436 SOUTH AMERICA— THE ANDES REGIONS. 



As it approactes the equator, the south wind setting along the Chilian coast is 

 gradually heated, and thus becomes proportionately drier, for heat raises the point 

 of saturation — that is, increases the capacity for containing aqueous vapour. On 

 the other hand, the northern winds become more moist by losing their high 

 temperature, and the aqueous vapour is thus precipitated in the form of rain. 

 On the coasts of Chili proper the proportion of rain water increases with the 

 latitude. Thus the average number of wet or showery days rises from 1 at 

 Copiapo, and 3 or 4 at Coquimbo, to 21 at Santiago and as many as 150 at 

 Valdivia ; the MauUhi, meaning the " Rainy Hiver," fully justifies its Indian 

 name. 



In the Magellanic arch'pelagoes it rains throughout the whole year, and in 

 the Straits of Messier and Smyth, King recorded in 4 1 days a rainfall of over 

 120 inches. This superabundance of moisture, which in the upper atmospheric 

 regions assumes the form of snow, explains the great development of the glacier. 

 These frozen rivers reach right down to the sea under latitudes corresponding to 

 regions of the northern hemisphere where winter snows are rare. Thus the San 

 Rafael glacier lies under 46° 30' south latitude, that is to say, it is as near the 

 equator as the mouth of the Gironde below Bordeaux, while the lower limit of 

 perpetual snow descends to the level of 4,000 feet on the flank of the mountain 

 where it has its source. On the other hand, Aconcagua, less than 950 miles farther 

 north, has been seen free of snow at altitudes of 18,000 or 20,000 feet. 



Climate of Chiloe and Fuegia. 



Even in Chiloe the moisture is excessive. In winter it rains incessantly, " six 

 days in the week," say the natives, " and on the seventh the sky is overcast." In 

 summer the vapoury veil lifts oftener, but even then a succession of a few bright 

 days is a rare occurrence ; the horizon remains cloudy and the forests and heights 

 of the interior are shrouded in greyish mists. The annual rainfall, ranging from 

 80 to 100 inches, transforms the underwoods to morasses. Those engaged in 

 clearing the forests for cultivation find it difficult to fire the trees, which rot as 

 they stand and are blown down by every gale ; few crops succeed, and on the dank 

 soil the green corn grows mouldy in the ear. 



The Magellanic land resembles Alaska, not only in the form of seaboard 

 indented by a labyrinth of inlets, but also in its heavy downpours and its wood- 

 lands springing from a flooded soil. But thunderstorms are rare, although the 

 tempests rage at times with fury. Magellan Strait is occasionally swept by 

 sudden squalls from the lateral gorges, the williwaws of the English sailors, who 

 compare them to avalanches. 



According to the natives there is always a coincidence between the earth- 

 quakes and the torrential rains. At the same time the snows and glaciers on the 

 slopes of the cordillera give an index to the mean temperature of the land, which 

 may be determined by the level to which the frozen masses descend on the flanks 

 of the mountains, as well as by the greater or less abundance of moisture, and the 



