6\6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1780. 



witness to several glorious picturesque effects produced by the reflection of the 

 deep red fire, which issued from the crater of Vesuvius, and mounted up in the 

 midst of the huge clouds, when a summer storm, called here a tropea, came on 

 suddenly, and blended its heavy watry clouds with the sulphureous and mineral 

 ones, which were already like so many other mountains, piled over the summit 

 of the volcano: at this moment a fountain of fire was shot up to an incredible 

 height, casting so bright a light, that the smallest objects could be clearly dis- 

 tinguished at any place within 6 miles or more of Vesuvius. That which followed 

 the next evening was indeed much more formidable and alarming; but this was 

 more beautiful and sublime than even the most lively imagination can paint to 

 itself. This great explosion did not last above 8 or 10 minutes, after which 

 Vesuvius was totally eclipsed by the dark clouds, and there fell a heavy shower 

 of rain. Some scoriae and small stones fell at Ottaiano during this eruption, 

 and some of a very great size in the valley between Vesuvius and the Hermitage. 



August 8, Vesuvius was quiet till towards 6 o'clock in the evening, when a 

 great smoke began to gather again over its crater, and about an hour after, a 

 fumbling subterraneous noise was heard in the neighbourhood of the volcano; 

 the usual throws of red-hot stones and scoriae began, and increased every 

 instant. At about Q o'clock there was a loud report, which shook the houses 

 at Portici and its neighbourhood to such a degree as to alarm their inhabitants, 

 and drive them out into the streets; and many windows were broken, and walls 

 cracked, by the concussion of the air from that explosion, though faintly heard 

 at Naples. In an instant a fountain of liquid transparent fire began to rise, 

 and, gradually increasing, arrived at so amazing a height as to strike every 

 beholder with the most awful astonishment. The height of this stupendous 

 column of fire could not be less than 3 times that of Vesuvius itself, which rises 

 perpendicularly near 3700 feet above the level of the sea. Puff's of smoke, as 

 black as can possibly be imagined, succeeded each other hastily, and accompanied 

 the red-hot, transparent, and liquid lava, interrupting its splendid brightness 

 here and there by patches of the darkest hue. W^ithin these pufis of smoke, at 

 the very moment of their emission from the crater, could be perceived a bright, 

 but pale, elecirical fire, briskly playing about in zig zag lines.* 



The liquid lava, mixed with stones and scoriae, after having mounted at the 

 least 10 thousand feet, was partly directed by the wind towards Ottaiano, and 

 partly falling almost perpendicularly, still red-hot and liquid, on Vesuvius, 

 covered its whole cone, part of that of the mountain of Somnia, and the valley 

 between them. The falling matter being nearly as vivid and inflamed as that 



* Sir W. mentions this circumstance to prove, that the electrical matter, so manifest during this 

 eruption, actually proceeded from the bowels ot tlie volcano, and was not attracted liom a great 

 height in the air, and conducted into its crater by the vast column of smoke. 



