^0 the WONDERS OF GEOLOGY. Lect. VIII. 



10. Eruptions of Vesuvius. — In the early periods of 

 activity, violent gaseous explosions, with showers of scoriae, 

 ashes, and sand, characterized the eruptions of Vesuvius;* 

 but since the existence of the present crater, lava -currents 

 have generally been ejected. The appearance of an ordi- 

 nary eruption, seen by night, is thus graphically described 

 by a late traveller: — 



" It was about half-past ten when we reached the foot 

 of the craters, which were both tremendously agitated ; the 

 great vent threw up immense columns of fire, mingled with 

 the blackest smoke and sand. Each explosion was preceded 

 by a bellowing noise like thunder in the interior of the 

 mountain. The smaller vent was the most active ; and the 

 explosions followed each other so rapidly that we could 

 not count three seconds between them. The stones which 

 were emitted were fourteen seconds in falling back to the 

 crater ; consequently, there were always the discharge of 

 five or six explosions — sometimes more than twenty — in 

 the air at once. These stones were thrown up perpendicu- 

 larly, in the shape of a wide-spreading sheaf, producing 

 the most magnificent effect imaginable. The smallest 

 stones appeared to be of the size of cannon-balls; the 

 greater were like bomb-shells ; but others were pieces of 

 rock, five or six cubic feet in size, and some of most 

 enormous dimensions : the latter generally fell on the ridge 

 of the crater, and rolled down its sides, splitting into frag- 

 ments as they struck against the hard and cutting masses 

 of cold lava. The smoke emitted by the smaller cone was 

 white, and its appearance inconceivably grand and beau- 

 tiful; but the other crater, though less active, was much 

 more terrible ; and the thick blackness of its gigantic 

 volumes of smoke partly concealed the fire which it vomited. 

 Both vents occasionally burst forth at the same instant, and 



* The craters of Auvergne, (ante, p. 268,) that exhibit no tin 

 Java currents, are also supposed to have been produced by explosions. 



