496 PHILOSOPHICAL TRANSACTIONS. [aNNO I768. 



mountain ran violently ; but there was little or no noise till about Q o'clock at 

 night, when the same uncommon rumbling began again, accompanied with ex- 

 plosions as before, which lasted about 4 hours ; it seemed as if the mountain 

 would split in pieces ; and indeed it opened this night by a large orifice. Wed- 

 nesday 21st was more quiet than the preceding days, though the lavas ran 

 briskly. Portici was once in some danger, had not the lava taken a different course, 

 when it was only a mile and a half from it ; towards night the lava slackened. 



Thursday 22d, about ten in the morning, the same thundering noise began 

 again, but with more violence than the preceding days. The ashes, or rather 

 small cinders, showered down so fast, that the people in the streets were obliged 

 to use umbrellas, or flap their hats, these ashes being very offensive to the eyes. 

 The tops of the houses, and the balconies, were covered above an inch thick 

 with these cinders. Ships at sea, 20 leagues from Naples, were also covered 

 with them, to the great astonishment of the sailors. , 



Friday 23d, the lavas still ran, and the mountain continued to throw up quan- 

 tities of stones from its crater ; there was no noise heard at Naples this day, and 

 but little ashes fell there. 



Saturday 24th, the lava ceased running ; the extent of the lava, from the spot 

 where it broke out, to its extremity where it surrounded the chapel of Saint VitO, 

 is above 6 miles. In the Atrio di Cavallo, and in a deep valley, that lies between 

 Vesuvius and the hermitage, the lava is in some places near 2 miles broad, and 

 in most places from 6o to 70 feet deep. The lava ran down a hollow way, 

 called Fossa grande, made by the currents of rain water ; it is not less than 200 

 feet deep, and 1 00 broad ; yet the lava in one place has filled it up. On this 

 day Vesuvius continued to throw up stones as on the preceding days ; during the 

 whole of this eruption it had differed in this circumstance from the eruption of 

 1776, when no stones were thrown out of the crater from the moment the lava 

 ran freely. 



Sunday 25th, small ashes fell all day at Naples : they issued from the crater of 

 the volcano, and formed a vast column, as black as the mountain itself, so that 

 the shadow of it was marked out on the surface of the sea ; continued flashes of 

 forked, or zig-zag lightning shot from this black column, the thunder of which 

 was heard in the neighbourhood of the mountain, but not at Naples ; there were 

 no clouds in the sky at this time, except those of smoke issuing from the crater 

 of Vesuvius. Monday 26th, the smoke continued, but not so thick, neither 

 were there any flashes of the mountain lightning. Tuesday 27 th, no more black 

 smoke, nor any signs of eruption. 



This paper was accompanied with some eng^raved views of the mountain, and 

 the adjacent country ; for which, and several other particulars relating to this 

 explosion, we refer to the separate volume published by Sir W., in which he col- 

 lected all these accounts from the Philos. Trans. 



