TERRESTRIAL PHENOMENA. 59 



others have suffered through being dried up too much. 

 This happened, he adds, in Greece, for, about the time of 

 the Trojan War, Argos was swampy and could support 

 only a small population, while Mycenae was prosperous, but 

 now it is the other way about, for Mycenae has become quite 

 parched, while the lands at Argos, which were formerly 

 useless because of their swampiness, are now cultivated.* 



Aristotle records and makes interesting observations 

 about several great earthquakes and volcanic eruptions. 

 There was, he says, an earthquake in Achaia and an inflow 

 of the sea about the time of the great comet, which was 

 seen during the archonship of Asteus.t Just lately, he 

 says, an earthquake took place at Heraclea, in Pontus, and, 

 some time before this, another occurred in the Sacred Isle, 

 one of the -^olian Islands. Here, a part of the ground 

 swelled up and rose into a hillock, the swelling up being 

 accompanied by a great noise, until the hillock burst and a 

 great quantity of a spirituous vapour {ttveu/mz) issued forth, 

 carrying with it both sparks and ashes. The capital of 

 the Liparseans, not far away, was completely burnt, and 

 the ashes reached some of the cities of Italy. Even now, 

 he says, it can be seen where this eruption took place, t 

 It was from observations on eruptions such as this that 

 Aristotle concluded that earthquakes and volcanic eruptions 

 were due to a violent circulation within, and final discharge 

 from, the interior of the Earth of a kind of air, gas, or 

 vapour, which he calls " wind " {av£/xo;} in some passages 

 and " spirituous vapour " {weuf^a) in others. 



When the spirituous vapour is abundant, he says, a 

 lateral tremor of the earth takes place, or, occasionally, 

 a vertical pulsation. In this kind of earthquake a large 

 quantity of stones comes to the surface, just like anything 

 which rises to the top in a winnowing-fan. The parts 

 about Sipylus, the Phlegrsean Plain, and the Lygian region 

 were overturned by earthquakes of this kind.§ 



He asserts that islands in a deep sea are less liable to 

 earthquakes than those situated near land, because of the 

 cooling and restraining effect of so large a quantity of sea- 

 water on the spirituous vapours or exhalations, and because 

 the islands could not be disturbed without the necessity of 

 moving the whole of the sea surrounding the islands, ii 



* Meteorol. i. c. 14, ss. 14 and 15. f Ibid. i. c. 6, 8. 8. 

 I Ibid. ii. c. 8, ss. 18 and 19. j Ibid. ii. c. 8, ss. 4G and 47. 



i. Ibid. ii. c. 8, ss. 48 and 49. 



