_A._ I confess it is probable. The Greeks have the word φρίκη (whence the Latins have their word _frigus_) to signify the curling of the water by the wind; and use the same also for horror, which is the passion of one that cometh suddenly into a cold air, or is put into a sudden affright, whereby he shrinks, and his hair stands upright. Which manifestly shows that the motion which causeth cold, is that which pressing the superficies of a body, sets the parts of it closer together. But to proceed in my queries. Monsieur Des Cartes, whom you know, hath written somewhere, that the noise we hear in thunder, proceeds from breaking of the ice in the clouds; what think you of it? Can a cloud be turned into ice? _B._ Why not? A cloud is but water in the air? _A._ But how? For he has not told us that. _B._ You know that it is only in summer, and in hot weather, that it thunders; or if in winter, it is taken for a prodigy. You know also, that of clouds, some are higher, some lower, and many in number, as you cannot but have oftentimes observed, with spaces between them. Therefore, as in all currents of water, the water is there swiftest where it is straitened with islands, so must the current of air made by the annual motion be swiftest there, where it is checked with many clouds, through which it must, as it were, be strained, and leave behind it many small particles of earth always in it, and in hot weather more than ordinary. _A._ This I understand, and that it may cause ice. But when the ice is made, how is it broken? And why falls it not down in shivers? _B._ The particles are enclosed in small caverns of the ice; and their natural motion being the same which we have ascribed to the globe of the earth, requires a sufficient space to move in. But when it is imprisoned in a less room than that, then a great part of the ice breaks: and this is the thunder-clap. The murmur following is from the settling of the air. The lightning is the fancy made by the recoiling of the air against the eye. The fall is in rain, not in shivers; because the prisons which they break are extreme narrow, and the shivers being small, are dissolved by the heat. But in less heat they would fall in drops of hail, that is to say, half frozen by the shaving of the air as they fall, and be in a very little time, much less than snow or ice, dissolved. _A._ Will not that lightning burn? _B._ No. But it hath often killed men with cold. But this extraordinary swiftness of lightning consisteth not in the expansion of the air, but in a straight and direct stream from where it breaks forth; which is in many places successively, according to the motion of the cloud.