58 SECRETS OF EARTH AND SEA 



Pompeii. Many thousand persons perished, choked by 

 the vapours or overwhelmed by the hot cinders or engulfed 

 in the boiling mud. 



The great naturalist Pliny was in command of the 

 fleet at Cape Misenum, and went by ship across the bay 

 to render assistance to the inhabitants of the towns at the 

 foot of Vesuvius. Pliny's nephew wrote two letters to 

 the historian Tacitus, giving an account of these events 

 and of the remarkable courage and coolness of his uncle, 

 who, after sleeping the night at Stabiae, was suffocated by 

 the sulphurous vapours as he advanced into the open 

 country near the volcano. The friends who were with 

 him left him to his fate and made their escape. The 

 younger Pliny had prudently remained, out of danger, 

 with his mother at Misenum. 



The alternating periods of activity and of rest exhibited 

 by volcanoes seem to us capricious, and even at the 

 present day are not sufficiently well understood to enable 

 us to discern any order or regularity in their succession. 

 Vesuvius is a thousand centuries old, and we have only 

 known it for thirty. We cannot expect to get the time- 

 table of its activities on so brief an acquaintance. Strangely 

 enough, Vesuvius, having, after immemorial silence, spas- 

 modically burst into eruption and spread devastation 

 around it, resumed its slumber for many years. There 

 is no mention of its activity for 130 years after A.D. 79. 

 Then it growled and sent forth steam and cinder-dust to an 

 extent sufficient to attract attention again ; its efforts were 

 thereafter recorded once or so in a century, though little, if 

 any, harm was done by it. In A.D. 1139 there was a great 

 throwing-up of dust and stones, with steam, which reflected 

 the light of molten lava within the crater, and looked 

 like flames. And then for close on 500 years there was 

 little, if any, sign of activity. The " eruptions " between 

 that of A.D. 79 and that of A.D. 1 139 had been ejections of 



