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All this time there is not the ſmalleſt appearance of fire or ſmoke from the crater on the ſummit of Veſuvius; but the black ſmoke and aſhes iſſuing continually from ſo many new mouths, or craters formed an enormous and denſe body of clouds over the whole mountain, and which began to give ſigns of being replete with the electric fluid, by exhibiting flaſhes of that ſort of zig zag lightning, which in the volcanic language of the country is called ferilli, and which is the conſtant attendant on the moſt violent eruptions.
Sir William Hamilton proceeds to remark, that during thirty years that he had reſided at Naples and in which ſpace of time he had been witneſs to many eruptions of Veſuvius, of one ſort or other he never ſaw the cloud of ſmoke replete with the electric fire, except in the two great eruptions of 1767, that of 1779, and during this more formidable one. The electric fire, in the year 1779 that played conſtantly within the enormous black cloud over the crater of Veſuvius, and ſeldom quieted it, was exactly ſimilar to that which is produced, on a very ſmall ſcale, by the conductor of an electrical machine communicating with an inſulted plate of glaſs, thinly ſpread over with metallic filings, &c. when the electric matter continues to play over it in zig zag lines without quitting it. He was not ſenſible of any noiſe attending that operation in 1779; whereas the diſcharge of the electrical matter from the volcanic clouds during this eruption, and particularly the ſecond and third days, cauſed exploſions like thoſe of the loudleſt thunder: and indeed the ſtorms raiſed evidently by the ſole power of the volcano, reſembled in every reſpect all other thunder-ſtorms; the lightning falling and deſtroying everything in its courſe. The houſe of the Marquis of Berio at St. Jorio, ſituated at the
