the late Eruption of Mount Vesuvius. 105 
round them has been covered with- a thick bed of fine ashes, 
whatever was thrown up during the force of the eruption lies 
buried under those ashes. Should we find similar stones with 
the same vitrified coat on them on Mount Vesuvius, as I told 
Lord Bristol in my answer to his letter, the question would 
be decided in favour of Vesuvius ; unless it could be proved 
that there had been, about the time of the fall of these stones 
in the Sanese territory, some nearer opening of the earth, at- 
tended with an emission of volcanic matter, which might very 
well be, as the mountain of Radicofani, within 50 miles of 
Sienna, is certainly volcanic. I mentioned to his lordship ano- 
ther idea that struck me. As we have proofs during the late 
eruption of a quantity of ashes of Vesuvius having been car- 
ried to a greater distance than where the stones fell, in the 
Sanese territory, might not the same ashes have been carried 
over the Sanese territory, and mixing with a stormy cloud, 
have been collected together just as hailstones are sometimes 
into lumps of ice, in which shape they fall ; and might not the 
exterior vitrification of those lumps of accumulated and hard- 
ened volcanic matter have been occasioned by the action of the 
electric fluid on them? The celebrated Father Ambrogio 
Soldani, professor of mathematics in the university of Sienna, 
is printing there his dissertation upon this extraordinary phe- 
nomenon ; wherein, as I have been assured, he has decided 
that those stones were generated in the air independantly of 
volcanic assistance. 
Until after the 7th of July, when the last cloud broke over 
Vesuvius, and formed a tremendous torrent of mud, which took 
its course across the great road between Torre del Greco and 
the Torre delf Annunziata, and destroyed many vineyards, 
MDCCXCV. P 
