But I would not deny, that there may exist showers and winds, independent of these causes, since it is certain that an exhalation proceeds from the earth, which is sometimes moist, and at other times, in consequence of the vapours, like dense smoke; and also, that clouds are formed, either from the fluid rising up on high, or from the air being compressed into a fluid[1]. Their density and their substance is very clearly proved from their intercepting the sun's rays, which are visible by divers, even in the deepest waters[2].
1. vapor, nubes and
nebula, respectively. The
distinction, however, between the two latter does not appear very clearly
marked either in the Greek or the Latin, the two Greek words being
indiscriminately applied to either of the Latin terms.
2.