Vol. 62.] THE RECENT ERUPTION OF VESUVIUS. 479 



a grey shroud, which even at a distance of over 9 miles from the 

 crater approaches an inch in thickness. 



On the morning of the 9th the wind veered round to the north-east, 

 blowing the dense column of dust, which interposed like a great veil 

 between Naples and Sorrento (fig. 2, p. 480), first towards Ischia 

 and then towards Capri, causing it to drift south-westward until it 

 deposited the material with which it was laden far into Spain. This 

 wind lasted over the whole of the 10th of April as well — with grave 

 results to Torre del Greco, which, lying directly in the track of the 

 dust-cloud, was enveloped in pitch-darkness for two days, buried 

 under a layer of dust a foot thick, and would have assuredly suffered 

 the same fate as Ottajano, had not the wind again veered in the 

 night of the 10th to the 11th, impelling northward the death -dealing- 

 cloud. Blown hither and thither, now by the sea-breeze, now by the 

 land-breeze, this cloud hovered over the environs of Naples during 

 the 11th and 12th, until on the day on which I am writing (the 

 13th) it seems finally to have bent its course to the northward. 



Although several violent outbursts have taken place at intervals, 

 there is no doubt that the height of the cloud-column (or ' pine ') 

 and the quantity of dust have on the whole diminished continuously 

 from the 9th until this day (the 13th), and probably they will go on 

 decreasing until all but complete exhaustion of the steam. The very 

 character of the dust is no longer the same. That of the 5th of 

 April consisted of dark blunt-edged granules, derived directly from 

 the (as yet unaltered) new cone ; while that of the 6th, 7th, and 8th 

 became increasingly mixed with fragmental material of a lighter 

 colour ; the dust of the evening of the 8th and the following days, 

 of a grey or pinkish colour, was entirely made up of debris of the 

 broken-down old cone, which had already been subjected to the 

 influence of fumarolic and atmospheric agencies. 



The great cone, owing to the collapse of its upper portion, now 

 presents, as seen from Naples, an almost horizontal rim, very little 

 higher than the summit of Monte Somma, with a crater which may 

 exceed 1500 feet in diameter. The base of the cone has been 

 considerably broadened by the great mass of fragmentary material 

 which has been projected from it. Moreover, the cone itself now 

 looks white, as if covered with snow, owing to the pale coloration 

 of the ash and the sublimates of ammonium-chloride and sodium- 

 chloride with which it is encrusted, with perhaps, in places, chlorides 

 of iron. 



The effect on vegetation of that suffocating pall of dnst cannot but 

 be baneful. There where the lapilli and scoriae fell thickest, dead 

 birds are seen to bestrew the ground, with wide-open beaks, as if 

 asphyxiated. Asphyxia, then, was one form of peril, but the greatest 

 havoc was wrought by the very weight of the ejectamenta which 

 crushed in the buildings, as was the case at Pompei. The lava- 

 flows, on the other hand, although they permanently bury the 

 ground out of sight, leave time to man and beast to seek safety in 

 flight. The smaller plants take fire at the touch of the lava ; but 

 the bigger trees, whether struck down or left erect, do not catch fire, 



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