260 THE BORDERLAND OF SCIENCE. 



nor in the silver mines 500 yards beneath it, was any 

 movement of the earth perceptible. 



Earthquakes occur in all regions adjacent to active 

 yolcanoes. Thus the neighbourhood of Vesuvius, Etna, 

 and Teneriffe is infested by subterranean convulsions, 

 which also are frequent over the neighbourhood of the 

 Greek Archipelago, and in Syria. In fact it seems prob- 

 able that the whole of the Mediterranean basin and the 

 surrounding lands for a distance of many miles from 

 its shores form a single earthquake district, whereof 

 Teneriffe, Vesuvius, Etna, Stromboli, the Archipelagic 

 and the Syrian volcanoes are the safety-valves. Then 

 there is another earthquake region surrounding Hecla 

 or some say extending in a long line from the Jan 

 Mayen volcano, through Hecla, the Azores, and the 

 Cape Verde Islands, to St. Helena and Tristan d'Acunha. 

 Japan, Sumatra, Java, and the Islands of the East 

 Indian Archipelago are liable to fearful earthquakes, 

 some of the most destructive of which have occurred 

 within the past few years. In the West Indies there is 

 another earthquake region, to which must be referred 

 those which have recently taken place. Probably this 

 district belongs to the great earthquake region in 

 Columbia and Peru, around the celebrated volcanoes 

 Cotopaxi and Chimborazo. The south-western district 

 of the United States are also liable to earthquake 

 shocks, apparently referable to the great Mexican 

 volcanoes. There is one region of the earth in which 

 subterranean shocks occur which cannot be referred to 

 the neighbourhood of volcanic vents. Upper India and 

 parts of Western India are liable to frequent earthquakes, 



