854 Prof. Bischof on the Natural History of 



of the hills, the latter threw off the former, which glided down. 

 Lastly, there are also instances of shocks extending irregularly 

 in rocks.* 



Many instances present themselves of earthquakes, which, in 

 extending longitudinally, follow the direction of the rocks. 

 This is the case, according to Palassou,-]- in the Pyrenees. Re- 

 markable instances are presented in the phenomena of the 28th 

 Dec. 1779 ; the 10th July 1784 ; the 8th July 1791 ; the 22d 

 May 1814, &c. The regions situated more to the south, are, 

 however, more affected than the chain itself.| Earthquakes 

 in South America seem also to follow the direction of the 

 mountains. Thus, that at Caraccas (1812) followed the direc- 

 tion of the Httoral Cordilleras from E.N.E. to W.S.W.|| 

 That of Cumana VlQl^ presented an instance of the same fact. 

 The predominant direction of the frequent earthquakes on the 

 coasts of Chili and Peru^ is also that of the large chain of the 

 Andes, which is parallel to the coast. § All the older reports like- 

 wise state, that in these countries their direction is from S. to 

 N., or vice versa ; and Mrs Graham remarked, that she felt, 

 during the violent earthquake in Chili 1822, as if the whole 

 ground from north to south were suddenly raised, and then 

 sunk again. Von Hoff^ has also related the circumstance, 

 that the shocks of earthquakes are most common in the same 

 direction as that of the basaltic masses themselves, and around 

 a certain distance on either side of the line in which they 

 occur. 



On the other hand, there are many instances of the countries 

 of Europe having been agitated in all directions, without ha- 

 ving been influenced by the mountains. Thus, earthquakes 

 have extended from Upper Italy across the Alps to Switzerland. 

 That at London (19th March 1750) followed the direction 

 from W. to E., although the direction of the mountains in 



* Berghaus* Almanack fiir das Jahr 1837, P- 72. 

 t M^m. pour servir h I'Hist. Nat. des Pyren., p. 260. 

 + Ibid. p. 910. II Von Humboldt, Rel, Hist. t. v. 



. § That at Cumana followed the direction from N. to S., which is ex- 

 tremely singular, 1. cit. t. iv. p. 16. 



% Geschichte der Veranderungen der Erdoberfliiche, t. ii. 



