18G9.] Vesuvius. 191 



strikingly different. Somma, the broken external crest of the 

 greater and earlier volcanic crater, has been unmoved in place, un- 

 changed in form and height (save by atmospheric denudations) 

 through eighteen centuries. 



Vesuvius, born of Somma, and seated within the encircling 

 grasp of its parent, is a variable heap, thrown up from time to time, 

 and again, not seldom, by a greater effort of the same force, tossed 

 away into the air, and scattered in clouds of dust over far away 

 countries. 



Thus it has happened often, in the course of these variations of 

 energy, that Vesuvius has risen to a conical height exceeding that 

 of Somma by 500 or 600 feet, and again the top has been truncated 

 to a level as low as Somma, or even as much below that mountain 

 as we now behold it above it.'^ 



Within the last four hundred years the cone of Vesuvius has 

 been five several times gutted by explosive eruptions of a paroxysmal 

 character, viz. in 1794, 1822, 1831, 1839, and 1850; and its 

 central craters formed in this manner as often gradually refilled 

 with matter, to be again in due time blown into the air. 



B.C. 72 Vesuvius was unborn ; and the great crater of Somma, 

 a mile in diameter, its summit encompassed on all sides — save one 

 which had a narrow breach — with broken and slippery precipices 

 covered with wild vines, reared its truncated cone in silent grandeur 

 unbroken by the least fretful token of an eruption. 



To this wild spot retreated Spartacus and his smaU army at the 

 beginning of the Servile War, the floor of the crater being then a 

 nearly level surfece, but deeply sunk below the encu'cling walls. 



It was, no doubt, the great eruption of a.d. 79 which blew 

 away nearly three quarters of the crater- walls of Somma, beneath 

 whose ponderous ruins the towns of Herculaneum, Pompeii, and 

 Stabias he buried ; and to this day we trace in the platform of the 

 Pedimentina the outline of the base of the south-western portion of 

 the ancient Somma, although, of course, much obscured by modern 

 lava-flows. 



Meantime, what remains of the old external crater is itself be- 

 coming choked up by the accumulation of all the lava- streams and 

 fragmentary matter that are exjoelled towards the northern and 

 outer side of the cone, which is also growing in bulk all round. It 

 would therefore be in exact accordance with the habit of this 

 volcano (as of volcanic mountains in general), if at length the 

 valley of the " Atrio," which at present separates the remains of the 

 ancient and far larger cone of Somma from the modern cone of 

 Vesuvius, should be completely filled up, the two cones combined 

 into one, of increased height and bulk, and ultimately, perhaps, 



* Phillips, p. 174. 



