xti.] EARTHQUAKES AND VOLCANOES. 197 



enormous column of steam, mingled with ashes and stones, 

 shoots up from the crater to a height of a thousand or 

 twelve hundred feet, where the clouds spread out in hori- 

 zontal masses, some miles m breadth, while the ashes and 

 stones fall down in showers. Attracted by so curious a 

 sight, the elder Pliny went to Stabiai, about ten miles from 

 Vesuvius, but his eagerness to witness the spectacle cost 

 him his life. His nephew, who stayed at Misenum, de- 

 scribes the scene — the showers of ashes, the ejection of 

 redhot stones, the movement of the land, the retreat of the 

 sea, and other phenomena characteristic of the eruption of 

 a volcano attended by an earthquake. So vast were the 

 quantities of ashes and other fragmentary matter ejected, 

 either dry or mixed with water, that the unfortunate cities of 

 Herculanaeum, Pompeii, and Stabise were buried beneath 

 deposits, in some places, thirty feet in thickness. It is 

 doubtful, however, whether any true lava was erupted on 

 this occasion. From that date to the present day, Vesu- 

 vius has been more or less active, though sometimes quiet 

 for considerable intervals. During the great eruption just 

 referred to, the south-western side of the original cone was 

 destroyed, but the half which was then left has remained in 

 existence up to the present time, and foyms the semi-cir- 

 cular hill known as Monte Somma. Fig. 56 is a viev,- 

 of Vesuvius half encircled by the cliffs of this ancient 

 crater.^ 



When a volcano is situated near the coast — and by far 

 the larger number of existing volcanoes are so situated — the 

 ashes may be showered into the sea, or be borne thither by 

 the wind, and may, in this way, get mixed with the detrital 

 matter which is spread over the sea-bottom. A curious series 



1 Figs. 51 to 57 are taken, by Prof. Judd's permission, from the late 

 Mr. Poulett Scrope's work on Volcanoes. 



