the polar basin did not exist,
I am still of opinion that in some other way a body of water must
collect in it, sufficient to form a polar current. In the first place,
there are the North European, the Siberian, and North American rivers
debouching into the Arctic Sea, to supply this water. The fluvial basin
of these rivers is very considerable, comprising a large portion of
Northern Europe, almost the whole of Northern Asia or Siberia down
to the Altai Mountains and Lake Baikal, together with the principal
part of Alaska and British North America. All these added together
form no unimportant portion of the earth, and the rainfall of these
countries is enormous. It is not conceivable that the Arctic Sea of
itself could contribute anything of importance to this rainfall; for,
in the first place, it is for the most part covered with drift-ice,
from which the evaporation is but trifling; and, in the next place,
the comparatively low temperature in these regions prevents any
considerable evaporation taking place even from open surfaces of
water. The moisture that produces this rainfall must consequently in
a great measure come from elsewhere, principally from the Atlantic
and Pacific oceans, and the amount of water which thereby feeds the
Arctic Sea must be very considerable. If we possessed sufficient
knowledge of the rainfall in the different localities it might be
exactly calculated. [5]

"The importance of this augmentation appears even greater when we
consider that the polar basin is comparatively small, and, as has
been already remarked, very shallow; its greatest known depth being
from 60 to 80 fathoms.

"But there is still another factor that must help to increase
the quantity of water in the polar basin, and that is its own
rainfall. Weyprecht has already pointed out the probability that
the large influx of warm, moist atmosphere from the south, attracted
by the constant low atmospheric pressure in the polar regions, must
engender so large a rainfall as to augment considerably the amount
of water in the Polar Sea. Moreover, the fact that the polar basin
receives large supplies of fresh water is proved by the small amount
of salt in the water of the polar current.

"From all these considerations it appears unquestionable that the
sea around the Pole is fed with considerable quantities of water,
partly fresh, as we have just seen, partly salt, as we indicated
further back, proceeding from the different ocean cur