TRUE VOLCANOES. 427 



unfruitful, and having an ashy appearance. It exhibits 

 fissured hollows of red-coloured rock, as if it were corroded 

 by fire, so that it might be supposed that this place had 

 formerly burned and had gulphs of fire, which, however, had 

 died away when the fuel became consumed." (Strabo, lib. v. 

 page 247, Casaub.) This description of the primitive form 

 of Vesuvius indicates neither a cone of cinders nor a crater- 

 like hollowing 33 of the ancient summit, such as, being walled 

 in, could have served Spartacus 34 and his gladiators for a 

 defensive stronghold. 



33 This description is therefore totally at variance with the often 

 repeated representation of Vesuvius, according to Strabo, given in 

 Poggendorffs Annalen der Physik, Bd. xxxvii, s. 190, Tafel 1. It 

 is a very late writer, Dio Cassius, under Septimius Severus, who 

 first speaks, not (as is frequently supposed) of the production of 

 several summits, but of the changes of form which the summits 

 have undergone in the course of time. He records (quite in con- 

 firmation of Strabo) that the mountain formerly had everywhere a 

 flat summit. His words are as follows (lib. Ixvi, cap. 21, ed. Sturz, 

 vol. iv, 1824, p. 240): "For Vesuvius is situated by the sea near 

 Naples, and has numerous sources of fire. The whole mountain was 

 formerly of uniform height, and the fire arose from its centre, for at 

 this part only is it in a state of combustion. Outwardly, however, the 

 whole of it is still down to our times devoid of fire. But, while the 

 exterior is always without conflagration, and the centre is dried up 

 (heated) and converted into cinders, the peaks round about it have still 

 their ancient height. But the whole of the igneous part, being con- 

 sumed by length of time, has become hollow by sinking in, so that the 

 whole mountain (if we may compare a small thing with a great) 

 resembles an amphitheatre." (Comp. Sturz, vol. vi, Annot, ii, p. 568). 

 This is a clear description of those mountain-masses which, since the 

 year 79, have formed the margins of the crater. The explanation of 

 this passage, by referring it to the Atrio del Cavallo, appears to me 

 erroneous. According to the large and excellent hypsometrical work 

 of that distinguished Olmutz astronomer, Julius Schmidt, for the year 

 1855, the Punta Nasone of the Somma is 3771 feet, the Atrio del 

 Cavallo, at the foot of the Punta Nasone, 2661, and the Punta or 

 Rocca del Palo (the highest edge of the crater of Vesuvius to the 

 north, pp. 112116; 3992 feet high. My barometrical measurements 

 of 1822 (Views of Nature, pp. 376377) gave for the same three points 

 3747 feet, 2577 feet, and 4022 feet showing a difference of 24, 84, and 

 30 feet respectively. The floor of the Atrio del Cavallo has, according 

 to Julius Schmidt (Eruption des Vesuvs im Mai 1855, p. 95), undergone 

 great alterations of level since the eruption of Feb. 1850. 



14 Velleius Paterculus, who died under Tiberius, mentions Vesuvius, 

 it is true, as the mountain which Spartacus occupied with his gladiators 

 (ii. 30), while Plutarch, in his Biography of Crassus, cap. ii, speaks only 



