s, where the extremities of
the present continents are not opposite to it; and this circumstance
seems explicable only on the principle above alluded to, of the
radiation of heat from the lands so situated.

The cold of the antarctic regions was conjectured by Cook to be due to
the existence of a large tract of land between the seventieth degree of
south latitude and the pole. The justness of these and other
speculations of that great navigator have since been singularly
confirmed by the investigation made by Sir James Ross in 1841. He found
Victoria Land, extending from 71 degrees to 79 degrees S. latitude,
skirted by a great barrier of ice, the height of the land ranging from
4000 to 14,000 feet, the whole entirely covered with snow, except a
narrow ring of black earth surrounding the huge crater of the active
volcano of Mount Erebus, rising 12,400 feet above the level of the sea.
The position of a mountainous territory of such altitude, so near the
pole, and so obvious a source of intense cold, fully explains why
Graham's and Enderby's Land, discovered by Captain Biscoe in 1831-2
(between lat. 64 degrees and 68 degrees S.), presented a most wintry
aspect, covered even in summer with ice and snow, and nearly destitute
of animal life. In corresponding latitudes of the northern hemisphere we
not only meet with herds of wild herbivorous animals, but with land
which man himself inhabits, and where he has even built ports and inland
villages.[179]

The distance to which icebergs float from the polar regions on the
opposite sides of the line is, as might have been anticipated, very
different. Their extreme limit in the northern hemisphere is lat. 40
degrees, as before mentioned, and they are occasionally seen in lat. 42
degrees N., near the termination of the great bank of Newfoundland, and
at the Azores, lat. 42 degrees N., to which they are sometimes drifted
from Baffin's Bay. But in the other hemisphere they have been seen,
within the last few years, at different points off the Cape of Good
Hope, between lat. 36 degrees and 39 degrees.[180] One of these (see
fig. 2) was two miles in circumference, and 150 feet high, appearing
like chalk when the sun was obscured, and having the lustre of refined
sugar when the sun was shining on it. Others rose from 250 to 300 feet
above the level of the sea, and were therefore of great volume below;
since it is ascertained by experiments on the buoyancy of ice floating
in sea-water, t