EARTHQUAKES. 



65 



In nil countries subject to earthquakes, the point 

 at which the effects are greatest is considered as 

 the source or focus of the shocks. We forget that 

 the rapidity with which the undulations are propa- 

 gated to great distances, even across the basin of 

 the ocean, proves the centre of action to be very re- 

 rr te from the earth's surface. Hence it is clear 

 that earthquakes are not restricted to certain species 

 of rocks, as some naturalists assert, but pervade all ; 

 although sometimes, in the same rock, the upper 

 strata seem to form an insuperable obstacle to the 

 propagation of the motion. It is curious also, that 

 in a district of small extent certain formations in- 

 terrupt the shocks. Thus, at Cumana, before the 

 catastrophe of 1797, the earthquakes were felt only 

 along the southern or calcareous coast of the Gulf 

 of Cariaco, as far as the town of that name, while 

 in the peninsula of Araya, and at the village of Man- 

 iquarez, the ground was not agitated. At present, 

 however, the peninsula is as liable to earthquakes 

 as the district around Cumana. 



In New- Andalusia, as in Chili and Peru, the shocks 

 follow the line of the shore, and extend but little 

 into the interior, — a circumstance which indicates 

 an intimate connexion between the causes that pro- 

 duce earthquakes and volcanic eruptions. If the 

 land along the coasts is most agitated because it is 

 generally lowest, why should not the shocks be 

 equally strong in the savannas, which are only a 

 few yards above the level of the sea 1 



The earthquakes of Cumana are connected with 

 those of the West Indies, and are even suspected to 

 have some relation to the volcanic phenomena of 

 the Andes. On the 4th November, 1797, the prov- 

 ince of Quito underwent so violent a commotion that 

 40,000 persons were destroyed ; and at the same 

 period shocks were experienced in the Eastern An- 

 tilles, followed by an eruption of the volcano of 

 Guadaloupe, in the end of September, 1798. On the 



