i9o6.] SEE— THE CAUSE OF EARTHQUAKES. 281 



phenomena depend upon the common cause of steam pressure 

 formed deep in the earth's crust, principally by the leakage of waters 

 from the sea. This highly explosive agency is developed so abun- 

 dantly in the infinitely thin crust between the underlying molten 

 globe, and the overlying oceans, the outcome of a fire beneath and 

 of water above, as in a boiler, that one should not wonder at ter- 

 rible explosive or eruptive phenomena appearing upon our planet. 

 Considering the vast extent of the oceans it would be strange indeed 

 if something like volcanoes and earthquakes were not inseparably 

 associated with the very nature of the terrestrial spheroid. 



If we consider with attention the various causes which might 

 be assigned to explain earthquakes and volcanoes, taking into account 

 their recognized geographical distribution and relation, the relative 

 situation of the inner globe of fire and the overlying layer of water 

 separated from it only by the thin and leaky bottom of the sea, and 

 remembering that both phenomena are augmented to the maximum 

 in regions characterized by high mountains near the deepest oceans, 

 as on the west coast of South and Central America, the Aleutian 

 and Kurile Islands, Japan, Sumatra, Java and other islands of the 

 East Indies, bordering on the deep waters of the Indian Ocean, New 

 Zealand, and the Lesser Antilles in the West Indies, Iceland, .Italy, 

 Greece, etc., we shall find the probabilities that steam pressure 

 developing in the earth's crust is the true and common cause both 

 of earthquakes and volcanoes, are as infinity to one against any other 

 conceivable cause, or all other causes combined. The widely ex- 

 tended relationship here pointed out is so intimate and everywhere 

 so confirmatory of the theory that we cannot suppose it to be due 

 to chance. 



§ 3. Viezvs of Professor Milne and his methods of analysis. 



It has been justly remark-ed by many seismologists that the 

 greatest belt of earthquakes surrounds the Pacific Ocean. Now each 

 part of this great " fire . girdle of volcanoes " with innumerable 

 earthquake disturbances has been studied with care by one or more 

 investigators. Without going into the detailed methods of record- 

 ing and charting developed by Professor Milne, Professor Ewing, 

 Dr. Davidson, Major De Montessus de Ballore, Dr. Agamennone, 

 Dr. Cancani, Dr. Vicentini, Grablowitz, Omori, Koto, Nagaoka, and 



