THE GRAND ERUPTION OF VESUVIUS IN igo6 637 



of Somma to its present fragmentary form, and laid the foundations 

 of the inner cone — Vesuvius proper. The letters of Pliny the Younger 

 to Tacitus describe the cloud above the crater during this eruption 

 as resembling a great pine (from which the canopy form of the 

 stone pine must be understood), and this simile has ever since served 

 for illustration. 



Of the eight eruptions which are recorded between 79 and 163 1 

 we know but little/ and the chief interest attaches to the long period 

 of repose which, except for a shght ash eruption (1500), extended 

 over nearly 500 years (1139 to 1631). During this time the crater 

 was forested and overgrown with vines, as it had been for a long 

 time previous to 79; and it is of considerable interest to note that 

 the activity of Vesuvius was in this interim apparently transferred 

 to the Phlegraean Fields west of Naples, where the Solfatara erupted 

 in 1 198 and in 1538 a new volcano (Monte Nuovo) formed on the 

 shore of the Lake Lucrinus. Monte Epomeo on the island of Ischia 

 also erupted in 1302. 



The greatest Vesuvian eruption of which we have full accounts 

 was that of December 15-19, 1631; which serves as type of the 

 paroxysmal, as does that of 79 for the explosive eruption. This 

 outburst of 1 63 1 began with rumblings within the crater, followed 

 by the opening of a cleft upon the east side of the mountain and the 

 emission of steam and ash. On the following day another fissure 

 opened upon the south side and sent up the characteristic "pine 

 cloud" of steam and ash to overwhelm Nola, Palma, Lauro, and 

 Ottaiano; thus indicating that a southwest wind was blowing as 

 at the time of the present eruption. The chmax of this eruption 

 was reached upon the i8th, when lava poured from the crater in four 

 great streams: one of which overran Bosco and Torre Annunziata; a 

 second Torre del Greco; a third Portici and Resina, with the loss of 

 some 3,000 persons; and a fourth Massa di Somma, San Sebastiano, 

 and Sant' Anastasio upon the northwest slope. All streams save the 

 last mentioned precipitated themselves into the sea, where they pro- 

 duced ebullition over a considerable area. It is stated that the cone of 

 Vesuvius was reduced in height by some 170 meters at this time. 



I The best edited account of these eruptions will be found in the work by Justus 

 Roth, Der Vesuv und die Umgebung von Neapel (Berlin, 1857). 



