298 
THE SNOW LINE OF TUE ANDES. 
doza and Santiago de Chile. The road leading from one 
01 those towns to the other, rises gradually from 700 to 
3987 toises; and after passing the Col des Andes (La 
Cumbre, between the houses of refuge called Las Calaveras 
and Las Cuevas), it descends continually as far as the 
temperate valley of Santiago de Chile, of which the bottom 
IS only 409 toises above the level of the sea. The same 
survey has made known the minimum of height at Chile of 
the lower limit of snow, in 88° south latitude. The 
limit does not lower in summer to 2000 toises.* I think we 
may conclude according to the analogy of the Snowy Moun- 
tains of Mexico and southern Europe, and considering the 
difference of the summer temperatui-e of the two hemi- 
spheres, that the real Isevadas at Chile, in the parallel of 
V aldivia (lat. 40°), cannot be below 1300 toises ; in Valpa- 
raiso (lat. 33°) not lower than 2000 toises, and in that of 
Copiapo (lat. 27°) not below 2200 toises of height. These 
are the limit-numbers, the minimum of elevation, which the 
rhlge of the Andes of Chile must attain in different degrees 
of latitude, to enable their summits to rise above the line 
of perpetual snow. The numerical results which I have 
just marlred, and which are founded on the laws of distri- 
bution of heat, have still the same importance which they 
possessed at the time of my travels in America ; for there 
does not exist in the immense extent of the Andes, from 
8 south latitude to the Straits of Magellan, one iNevada of 
which the height above the sea-level has been determined, 
either by a simple geometric measure, or by the combined 
means of barometric and geodesic measurements. 
Between 33° and 18° south latitude, between the paral- 
lels of Valparaiso and Arica, the Andes present towards the 
east three remarkable spurs, the Sierra de Cordova, the 
Sierra de Salta, and the Nevados de Cochabamba. Travellers 
partly cross, and partly go along the side of the Sierra de 
Cordova (between 33° and 31° of latitude), in their way from 
Buenos Ayres to Mendoza; it may be said to be the most 
southern promontory which advances, in the Pampas, to- 
wards the meridian of 65® ; it giyes birth to the great river 
known by the name of Desaguadero de Mendoza, and extends 
* On the southern decKvity of the Hinialavas inow begins ^3® nearer the 
equator) at 1V70 toises. • ' 
