ARCTIC ICE AND ITS NAVIGATION; 681 



on our coasts. There is but one narrow passage for the Bering 

 floes, and the ice after passing through the strait scatters and be- 

 comes easier to avoid. The pack is not confined and caused to 

 revolve between immense icebergs or many narrow passages, as 

 in Greenland or eastern waters, so that the recent employment of 

 steam whalers, instead of the old-time sailing vessels, has been 

 dictated more by a desire for increased profits than by actual ne- 

 cessity. 



But there is another and more dangerous ice than floe ice, as 

 it takes many years for its formation. It is met with in isolated 

 floes, but rarely if ever in pack below Smith's Sound, and the 

 Scotch whalers seldom encounter it. Ships have been nipped 

 hundreds of times in floe ice and escaped, but few if any have ever 

 freed themselves from the fierce grasp of the ancient ice of the 

 arctic, called by Nares floe-berg or paleocrystic ics. This bears 

 evidence of great age, the part above water being from fifteen to 

 forty-five feet in thickness, which would make its depth from one 

 hundred and thirty -five to four hundred and five feet ; the stout- 

 est-built ship that ever put to sea would be crushed into match- 

 sticks by the pressure of two such floes upon her sides. This ice 

 forms the northern limit of the cruising-grounds of the American 

 whalers north of Alaska. Some years it moves to the southward 

 and closes up on them ; again, it recedes, disclosing more of the 

 mystery of the farther north. Scattered here and there through 

 it are polynias, or lakes of ice, of one year's growth, inclosed by 

 heavy floes arched and keyed together. 



Paleocrystic ice is old pack ice built up by successive deposits 

 of snow during a long period of time, thus giving it an appear- 

 ance of stratification. There is an alternation of soft white and 

 hard blue ice, representing, respectively, compressed snow and 

 water formed during the sunshine by thaws, and frozen at night 

 or when cloudy. (It is a remarkable fact that snow will melt and 

 seep through floe ice in sunlight though the thermometer may 

 record far below the freezing-point.) Eventually, during the long 

 summer day, the floe is left bare and dry, but soft and porous, 

 unless so far north that the snow-storms continue all the year 

 round. Over some strata are layers of atmospheric dust, such as 

 Nordenskiold found on the Greenland glaciers ; also the gradual 

 decrease of the thickness of the layers — due to pressure and in- 

 crease of blue ice — because of greater infiltration, as the lower part 

 of the berg is approached, make certain the progressive nature of 

 the formation. 



Beyond the Melville Bay pack, averaging six feet in thickness, 

 lies the " north water " of the whalers, corresponding to the open 

 space usually found between the paleocrystic pack and Bering 

 Strait. This is dotted with hummocks, rubble ice, or broken-up 



