ave a tapering unequal surface,
must be formed on, or under, the side of a coast composed of pointed
rocks and precipices, or some such uneven surface. For we cannot suppose
that snow alone, as it falls, can form, on a plain surface, such as the
sea, such a variety of high peaks and hills, as we saw on many of the
ice-isles. It is certainly more reasonable to believe that they are
formed on a coast whose surface is something similar to theirs. I have
observed that all the ice-islands of any extent, and before they begin
to break to pieces, are terminated by perpendicular cliffs of clear ice
or frozen snow, always on one or more sides, but most generally all
round. Many, and those of the largest size, which had a hilly and spiral
surface, shewed a perpendicular cliff, or side, from the summit of the
highest peak down to its base. This to me was a convincing proof, that
these, as well as the flat isles, must have broken off from substances
like themselves, that is, from some large tract of ice.

When I consider the vast quantity of ice we saw, and the vicinity of the
places to the Pole where it is formed, and where the degrees of
longitude are very small, I am led to believe that these ice-cliffs
extend a good way into the sea, in some parts, especially in such as are
sheltered from the violence of the winds. It may even be doubted if ever
the wind is violent in the very high latitudes. And that the sea will
freeze over, or the snow that falls upon it, which amounts to the same
thing, we have instances in the northern hemisphere. The Baltic, the
Gulph of St Laurence, the Straits of Belle-Isle, and many other equally
large seas, are frequently frozen over in winter.[12] Nor is this at all
extraordinary, for we have found the degree of cold at the surface of
the sea, even in summer, to be two degrees below the freezing point;
consequently nothing kept it from freezing but the salt it contains, and
the agitation of its surface. Whenever this last ceaseth in winter, when
the frost is set in, and there comes a fall of snow, it will freeze on
the surface as it falls, and in a few days, or perhaps in one night,
form such a sheet of ice as will not be easily broken up. Thus a
foundation will be laid for it to accumulate to any thickness by falls
of snow, without its being at all necessary for the sea-water to
freeze. It may be by this means these vast floats of low ice we find in
the spring of the year are formed, and which, after