ON THE ORIGIN AND CAUSES OF SUBTERRANEAN THINGS, BOOK I

...it does not grow cold and condense, but sometimes heating up under the sun's fire, it is reduced to a thin state, and at other times it is expanded, stirred by the force of the winds. But since humid things—whether they are waters, or juices, or earths mixed with waters or juices—only exhale, it is necessary that vapor original: "halitus" arises there only where there was previously moisture or earth dampened by moisture. Therefore, vapors are not so much the cause of waters as waters are the cause of vapors. For those humid bodies, or earthy ones imbued with moisture, existed before the vapors from which waters might be generated. Thus, Aristotle, who sowed the seed of this opinion, correctly says that the earth is dry by itself, but that it contains within itself much and abundant moisture, conceived from rains, which, when heated, evaporates and generates vapor. For he says: "Mountainous and elevated places, like a sponge suspended, leap and drip water, albeit gradually and from all sides." For they conceive a great force of water flowing down from the air, and they cool the raised vapor and condense it into water. But he did not sufficiently explain what the rarity porosity of mountains is, so that they can be compared to a sponge. For the whole body of mountains, nor of all of them, consists of rare earths and rocks that imbibe water and in which vapor, destined to become water, resides. But the matter is as follows: where rare earths and rocks are lacking in mountains, there are joints of rocks, veinlets, and in some places even caverns, through which vapor can seep, and there, cooled, be condensed back into water.

Nevertheless, the channels that mountains in hot regions possess, in which rains are barely gathered even for three months of the year, do not seem able to conceive such great rains as would suffice for the nine continuous months during which the earth conversely dries out from drought. Indeed, solid rocks, which occupy by far the greatest part of mountains, imbibe no rains. What then? Do these veins, which consist entirely of solid stones, not exclude all moisture entirely? What of the veinlets, whose stones similarly possess solidity—do they not also take in no waters? What of the joints of rocks, which are generally barely an eighth of a finger wide—do they not absorb very few rains? As for the earths, stones, and rocks becoming externally damp, and some of them internally as well, not even a tenth part of the mountains is capable of holding waters: because the rocks, which occupy the greatest space, frequently have rare joints; and because the veinlets are rarer; and because a vein is often 100 feet or more distant from another vein; and because, finally, most mountains have no caverns. But if not many more waters can be generated from vapors than there was moisture from which the vapors arose, and according to Aristotle's opinion, the water that flows out exceeds the mass of the earth, or does not fall much short of it, who does not see that Aristotle does not suffer a lighter blow than he himself inflicted on others who say that water flows from reservoirs? And besides rain, there is another water by which the interior earth is partially moistened, so that heating up, it can continuously emit vapors, from...