2. Rains (pluviae) are so called because they flow, as if fluviae. They arise by exhalation from earth and sea, and being carried aloft they fall in drops on the lands, being acted upon by the heat of the sun or condensed by strong winds.
13. Shadow (umbra) is air that lacks sun, and is so called because it is made when we interpose ourselves in the rays of the sun. It moves and is ill-defined, because of the motion of the sun and the force of the wind. As often as we move in the sun, it seems to move with us, because wherever we encounter the rays of the sun, we take the light from that place, and so the shadow seems to walk with us and to imitate our motions.
Chapter 11. On the winds.
2. There are four chief winds. The first of these is from the east, Subsolanus, and Auster from the south, Favonius from the west, and from Septentrio (north) a wind of the same name blows. These winds have kindred winds one on each side.
3. Subsolanus has on its right Vulturnus, on its left Eurus; Auster has on its right Euroauster, on its left Austroafricus; Favonius on its right Africus, on its left Corus. Further, Septentrio has on its right Circius, on its left Aquilo. These twelve winds surround the globe of the universe with their blasts.
20. ... In the spring and autumn the greatest possible storms appear when it is neither full summer nor full winter, whence, as [the time] is an intervening one, bordering on both seasons, storms are caused from the conjunction of contrary airs.
Chapter 12. On the waters.
2. The two most powerful elements of human life are fire and water, whence they who are forbidden fire and water are seriously punished.
3. The element of water is master of all the rest. For the waters temper the heavens, fertilize the earth, incorporate air in their exhalations, climb aloft and claim the heavens; for what is more marvelous than the waters keeping their place in the heavens!
4. It is too small a thing to come to such a height; they carry with them thither swarms of fishes; pouring forth, they are the cause of all growth on the earth. They produce fruits, they make fruit trees and herbs grow, they scour away filth, wash away sin, and give drink to all living things.