1834.] DESCENT OF GLACIERS. 2-! 5 



be determined by the extreme heat of the summer, rather than 

 by the mean temperature of the year, we ought not to be sur- 

 prised at its descent in the Strait of Magellan, where the sum- 

 mer is so cool, to only 3500 or 4000 feet above the level of the 

 sea ; although in Norway, we must travel to between lat. 67° 

 and 70° N., that is, about 14^ nearer the pole, to meet with 

 perpetual snow at this low level. The difference in height, 

 namely, about 9000 feet, between the snow-line on the Cordil- 

 lera behind Chiloe (with its highest points ranging from only 

 6600 to 7oOO feet) and in central Ciiile* (a distance of only 9"" 

 of latitude), is truly wonderful. Tiie land from the southward 

 of Chiloe to near Concepcion (lat. 37^), is hidden by one dense 

 forest dripping witli moisture. Tiie sky is cloudy, and we have 

 seen how badly the fruits of southern Europe succeed. In 

 central Ciiile, on the o-tiier hand, a little northward of Con- 

 cepcion, the sky is generally clear, rain does not fall for the 

 seven summer months, and southern European fruits succeed 

 admirably ; and even the sugar-cane has been cultivated. | No 

 doubt the plane of ])erpetual snow undergoes the above remark- 

 able flexure of 9000 feet, unparalleled in other parts of the 

 %Yorld, not far from the latitude of Concepcion, wiiere the land 

 ceases to be covered with forest-trees ; for trees in South America 

 indicate a rainy climate, and rain a clouded sky ajid little heat 

 in summer. 



The descent of glaciers to the sea must, I conceive, mainly 

 depend (subject, of course, to a proi)er supply of snow in tiie 

 upper region) on the lowness of the line of perpetual snow on 

 steep mountains near the coast. As the snow-line is so low in 

 Tierra del Fuego, we might have expected tliat many of the 

 glaciers would have reached tlie sea. Nevertlieless I was asto- 

 nished ^^ hen I first saw a range, only from 3000 to 4000 feet in 

 lieight, in the latitude of Cumberland, with every valley filled 



* On the Cordillera of central Chile, I believe the snoM-line varies ex- 

 ceedingly in height in different summers. I was assured that during one 

 very dry and long summer, all tlie snow disappeared from Aconcagua, 

 although it attains the prodigious height of 23,000 feet. It is probable that 

 much of the snow at these great heights is evaporated, rather than thawed. 



t Miers's Chile, toI. i. p. 415. It is said that the sugar-cane grew at 

 Ingenio, lat. 32^ to 33°, but not in sufficient quantity to make the manufacture 

 profitable. In the valley of Quillota, south of Ingenio, I saw some large 

 date palm-trees. 



