BOOK VI

TREATING OF EARTHQUAKES

CHAP.		PAGE
I.	EARTHQUAKE at Pompeii and the alarm it caused, many giving up Campania as a residence altogether. If the solid earth fails, what can be done? Refuge from tempest, fire, thunderstorm, and war is possible, but not from earthquake. But (1) the whole earth is subject to such movement: we cannot escape by changing our ground—Tyre, Asia Minor, and Achaia have all suffered. (2) Death is the same in whatever form it comes; the circumstances matter little—a stone is all one with a mountain .	221
II.	We cannot escape death. The hopeless find refuge in despair. The knowledge of our frailty and mortality is our true solace. Death must come; a death with circumstance is rather to be preferred than otherwise. In an earthquake, the earth shows itself mortal as men are . . . . . .	225
III.	Our fears are due to ignorance. Through lack of a philosophical view of the universe, we consider phenomena strange which are merely rare, e.g., eclipses. Fear may be removed by knowledge	228
IV.	The study of such problems is the very worthiest; it reveals the secrets of nature and is disinterested. But it is highly profitable at the same time . . . . . .	229
V.	Various explanations of earthquakes have been suggested. The earlier ones are crude, but not therefore to be despised. Every subject develops as time goes on. Gratitude is due to the investigators who first dared to question nature . . .	230
VI.	The cause of earthquakes is by some said to be water. Thales of Miletus explains how this takes place, but he must be wrong: the analogy of a ship sailing the ocean will not apply to the earth (compare III. xiii.) . . . . . . .	231
VII.	Water may be the cause, but may operate in quite different ways from those supposed by Thales. Storms, etc., in subterranean seas may cause earthquakes . . . . . .	233
VIII.	There must be such subterranean water. The Tigris and Arethusa prove it. Nero, the virtuous and the veracious, sent two officers to investigate the sources of the Nile; their account confirms the assumption . . . . . .	235
IX.	Fire is another alleged cause. It either bursts out through opposing obstacles, as in the clouds (Anaxagoras), or burns away the foundation and causes a subsidence at the spot . .	236
X.	Pieces of the earth falling in merely through the decay of age may produce the effect without fire or any external influence. This is Anaximenes' opinion . . . . . .	237
XI.	Fire is supposed by some to cause earthquakes by expanding the vapor which it first causes to be given off from the subterranean waters . . . . . . . .	238
XII.	Archelaus sets down the cause as air pressing up the earth's internal wind which is already condensed to the bursting point .	239