392 T. C. CHAM BERLIN 



film of brine would be unable to sink through the warm layer next 

 below and give rise to the cold abysmal layer at the bottom. 



So far as concerns such freezing as may take place on the under 

 side of the thick Arctic ice already formed, this view seems well 

 taken, for the freezing beneath the thick ice, even in the Arctic 

 regions, is slow and Hmited in amount. The layer of briny water 

 formed by it is thin and subject to mixture while in the process of 

 forming, for more or less of motion between the ice mantle and the 

 water below arises from tides and winds. 



But there is a special type of freezing action that is much more 

 rapid, while at the same time the film of brine it forms is subject 

 to prompt downward, edgewise propulsion. This requires a careful 

 study of details. 



A combination of rapid freezing, brine formation, and downward 

 propulsion. — -While freezing under the cover of thick ice that gen- 

 erally mantles the Polar Sea is slow, very rapid freezing takes place 

 in the cold season where open lanes of water are formed rather sud- 

 denly by the action of winds and tides. According to Peary and 

 other explorers who have traversed the Polar Sea in the freezing 

 months, the opening of such lanes is frequent and often sudden. 

 Just where and when they will open cannot be foretold, and they are 

 often so swift in action that it is wise to sleep prepared for a possible 

 plunge into the icy waters of the opening chasm. The lanes are 

 often so wide and long as to constitute a most serious obstacle to 

 reaching the pole over the ice-fields of the Polar Basin. Peary 

 describes these lanes or "leads" as being "sometimes mere cracks," 

 "sometimes just wide enough to be impossible to cross," and 

 "sometimes rivers of open water from half a mile to two miles 

 in width, stretching east and west farther than the eye can 

 see.""^ He says that the old floes which are traversed by these 

 "leads" are not simply the products of freezing in place but are 

 formed by the crumpKng, crushing, and piling up of such original 

 ice by the almost irresistible power of the great polar ice-sheet, or 



^Robert E. Peary, The North Pole (1910), p. 197. Peary's narrative of his trip 

 to and from the pole (pp. 236-85), gives a very realistic impression of the frequency 

 and extent of the formation of these "leads," and especially of the formidable nature 

 of the "Big Lead," formed over the edge of the continental shelf, in which Marvin lost 

 his life. 



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