to sacrifice one of the ship's steel cables in order
to make a lead-line. It was not difficult to find sufficient space
on the ice for a rope-walk, and although a temperature of from 22 deg.
Fahr. below zero (-30 deg. C.) to 40 deg. Fahr. below zero (-40 deg. C.) is not
the pleasantest in which to manipulate such things as steel wire,
yet for all that the work went on well. The cable was unlaid into
its separate strands, and a fresh, pliant lead-line manufactured by
twisting two of these strands together. In this way we made a line of
between 4000 and 5000 metres (2150 to 2700 fathoms) long, and could
now at last reach the bottom. The depth proved to range between 3300
and 3900 metres (1800 to 2100 fathoms).

This was a remarkable discovery, for, as I have frequently mentioned,
the unknown polar basin has always been supposed to be shallow,
with numerous unknown lands and islands. I, too, had assumed it to be
shallow when I sketched out my plan (see page 24), and had thought it
was traversed by a deep channel which might possibly be a continuation
of the deep channel in the North Atlantic (see page 28).

From this assumption of a shallow Polar Sea it was concluded
that the regions about the Pole had formerly been covered with an
extensive tract of land, of which the existing islands are simply the
remains. This extensive tract of polar land was furthermore assumed to
have been the nursery of many of our animal and plant forms, whence
they had found their way to lower latitudes. These conjectures now
appear to rest on a somewhat infirm basis.

This great depth indicates that here, at all events, there has not
been land in any very recent geological period; and this depth is,
no doubt, as old as the depth of the Atlantic Ocean, of which it is
almost certainly a part.

Another task to which I attached great importance, and to which I have
frequently alluded, was the observation of the temperature of the
sea at different depths, from the surface down to the bottom. These
observations we took as often as time permitted, and, as already
mentioned, they gave some surprising results, showing the existence
of warmer water below the cold surface stratum. This is not the place
to give the results of the different measurements, but as they are
all very similar I will instance one of them in order that an idea
may be formed how the temperature is distributed.

This series of temperatures, of which an extract is given here,
wa