136 Physical Notices of the Bay of Naples. 



Toises. 



Probable true height, - - - . 645 



D* Puilta Nasone. Highest part of the Somma. 

 Shuckburgh, 1794, barometer, - - - 584 



Humboldt, 1822, ditto, - - - . 586 



E. Valley of the Atrio del Cavallo. 

 Humboldt, 1822, - - r. . - 403 



F. Foot of the cone of ashes. 

 Gay-Lussac, De Buch, and Humboldt, 1805, - 370 

 Humboldt, 1822, - ... 388 



G. Hermitage of St Salvador. 

 Gay-Lussac, De Buch, and Humboldt, 1805, - 300 

 Lord Minto, 1822, . - . . 308.9 

 Humboldt, 1822, - - 307.7 



Humboldt has no doubt that, in the period 1816-22, the 

 height of the Rocca del Palo had been about 12 toises higher 

 than during the period 1773-1805, which he considers a sin- 

 gular proof of gradual internal elevation. The points A, D, 

 and E, correspond respectively to C^ A, and B, of my section 

 of Vesuvius in last Number. The continuation of these im- 

 portant observations cannot fail to be of the greatest interest. 

 Humboldt mentions the statement I noticed (No. xviii. p. 206) 

 of gold existing in the volcanic dust, and states, that the re- 

 cent experiments of the best chemists disprove the assertion. 

 I have learned, that, since the slight eruption of March this 

 year, Vesuvius has been in a state of great agitation during 

 the summer ; but particulars have not reached me. I hope the 

 length of this note will be excused, as the facts it notices are 

 of great importance in surveying the phenomena of Vesu- 

 vius. 



A . 



