210 LIGHT SCIENCE FOR LEISURE HOURS. 



tated Peru fully equalled, if it did not surpass, the most 

 terrible catastrophes which have ever befallen that 

 country. It presents, too, all the features which have 

 hitherto characterized earthquakes in this neighbor- 

 hood. These are well worthy of careful study, and 

 appear to have an important bearing on the modern 

 theory of earthquakes. 



It has been commonly held that the seat of disturb- 

 ance in the earthquakes which have shaken the country 

 west of the Andes has lain always at some point or 

 other beneath that range of mountains. The fact that 

 several large volcanoes are found in the Cordilleras 

 has seemed confirmatory of this view. The accounts 

 we have also of the great earthquake at Riobamba in 

 1797, seem only explicable by supposing that the seat 

 of disturbance lay almost immediately beneath that 

 city. The inhabitants were flung vertically upward 

 into the air, and to such a height that Humboldt found 

 the skeletons of many of them on the summit of the 

 hill La Culca, on the farther side of the small river on 

 which Kiobamba is built. The ruins of many houses 

 were also flung to the same spot. Here, therefore, 

 was evidence of that vertical (or, as Humboldt ex- 

 presses it, explosive) force which is only to be looked 

 for immediately above the centre of concussion. 



Yet the consideration of the evidence afforded by 

 the news we have just published, seems at first sight 

 somewhat opposed to this view, and to point rather to 



