from The Edinburgh Encyclopaedia, Vol. XIV, 1830

(Page 124, excerpt)

The Abbate Soldani, Professor of Mathematics in the University of Siena, has published a more detailed account of the same phenomenon. He informs us, that an alarming cloud was seen in Tuscany, near Siena and Radacofam, proceeding from the north, about seven o'clock in the evening, discharging sparks like rockets, and throwing out smoke like a furnace, with explosions more resembling the discharge of cannon and musketry than thunder, and casting down ignited stones to the ground, while the lightning which issued from it was remarkably red, and less rapid than an ordinary flash. To persons in different situations, the cloud appeared to be of different shapes; and, though it remained suspended for a considerable time, its fire and smoke were visible in every direction. Its altitude, from a combination of circumstances, was judged to be much above the common region of the clouds. One of the stones, which was of an irregular figure, weighed five pounds and a half, was black on the outside, as if suffused with smoke, and seems, internally, to be composed of matter of the colour of ashes, and in which were perceived small specks of metal, as of gold and silver. Besides this, about nineteen others were shewn to Soldani and all of them characterized by a black and glazed outer surface, by their resistance to acids, and by a degree of hardness which permitted them not to be scratched with the point of a penknife.

Signore Montauli, who observed the cloud as he happened to be travelling, described it as appearing much above the elevation of ordinary clouds, as wrapt in smoke and flame, and as gradually becoming white, without being visibly affected by the sun's rays, which beamed full on its lower portions. In the heart of it he could discern, as it were, the basin of a fiery furnace, with a rotatory motion.