Condition of Vesuvius. 281 



Art. IX. — On the condition of Vesuvius in July, 1834; by 

 James D. Dana, of the U. S. Navy. 



TO PROFESSOR SILLIMAN. 



U. S. Frigate United States, Smyrna, July 12th, 1834. 



Sir — Supposing it possible, that a statement of the present con- 

 dition of Vesuvius, — which I had the pleasure of visiting when at 

 Naples, a few weeks since, — may be of some interest to you, I take 

 the liberty of addressing to you, an account of my observations. — 

 The volcano for many years has almost incessantly shown some 

 signs of activity ; but since the summer of 1832, it has been, on the 

 whole, and still is, in what is considered a tranquil state. This 

 was very much the case, when we first arrived, May 29th, — and 

 hence, in my first view of Vesuvius, I was disappointed. I saw 

 a mountain rising before me, to the moderate height of three thou- 

 sand six hundred feet, from a broad base and with an acclivity by 

 no means steep, and having nothing, at a distant view of eight 

 miles, peculiarly bold or rugged in its outline. Some variety was 

 afforded by its double summit, Somma, standing near by to the north, 

 and nearly equalling Vesuvius in height. The crater was enveloped 

 in a light cloud, such as is usual about elevated peaks, whose cold 

 soil condenses the vapor of the atmosphere. In this instance how- 

 ever, I suppose the cloud to have been the vapor condensed, as it 

 issued fi-om the crater. Yet there was nothing in the appearance, to 

 convince one, that such was the case. Vesuvius resembled a vol- 

 cano, no more than other summits bounding the horizon to the south 

 of it, except in its brownish black sides, which alone told its real na- 

 ture. Thus it was, till favored by the darkness of the evening, when 

 it began to exhibit some evidences of its real nature. The vapory 

 cloud which shrouded the summit, was then bright with the light re- 

 flected from the crater ; and there were ejections, yet not very fre- 

 quent, of melted lava and heated cinders, to a considerable height 

 in the air. The succeeding day, owing to the eclipsing light of the 

 sun, it again assumed a non-volcanic aspect. But at night, the 

 eruptions were seen to occur every five or eight minutes. It was 

 in the following night, that, with a party of the officers of the ship, 

 I ascended the mount. 



At Resina near the foot of the mountain, we were provided, by 

 SaJxatore Madonna, the principal cicerone for this excursion, with 



Vol. XXVII.— No. 2. 36 



