ABOUT VOLCANOS AND EARTHQUAKES. 21 



complete body of fire, which could not be less than two 

 miles and a half in breadth, and of the extraordinary 

 height above mentioned ; casting a heat to the distance 

 of at least six miles around it. The brushwood of the 

 mountain of Somma was soon in a flame, which, being 

 of a different tint from the deep red of the matter thrown 

 out from the volcano, and from the silvery blue of the 

 electrical fire, still added to the contrast of this most 

 extraordinary scene. After the column of fire had con- 

 tinued in full force for nearly half an hour, the erup- 

 tion ceased at once, and Vesuvius remained sullen and 

 silent. ' 



(36.) The lightnings here described arose evidently in 

 part from the chemical activity of gaseous decomposi- 

 tions going forward, in part to the friction of steam, and 

 in part from the still more intense friction of the dust, 

 stones, and ashes encountering one another in the air, in 

 analogy to the electric manifestations which accompany 

 the dust storms in India. 



(37.) To give an idea of the state of the inhabitants 

 of the country when an explosion is going on, I will make 

 one other extract : " The mountain of Somma, at the 

 foot of which Ottaiano is situated, hides Vesuvius from 

 its sight : so that till the eruption became considerable 

 it was not visible to them. On Sunday night, when the 

 noise increased, and the fire began to appear above the 

 mountain of Somma, many of the inhabitants of the town 

 flew to the churches ; and others were preparing to quit 

 the town, when a sudden violent report was heard, soon 

 after which thev found themselves involved in a thick 



