Chap. 47.] torrent of Mud. 357 



dinary phenomenon : either thefe ftones have been 

 generated in this igneous mafs of clouds, which pro- 

 duced fuch imufual thunder, or, which is equally in- 

 credible, they were thrown from Vefuvius at a dif- 

 tance of at leaft two hundred and fifty miles; judge 

 then of its parabola.' One of the largeft ftones, when 

 entire, weighed upwards of five pounds. The outfide 

 of every ftone that was found, and afcertained to have 

 fallen from the cloud near Sienna, was evidently frefhly 

 vitrified, and black, having every fign of having pafied 

 through an extreme heat ; when broken, the infide 

 was found of a light-grey colour mixed with black 

 fpots, and fome mining particles, fuppofed to be 

 pyrites. Stones of the fame nature, at kail as far as 

 the eye can judge of them, .are frequently found on 

 Mount Vefuvius ; and mould fimilar ftones be found 

 there, with the fame vitrified coat on them, the 

 queftion would be decided in favour of Vefuvius, 

 unlefs it could be proved that there had been, 

 about the time of the fall of thefe ftones in the 

 Siennefe territory, fome nearer opening of the earth> 

 attended with an emifiion of volcanic matter, which 

 might very poffibly happen, as the mountain of Radico- 

 fani, within fifty miles of Sienna, is certainly volcanic. 

 The celebrated father Ambrogio Soldani, profefibr of 

 mathematics in the univerfity of Sienna, has printed 

 there a diflertation upon this extraordinary pheno- 

 menon ; wherein, it is faid, he has decided that thofe 

 ftones were generated in the air independently of vol- 

 canic affiflance. 



Until after the yth of July, when the laft cloud 

 broke over Vefuvius, and formed a tremendous torrent 

 of mud, which took its courfe acrofs the great road 

 between Torre del Greco and the Torre dell'Annun- 

 iata, and deftroyed many vineyards, the eruption 

 A a 3 could 



