ABSTRACT
THAT whirlwinds and tempests in northern places have a terrifying and dangerous force is unknown to none who has learnt the secrets of Nature and examines them, especially when the complex and unfailing causes of their origin and their components are discerned. 1 A whirlwind (turbo), then, as Isidore says, is a gyration of winds, and is named from earth (terra); it occurs whenever a wind rises and drives particles of earth in a rotatory motion, the whirlwind being produced by several winds striving with one another, as Seneca testifies in his Investigations of Nature. It is generated and moves where there is land, and so tears up trees by the roots and strips bare whatever soil it falls upon; meanwhile it snatches up woods and houses, travelling mostly below the clouds and certainly never higher. It is rounded in shape, and, rolling on like a spinning column, sweeps along faster than any cloud. Its movement is roving, discontinuous, and full of eddies; but it cannot last for long, for, when a wandering and unsettled breath of air has formed a spiral, the total force eventually yields to one wind. Therefore no great storm persists long; the more force wild tempests have, the shorter time they last, and, when the strength of their wind reaches its height, all their fury grows relaxed, for in their turmoil they necessarily draw towards extinction. No one therefore has seen a whirlwind active for a whole day, or even a whole hour. Its speed is marvellous and so is the briefness of its duration. The greater the violence and speed with which it rolls around the earth, the less dense it is, and for this reason it breaks up.
Whirlwind
Woods and houses are snatched up
Roving movement of the whirlwind
Nothing violent lasts for ever
