CLIMATAL EFFECTS OF ICEBERGS 139 



North Pole the ice streams pass to the sea through valleys in 

 which tlie material becomes much rifted. In the Antarctic 

 realm the accumulations of frozen water extend beyond the 

 shores, and probably move over the bottom for a great dis- 

 tance before they attain a depth in which they can float. 

 Thus the bergs of this region are to a great extent made out- 

 side of the valleys, and thus have a homogeneous structure 

 which causes them to wear away more uniformly than those 

 which are made in Greenland. 



We turn now to consider those parts of the general effects 

 of floating ice which may be supposed to have an interest for 

 the reader. First among these we must reckon the influence 

 they exercise on the climatal conditions of the countries bor- 

 dering on their paths. In the case of the floes and icebergs 

 which are borne southward by the Labrador currents, the 

 effect must be considerable ; they perceptibly cool the sea 

 over a large area, depriving a considerable part of its waters 

 of the warmth which their current would otherwise carry to 

 Northern Europe. If we could confine these wanderers from 

 the icy realm within the regions where they are formed, the 

 effect on the temperature of Northern Europe would be note- 

 worthy and even of economic importance. Their general 

 influence is to disseminate Arctic conditions over a wide area 

 of the more southern regions, where the climate tends through 

 the action of the ocean movements to partake of the tropical 

 warmth. The climate of the northeastern part of North 

 America would probably be distinctly warmer but for the 

 chilling of the neighboring sea which the abundant ice in- 

 duces. So, too, with the southern part of South America ; 

 the climate which now renders the country in good part unfit 

 for aoriculture would be much more tolerable but for the 



