178 THEORY OF AN OPEN POLAR SEA. 



sink. Dining the first part of its journey, as we 

 know, its great heat prevails over the other 

 influence, and it flows as a surface-current. But, 

 at a certain point in its northward route, it meets 

 with the cold, brackish, ice-bearing currents that 

 flow out of the arctic basin. Having lost much of its 

 heat (though still possessing a great deal more than 

 the arctic currents), the saltness of the Gulf Stream 

 prevails ; it dips below the polar waters, and thence- 

 forth continues its course as an under-current, salt, 

 and comparatively warm. 



To state the matter briefly : The hot water, which 

 ought to keep on the surface because of its heat, is 

 sunk by its superabundant salt ; and the cold 

 water, which ought to sink because of its cold, is 

 buoyed on the surface because of its want of 

 salt. 



Now arises the question What becomes of the 

 great quantity of salt that is thus being carried 

 perpetually into the polar basin *? Manifestly it 

 must be carried out again by the surface-current, 

 otherwise the polar basin would of necessity be- 

 come a basin of salt. The under-current must, 

 therefore, rise to the surface somewhere near the 

 pole, with its temperature necessarily only a little, 

 if at all, below the freezing-point which, be it ob- 

 served, is a warm temperature for such regions. 

 Here, then, where the warm waters from the south 

 rise to the surface, it is supposed this open Arctic 

 Ocean must exist. 



