VESUVIS. 199 



were not completely expelled, as happened of old with 

 the Greek colonists, yet a partial emigration took 

 place. 



The next eruption of Yesuvius occurred in 1306 ; 

 and then three centuries and a quarter passed during 

 which only one eruption, and that an unimportant one 

 (in 1500), took place. " It was remarked," says Sir 

 Charles Lyell, " that throughout this long interval of 

 rest, Etna was in a state of unusual activity, so as to 

 lend countenance to the idea that the great Sicilian 

 volcano may sometimes serve as a channel of discharge 

 to elastic fluids and lava that would otherwise rise to 

 the vents in Campania." 



Nor was the abnormal activity of Etna the only 

 sign that the quiescence of Yesuvius was not to be 

 looked upon as any evidence of declining energy in 

 the volcanic system. In 1538 a new mountain was 

 suddenly thrown up in the Phlegrsean Fields a district 

 including within its bounds Pozzuoli, Lake Avernus, 

 and the Solfatara. The new mountain was thrown up 

 near the shores of the Bay of Baiae. It is 440 feet 

 above the level of the bay, and its base is about a mile 

 and a half in circumference. The depth of the crater 

 is 421 feet, so that its bottom is only six yards above 

 the level of the bay. The spot on which the mountain 

 was thrown up was formerly occupied by the Lucrine 

 Lake ; but the outburst filled up the greater part of 

 the lake, leaving only a small and shallow pool. 



