THE NORTH POLAR BASIN. 393 



the sun's darts, which glance harmlessly on G feet of snow. In these 

 high latitudes the angle of incidence is yery small, even at midday in 

 midsummer. The sun's rays are reflected back into the dry air with as 

 little effect as a shell which strikes obliquely against an armor plate. 

 But the sun does not tight his battle alone. He has allies which, like 

 the arrival of the Prussians on the field of Waterloo, finally determine 

 the issue of the battle in his favor. The tide of victory turns earliest 

 in Norway, although the Scandinavian Fjeld forms a magnificent for- 

 tress, in which theforces of winter intrench themselves in vain. This 

 fort^es^• looks as impregnable as that on the opposite coast, and would 

 doubtless prove so were it not for the fact that in this part of the Polar 

 Basin the sun has a most potent ally in the Gulf Stream, which soon 

 routs the armies of winter and compels the fortress to capitulate. 



The suddenness of the arrival of summer m Siberia is probably largely 

 due to the geographical features of the country. In consequence of 

 the vastness of the area which is drained by the great rivers, and the 

 immense volume of water which tliey have to carry to the sea, the 

 break up of the ice in their lower valleys precedes, instead of being 

 caused by, the melting of the snow toward the limit of forest growth. 

 The ice on the effluents either breaks up after that on the main river, 

 or is broken up by irresistible currents from it which flow up stream, — 

 an anomaly for which the pioneer voyager is seldom i)repared; and 

 when the captain has escaped the danger of battling against an attack 

 of pack ice and ice floes from a quarter whence it was entirely unex- 

 pected, he may l)e suddenly called upon to face a second army of more 

 tbrmidable ice floes and pack ice from the great river itself, and if his 

 ship survive the second attack a third danger awaits him in the alter- 

 nate rise and fall of the tributary as each successive barrier where the 

 ice gets jammed in its march down the main stream below the junction 

 of the river accumulates iintil the pressure from behind becomes irre- 

 sistible, when it suddenly gives way. This alternate advance and 

 retreat of the beaten armies of winter continued for about ten days 

 during the battle between summer and winter of which 1 was a witness 

 in the valley of the Yenisei. On one occasion I calculated that at least 

 50,000 acres of pack ice and ice floes had been marched up the Ivureika. 

 The marvel is what became of it. To all appearance half of it never 

 came back. Some of it no doubt melted away during the ten days' 

 marches and countermarches: some drifted away from the river on the 

 flooded places, which are often many square miles in extent; some got 

 lost in the adjoining forests, and was doubtless stranded among the 

 trees when the flood subsided; and some were piled up in layers one 

 upon the top of the other, which more or less imperfectly froze together 

 and formed icebergs of various shapes and sizes. Some of the icebergs 

 which we saw going down the main stream were of great size, and as 

 nearly as we could estimate stood from 20 to 30 feet above the surface 

 of the water. These immense blocks appeared to be moving at the 

 rate of from 10 to 20 miles an hour. The grinding together of the 



