VOLCANOES AND 



discharge white smoke, and others are still surrounded 

 with a carpet of sulphur several yards in depth.' 1 



After the great eruption of Mount Pelee in 1902 it was 

 found by measurement that a considerable portion of the 

 adjacent sea bottom had sunk down many fathoms. It 

 is impossible to believe that this sinking had been caused 

 by the mere shaking of the earthquakes accompanying 

 that eruption. We must, therefore, suppose that after 

 the dreadful explosions which destroyed St. Pierre and 

 devastated Martinique a subsidence near the roots of the 

 mountain (which is just by the sea) took place. What 

 we should judge to have happened is that by some means 

 an explosion took place below the sea bottom ; that parts 

 of the molten rock, moved by the forces of the explo- 

 sion, were moved towards the mountain (Mount Pelee), 

 which thereupon broke into eruption, acting as an outlet 

 for the imprisoned rocks. When these molten rocks 

 were thus removed a great cavity was formed in the bed 

 of the sea, which accordingly caved in. 



A similar explanation would account for the raising of 

 the Chilian coast-line after the great earthquakes of 1835, 

 of which we have already spoken. The coast and, indeed, 

 the whole country back to the Andes was slightly raised. 

 This could only be explained by the pushing in or forcing 

 in of a corresponding bulk of lava under the land ; and 

 this lava could come from nowhere except from under 

 the bed of the great trough in the adjacent sea. After 

 an explosion (which is caused by the sea penetrating 

 through to the molten rocks) the trough, where the 

 "accident" first took place, would naturally deepen. 



186 



