xvi PHYSICAL SCIENCE 



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 fail, what 

 can be done ? Refuge from tempest and fire and thunderstorm 

 and war is possible, but not from earthquake. But (i) the whole 

 earth is subject to such movement : we cannot escape by changing 

 our ground Tyre, Asia Minor, Achaia have all suffered. (2) 

 Death is the same in whatever form it come, the circumstances 

 matter not, 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 philosophic 

 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 



(cp. 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 

 vapour 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 bursting point . 239 



