...by the end of the third week
of February 1874, as Challenger moved among the icebergs
only a handful of miles from the Great Ice Barrier, Moseley
observed that the ice of the bergs showed layers of compaction.
He wrote, “The entire mass shows a well marked stratification,
being composed of alternate layers of white opaque looking,
and blue, more compact and transparent ice… the
color depending on the greater or less number and size
of the air-cells in the ice.”
(Moseley's
sketch of Antarctic icebergs showing the layers of compaction)
It was a clue that
in the same way that the sediments of the ocean floor
are the library of time, the ice of the Antarctic also
preserves a record of climate change...
It was the first hint that ice,
like deep ocean sediments, has its own memory...
Termination Land, 61o18'S, 94o
47'E
On February 16, 1874, Challenger
was as far south as she was destined to go, a latitude
of 66o 40' S and a longitude of 78o 22' E. She was on
the edge of the Great Ice Barrier and only 1,400 miles
from the South Pole, the attainment of which would engender
so much heartache and privation for the expeditions of
Amundsen, Scott, and Shackleton a few decades later. But
Nares was under strict orders not to try to proceed any
farther. Both victuals and coal were in short supply and
the risk of getting trapped in the ice was too great.
They would certainly not survive a winter in those grim
latitudes. As Wyville Thomson put it, “As the season
was advancing, and as there was no special object in our
going farther south, a proceeding which would have been
attended with great risk to an unprotected ship…
once or twice the water began to show that “sludgy”
appearance which we know “sets” so rapidly,
converting in a few hours an open pack into a doubtfully
penetrable barrier,—Captain Nares decided upon following
the edge of the pack to the northeastward, towards the
position of Wilkes' “Termination Land.”'
The expedition's orders made it
clear that proving the existence or otherwise of Wilkes's
Termination Land was a priority.
As recently as 1840 Captain Wilkes
of the United States Navy had written, "In latitude
64o31' south longitude 93o east, we made what was believed
to be land to the south and west, at least as far as terra
firma can be distinguished when everything is covered
with snow. Soundings were obtained in 320 fathoms, which
confirmed all our previous doubts, for on later observation
a dark object, resembling a mountain in the distance,
was seen, and many other indications presented themselves
confirming it. Advancing to the westward, the indications
of the approach to land were becoming too plain to admit
of a doubt. The constant and increasing noise of the penguins
and seals, the dark and discolored aspect of the ocean
strongly impressed us with the belief that a positive
result would arise in the event of a possibility to advance
a few miles farther to the southward."
By the 23rd of February they were
approaching the area marked on the charts as being where
Wilkes had spied his great continent, but there was nothing
to be seen...
...During the night the weather
changed. By daylight on the morning of the 24th the wind
was rising fast; the sky was dark and threatening, with
frequent snow squalls that blew across the ship blinding
clouds of wheel-like crystals so intensely cold that they
burned when they touched the skin...
...“It was,” wrote
Matkin, “considered the worst and most dangerous
night we have had... Altho' we were all 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 all round us.”
(It was
the most dangerous night since Challenger had left the
English Channel. As Lieutenant Pelham Aldrich's sketch
shows, Challenger almost foundered that night among the
icebergs.)
There was still no
sign of Termination Land so the hunt for it was abandoned.
Spry wrote, “Wilkes' vision was at fault, and the
great Antarctic continent has turned out to be a Cape
Flyaway… Having now proceeded as far south as practicable
in an undefended ship, at noon course was altered to the
east …On reaching clear water studding sails were
set and we were off for Australia, Cape Otway, 2, 278
miles distant.”
So Challenger turned its back on
the Antarctic, much to the relief of all aboard, from
Captain Nares and Charles Wyville Thomson down to ship's
steward's assistant Joseph Matkin. But all aboard would
have been aghast to know the scientific discovery that
they were turning their back on, a discovery that would
be made a hundred years later by the Vostok Ice Core team...
The Lost World
In the mid 1970s—almost
exactly a hundred years after Challenger was in the region—an
airborne radar survey of the ice sheet around Vostok Station
revealed the presence of an enormous freshwater lake,
beneath the ice sheet, that covered an area of about 10,000
square kilometers. By the early 1990s observations from
satellites confirmed the presence of the lake, which was
named Lake Vostok, and the news was released to the public
by the Russian and American scientists who made the discovery.
The news caused a sensation, because
the central question was obvious to all: How could a lake
of liquid water survive under 4 kilometers of ice in the
coldest region on Earth...?
...Lake Vostock is now thought
to be the closest known analogue for the ocean under the
Europan ice cap and the probes that are being devised
to go to that Jovian moon to search for life will be tested
in its frigid waters.
This is the irony,
of course, for as we have seen, one of the main reasons
for the voyage of H.M.S. Challenger in the first place
was the desire to test the Darwinian notion that the oceans
were the domain of life forms that were, from the evidence
of the fossil record, extinct on land. It turned out,
however, that the ocean bottom was not so much the lost
world that Challenger sought, but rather a lake under
an ice cap.
So unequipped with the knowledge
she needed to find what she sought, Challenger turned
north and headed for the greatest outpost of Empire.
Australia.
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