POLAR ICE. INFLUENCE ON ATMOSPHERE. 297 



one side of a field, before it be perceptible on the 

 other ; and, 'while a storm prevails in open water, 

 ships beset within sight, will not experience one- 

 half of its severity. 



2. It is not uncommon for the ice to produce the 

 effect of repulsing and balancing an assailing wind. 

 Thus, when a severe storm blows from the sea di- 

 rectly towards the main body of ice, an opposite 

 current will sometimes prevail on the borders of 

 the ice ; and such conflicting winds have been ob- 

 served to counterpoise each other, a few [furlongs 

 distant from the ice, for several hours : the violence 

 of the one being, as it were, subdued by the frigo- 

 rific repulsion and greater density of the other. The 

 effect resulting, is singular and manifest. For, 



3. The moist and temperate gale from the south- 

 ward, becomes chilled on commixture with the north- 

 em breeze, and having its capacity for moisture there- 

 by diminished, discharges its surplus humidity in 

 the thickest snow * As the quantity of the snow 

 depends considerably on the difference of tempera- 

 ture of the two assimilating streams of air, it fol- 

 lows, that the largest proportion must be preci- 

 pitated on the exterior of the main body of ice, 



* It is almost needless to say, that the foundation of this, 

 and some of the following remarks, on the same subject, is de- 

 rived from Dr Hutton's ingenious Theory of Rain, an able 

 and beautiful illustration of which we have in Professor Les- 

 lie's Essay " On the Relations of Air to Heat and Moisture," 

 p. 122. 



