VOLCANIC ERUPTIONS 317 



peals of thunder. They destroyed houses in the neighbourhood of the mountain, 

 and are said to have done considerable damage even at places 250 miles off, to 

 which the cloud of volcanic dust and vapour was carried by the wind. I will read 

 a couple of extracts from Hamilton's paper. It is in the Philosophical Transactions 

 for 1795 : 



"The electric fire in the year 1779, that played constantly within the enormous black 

 cloud over the crater of Vesuvius, and seldom quitted it, was exactly similar to that which is 

 produced on a very small scale by the conductor of an electrical machine communicating with an 

 insulated plate of glass, thinly spread over with metallic filings, etc., when the electric matter 

 continues to play over it in zig-zag lines without quitting it. I 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 loudest 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 S. Jorio, 

 situated at the foot of Vesuvius, during one of these volcanic storms, was struck with lightning, 

 which, having shattered many doors and windows, and damaged the furniture, left for some 

 time a strong smell of sulphur in the rooms it passed through. Out of these gigantic and 

 volcanic clouds, besides the lightning, both during this eruption and that of 1779, I have, 

 with many others, seen balls of fire issue, and some of a considerable magnitude, which, 

 bursting in the air, produced nearly the same effect as that from the air-balloons in fire-works, 

 the electric fire that came out having the appearance of the serpents with which those fire- 

 work balloons are often filled. The day on which Naples was in the greatest danger from 

 the volcanic clouds, two small balls of fire, joined together by a small link like a chain-shot, 

 fell close to my casino at Posilipo. They separated, and one fell in the vineyard above the 

 house, and the other in the sea, so close to it that I heard a splash in the water; but, as I 

 was writing, I lost the sight of this phenomenon, which was seen by some of the company with 

 me, and related to me as above." 



"The Archbishop of Taranto, in a letter to Naples, and dated from that city the i8th 

 of June, said, ' We are involved in a thick cloud of minute volcanic ashes, and we imagine 

 that there must be a great eruption either of Mount Etna or of Stromboli.' The bishop did 

 not dream of their having proceeded from Vesuvius, which is about 250 miles from Taranto. 

 We have had accounts also of the fall of the ashes during the late eruption at the very 

 extremity of the province of Leece, which is still farther off; and we have been assured 

 likewise that those clouds were replete with electrical matter. At Martino, near Taranto, 

 a house was struck and much damaged by the lightning from one of these clouds. In the 

 accounts of the great eruption at Vesuvius in 1631 mention is made of the extensive progress 

 of the ashes from Vesuvius, and of the damage done by the ferilli, or volcanic lightning, 

 which attended them in their course." 



Sabine, while at anchor near Skye, remarked that the cloud-cap on one of the 

 higher hills was permanently luminous at night, and occasionally gave out flashes 

 resembling those of the aurora. I have not been able to obtain further information 

 as to this very important fact ; but I have recently received a description of a very 

 similar one from another easily accessible locality. 



