fQ2 M. De la Rive on the Formation of Hail 



which all the hail was formed, allowed none to escape beyond a 

 half league from the spot on which I was standing. Some, how- 

 ever, fell on the northern side of the mountain which inter- 

 cepted its progress, and I collected a certain number of the hail- 

 stones in a phial. I subsequently submitted the water to many 

 chemical tests, and I obtained a sensible precipitate, with nitrate 

 of silver, and muriate of barytes. 



All the hailstones appeared to be subjected to a very rapid ro- 

 tatory motion, but in different directions, so far as I could judge 

 by examining their movements at the moment of their fall on the 

 crown of my hat, which I held as much horizontal as possible 

 to receive them. Many other clouds, charged with hail, still 

 rose from the south, and now on one point, and now on another, 

 it hailed without interruption from one till four o''clock on the 

 chain of the Puys, from Mont Dore, as far as Riom and Volvic. 



Between four and five o'clock the hail ceased ; the clouds now 

 formed only a single stratum, but they often presented that 

 phenomenon I had noticed in the morning, viz. that they group- 

 ed together, and then poured out, along with flashes of light- 

 ning, enormous quantities of water. The south wind also had 

 now ceased, the west alone blew, and carried along with it these 

 frightful waterfalls. One of them discharged itself in my view 

 at Barraque, on the great road to Clermont. I was distant from 

 it about forty yards, and not a drop of water fell on me. A 

 heavily loaded carriage which was at a little distance, disap- 

 peared in the twinkling of an eye, under the mass of water which 

 the heavens poured down upon it. After the passage of the water- 

 spout, it was overturned in a ditch, and the postilions for a time 

 did not try to right it, so intense was the darkness in the midst 

 of the storm. Large pieces of pavement and great blocks of 

 granite were carried along by this waterspout, which still hur- 

 ried away before me, and reached Clermont half an hour be- 

 fore I could arrive. The storm of the 2d of August was 

 not so rapid in its progress as that of the 28th of July, and it 

 traversed a much shorter line. It began upon the mountains 

 of Cantal, and terminated upon the confines of Auvergne and 

 Bourbonnais. M. L. de Buch, who, that day, was at Cantal, 

 ineffectually attempted at ten in the morning to reach the sum- 



