No. I. — Account of' Mount Vesuvius. 19$ 



as warm, another salt, and a third bitter. * This curious de- 

 scription represents exactly the condition of the extinct vol- 

 cano of Astroni near Naples, which at a future time I shall 

 notice. In 1755 the bottom of the crater was so high that 

 the great plain in the centre of it was only 23 feet (French) 

 lower than the edge, and in the centre rose another cone 

 80 or 90 feet in height, having its own small crater through 

 which its size was increased. This in fact is the constant mode 

 of operation of the volcano, that the bottom of the crater is 

 raised by the matter ejected from below, and when fairly 

 emptied by some great eruption takes a long time to regain 

 its former level, and have the means, even though the internal 

 agency was there, of giving vent to a stream of lava. In look- 

 ing forward to the future operations of the volcano, it is im- 

 portant to consider what stage of this regular course of phe- 

 nomena it is in at present. Before 1822 (as I observed in my 

 former paper) the crater was only 5600 feet, or little more than 

 a mile in circumference ; but in that year the mountain having 

 disgorged with a fury unequalled in the memory of man, the 

 matter collected in its bowels carried off the summit, and trun- 

 cating the cone at a far lower point than before, left the present 

 yawning chasm of three and one-third miles round and 2000 

 feet deep from the extreme part of the existing summit. Now 

 this approaches much to the character of the crater before 1631 , 

 which, from its enormous size and the exhausted efforts of 

 the mountain in producing it, remained quiescent near 500 

 years. Cceteris paribus, we should be disposed to expect that 

 a considerable time will elapse before another great eruption ; 

 not a period, however, any thing like the one just mentioned ; 

 for then the volcanic agency seems to have been almost ex- 

 tinct, whereas now it is remarkably active, as the repeatedly 

 frequent paroxysms of the last few years indicate, especially 

 since there was one took place on the 22d of March this very 

 year (1828), but which, I presume, cannot be a very consi- 

 derable one. It is a very remarkable circumstance, that the 

 crater of Vesuvius as it stood when I saw it (1826-7) was 

 probably the largest in existence. u It might be laid down 



* Hamilton's Campi Pklegrcei, folio, vol. i. p. 62, and Breislak, Campa* 

 nie, Tom. i. p. 186. 



