On the Physical Geography of Norway. 309 



the interior. This is most conspicuous about lat. 60° to 62°, 

 where the difference, it would appear, amounts to perhaps 1000 

 feet ; but rapidly declines in lat. 64°, corresponding, in fact, 

 to the peculiar change in the form of the peninsula (referred 

 to at page 190), which there rapidly loses its massive and 

 elevated character, and the climate becomes in consequence 

 more maritime. The rise of the snow line may even be traced 

 on the east and west side of the outlying mountains near the 

 coast. It depends partly on the same cause as the rise of 

 the snow line in the interior of Asia — the comparative dry- 

 ness of the climate — but in great measure also on the greater 

 effect towards the interior of the solar rays, which at Bergen, 

 and on the coast generally, are so often obscured by clouds 

 and fog. Wahlenberg long ago remarked the superior im- 

 portance of the heat of the sun in melting snow, compared to 

 the effect of rain.* This is also true in Switzerland, though 

 exceptions are sometimes striking-! But in Norway, the 

 rain which falls on summer snow can have no great warmth, 

 nor be in any great quantity. We shall probably much ex- 

 aggerate its effect, if we suppose that one-fourth of the yearly 

 fall on the snow fields is in the state of rain, and that the 

 mean temperature of that rain is 40° F. This quantity would 

 thaw no more than one-fiftieth of the snow fallen at other 

 seasons.^ 



We observe in passing, as the result of the comparison of 

 the configuration of the country with the position of the snow 

 line, that though the surface actually covered by perpetual 

 snow in Norway be small, yet the mountainous districts and 

 table-lands everywhere approach it so nearly, that the snow 



* " Calore solis nix melius solvitur quam pluviis omnibus calidis;" and more 

 to the same purpose. — Flora Lapponica, Introd., lvi. 



+ The floods of September 1852 at Chamouni were caused mainly by a 

 deluge of warm rain, which acted simultaneously on the glaciers and snows up 

 even to the summit of Mont Blanc, which was seen all the while from Cha- 

 mouni, whereas falling snow always conceals it more or less. My guide Au- 

 guste Balmat mentioned these facts to me in a recent letter. 



| M. Durocher has computed, from the observations made at the convent of 

 the Great St Bernard in Switzerland, which is but little below the snow line, 

 that not more than one -ninetieth of the annual snow is dissolved by the rain. 



