No. I. — Account of Mount Vesuvius. 201 



volcano Jorullo, but have made the horizontal and perpendi- 

 cular scales the same, which alone can give a true idea of a 

 mountain. I have already mentioned that the crater is 3J 

 miles round ; but I soon saw that in the line of this section 

 (N.N.E. to S.S.W.) I could not give it the diameter of a mile. 

 In fact, the crater is oval, having its longer axis nearly N.W 

 and S.E. so that our section is nearly in the shorter diame- 

 ter; and after a comparison of a great many recent drawings 

 from the neighbourhood of Naples, I adopted f ths of the per- 

 pendicular height for the diameter of the crater, as seen in 

 the line of section. In Plate III. A represents the Monte 

 Somma, B the Atrio del Cavallo, C the highest point of Ve- 

 suvius, D the crater, E a flat space nearly level with the Atrio 

 del Cavallo, F the Camaldolese convent of St Angelo on a 

 hill of tufa, evidently raised by a volcanic explosion beyond 

 the memory of man, G the Mediterranean Sea. 



It is now time to turn our attention to a short consideration 

 of the mineral productions of Mount Vesuvius, which are so 

 numerous, so singular, and so important, as to have excited 

 especial attention when the wonders of the kingdom of na- 

 ture began to be accurately explored, and presented a glitter- 

 ing though laborious harvest to many of those who may be 

 termed the fathers of modern science. At the present period 

 the wonder seems to be, that these mineral treasures, explored 

 but feebly half a century ago, have not excited the spirit of in- 

 vestigation they deserve under the hands of philosophers of 

 this age ; and that the works which describe them, though ho- 

 nourable to the time in which they were written, are so ex- 

 ceedingly confused and imperfect in the present state of know- 

 ledge, as to throw almost as much darkness as light on the 

 subject they meant to elucidate. The great volcanos in the 

 two Sicilies have each had their own lithologist, Etna in Do- 

 lomieu, the Lipari Isles in Spallanzani, Vesuvius in Giceni. 

 All these works are quite antiquated on the science of which 

 they treat. From thirty to fifty years have elapsed since they 

 were composed ; and they are now ill fitted to aid the student 

 of nature in his researches. Perplexity, endless subdivision, 

 confusion of epithets, and ill-defined characters, abound in the 

 mineralogical works of that period ; and although at the pre- 

 sent time Messrs Monticelli and Covelli are publishing their 



