SCIENTIFIC RP^SULTS 



23 



warm Avinters not only prevents the formation of the .sheets but also 

 (oiitinually break and loosen them from the shore. Melville l^ay 

 remained well covered Avith fast ice during? the years 1915 and 19l"() 

 larti-ely on account of favorable weather conditions. If a cold, quiet 

 winter be preceded by an unusually wet autuiiui. conditions are 

 ideal for tiie producti<m of a nmxinium amount of fast ice. Copious 

 |)ieci})itation not only freshens the surface layers, thereby i-aisinir 

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

 stratification in the surface layers causin<r ice to form as in a saucer. 

 Xo correlations have ever been published, to our knowled<^e, on the 

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

 the fresher are the surface layers, the moiv swiftly will l^-ow tiie ice. 





An Ice foot at low t ide 



FUjUre 11*. — The ice foot is deflned as tbe ice formation winch builds up along the 

 water lines of the northern shores during (he 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 butfetino; and frictional pressure in the Arctic. 

 Tran.^ehe (192!S. p. 112) hi this connection, has called attention to 

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

 "stamuklii.'' These old tjrounded hummocks Avith a draft of about 

 l"i fathoms, which become strewn along the slopes of the Arctic basin 

 (liuinfr the summer, serve in winter as a seaAvard rampart protecting 

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

 the polar sea. therefore, coincide quite closely Avith the 12-fathom 

 I'athymetrical contour. The shore Avard border of fast ice Avhich 

 iiiulds out from the land, iinmoA^ed by tides or waves, is called the 

 i<e foot. The beaches, ledges, and cliffs of northern lands are 

 ■laturally chilled to very Ioav temperatures during Avinter. causing the 

 nnosixi— Ml 3 



