GREENLAND OR POLAR ICE. S^l 



Hence, as winds blowing from the north must 

 be replaced by air neither colder nor less damp, 

 and as every commixture with warmer streams, 

 must produce an increased capacity for moisture 

 therefore, no wind can occasion a detraction of 

 vapour from the circumpolar regions : on the con- 

 trary, as the snow deposited on the interior ice by 

 southerly storms, (from the nature of the circum- 

 stances), must be derived from evaporations out of 

 the sea ; it is evident, that there must be an in- 

 crease of snow in the icy latitudes, and that we can- 

 not possibly determine any limit beyond which it 

 may be affirmed that no snow can be deposited. 



3. On approaching a pack, field, or other com- 

 pact aggregation of ice, the phenomenon of the 

 ice-blink is seen whenever the horizon is tolerably 

 free from clouds, and in some cases even under a 

 thick sky. The ice- blink consists in a stratum of 

 a lucid whiteness, which appears in that part of 

 the atmosphere next the horizon. It is evidently 

 occasioned thus : those rays of light which strike 

 on the snowy surface of the ice, are reflected in-^ 

 to the superincumbent air, where they become 

 visible ; but the light which falls on the sea is in 

 a great measure absorbed, and the superincumbent 

 air retains its native ethereal hue. Hence, when 

 the ice-blink occurs under the most favourable 

 circumstances, it affords to the eye a beautiful and 

 perfect map of the ice, 20 or 30 miles beyond 

 the limit of direct vision, but less distinct in pro- 



