Physical Science in the Time of Nero: Naturales Quaestiones (1910) - Page 21

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III.	But wind does not thus depend on density; cloudy or misty weather does not necessarily produce wind, while wind is produced when the morning sun dissipates the air. Democritus is, therefore, wrong . . . . . . . . .	195
IV.	Wind arises in two ways—from the interior of the earth by emission—like wind in the stomach!—and from evaporation . . .	196
V.	The air has an inherent power of movement, which is the chief cause of wind, evaporation being a less powerful one. Water has the power of moving and of imparting life to animals and plants . .	197
VI.	Even fire, the destroyer, sometimes generates life. Air in like manner has a peculiar power of its own . . . . . .	197
VII.	Breezes before dawn arise from rivers, etc. They do not last long .	198
VIII.	The “gulf” wind (ἐγκολπίας): its origin and duration . . .	198
IX.	Connection of winds with seasons of the year and with the heat and light of the sun. The sun does not directly cause the winds	200
X.	Some cite the Etesian Winds as proof that it does. They blow in summer when the snows melt and the moisture is carried south .	201
XI.	But as to the effect of the sun, there is no analogy between the Etesian Winds, which do not spring up until late in the day, and the winds which rise at dawn and fall as the day advances . .	202
XII.	Cloud squalls (ἐκνεφίας). Their formation and combinations . .	203
XIII.	The breaking up of clouds produces wind. Air, in an effort to get free, or heat, may produce this. Interruption of free passage may produce a whirlwind, just as an obstacle in a river creates a whirlpool. Violent whirlwinds catch fire (πρηστήρ). Some winds produce different ones. An analogy holds between air and drops of moisture. A union of forces in air or in dew is necessary to give impulse and produce a current. Air and wind are merely a matter of degree . . . . . . . . . .	204
XIV.	Mode in which the subterranean winds are generated and make their escape . . . . . . . . . . .	205
XV.	Ancient miners of Philip’s saw rivers and vast underground reservoirs. It is some consolation to read such a story, which shows greed is no new vice: the older generations were as reckless as we are in their quest for treasure better left hidden . . .	207
XVI.	The four cardinal winds. The full list includes twelve. Their names and directions . . . . . . . . .	208
XVII.	The great circles of the earth which give twelve divisions, and therefore prescribe the possible number of the winds . . .	210
XVIII.	The uses of wind and the illustration afforded of the wisdom of Providence. The crops are dependent on it. So is commerce. But we make the sea a highway to war and not to peace. We go to seek for death, as if it were not always near. Xerxes, Alexander, and Crassus are warnings of the mischievous use of power to cross the sea. Better, perhaps, the winds had never been given at all. But the value of a natural gift must not be estimated by the depraved use of it. Every gift, even sight and speech, man has perverted in the same way . . . . .	212