ARCTIC SEA ICE 95 



winter, as has been stated, pack ice occupies the space between the 

 outer limit of the fast-ice and the outer edge of the Arctic Pack. Along 

 this edge all the year round (but mostly in summer) fragments of 

 the Arctic Pack are torn off by winds from its margin and driven into 

 the pack ice, becoming embedded in it. 



The Arctic Pack is the ice constantly drifting in a more or less 

 definite direction — "many-years-old, rafted [Russian, nahivnoi] ice 

 predominantly in the form of fields, i. e. areas whose limits cannot 

 be seen from a ship's mast. The distinctive characteristics of the 



Fig. s — The Arctic Pack in 87° 44' N. and about 10° 20' W. in May, 1925- Note the pressure 

 ' ridges and, in the left middle background, a level stretch of new ice. (Photograph from Lincoln 

 Ellsworth.) 



Arctic Pack are: its tremendous power, greater than that of the 

 pressure-formed ice in the marginal seas of the Arctic Ocean; its 

 solidity, due to the age, of many years' standing, of these rafted 

 ice formations — a solidity that gradually increases to such a degree 

 that the ice masses look like a compact and homogeneous whole; 

 and, finally, the size of the areas of rafted ice, so large that they 

 represent powerful hummocky fields in extent" (Kolchak). 



In autumn, with the beginning of frost, freezing of water takes 

 place over the whole area of the Arctic Sea.^ In the Arctic Pack 

 the only spaces of open water where new ice forms are leads, channels, 

 and lanes among massive, many-years-old fields (and also the 

 water, mostly fresh, in the hollow depressions on the fields). In 

 the pack ice the new ice covers the spaces of open water among the 

 floating pieces of ice, and, notwithstanding its insignificant thickness 

 of a few centimeters only, it strongly impedes their motion. 



< strictly speaking, the freezing of sea water and phenomena connected with it may be observed 

 among old floating ice during the whole severe Arctic summer. 



