98 FORT CONFIDENCE. 



surface. In unsheltered lakes the wind drifts the 

 snow to the beach, and would perhaps keep the ice 

 clean for great part of the winter, were it not that 

 in certain hygrometric conditions of the atmo- 

 sphere small starry tufts of most beautiful tabular 

 and latticed crystals are deposited at short in- 

 tervals on the ice, and freeze firmly to it. In a 

 dry atmosphere these crystals evaporate again, but 

 should a fall take place of the fine, dust-like snow, 

 which is the most common kind in the high lati- 

 tudes, they serve to detain it until it consolidates, 

 so as to resist the wind. It is rare, however, for 

 the snow to lie more than a foot deep on any of 

 the large lakes, unless where it has drifted under 

 the lee of piled-up slabs of ice, or of rocks, islands, 

 or other shelter. 



During winter the ice receives an increase of 

 thickness from beneath, and at the same time 

 evaporates above ; the latter process going on with 

 a rapidity that would scarcely be credible to one 

 ignorant of the extreme dryness of the air in an 

 arctic winter. The ice acquires a thickness of 

 from four to eight feet, according to the severity 

 of the season, the depth of the lake, and other 

 modifying circumstances ; and I desire here to 

 advert especially to the fact, that although it 

 is constructed of successive horizontal additions 

 beneath, when it decays in spring it consists of 



