SCIENTIFIC RESULTS 



23 



waiiu winters not only prevents the formation of the sheets but also 

 continually break and loosen them from the shore. Melville Bay 

 remained well covered with fast ice during the years 1915 and 1916 

 largely on account of favorable weather conditions. If a cold, quiet 

 winter be preceded by an unusually wet autumn, conditions are 

 ideal for tiie production of a maximum amount of fast ice. Copious 

 ])recipitation not only freshens the sui-face layers, thereby raising 

 the freezing point, but it also establishes a very pronounced state of 

 sti'atitication in the surface layers causing ice to form as in a saucer. 

 Xo correlations have ever been published, to our knowledge, on the 

 relation between rainfall and fast ice, but it is logical to assume that 

 the fresher are the surface layers, the more swdftly will grow the ice. 



An Ice foot at low Tide 



Fkjire 11;. — The ice foot is detined as the ice formation -which Imikls up along the 

 water lines of the northern shores during the colder months of the year. 

 (Photograph by C. Wagner.) 



The outer limit of fast ice is usually determined by waves in the 

 sub-Arctic and by buffeting and frictional pressure in the Arctic. 

 Transelie (1928, p. 112) in this connection, has called attention to 

 the imjiortant role played by the rafted masses of sea ice called 

 " stamukhi.'' These old grounded hummocks with a draft of about 

 12 fathoms, Avhich become strewn along the slopes of the Arctic basin 

 during the summer, serve in winter as a seaward rampart protecting 

 the fast ice from destruction. The outer bounds of the fast ice in 

 the ])olar sea. tliei'efoie. coincide quite closely with the 12-fathom 

 liathyiiu'trical contoui-. Tlie shoreward l)()r(ler of fast ice which 

 i>uilds out fi-om the land, unmoved l)y tides or waves, is called the 

 ice foot. The l)eaches. ledges, and cliffs of northern lands are 

 uaturalh'- chilled to very low tenq)eratiires during winter, causing the 



li»(>s60— 81 :J 



