THE EAUTH. B3 



fiiify is that ineiitioned by Pliny,' in uliich twelve cities in 

 Asia Minor were swallowed up in one night ; he tells us also 

 of another near the lake Thrasymene, which was not perceived 

 by the armies of the Carthaginians and Romans, that were then 

 engaged near that lake, although it shook the greatest part of 

 Italy. In another place'^ he gives the following account of an 

 earthquake of an extraordinary kind. " When Lucius Marcus and 

 Sextus .Julius were consuls there appeared a very straiige pro- 

 digy of the earth, (as I have read in the books of the Etruscan 

 discipline,) which happened in the province of Mutina. Two 

 mountains shocked against each other, approaching and retiring 

 with the most dreadful noise. They at the same time, and in 

 the midst of the day, appeared cast forth fire and smoke, while 

 a vast number of Roman knights and travellers from the ^nii- 

 liau Way, stood and continued amazed spectators. Several 



crusts, while it wa^ fonsd.idatinij, by breakirg and displai-inef its parts, 

 and [nay have been one I'ause of th<? confused and fractured appearance of 

 the primitive rocks. The same phenomena must exist even yet in the in. 

 terior of the earth, but its influence must be extremely feeble. The rents 

 and fractures produced still by contractions, especially in the interior, and 

 perhaps still more the gaseous matter disengaged during refrigeration (as 

 the phenomena of volcanoes prove,) but kept pent up within the exterior 

 shell exposed to an excessive temperature, explain the origin of earth, 

 quakes. These are most frequent in the >'egions of the globe where 

 we would expect the crust to be thinnest, and the operation of the 

 diNturbinif causes raoit violent- In all probability, it is the gaseous matter 

 disenijageJ from the rocks during refrigeration that impregnates those 

 mineral springs, in which a portion of such matter exists. M. Cordier ob- 

 serves that these springs should have been more numerous in early ages, and 

 various plienomena he thinks aimounce that tliis was the ease. The gradual re- 

 frigoration of the earth explains other facts which have perplexed philosophers. 

 It accounts, for instance, for so large a portion of fossil plants and animals 

 found in cold co jntries, having the characters of those species which now 

 belong to the tropics. Again, it has been observed, that the land surrounding 

 the upper parts of the Baltic has risen from two to three feet within a cen- 

 tury, while the French sciiv<i>is have inferred from certain marks at the 

 ruins of Tanis in Egypt, that t'\f African continent is subsiding at the rate 

 of a foot in a century. Considering all large portions of land as solid masses 

 floating over a liquid abyss, and receiving unequal additions from beh>n', 

 we can easily understand why one part may rise and another descend, 

 l-aslly, as the metals are undoubtedly mixed with the fluid mass below, and 

 the whole in consequence of its fluidity may have certain slow regular mo. 

 tions within itself, we have a key to the mysterious phenomeua of magne. 

 tiiiE— the variation of dip and polarity." 



1 riin. lib. iL cap. SB. 2 Ibid. lib. iil, can. 35. 



