ON ITS EXTERIOR. VOLCANOES. 411 



tian islands contain perhaps more volcanoes active 

 within recent historic times than does the whole conti- 

 nent of South America. Taking the earth altogether, 

 it is the region comprised between the 73rd W. and 

 127th E. meridian from Greenwich, and the parallels 

 of 47 S. and 66 K, extending from south-east to 

 north-west in the more western part of the Pacific, which 

 is the richest in volcanoes. 



If, in looking in a similarly general manner at the 

 great sea-gulf which we are accustomed to call the 

 Pacific Ocean, we consider it to be bounded on the north 

 by the parallel of Bering Strait, and on the south by 

 the parallel of New Zealand which is also that of South 

 Chili and North Patagonia, we find, and it is a result 

 very deserving of notice, that within this basin, and 

 on the American and Asiatic shores which surround it, 

 there are 198, or nearly seven eighths of the whole 

 number of active volcanoes (225) on the surface of the 

 globe. The volcanoes nearest to the poles are, ac- 

 cording to our present geographical knowledge, in the 

 northern hemisphere, the volcano of Esk, on the little 

 island of Jan Mayen, in 71 I' lat, and 7 29' W. long., 

 and, in the southern hemisphere, Mount Erebus, which 

 sends forth reddish flames visible even in daylight, and 

 which in 1841 was discovered by Sir James Eoss in his 

 great antarctic voyage ( 563 ), and found by him to be 

 12,400 feet high, or about 240 feet higher than the 

 Peak of Teneriffe, in 77 33' lat. and 167 E. longitude 

 from Greenwich. 



The great comparative frequency of volcanoes on islands 

 and on the coasts of continents, could not but early lead 

 geologists to inquire into the causes of this phenomenon. 



