NOTES. cxliii 



von Buch, in the Appendix to his masterly description of the Canaries, and 

 Landgrebe. in his Geography of Volcanoes, have not hazarded any general 

 numerical estimate. 



( 557 ) p. 407. This description is quite opposed to the often repeated repre- 

 sentation of " Vesuvius according to Strabo," given hi Poggendorff's Annalen der 

 Physik, Bd. xxxvii. S. 190, Tafel I. A very late writer, Dio Cassius, under 

 Septimius Severus, was the first to discuss, not the origination of several sum- 

 mits, as has often been asserted, but the first who tried to show how in course 

 of time the form of the summit has altered. He recalls (quite in confirmation 

 of what had been said by Strabo) that formerly the mountain had an everywhere 

 flat summit. His words (lib. Ixvi. cap. 21, ed. Sturz, vol. iv. 1824, p. 240) 

 are to this effect: " For Vesuvius is situated on the sea near Naples, and has 

 abundant sources of fire. The whole mountain was formerly of equal height, 

 and the fire rose out of its middle; for in that part only it is burning, its whole 

 outside being free from fire. Since then the exterior is always without fire, 

 while the interior is parched with heat and turned into ashes ; the pointed parts 

 around have hitherto retained their ancient height, while the whole fiery inside, 

 consumed by time, has sunk down and become hollow, so that, to compare great 

 things with small, the mountain resembles an amphitheatre." (Compare Sturz, 

 vol. vi. annot. ii. p. 568.) This is a sufficiently clear description of those parts 

 of the mountain which, since the year 79, have become the crater-margins. The 

 interpretation which refers this passage to the Atrio del Cavallo appears to me 

 incorrect. According to the excellent hypsometric investigation made in 1855 

 by the active and distinguished Ohntttz astronomer, Julius Schmidt, Punta 

 Nasone of the Somma is 3772 feet high; the Atrio del Cavallo at the foot of 

 Puiita Nasone, 2666 feet; and Punta, or Kocca, del Palo (the highest northern 

 crater-margin of Vesuvius), 3990 feet. My barometric measurements in 1822 

 (Ansichten der Natur, Bd. ii. S. 290 292) gave for the same three points 

 3746, 2577, and 4022 feet (the differences are 26, 89 , and 32 feet). The 

 floor of the Atrio del Cavallo has undergone great alterations of level since the 

 eruption in February 1850, according to Julius Schmidt (Eruption des Vesuvs 

 im Mai 1855, S. 95). 



( M8 ) p. 408. Velleius Paterculus, who died under Tiberius, does, indeed 

 (ii. 30), name Vesuvius as the mountain which Spartacus occupied with his 

 gladiators; whereas Plutarch, in the biography of Crassus, cap. ii., speaks only 

 of a locality amidst rocks having a single narrow entrance. The servile war ut' 

 Spartacus was in the year of Rome 681, therefore 152 years before Pliny's 

 eruption of Vesuvius, on the 24th of August 79 A.D. That Florus a writer 

 living under Trajan, and who, therefore, being cognizant of the eruption just 



