192 LIGHT SCIENCE FOR LEISURE HOURS. 



districts of active with those of extinct volcanoes. It 

 is said that in Chili a year scarcely ever passes with- 

 out shocks of earthquake being felt ; in certain regions, 

 not even a month. A similar persistence of earthquake- 

 disturbance characterises Peru. Yet, although both 

 districts are shaken in this manner, there seems to be 

 distinct evidence of alternating disturbance as respects 

 the occurrence of great earthquakes. Thus in 1797 

 took place the terrible earthquake of Kiobamba. 

 Then, thirty years later, a series of great earthquakes 

 shook Chili, permanently elevating the whole line of 

 coast to the height of several feet. Now, again, after 

 another interval of about thirty years, the Andes are 

 disturbed by a great earthquake, and this time it 

 is the Peruvian Andes which experience the shock. 

 Between Chili and Peru there is a space upwards of 

 five hundred miles long, in which no volcanic action 

 has been observed. Singularly enough, this very por- 

 tion of the Andes, to which one would imagine the 

 Peruvians and Chilians would fly as to a region of 

 safety, is the part most thinly inhabited, insomuch that, 

 as Von Buch observes, it is in some places entirely 

 deserted. 



Near Quito the trembling of the earth is almost 

 incessant, according to M. Boussingault. He considers 

 that the frequency of the movement is due rather to 

 the continual falling in of masses of rock which have 

 been fractured in recent earthquakes, than to the per- 

 sistence of subterranean action. He adds that the 

 height of several mountains in the Andes has diminished 



