S50 Limits of perpetual Snow in the North. [May, 



shown clearly by liis journey of this summer in Switzerland. Tlie 

 Scotch Jir, which in Lapland ascends far above the spruce fo-, ceases 

 to grow in Switzerland at the Iieight of little more than 3000 feet, 

 while tlie spruce fir rises higher than 7000 feet. The beech in 

 Sweden is not to be found farther north than West Gothland; but 

 upon the Alps it ascends to the climate of Lapland. The grey 

 alder {alnus incana) stops considerably below the spruce fir, while 

 in Lapland it is one of the last trees that yields to the severity of the 

 climate. 



In the valleys of the Valais and Savoy, as far as Mount Cenis, I 

 have observed however a similar gradation in the height to which 

 particular species of trees climb, if we attend only to particular 

 localities. Such, for example, are the valleys, which being tra- 

 versed as passes are quite naked of trees. The wind rushing 

 through these passes does not permit trees to grow. We find trees 

 much higher in valleys surrounded by snow mountains, or on the 

 declivities at the heads of valleys. These declivities are so steep, 

 that the warmth from the valley is able to reach them, and conse- 

 quently to produce a modification in the height at which trees grow. 

 The following is a small table of the result of my observations 

 between latitude 45^° and 46i°, excluding the effect of such acci- 

 dental causes : — 



English Feet. 



Snow line .^ 9080 



Rododendron line 7-!)0 



Line of spruce firs 6842 . 



Line of beeches 5132 



Line of cherries 4438 



Line of nuts 3/^8 



Line of vines 2592 



The difference between the absolute height of these lines in 

 Savoy and in the northern parts of Switzerland is considerable. But 

 the observations which 1 made in Appenzel are too uncertain and 

 too crude to enable us to determine how far this difference liolds in 

 them all. At Amman, above the lake of IVallenstadl, Mr. Horner 

 and 1 observed the last nut-tree at the height of 3108 feet, the last 

 cherry-tree at the height of 3556, and the last beech-tree at 

 Thurgau at the height of 4458 feet. This gives us 



AtTliurgau. In tbe Valais. 



The distance of the beeches from the? TO -rx i- . io,or ... 



( iSoO ieet . . . .1333 feet 

 nut-trees 3 



Ditto between the beeches and cher- 7 »r.« i-n . 



> yoz 694 



Ties 3 



If these differences be correct, the snow line in Appenzel must 

 be 100 fathoms lower than in the Vulajs and in Savoy, and could 

 not exceed the height of 8402 feet. 



