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VII. An Jccount of some coloured Sfiow a tid Hoar-frost which 

 fell at Jiezzo March 1813. By M. Fabroni, ofArezzo*. 



Jtliny and Livy have mentioned showers of burnt bricks, and 

 much ridicule has been throAvn upon them for it. 



If tlieir expressions however are to be interpreted, as seems 

 to be reiisonable, by the fall of a powder similar to that of 

 pounded bricks, this phaenoinenon was seen in our days through- 

 out the whole of Tuscany, and perhaps still further. 



I now write from Arczzo, in the department of the Arno, and 

 all that I am goina; to say on this extraordinary and curious 

 subject is applicable to the spot where I now am. 



During the evening of the 13th of March 1813, the ground 

 being almost entirely covered with snow, there fell a new quan- 

 tity of snow, or rather hail not very compact, of a reddish-yel- 

 low colour, which the people improperly called red. 



This hail seems to have begun to fall at nine in the evening, 

 and to have continued until next morning. The heaviest fall 

 took place about three in the morning. 



Lightning v.as visible during the niglit : the north wind blew 

 with cousideraljle force at intervals, and a dull uniform noise 

 was heard in the atmosj)here, similar to what is produced at a 

 great distance from the sea bv a tempest. The sky seemed to 

 threaten snow, and some persons thought it was variegated with 

 reddish-vellow clouds. 



The thunder roared once or twice at the time of the heaviest 

 fall of the hail. Next day this hail formed a separate stratum 

 above tlie snow, from which it was easily distinguished by its 

 colour. The snow which had fallen first was v/hite, although it had 

 acquired a state of congelation very similar to the hail. The co- 

 lour was the same not only in all the parts of one and the same 

 mass of hail, but also in what fell in the interior of the town, in 

 the phiins, and on the adjacent mountains. 



When placed in a clean vessel, the surface was covered vvith a 

 foreign substance in proportion as it melted, and after its fusion 

 it precipitated an earthy sediment and remained turbid for a 

 few hours. 



If before liquefying it, it was carefully vv'ashed until it lost its 

 colour, the ice remaining melted without yielding any precipi- 

 tate : in short, it did not diftor from the water from which the 

 sediment al)()ve mentioned was bcparated. 



This water when filtered was iasipid, inodorous, transparent, 

 without colour, incapable of changing turnsole tincture, and of 

 disturbing the solution of nitrate of silver ; but it became slightly 



* Annales de Chimie, tome Ixixviii. p. 146. 



B 4 opaline 



