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‘Noo. 7, 1872] 
four large sharp-edged steps of more than a metre 
high, arranged stair-wise, the formation of which can 
scarcely be explained otherwise than bya deposit or a 
flow of ashes accumulated at the end of the last erup- 
_ tion, 
4 A vast transverse funnel, much larger than it is broad, 
occupies the south-west part of the summit of the cone, 
and this gulf is itself divided at the bottom by a partition 
of rocks which divides it intotwo compartments. A third 
crater occupies the north part, and is separated from the 
first by a considerable wall of rocks. This latter crater 
opens into the great north fissure which descends into 
Atrio del Cavallo ; it was opened during the last eruption 
at the expense of an adventitious cone raised in 1855, 
and appears to have been the most active, since it is 
upon its side that the mountain is rent as far as the base 
_of the cone ; however, it has not ejected any lava, this 
having found its way out by the bottom of the fissure. 
During the eruption the lava was raised as far as the 
summit of the mountain—it has filled to the brim the 
_ double crater on the south-west—yet two days after this 
the lava had escaped by the south side ; for on the 24th 
of April it overflowed the crater and formed three streams 
on the south, the west, and the north-east, which flowed 
down the slopes of the cone, and lost themselves among the 
fields of lava underneath. After this event the lava fell 
_ back to the bottom of the craters. 
__ The depth of the crater may be estimated at about 130 
metres. The bottom appears to be full of dééris and 
ashes, but shows no sign of incandescence, nor of any 
- adventitious cone ; no smoke ascends, and the volcano, 
after its convulsion, has apparently fallen into a complete 
sleep. The only signs of activity are seen in the nume- 
_ rous unimportant jets of white vapour which escape either 
from the bottom or from various points in the walls, and 
which appear to dissolve in the atmosphere. Neverthe- 
less, as seen from Naples, Vesuvius always appears with a 
light smoke hanging over it, which is invisible on the 
_mountainitself. On the side next Pompeii only, to the east 
and north-east the slopes are macadamised by bomb- 
like blocks of the size of the head. The crater mus 
have projected from all sides a shower of such blocks 
but over all the other parts of the mountain this de, 
“posit must have been covered by a thick bed of ashes ; 
and since these blocks are seen only on the east, it is evi- 
dent that at the time of the last eruption of cinders a violent 
wind must have blown them to the opposite side. The large 
_ blocks, if they have been thrown up to the height of 1,500 
_ metres, appear to have fallen back at a short distance 
from the crater. Shot vertically, they fell so, while the 
ashes, on account of their greater lightness, have been 
carried to a greater distance. 
The crater on the south-west is divided through and 
through by a narrow rent, which is doubtless the pro- 
longation of that which on the 24th emitted, half way up, 
the lava which went in the direction of Torre del Greco. 
This rent divides the south'crest, and may be traced upon 
the walls of the crater, where it looks only like a simple 
fissure ; itre-appears more distinctly on the opposite side, 
Another disappears among the cracks of the rocks. This 
_ rent exhaled at the summit of the crater burning gases, 
_ which formed upon the sides abundant deposits. The 
_ south crest was sufficiently filled up by sand to enable 
a 
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a 
NATURE gaiee : 
one to cross it, but such a quantity of sulphurous vapours 
was emitted, that to escape being asphyxiated it was 
necessary to make several rapid leaps. On the west side 
of the crater the rent still gapes, and has not been filled 
up, notwithstanding the heat which escaped. 
The eruption of April 26 which followed the rending of 
Vesuvius, reopening the same vent, suddenly made its way 
to the same point, shattering the manifold bed of lava, 
and ejecting to the surface immense blocks, probably torn 
from their beds far below. Of this débris, mixed with in- 
candescent lava, there is formed an elongated ridge of 
about 50 metres high, from the base of which there sprung 
an enormous mass of lava that swept over the little cone 
of Atrio, The lava burst forth at first in all directions, 
even a little behind in ascending the valley. It filled all 
Atrio, without, however, encrusting anywhere the sides of 
the rocks of the Amphitheatre of La Somma, and flowed 
along the valley in the form of a current of about 1,000 
metres broad. Subsequently encountering the ridge of 
Canteroni, it was turned to the right, though a part of it 
was separated by the upper extremity of this knoll, and 
diverted to the left on to the slopes of Piano, where it 
contorted somewhat the foot of the mountain, thanks to 
the lava of 1858, which, having changed the slope of the 
ground, prevented it from continuingits route. The prin- 
cipal stream continued to follow the valley of the Fosso 
de la Ventrana, running at the rate of about one kilometre 
and a half in two hours, passing under the Observatory, 
where the lava was seen to boil up at places and shoot 
forth into little eruptions, projecting jets of steam and 
scoriz ; then it was precipitated in a cascade of fire over 
a wall of rock, and continued its course by the same 
ravine as the stream of 1855, and for the greater part of 
its course overrunning the lava of that year. It passed, 
exactly as its predecessor did, between the villages of 
Massa and San Sebastiano, sweeping away likewise a 
portion of the houses, part of it at last lodging itself on 
the south of Cercola, while a branch of the current con- 
tinued in the direction of San Giorgio. 
The imagination is unable to comprehend how such a 
mass of matter could escape in a single day from a single 
fire, and spread itself over an area of seven kilometres. 
The elongated ridge formed in the Atrio, at the time of 
the eruption, upon the site of the centre of the outbreak, 
appears at present only like a huge bubble on the sea of 
lava. It is composed of recent black lava, strewed with 
enormous blocks of old bleached lava encased in the new. 
These blocks are, without doubt, the débris of subjacent 
beds which have been broken and driven back by the 
lava at the time of its outbreak ; the mass of them en- 
crusted with the same lava having formed a whole so 
solid that it could not be swept away by the general 
current. This ridge does not now overtop the surface of 
the lava more than fifteen to twenty metres, from which 
we may conclude that the bed of lava at this point has an 
enormous depth. 
The general effects of the eruption of 1872 have been 
somewhat as follows, according to M. de Saussure :— 
1, The mountain of Vesuvius has been divided by a 
rent running nearly from north to south-south-west. 
2. The lava, rising in the rent, has rushed along the 
two sides, on the north tothe very foot of the cone, on the 
south half-way down in much less abundance. 
