SNOW LINE. 213 



In lat. 65° N., the snow remains continually on the 

 ground from the middle of October till the beginning of 

 May, at which time the soil begins to appear after it has 

 been covered up for 200 days. The thickness of the 

 snowy covering materially affects the depth to which the 

 low winter temperature can be traced into the subsoil. 

 In places of small extent, sheltered from cold winds, and 

 having a good drainage, with a southern aspect, the vernal 

 rays of the sun assist in removing the snow early ; while 

 a retentive clay, even in lower and more southern localities, 

 produces a tardy summer and late frosts. Such are the 

 hypogenous or primitive districts, which from their cold 

 climate and ungenial soil have been justly named " barren 

 grounds," and are analogous to the terra damnata of 

 Lapland, described by Linnaeus ; or the tundras of Arctic 

 Siberia ; in such tracts the snow falls early and remains 

 Ions. The active vegetation of forest lands reacts on 

 the soil; excited by the sun's rays, the trees are roused 

 from their winter's sleep, while the soil is still as hard 

 as a rock, and the snow disappears sooner from over 

 their roots than elsewhere. At the Equator the per- 

 manent snow line is said to vary from 15,000 feet of 

 altitude to 20,000, to sink to 3,800 on the 60th parallel 

 of latitude, and to be one foot high on the 75th parallel.* 

 The latter assumption does not, however, accord with 

 observations in the northern hemisphere. In no arctic 

 district to which man has yet penetrated, is there a 

 permanent covering of snow through any wide extent of 

 low country. Even at Spitzbergen, only nine degrees from 

 the Pole, there is a summer in which vegetation pro- 

 ceeds, of which we have witnesses in the flora and fauna. 

 The well-fed herds of reindeer, which that hyperborean 



* Von Buch states the height of the snow line at the North Cape 

 (Europe) at 2,275 Prussian feet. — Meyen, Geog. of Plants. 



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