EARTHQUAKE \VAVES. 5 



break of all occurred on the 26th and 27th of August, when 

 an incessant rumbling was heard accompanied by short, 

 loud reports, as if from heavy guns. No shocks of earth- 

 quake were observed, but the blast of air produced by these 

 explosions was so violent that walls were rent at a distance of 

 some 500 miles. 



The island of Krakatoa consisted of three peaks, of 

 which the most lofty was 2,700 feet high ; but the whole of 

 the northern part with two craters has disappeared in the 

 sea, and half the remaining peak has sunk likewise, having 

 been cut in two from the very summit, so that it now forms 

 a cliff between two and three thousand feet high. A great 

 wave, caused no doubt, by the sudden subsidence of this 

 peak, started from Krakatoa with a height of twenty-seven 

 feet, dashed upon Java and Sumatra, and opposite Anjer, 

 in the narrow throat of the Straits, rose to from forty to a 

 hundred feet, sweeping the shore of thousands of its 

 inhabitants. The effects of this wave were felt on both coasts 

 of America ; ashes thrown up by the volcano fell over an 

 area almost as large as Norway and Sweden together ; dust 

 fell to the depth of two inches upon a vessel 1,000 miles 

 off, and another vessel, which was near the Straits, passed 

 masses of floating pumice seven feet thick, which in some 

 places were so extensive as to impede navigation. 



And here we must remark that, although we have hitherto 

 considered them almost exclusively in their destructive 

 character as dust-makers, yet earthquakes and volcanoes, 

 like many of Nature's other labourers, do double work, and 

 build up as well as pull down. Indeed, it is no exaggeration 

 to say that without them the whole of the dry land on the 



