88 DISCUSSIONS IN CLIMATOLOGY. 



the two midsummer months that Siberia, even with 

 its inconsiderable snowfall, is not at the present day 

 covered with permanent snow and ice. Mr. Wallace 

 mentions that " in Siberia, within and near the Arctic 

 circle, about six feet of snow covers the country all 

 the winter and spring, and is not sensibly diminished 

 by the powerful sun so long as northerly winds keep 

 the air below the freezing-point, and occasional snow- 

 storms occur. But early in June the wind usually 

 changes to southerly, and under its influence the snow 

 all disappears in a few days." But what would be 

 the consequence were these northerly winds to con- 

 tinue during the whole of June and July ? It would 

 probably be that the snow of autumn would begin to 

 fall before that of spring had disappeared. Were this 

 to result, the country would soon become covered with 

 permanent ice. Matters would be still worse if these 

 southerly winds, instead of ceasing, were simply to 

 change from June and July to December and January, 

 for then, in place of producing a melting effect, they 

 would greatly add to the snowfall. 



The only Continental Ice on the Globe probably on 

 Lowlands. — The only two continents on the globe 

 covered by permanent ice and snow are Greenland and 

 the Antarctic. But are these continents to be regarded 

 as high lands or as low lands ? Mr. Wallace maintains 

 that they are high lands. " It is," he says, " only 

 where there are lofty mountains or elevated plateaus, 

 as in Greenland, &c, that glaciers accompanied by 

 perpetual snow cover the country. The north polar 

 area is free from any accumulation of permanent ice, 

 excepting the high lands of Greenland and Grinnell 

 Land." And in regard to the Antarctic continent he 

 says, " The much greater quantity of ice at the south 

 pole is undoubtedly due to the presence of a large 



