﻿Trof. Milne — Across Europe and Asia. 



467 



Name of liiver. 



Basiu of! 

 the Obi. 1 



Basin ( 

 of the 

 Yenisei. ( 

 Basin of f 

 the Lena. \ 

 Basin of \ 

 theYana. I 



Sir Daria, near Aral. 

 Obi, near Barnaul. 

 Tobol, near Kurgan. 

 Irtish, near Tobolsk. 

 Obi, near Obdorsk. 

 Angara, near Irkutsk. 

 Lake Baikal.* 

 Yenisei, near Krasnoiarsk. 

 Lena, near Kirensk. 

 Lena, near Yakutsk, 



Yana, near Ust Yansk. 



,N. Lat. 



Ice Forms. 



45° 0' 



Nov. 20 



63° 14' 



Oct. 30 



55° 32' 



Oct. 26 



58° 20' 



Oct. 24 



67° 28' 



Oct. 20 



62° 20' 



Dec. 30 



53° C 



Dec. 23 



56° 6' 



Oct. 29 



57° 40' 



Oct. 26 



61° 58' 



Oct. 21 



71° 23' 



Sept. 6 



Ice breaks up. 



March 22. 

 April 15. 

 April 

 April 

 May 

 May 

 April 

 April 20 

 April 30 

 May 13 



15. 



20. 

 20. 

 20. 

 20- 



•MaylO. 



May 



* Lake Baikal, -which is introduced amongst the table of rivers, like the rapid 

 Angara which flows from it, is very irregular in its time of freezing and in opening. 

 These times also vary in diiferent parts of the lake, as might be expected from its 

 north and south extension. 



is that on the same river, the northern portion of tlie river freezes 

 only a little earlier than the southern part, whilst it, comparatively 

 speaking, breaks up a considerable time later. Thus, for instance, 

 on the Obi, at Obdorsk, near its mouth, the ice only forms about one 

 week before it does at Barnaul, which is a considerable distance to 

 the south, whilst it breaks up a month later. 



For illustration, suppose we take the Eiver Nile near its mouth, 

 and partially reduce the area of its channel with a blockade of ice 

 for a week : I think we might reasonably expect a flood. Floods of 

 this kind may be observed in low latitudes, as on the Angara near 

 Irkutsk. In 1870, a sudden frost rapidly freezing the river over, a 

 flood was caused which did great damage to the town. But this is 

 not the worst aspect of the action which may be illustrated by taking 

 the Nile, not at an ordinary season, but at the time when it is drain- 

 ing off an unusually large quantity of water from the south, and at 

 such a time placing a barrier across its mouth, not for one week, but 

 for three or four. The consequences would be, I think, disastrous. 

 It will be observed that it is at these times when the Siberian rivers 

 have the most water, from the melting of the southern ice and snow, to 

 drain away, that their mouths are for the longest period dammed up. 



During past times, when the cold was probably more intense, these 

 barriers of ice may have been more continuous and complete, and 

 thus have kejDt the plains — which were then smaller than ilxej are at 

 present, because their northern ends were beneath the sea — more or 

 less constantly covered with a lake of turbid water. As this flood 

 varied in its nature, being more or less dependent upon the accumu- 

 lation and breaking up of the ice, so we had beds of a varying 

 nature deposited; sometimes they were of silt, and sometimes they 

 were of sand. 



And in this way, whilst accepting the main feature in Mr. Belt's 

 argument that it was a barrier of ice which caused a freshwater 

 lake, I should endeavour to explain the origin of the Siberian 

 Steppes, without seeking the aid of a Polar Ice Cap. 



We have now a Palseocrystic Ice Cap upon our northern hemi- 



