CHAP. 50.—TORNADOES; BLASTING WINDS; WHIRLWINDS[1], AND OTHER WONDERFUL KINDS OF TEMPESTS.

But if it burst from the cavity of a cloud which is more depressed, but less capacious than what produces a squall, and is accompanied by noise, it is called a whirlwind, and throws down everything which is near it. The same, when it is more burning and rages with greater heat, is called a blasting wind[2], scorching and, at the same time, throwing down everything with which it comes in contact. (49.) Typhon never comes from the north, nor have we Ecnephias when it snows, or when there is snow on the ground. If it breaks the clouds, and, at the same time, catches fire or burns, but not until it has left the cloud, it forms a thunderbolt. It differs from Prester as flame does from fire; the former is diffused in a gust, the latter is condensed with a violent impulse[3]. The whirlwind, when it rebounds, differs from the tornado in the same manner as a loud noise does from a dash.

The squall differs from both of them in its extent, the clouds being more properly rent asunder than broken into pieces. A black cloud is formed, resembling a great animal, an appearance much dreaded by sailors. It is also called a pillar, when the moisture is so condensed and rigid as to be able to support itself. It is a cloud of the same kind, which, when drawn into a tube, sucks up the water[4].

1. The terms here employed are respectively "turbines," "presteres," and "vortices."

2. prhsth\o, a prh/qw, incendo. Seneca calls it "igneus turbo;" Nat. Quæst. v. 13. p. 762. See also Lucretius, vi. 423.

3. Plutarch.

4. A water-spout. We have a description of this phenomenon in Lucretius, vi. 425 et seq.