Physical Science in the Time of Nero: Naturales Quaestiones (1910) - Page 23

CHAP.		PAGE
XIII.	Aristotle and Theophrastus take evaporation to be the cause. Strato, much in the same way, thinks that differences of internal temperature are the cause . . . . . .	240
XIV.	By some it is thought that air is the cause, but that its operation, along with water, is like that of blood and air in the vessels of the body. The earth, it is assumed in this case, admits air, which must find an exit. When it does so violently, the result is an earthquake . . . . . .	242
XV.	The earth is porous, perforated at many points, and it is thus that the air enters . . . . . . .	243
XVI.	The earth is full of air, nourishing plants rooted in it, and exhaling enough to feed the sun and the other heavenly bodies. Air is the most movable of elements; therefore the earth, if it is full of air, must also have frequent movements . . . .	244
XVII.	Obstruction of air, just as of water, causes greater impetuosity when it escapes. Wind is frequently associated with earthquakes, as at Chalcis . . . . . . .	245
XVIII.	Additional considerations to prove that the great cause of earthquakes is air, i.e., wind . . . . . .	247
XIX.	Metrodorus of Chios compares the rumbling of an earthquake to the resonance of the voice in a tub; the underground caves impart the sound . . . . . . .	248
XX.	Various combinations of water and air supposed by Democritus and Epicurus to co-operate in the production of earthquakes .	249
XXI.	Air must be the cause. Different kinds of earthquakes . .	251
XXII.	First species—shaking of the earth: its causes . . .	252
XXIII.	Next comes the form of concussion caused by air. The great Callisthenes, who braved the fury of Alexander and lost his life for it, supports this view. Submarine effects of it are particularly noticeable . . . . . . .	253
XXIV.	Different explanations may be given of the exact method in which air acts . . . . . . .	255
XXV.	The striving of the air in subterranean caverns produces a concussion or collapse in the earth above. The area of disturbance is limited, never over 200 miles, as numerous instances prove. The Peneüs and Ladon rivers were thus produced . . . .	256
XXVI.	The nature of the soil composed of muddy accretions without interstices is said to account for the exemption of Egypt from earthquakes. So Delos in the sea has porous rocks which emit the air easily. But the facts are wrong. There is abundant proof that proximity to the sea is no safeguard against shock .	258
XXVII.	A peculiarity of the Campanian earthquake, that it killed 600 sheep, is explained by the emission of pestilential vapor, by which sheep, with their heads close to the ground, naturally were most readily affected . . . . . .	259
XXVIII.	Noxious vapors are not, however, peculiar to earthquakes. They are found in several parts of Italy habitually. Such, too, is the origin of new diseases . . . . . .	261
XXIX.	Excessive fear drives people mad. Earthquakes split statues and divide kingdoms, e.g., Sicily from Italy, Spain from Africa .	262