18 



ETNA. 



[Ch. XXVI. 



from 



which, with all their irregularities, will have a general slopo 



the centre and summit of Etna towards the sea. 

 :gin of the Vol del Bove.—li will be seen by the ideal 



section given in fig. 72, p. 12, that I suppose the modern 



centre of eruption (that of Mon 



to have over- 



whelmed the ancient lateral cone formed by B, so as to reduce 



symmetrical form, the present valley 

 existence. In what manner this 



Ji having then no 



K, I, 



enormous gulf was formed has been a fertile subject of con- 

 jecture. So late as the year 1822, as we shall see in the 

 next chapter, during a violent earthquake and volcanic erup- 



tion in Java, one 



mountain 



Galo 



ngooii^ 



which was covered by a dense forest, became an enormous 

 gulf in the form of a semicircle. The new cavity was about 

 midway between the summit and the plain, and surrounded 



by steep rocks. 



It will be shown that in that instance vast quantities of 

 boiling water and mud were thrown up like a waterspout, 

 and great blocks of basalt were projected to a distance of 



7 



as 40 miles. 



mil 



and ashes and lapilli of the size of nuts as far 



Numerous villages 24 m 



centre of eruption were completely buried, implying that tlie 



matter 



of steam was 



voluminous enough to account for the formation of the new 

 cavity, vast as were its dimensions. 



It will be also seen in the thirtieth chapter, that in the 

 year 1772, Papandayang, the largest volcano in the island 



F 



of Java, lost 4,000 feet of its height, at the same time that 

 40 villages, spread over an area 14 miles in length and 6 in 

 breadth, were destroyed. According to the earlier accounts 

 they were engulphed, and the truncation of the cone was attri- 

 buted to subsidence; but the subsequent investigations of 

 Junghuhn about seventy years after the explosion have shown 

 that the villages were overwhelmed by volcanic sand and 

 scorise, under which they now lie buried ; and it cannot be 

 doubted that the loss of heio-ht of the OTcat cone, attributed 

 to subsidence, was caused in great part at least by explosion- 

 The summit of Carguairazo, one of the loftiest of the Andes 

 of Quito is said to have 'fallen in' on July 19, 1698, and 



A h 



i 



i 



CH'' 



t 



5^ 



aflO 



tlic 



t 



cones tr 



be i^»^' 

 the ff'^^ 



priiiciP^ 

 111 th- 



(see 3la: 

 which tl 

 of abou< 

 vertical 

 scoriae, 

 of the ■ 



during < 



greater 

 of peri 



during 

 a temp 

 liaye ca 



Erup 



cone.~\ 



Etna as 



aerial 



( 



scorife fr 



ipheaval 

 ^^e proI)j 



founded 



«f the mc 



°^iect of i 



tim 



Etna 

 ofti 



es 



H 





42.1 



•^B 



til 



c. 



5 < 



