On the 3 phenomena: wind, rain and hail. That part of the body travels the greater distance which comes nearest to the cold. * The cloud freezes above and below and at the sides and not in the middle, because heat works more upward than at the sides. Therefore ... * The cloud freezes above, and not below, and at the sides, and not in the middle, because heat works more upward than at the sides, and more at the sides than downward. A thing becomes lighter the more it is heated, and gains more weight the more it is cooled. A thing heats the more, the more it is condensed. A thing heats still more, the nearer it comes to the source of heat. There follows the converse, which says: a thing heats the less, the further it is removed from the heat.

The cloud, borne by the heat enclosed within it toward the sphere of fire, meets the cold region of the air, which freezes it on the outside and does not freeze it within, because the heat that carries it up there defends it from such cold. Whence here are generated 3 phenomena, of which the first is the exhalation of the moisture, which, through the enclosed heat, breaks up and vaporizes and generates a furious wind; the second is the rain, which is generated by the gathering of the particles of vaporized moisture that, striking one another in swift motion and driven by the heat against those that lag behind, on meeting the part of the cloud that toward its edge grows cold, the particles of moisture cling together and gain weight, which descends to earth in large drops. And toward the outermost edge of such a cloud the particles of moisture freeze continually into various globules, which, through the intense cold, cannot spread out and with swift motion run together to the place that produces the roundness of the drop; and therefore hail is composed of many globules which, joined together, etc.