1 86 The National Geographic Magazine 



crosses the boundary line in latitude 65°. 

 It reaches its most northern point just 

 on the Arctic Circle, in longitude 146°, 

 and thence flows southwestward to its 

 mouth. It is navigable for small steam- 

 ers throughout its course in Alaska, and 

 when not closed by ice— that is, from 

 June to October— carries much traffic, 

 since nearly all of the food, supplies, 

 niachinery, and other goods for the sup- 

 port of the mines in Alaska and the 

 Klondike come by this route. 



North of the Yukon most of the land 

 is permanently frozen at a depth, thaw^- 

 ing only near the surface in summer. 

 Whenever the slopes are at all gentle 

 such ground is marshy, forming the 

 well-known tundra of the Arctic regions. 



CLIMATE 



We must speak of the climates rather 

 than the climate of Alaska, for different 



parts of the Territory differ in climate, 

 not in degree only, but in kind. The 

 Pacific coast has a chmate of its own, 

 the coast of Bering Sea has another, and 

 both differ widely from that of the in- 

 terior. 



The climate of the Pacific coast, from 

 Portland Canal in the extreme southeast 

 to Attn Island at the west end of the 

 Aleutian chain, may be characterized, 

 in a word, as ' ' chilly. ' ' Take the well- 

 known climate of San Francisco, with 

 its dampness, fogs, and cold sea winds, 

 reduce the temperature 15 to 18 degrees 

 and increase the dampness and fog in 

 proportion, and you have a fair idea of 

 the chmate of the Alaska Pacific coast. 

 At Sitka, in latitude 57°, the mean an- 

 nual temperature is 43° Fahrenheit, 

 which is about the same as at Eastport, 

 Maine, 12 degrees farther south. The 

 extreme range of temperature on record 



Photo by C. Hurt Meiriam 



Amherst Glacier, College Fiord 



