180 REACTION OF THE INTERIOR OF THE EARTH 



quil ; and inversely, volcanoes have had great and long- 

 continued eruptions without earthquakes having been felt 

 in the country around, either previously or at the same 

 time. The most devastating earthquakes recorded in 

 history, and which have passed through very many 

 thousands of square miles, are precisely those which, so 

 far as could be perceived at the surface of the earth, had 

 no connection with the activity of volcanoes. This class 

 has latterly been termed plutonic, in opposition to 

 properly volcanic earthquakes which are mostly limited 

 to lesser areas. This nomenclature, which would require 

 far the greater number of earthquakes to be called 

 plutonic, is not to be approved as respects more ge- 

 neral views. 



We have everywhere beneath our feet that which may 

 produce earthquake shocks; and the consideration that 

 almost three fourths of the earth's surface are covered by 

 sea, and (omitting a few sporadically scattered islands) 

 without any permanent communication between the in- 

 terior and the atmosphere (i.e. without active volcanoes), 

 sufficiently refutes the erroneous but widely-spread 

 belief, that all earthquakes are to be attributed to 

 the eruption of a distant volcano. Continental earth- 

 quakes are indeed often propagated over the bottom of 

 the sea, and the agitation communicated from the 

 coast, causes those formidable sea-waves of which the 

 earthquakes of Lisbon, Callao, and Chili have given 

 such memorable examples. When, on the other 

 hand, the earthquake proceeds from the bottom of the 

 sea, from the dominions of the earth-shaking Poseidon 

 (cn-iaixdaiv, Kiin}(jiyQ<>v), and is not accompanied by an 

 upheaval producing an island (as in the ephemeral 



