Lives and Opinions of Eminent Philosophers

​just as is observed in the case of some things viewed from a distance that produce certain blows. Thunderbolts admit of coming to be both by greater collections of winds and their compression and violent ignition; and by the rupture of a portion and its more violent fallout upon the lower regions, the rupture occurring because the adjacent regions are denser on account of the compression of clouds; and also by the very fallout of the fire as it winds about, just as thunder too admits of coming to be, when the fire has become more abundant and more violently charged with wind and has ruptured the cloud because it is unable to give way into adjacent regions, since compression occurs [mostly against some high mountain, where thunderbolts fall most often] always against one another.

​And thunderbolts admit of being brought to completion in many other ways as well; only let myth be absent; and it will be absent, if someone, following the phenomena well, draws inferences concerning unseen matters. "Whirlwinds admit of coming to be both by the descent of a cloud into the lower regions in the manner of a pillar, having been driven by dense wind and borne on by abundant wind, while the wind outside at the same time drives the cloud sideways; and by the circling of wind in a ring, when some air is compressed together from above; and when a great flow of winds arises and is unable to flow away to the sides on account of the compression of the surrounding air.

​And as long as the whirlwind descends to the earth, tornados arise, just as the generation also occurs according to the motion of the wind; while as long as it reaches the sea, waterspouts are brought to completion. "Earthquakes admit of coming to be both by the trapping of wind in the earth and its juxtaposition beside its small masses and continuous motion, whenever it causes a tremor in the earth; and the earth either embraces this wind from outside, or from masses of earth falling inward into cavernous places of the earth and blowing into wind the trapped air. And by the propagation itself of the motion from the falls of many masses of earth, and again their rebound when they encounter more solid masses of the earth, earthquakes admit of being brought to completion.

​And in many other ways too these motions of the earth can occur. "Winds happen to arise over time as something of an alien nature always insinuates itself little by little, and by the collection of abundant water; the remaining winds arise also when a few fall into the many cavities, as a propagation of these occurs. "Hail is brought to completion both by a stronger freezing and the surrounding on all sides of certain windy particles and then their partition; and by a more moderate freezing of certain watery particles, while certain windy particles border upon them and simultaneously cause their compression and rupture, so that they coagulate part by part as they freeze and in mass.

​Its roundness is not incapable of coming to be both by the melting away of the extremes from all sides and, in the formation, by the surrounding on all sides evenly, part by part, as it is said, whether of certain watery or windy particles. "Snow admits of being brought to completion both when fine water is poured out from the clouds through the proportion of pores and the violent compressions of suitable clouds always by the wind, and then this takes on freezing during its conveyance on account of a certain violent encirclement of coldness in the regions below the clouds. And by freezing in clouds possessing uniform rarity, such an emission from the clouds would occur when the watery particles are squeezed against one another and set side by side; which, causing a kind of compression, bring to completion hail, which occurs most of all in the spring."