190 Physical Notices on the Bay of' Naples. 



writings of others, nor the crude ideas only which the residence 

 of six or seven weeks in the vicinity could furnish, I hope to 

 make my work not uninteresting to the general reader, nor 

 unworthy of the attention of those who may hereafter visit 

 this famous, but not overpraised part of Italy. As the most 

 conspicuous and important object in the Bay, I commence 

 with Vesuvius, of which, however, from a regard to the limits 

 of the paper, my account must form a very imperfect sketch. 

 — I remain, Sir, your most obedient servant, 



A 

 August 9th, 1828. 



In the following observations on Vesuvius, my wish is to 

 avoid the unnecessary prolixity in historical and speculative 

 details in which my predecessors have indulged, and to confine 

 myself chiefly to the topograpical and scientific description, 

 which a repeated survey of the locality, and a perusal of the 

 principal works on the subject, may enable me to combine. 



Vesuvius, I have always geologically considered as stand- 

 ing near the border of a great plain, owing its existence to the 

 same causes which produced the volcano, bounded on the 

 S. W. by the sea, and on the other sides by the Apennines, at 

 the distance sometimes of near twenty miles from the sea. 

 Though almost all this plain owes its origin to subterranean 

 heat, those agencies are more distinctly marked in the vicini- 

 ty of the burning mountain, which acts as the funnel or chim- 

 ney of the whole, and, as Humboldt says of the Peak of Te- 

 neriffe, is a safety valve for the country round, though, as we 

 shall see hereafter, not always an efficient one for the vicinity 

 of Naples. 



But my space is limited, and my subject so extensive that 

 I must hasten to an outline of the topography of the volcano. 

 It is divided into two distinct parts, the Monte Somma and 

 Vesuvius, properly so called. The former is a ridge forming 

 the segment of a circle ; it is precipitous in the interior^ but its 

 exterior surface slopes gently to the country below. It is en- 

 tirely composed of lava and tufaceous substances, and has 

 be"en supposed, and with good reason, to be part of the wall of 

 the original crater of the mountain previous to the tremendous 



