutenant George Campbell, who obviously liked to keep his ship clean and tidy.  ‘The mud!’ he complained, ‘Ye gods.  Imagine a cart full of whitish mud, filled with the minutest shells, poured all wet and sticky and slimy onto some clean planks and you may have some faint idea of what globigerina mud is like.  In this the naturalists paddle and wade about, putting spadefuls into successively finer and finer sieves till nothing remains but the minute shells, &c.’ 

Oblivious of Campbell’s waning enthusiasm for this leisurely ‘ooze cruise’, the scientists began to formulate theories about the presence or absence of specific sediments at different depths, which they measured on a spectacular scale across the ‘mountains’ of the mid-Atlantic ridge;  they were able to trace this latter feature, now known to be the boundary of several tectonic plates, from the North right down to the South Atlantic.  In 1873 Challenger actually crossed and re-crossed the Atlantic four times, working her way down to Simonstown in South Africa where the crew had to throw water on her decks to stop the pitch from melting in the heat.


Chart from the expedition showing occurrence of oozes, muds and clays


Soon they were proceeding towards the Antarctic, where the winds of the Roaring Forties chilled their bones and heavy waves tossed the ship around like a ‘little cockleshell’, as Navigating Sub-lieutenant Herbert Swire put it.  On Christmas Day the crew assembled on deck and sang ‘The Roast Beef of Old England’ before descending, no doubt with severe pangs of nostalgia, to a simple dinner of salt pork and pea soup.  The officers probably fared slightly better, but ’Oh,’ wrote George Campbell with deliberate irony, ‘the pleasure of keeping watch on wet decks, with sharp hail and sleet pelting one’s face and freezing one’s toes.’

On 16th February 1874, on the edge of the Great Ice Barrier (now called the Ross Ice Shelf), Challenger reached her ‘furthest south’, a latitude of 66°44’ S;  she was only 1,400 miles from the South Pole.  Shortly afterwards, while seeking shelter from violent squalls, she struck an iceberg.  Luckily the damage was light, but after several days of relentless storms and thick fog, the crew were exhausted by the need to keep a constant vigil.  The steward’s assistant, Joe Matkin, wrote:  ‘Although we were eager to see an iceberg, we are just as anxious to lose them now, it is so dangerous sailing these foggy nights with such masses of destruction around us.’  


HMS Challenger was a three-masted corvette, powered by sail with an auxiliary steam engine (coal-fed).  The engine was used to maintain a steady position while depth-sounding.  Painting by Navigating Sub-Lt Herbert Swire, showing Challenger at ‘furthest south’ in Antarctic.


As they moved into the western Pacific, the Challenger scientists made one of their most famous discoveries:  the mind-boggling Mariana Trench, the deepest region of the world’s oceans.  Now known to have a maximum depth of around 36,000 feet (nearly seven miles!) the Mariana Trench could submerge Mount Everest with a mile to spare.  It is easy to imagine the scientists’ growing astonishment as they paid out mile after mile of rope into an area of the Mariana Trench that became known as the Challenger Deep;  even the ship’s parrot, which belonged to Rudolf von Willemoes Suhm, would have been seriously understating the matter with his regular announcements of “Two thousand fathoms and no bottom!”

In Hawaii, some of the officers climbed up to the volcanoes of Kilauea and Mauna Loa.  George Campbell expressed his horror at the sulphur-vapour bath, a box-like contraption that had been erected over a small volcanic vent, apparently for the benefits of a person’s health.  Sitting inside it, according to Campbell, you could either be ‘skinned alive… or else you can be steamed into a damp pulpy condition.’  In his account of the voyage, Engineering Sub-lieutenant William Spry described seeing red-hot lava breaking and surging in the caldera of Kilauea.  ‘All was confusion and commotion,’ he wrote;  ‘I can hardly find words suitable to describe my sensations after seeing such a spectacle.’  (Out of respect for Isabella Bird, I have to point out that she sat in the vapour bath and climbed up all of Hawaii’s volcanoes two years before them, in 1873!)

In the ship’s laboratories, thousands of marine creatures were preserved in glass jars filled with alcohol.  Because space was severely limited, the scientists took every opportunity to send these specimens back to Britain whenever they arrived in port.  In all, the Challenger expedition yielded some 4,700 species of plants and animals that were new to science, including about 10% of all known starfish.  A species of brachiopod, found at a depth of more than 15,700 feet and named Abyssothyris wyvillei after Charles Wyville Thomson, was just one of a myriad deep-sea creatures whose existence proved conclusively that life could exist way below 300 fathoms.  Discoveries of plankton resulted in two new genera, which were called Challengeron and Challengeria (the latter is now named Protocystis).


A species of anglerfish found near the Admiralty Islands in the South Pacific.  It was named the Challenger monkfish (Latin name Lophius naresii, after Capt George S Nares).  Illustration from the Challenger report, Vol. I.


Some of the most curious discoveries were infinitesimally small.  The Challenger expedition was the first to collect micro-meteorites from deep-sea sediments, which appeared under a microscope as tiny spherules with a metal core.  It is now recognised that micro-meteorites are falling to Earth from space all the time, many landing in the oceans, and because they react with oxygen and carbon dioxide in the atmosphere, they can reveal details about the Earth’s atmosphere many millions of years ago.

Easier to see, but just as puzzling, were the strange potato-sized nodules that were dredged up from many locations on the sea bed.  They looked like metallic lumps of coral, and when sliced open they showed concentric rings;  tests showed that they contained manganese and iron hydroxides along with elements such as cobalt, nickel and copper.  At the core of each nodule lay a tiny fragment of detritus, either from a shark’s tooth, a pebble, or a tiny fragment of volcanic pumice.  These manganese nodules (now better described as polymetallic nodules) puzzled Wyville Thomson’s team, and they are still being studied today.  In recent years their rich metallic content has attracted the attention of global mining companies who intend to exploit them, but at present they are being forced to consider the environmental impacts of proposed deep-sea mining.

Among the many astonishing statistics of Challenger’s voyage is the unexpectedly high number of men who jumped ship:  more than a quarter of her crew deserted.  It has been observed that many of them worked in the engine-room as stokers, shovelling coal in conditions of intense heat for long stretches at a time, and the obvious conclusion is that they couldn’t face the prospect of doing this job for four years.  Other experts have suggested that they were simply bored, and left in search of more exciting activities.  Early on in the voyage, Captain Nares persuaded Charles Wyville Thomson to give regular lectures to his officers and crew about the scientists’ findings, which many of them enjoyed, but even so the monotonous routine of depth-sounding and dredging, combined with the necessarily slow progress of the ship, didn’t exactly produce a life of swashbuckling adventure on the high seas. 

There were moments of sheer beauty, however.  One night, as Challenger crossed the Equator somewhere off the coast of West Africa, Sub-lieutenant George Campbell stood and gazed around him in awe.  The sea was glowing with phosphorescence, and every wave as far as the distant horizon flashed brightly as it broke, while the sky above held a faint but visible white glow.  Deep below the stern, as the keel cut through the water, a luminous emerald-green band emitted a spray of yellow sparks that rose up to the surface in a continuous shower of light, glittering and dancing in the ship’s wake.  It felt, wrote Campbell, ‘as if the Milky Way… had dropped down on the ocean, and we were sailing through it.’

The Challenger expedition revolutionised our understanding of the world’s oceans, and was hugely influential in shaping the future of oceanography.   On its return to Britain in May 1876, Charles Wyville Thomson set up the Challenger Expedition Offices at 32 Queen Street, Edinburgh.  Here, specimens were carefully catalogued and distributed to experts for study.   After Wyville Thomson’s death in 1882 the mammoth task of publishing the official report fell to John Murray, the man who has been called ‘the father of oceanography’.   The report ran to 50 volumes, which were published between 1885 and 1895;  as a result, Edinburgh became a centre for ocean science for several decades.  Around 100,000 samples and specimens were collected by the Challenger expedition, many of which are now held by the Natural History Museum in London, where they still provide valuable information for scientists studying changing conditions in the oceans. 




With thanks to Margaret Wilkes, Jane Griffiths and Pat Brown, RSGS Collections Team




While Challenger was in Hong Kong in November 1874, Captain George Nares was called back to Britain to lead the British Arctic expedition of 1875-76.  He was replaced by Captain Frank Thurle Thomson.


Sir John Murray had a long and active involvement with RSGS.  He joined the Society in 1886, became a Council Member, and served as President between 1898 and 1904, remaining a Vice-President until his death in 1910.  He was awarded the RSGS Livingstone Medal in 1910 in recognition of his contributions to oceanography and for his Bathymetrical Survey of Scottish Freshwater Lochs.  


John Young Buchanan was awarded the RSGS Gold Medal (now the Scottish Geographical Medal) in 1911 ‘for his distinguished services to geography, especially in connection with oceanographical research.’



Quotes and reference:


Richard Corfield, ‘The Silent Landscape’ (2004)

Eric Linklater, ‘The Voyage of the Challenger’ (1972)

George Granville Campbell, ‘Log Letters from The Challenger’ (1876)

W J J Spry, ‘The Cruise of HMS Challenger’ (1877)

Sir Charles Wyville Thomson, Sir John Murray, et al., ‘Report on the Scientific Results of HMS Challenger, 1873-76’ (1885-95)

National Oceanography Centre:  Podcast ‘Into the Blue’ with Dr Alejandra Sanchez Franks, Dr John Gould, Victoria Ingles:

BBC Radio 4, ‘In Our Time’ with Melvyn Bragg, Dr Erika Jones, Dr Sam Robinson, Dr Giles Miller

The Challenger Society for Marine Science:  History of the Challenger Expedition

HMS Challenger Collections

The Geological Society (deep-sea nodules)

Natural History Museum:  The Challenger Museum and its Legacy

James Ashworth, for Natural History Museum, 6 Sept 22:  ‘HMS Challenger - How a 150-year-old expedition still influences scientific discoveries today’

Papers and Obituary of Sir John Murray in Scottish Geographical Magazine