Book 7
1.153
A shooting star is the sudden kindling of a mass of fire in rapid motion through the air, which leaves a trail behind it presenting an appearance of length. Rain is the transformation of cloud into water, when moisture drawn up by the sun from land or sea has been only partially evaporated. If this is cooled down, it is called hoar-frost. Hail is frozen cloud, crumbled by a wind; while snow is moist matter from a cloud which has congealed: so Posidonius in the eighth book of his Physical Discourse. Lightning is a kindling of clouds from being rubbed together or being rent by wind, as Zeno says in his treatise On the Whole; thunder the noise these clouds make when they rub against each other or burst.
1.154
Thunderbolt is the term used when the fire is violently kindled and hurled to the ground with great force as the clouds grind against each other or are torn by the wind. Others say that it is a compression of fiery air descending with great force. A typhoon is a great and violent thunderstorm whirlwind-like, or a whirlwind of smoke from a cloud that has burst. A prester is a cloud rent all round by the force of fire and wind. Earthquakes, say they, happen when the wind finds its way into, or is imprisoned in, the hollow parts of the earth: so Posidonius in his eighth book; and some of them are tremblings, others openings of the earth, others again lateral displacements,For καυματίας of mss. Cobet reads κλιματίας. and yet others vertical displacements.
