‹‹‹ Vitr. 8.1.6 | Table of Contents | Vitr. 8.2.1 ›››
7Valleys in the midst of mountains receive a very large proportion of rain, and from the closeness of their woods, as well from the shade which the trees afford, added to the snow, which so long remains on them, allow it to percolate through their strata, and thus arrive at the foot of the mountain, when, issuing forth, it becomes the source of a river. On the contrary, in a champaign country, much water will not probably be found; or if it should, it will not be wholesome, because the great power of the sun, unobstructed by shade, attracts and carries off all humidity from the plains; and were even the water to appear, the air would attract and dissipate the lightest, subtlest, and wholesomest parts, and leave the heaviest, most unpleasant, and most unwholesome in the spring.
7The valleys among the mountains receive the rains most abundantly, and on account of the thick woods the snow is kept in them longer by the shade of the trees and mountains. Afterwards, on melting, it filters through the fissures in the ground, and thus reaches the very foot of the mountains, from which gushing springs come belching out.
But in flat countries, on the contrary, a good supply cannot be had. For however great it is, it cannot be wholesome, because, as there is no shade in the way, the intense force of the sun draws up and carries off the moisture from the flat plains with its heat, and if any water shows itself there, the lightest and purest and the delicately wholesome part of it is summoned away by the air, and dispersed to the skies, while the heaviest and the hard and unpleasant parts are left in springs that are in flat places.