This polar bear with tzvin cubs on a rotting 

 will swim back to shore or to the ice front. 



berg may 



drifted for hundreds of tnilc 



tumbled ice, the whole world seems to be floodlighted with ten 

 million colored arcs for twenty-four hours a day. never quite the 

 same but never going away, and all often cast upon a backdrop 

 of dark rocks and sculptured ice. 



THE POLAR ICE RAFT 



Even the Arctic ice raft itself is not. despite its somewhat deplor- 

 able appearance at first, a complete waste. It is a great cap of 

 sea ice. very slightly curved to fit the earth, varying in thickness 

 from a few feet to — as the submarines which have now traveled 

 under it have shown — some four hundred feet, and compounded 

 of frozen sea surface and snow that has fallen upon the surface 

 of the ice and compacted. It is a thousand miles wide measured 

 from the top of the Atlantic via the Pole to the Pacific, but only 

 six hundred miles wide measured at right angles to that line. 

 The extra mass lies on the Pacific side, north of Siberia and 

 Alaska. It is not homogeneous, for there is ice of various origins 

 and ages in its composition, and it contains some vast rafts of 

 what are called palaeocrystic ice. These behave like huge float- 

 ing islands and are very ancient; they may even be relics of an 



ice raft formed before this great sea unfroze the last time — this 

 it may have done, according to some climatologists. in immedi- 

 ately prehistoric times. Some of these ice islands are today used 

 as permanent bases and landing fields for aircraft. Held in the 

 thinner, newer ice. they drift slowly round the pole. The polar 

 ice raft as a whole is not. however, permanent. It is continuously 

 being added to on top and melting away below; and it is aug- 

 mented all around its edge by sea-formed pack ice. It has holes 

 in it that open and close hither and yon. and its various parts 

 move reciprocally about among themselves so that ships caught 

 in it may wander in all directions, their courses leaving extraor- 

 dinary patterns on a chart. As a whole, it revolves slowly rela- 

 tive to the adjoining land, due to being unable to quite keep up 

 with the spin of the earth, so that its edge moves from east to 

 west as looked at from the south. 



The polar pack ice lies right against the upper edge of this 

 continent. One would have thought, therefore, that these shores 

 would also be profoundly icebound and snow-covered. Very 

 surprisingly, this is not the case; the Cape Maurice Jesup area at 

 the northern tip of Greenland is not glaciated at all. Even in 

 winter comparatively little snow falls there and this usually 

 melts off quite fast. In summer it is an almost lush land with a 



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