old. Also, melting and gravity drift of salt particles downward combine 

 to produce the typical appearance of polar ice after one Bummer's thawing. 

 Once the winter ice fails to melt completely and becomes polar ice, it 

 soon assumes the properties of polar ice' and melts very slowly, eventually 

 drifting into the East Greenland current. From the air the polar ice has 

 a distinctive appearance arid is readily distinguished, from' vdnter ice 

 during the,s.umraer months. The m'^lt puddles^ in winter ice form regular 

 patterns, vitiile the eroded pressure, ridges and: hummocks of old polar ice 

 are irregular in pattern. 



In forecasting the movement, of thp polar ice, its composition must be 

 taken into account. The oceanographic factors influence winter ice much 

 more than polar ice, so that the forecast will be different for different 

 compositions of the pack. It will also be different in the region around 

 the North Pole, v.'here there is little winter ice, than it is in the Beaufort 

 and Chukchi Seas where there is' a large percentage of winter ice. The 

 average age of the ice is greatest in the Lincoln Sea, where paleocrystic 

 ice is the typical form. 



From the above analysis of ice age and coverage, it appears possible 

 to estimate the feasibility of taking a ship to the North Pole, the dream 

 of many Arctic explorers. The approach frou Greenland seems the most 

 difficult and nearly impossible. The nearest approach to the pole was 

 made by the icebreaker Sedov which was frozen into the ice and reached 

 86'39»N in August 1939, slightly north of the farthest point reached by 

 the Fram in 1895. However, these ships were frozen into the ice and were 

 not maneuverable. Consequently, th^y may be considered in the same class 

 as rafts or ice floes like the Russian Station North Pole. In order to 

 qualify as a maneuverable ship, the icebreaker should be able to change 

 position during summer months and break out of the pack vfhen necessary. 

 On the basis of prp sent, experience, no' ship has ever been built which is 

 powerful enough to reach the North Pole under its own pov/er. However, if 

 the warming of the Arctic continues, it is possible that the more power- 

 ful ships of the future will be able to maneuver more and more v/ithin the 

 Polar Basin. In the far distant future, all the ice may be melted and the 

 Arctic Ocean may become another highway for seaborne commerce. 



