1834.) DESCENT OF GLACIERS. 245 
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- 
Jera behind Chiloe (with its highest points ranging from only 
5600 to 7500 feet) and in central Chile* (a distance of only 9° 
of latitude), is truly wonderful. The land from the southward 
of Chiloe to near Concepcion (lat. 37°), is hidden by one dense 
forest dripping with moisture. The sky is cloudy, and we have 
seen how badly the fruits of southern Europe succeed. In 
central Chile, on the other 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 perpetual snow undergoes the above remark- 
able flexure of 9000 feet, unparalleled in other parts of the 
world, not far from the latitude of Concepcion, where the land 
ceases to be covered with forest-trees ; for trees in South America 
indicate a rainy climate, and rain a clouded sky and little heat 
in summer. 
The descent of glaciers to the sea must, I conceive, mainly 
depend (subject, of course, to a proper supply of snow in the 
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 that many of the 
glaciers would have reached the sea. Nevertheless I was asto- 
nished when I first saw a range, only from 3000 to 4000 feet in 
height, in the latitude of Cumberland, with every valley filled 
* On the Cordillera of central Chile, I believe the snow-line varies ex- 
ceedingly in height in different summers. I was assured that during onc 
very dry and long summer, all the 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. 
+ Miers’s Chile, vol. 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. 
