156 DR. DAUBENY ON THE ERUPTION OF VESUVIUS. 



slackened in its progress, and stopped at a distance of about a quarter of a mile be- 

 yond the road from Torre to Ottayano. 



The lava is said to have been accompanied throughout its progress by a cloud of 

 black sand, which hovered over its path, and from this cloud emanated frequent 

 flashings of very vivid lightning, sometimes, but not always, followed by thunder. 



These flashings Monticelli refers to the particles of sand being in an opposite 

 state of electricity to that of the air, and consequently, when diff'used through it by 

 the wind, producing a discharge of electrical light. The same phenomenon was re- 

 marked by him in the preceding month of May, at which time the volcano, as has 

 been stated, emitted a cloud of light volcanic sand. This was diffused by the wind 

 over the whole of the circumambient atmosphere, and from the edges of this cloud, 

 where the lightest and finest particles only of the sand were present, frequent corus- 

 cations of lightning appeared to emanate, whilst in its denser and blacker portion 

 none such were discernible. 



Towards the close of this eruption there occurred a phenomenon, which may per- 

 haps be attributable to the volcanic action going on under Vesuvius. In a pond be- 

 longing to a private individual at Puzzuoli, all the fish suddenly died. In the lake 

 of Fusaro, at this time, from twelve to thirteen hundred weight of fish were calcu- 

 lated to have perished ; and it was remarked, that the victims principally belonged 

 to those species which congregated at the bottom of pools, such as eels. Thus, too, 

 a vast number of oysters at the bottom of this lake were found dead, whereas those 

 which had attached themselves to the stones or the reeds on its sides are said to 

 have escaped. In the neighbouring lake of Licola, also, several of the same species 

 of fish were found to have perished. 



After the 29th of August no further signs of internal commotion were exhibited by 

 the mountain during the past year, except that disengagement of aqueous and aeri- 

 form vapours from the crater which is scarcely ever entirely absent. 



So tranquil a condition of the volcano, although to a general observer it might 

 appear deficient in that lively interest which belonged to the state of things that had 

 preceded it, was at least favourable to a detailed examination of the several parts of 

 the mountain, and allowed of my descending twice into the interior of the crater, which, 

 owing to the falling in of the two conical hillocks alluded to, presented at that time a 

 comparatively level surface. There were, indeed, three depressions or pits of con- 

 siderable depth in the midst of it, which, though without any visible communication 

 with the interior, were so charged with the noxious vapours evolved from an infinity 

 of minute and scarcely visible spiracles, that it was judged unsafe to venture down into 

 them. The rest of the crater, however, was a concavity of no great depth, which was 

 traversed by my guide and myself with comparative facility, after we had remained 

 within its precincts time enough, to collect the various sublimations that lined its 

 walls, and to condense some of the vapours still copiously exhaled from its crevices. 

 The sides of the crater consisted of strata which might be traced for a considerable 



