Page:A sketch of the physical structure of Australia.djvu/100

88 clothed with the densest forest, and often, as in Chiloe, drowned in perpetual torrents of rain. North of 30&deg; or in the region of the easterly trade winds the exact opposite is the case. Here the whole country of Brazil and the neighbouring territories east of the great chain are clothed with magnificent forests, refreshed by frequent rains, and traversed by magnificent rivers that, springing from the snows of the Andes, are kept up and replenished, and continually added to by streams flowing from every portion of the country, while, on the western slope of the great chain in the narrow belt of Peru occur great deserts without a drop of water, and rain is seldom, or in many places, never known to fall. In each case the wind loaded with the moisture it has taken up in passing over the ocean is effectually drained of it in crossing the cold altitudes of the mountain chain. It is obvious that if we changed the position of the Andes while the winds remained the same, if the mountain chain ran along the eastern coast of South America, the position of the fertile and desert tracts would be reversed. Patagonia would be covered with forest, while Brazil would be a hot, desert, and arid region, with a mere strip of watered and fertile country along the eastern coast. Now, this supposed case, is exactly that of Australia, with the difference, that as the eastern chain of Australia