1910.] INLAND-ICE OF THE ARCTIC REGIONS. 101 



the isblink to a notable increase of its specific gravity through con- 

 tact with and consequent cooHng by the snow surface.'*' 



Foehn Winds Within the Coastal Belt. — The sHding down of 

 masses of heavy air upon the snow surface of the Greenland ice 

 must bring about adiabatic heating of the air and a consequent ele- 

 vation of the dew point. The increase of temperature being about i° 

 C. for every lOO meters of descent, a rise of temperature of as 

 much as 20° C. or 36° F. will result in a descent from the summit 

 of the plateau, assuming this to have an elevation of 10,000 feet. 

 Some reduction in the amount of this change of temperature will, 

 of course, result from the contact of the air with the cold snow 

 surface during its descent, this modification being obviously de- 

 pendent upon the velocity of the current. The warm, dry winds 

 which in different districts have been described under the names 

 foehn and chinook are the inevitable consequence of such condi- 

 tions, and are, moreover particularly characteristic of steep moun- 

 tain slopes more or less covered by glaciers. Such foehn winds 

 have long been recognized as especially characteristic of western 

 Greenland. Dr. Henry Rink, who was a pioneer in the scientific 

 study of Greenland, wrote in 1877 :'^ 



Among the prevailing zi-inds in Greenland the warm land zvind is the 

 most remarkable. Its direction varies according to locality from true E.S.E. 

 to E.N.E. always proceeding though warm from the ice-covered interior, 

 and generally following the direction of the fjord. It blows as frequently 

 and as violently in the north as in the south, but more especially at the fjord 

 heads, while at the same time in certain localities it is scarcely perceptible. 

 It often turns into a sudden gale; the squalls in some fjords rushing down 

 between the high rocks, in certain spots often sweep the surface of the 

 water with the force of a hurricane, raising columns of fog, while the sur- 

 rounding surface of the sea remains smooth. 



^ Professor v. Drygalski has shown that in the Great Karajak glacier 

 near the coast in central western Greenland, the temperature of the snow and 

 ice down to a depth of 60 feet or more undergoes a fall of temperature in 

 response to the severity of the winter's cold, but in time this fall in tempera- 

 ture lags behind the period of maximum cold. Below that depth, however, 

 it approximates in temperature to the zero of the centigrade scale. Tem- 

 peratures of the snow measured just below the surface, varied from — 11° 

 to — 26° C. (E. von Drygalski, " Gronland- Expedition der Gesellschaft fiir 

 Erdkunde zu Berlin," 1891-1893, Vol. i, 1897, pp. 470-472.) 



" Henry Rink, " Danish Greenland, Its People and Its Products," 

 London, 1877, p. 468. 



