182 Accoimt of the Eruption of Vesuvius , 



wards, with a steep and regular slope, to the base of the 

 mountain. 



Another interesting parallel may also be drawn between the 

 large accumulations of volcanic sand (or ashes) and frag- 

 mentary lava, (commonly called lapillo,) washed down from 

 the sides of Vesuvius by the rains, which fell with great vio- 

 lence during the late eruption, and those large deposits of 

 tufaceous conglomerates, in the volcanic country of France, 

 to which I assigned, upon the spot, a similar origin. Nothing 

 could be more confirmatory of the justness of that hypothesis, 

 or more clearly illustrate the mode of formation of such rocks, 

 than the phenomena which took place on all sides of Vesuvius, 

 a few days after the great crisis of the eruption in October last. 

 The fine impalpable sand thrown out from the crater for many 

 days together, had covered the surface of the mountain to the 

 depth of from one to five feet; and necessarily impeded what- 

 ever rain fell upon this space, from draining off, as usual, 

 through the porous and loose matters which compose the sides 

 of the volcano. In this state of things, on the 27th October, 

 the clouds, which had long gathered in dense masses round 

 and above the cone, began to discharge their contents in pro- 

 digious quantities ; and, in consequence, torrents of sand, mixed 

 with water, appearing like liquid mud, swept, with terrible 

 impetuosity, down the slopes, tearing them up in their passage, 

 hurrying along fragments and blocks of lava, of great size, 

 (some even from 40 to 50 feet in girth,) and depositing heaps 

 of alluvium on the sides and at the foot of the mountain. The 

 damage occasioned by these " lave d'acqua," or " di fango" 

 as they are called in the language of the country, was far 

 greater than what was suffered from the " lave difuoco." The 

 latter only destroyed a few acres of wood and vineyard, but 

 by the former a much larger space of cultivated soil was de- 

 vastated, walls were overthrown, houses and streets filled with 

 sand and stones, and some lives even lost, from the suddenness 

 of their descent. 

 There can be no doubt, that a great portion of the tufa 



