206 THE PHYSICAL GEOGRAPHY OF THE SEA. 



The under current I^avis' Strait iiito the Arctic Ocean, and there is a 

 Ocean — its Infli- surface currcnt setting out. Observations have 

 ^°^^^- pointed out the existence of this under current 



there, for navigators tell of immense icebergs which they have 

 seen drifting rapidly to the north, and against a strong surface cur- 

 rent. These icebergs were high above the water, and their depth 

 below, supposing them to be parallelopipeds, was at least seven 

 times greater than their height above. No doubt they were drifted 

 by a powerful under current. Now this under current comes from 

 the south, where it is warm, and the temperature of its waters is 

 perhaps not below 30° ; at any rate, they are comparatively warm. 

 There must be a place somewhere in the Arctic seas where this un- 

 der current ceases to flow north, and begins to flow south as a sur- 

 face current ; for the surface current, though its waters are mixed 

 with the fresh waters of the rivers and of precipitation in the po- 

 lar basin, nevertheless bears out vast quantities of salt, which is 

 furnished neither by the rivers nor the rains. These salts are 

 supplied by the under current; for as much salt as one current 

 brings in, other currents must take out, else the polar basin would 

 become a basin of salt ; and where the under current transfers its 

 waters to the surface, there is, it is supposed, a basin in which the 

 waters, as they rise to the surface, are at 80°, or whatever be the 

 temperature of the under current, which we know must be above 

 the freezing point, for the current is of water in a fluid, not in a 

 solid state. An arrangement in nature, by which a basin of con- 

 siderable area in the frozen ocean could be supplied by water 

 coming in at the bottom and rising up at the top, with a temper- 

 ature not below 30°, or even 27^.2 — the freezing point of sea wa- 

 ter — would go far to mitigate the climate in the regions round 

 about. 



425. And that there is a warmer climate somewhere in that in- 

 indicationsofamiid- hospitablc sca, the observations of many of the ex- 

 er climate. plorcrs who havc visitcd it indicate. Its existence 



may be inferred also from the well-known fact that the birds and 

 animals are found at certain seasons migrating to the north, evi- 

 dently in search of milder climates. The instincts of these dumb 

 creatures are unerring, and we can imagine no mitigation of the 

 climate in that direction, unless it arise from the proximity, or the 

 presence there of a large body of open water. It is another fur- 



