Junej 1834. height of snow-line. 2^5 



the line of perpetual congelation in a climate such as this of 

 the southern hemisphere, than m the opposite one subject to 

 extremes. 



The height of the plane of perpetual snow in any country, 

 seems chiefly to be determined by the extreme heat of 

 summer, rather than by the mean of the year. As the 

 summer in Tierra del Fuego is so very wretched, we ought 

 not to feel surprised at the fact stated by Capt. King, 

 — that in the Strait of Magellan, the line descends to about 

 3500 or 4000 feet. In the northern hemisphere, we must 

 travel about fourteen degrees nearer the pole to meet with 

 so low a limit, namely, between lat. 67^ and 70° on the 

 mountains of Norway. 



In the Cordillera of South America, between latitudes 

 41° and 43° 30', the culminant peaks have altitudes pretty 

 nearly equal. Several were measured by the officers of the 

 Beagle with considerable care, by angles of elevation, the posi- 

 tions of the mountains being accurately known. Osorno is 

 7550 feet; mountain south of Osorno 5609; Minchinmadiva 

 7046; northern end of same range 6862; Corcovado 7510; 

 Yntales 6725. Not only these points, but a great part of 

 the range* was thickly clothed with snow, in the beginning 

 of February (answering to our August), which descended 

 some way down the mountains, and presented to a distant 

 beholder a perfectly horizontal line. We were assured that 

 the snow, which it appeared must inevitably be the case, 

 remained throughout the year. On January 26th, after a 

 week of uncommonly fine weather, Mr. King measured with 

 a pocket sextant, the angle of this line with the summit 

 of the Corcovado ; and subtracting the result from the total 

 height, the snow-line was found to descend to 4480 feet. 

 It is possible that there may have existed some unknown 

 cause of error ; but as the average height of the few highest 



* Mr. Sulivan, who surveyed this part of Chiloe, informs me, that 

 between Osorno and Yntales, there are probably many mountains which 

 rise to a height of nearly 6000 feet. He says he does not recollect any 

 one summit, which (during January) M'as not covered with snow. 



T 2 



