200 On Stones which have fallen from the Heavens. 



taken i»* diredion towards Siena; that when within a cer- 

 tain diftance of the earth it had difcharged itfelf j and that 

 ill confequence of tills difcharge it had burfl, fo that the 

 fraaments fell down in the (tate of ignited ftones *. 



On the other hand, however, it i* known that no fuch 

 ftones are found on Mount Vcfnvius. It has been lately 

 fliown by the mineralogical defcription of Count de Bour- 

 non, and the chemical analyfis cf JNJr. Howard, that the 

 ftones found at Siena have a perfe6l refeniblance to all the 

 other ftones which have been feen to fall from the heavens, 

 and which certainly cannot be produ6lions of our earth \. 

 My former explanation and conjeclures fall therefore to the 

 ground, and we muft clafs the ftones of Siena among thofe 

 which are formed by nature in fome mode with which we 

 are unacquainted, and which burfting always with the ap- 

 pearance of light fall down to the earth. 



Since the time when naturalifts firft ventured, or were 

 obliged, to believe in the falling of fuch ftones, it has been 

 found that this phsenomenon is not fo uncommon as was 

 fuppofed. During the laft century, fourteen or fifteeii in- 

 fiances at leaft can be quoted. 



When I erroneoufly afcribed in mv leftures the ftones 

 found at Si<.na to an eruption of Veiuvius, the nature of 

 other ftones fallen from the heavens, which certainly were 

 not of volcanic origin, had given ocrafion to the queftion, 

 whether it was impofilble that heavy maftes could be pro- 

 jected to the earth from other heavenly bodies, and particu- 

 larly from the moon? The celebrated (lone which fell near 

 Arfos Potamos, in the year 462 before ChriftJ, induced me 

 in particular to undertake an examination of this queftit*) ; 

 and on this occafion my learned friend, Mr. IJredenkamp, 

 clergyman of Bremen, was fo kind as to colledl for me all 

 the paft;iges in antient authors which make mention of this 

 ftone. In regard to the reft, the reader may confult what 

 Struyk. Pingre § and Chladni || have faid on the fubjeft. 



It appears from calculation, that when a greater vertical 

 velocity than 3443.57 Paris feet in a fecond can be given to 

 a heavy body projefted from the earth's furface, fuppofing 

 the atmofphere to oppofe no rcfiftance, this body would not 



• The abbe Tata aftually f;.'.v a large fire-ball thrown up from Vefu- 

 vius, which when it had reached a certain diltance burft, and the abbe 

 then heard a noife like that of ftones falling down, 



+ Howard's Experiments and Obfcrvatiorii on certain Stony and Me- 

 tali ne Subftances, &c. — Philofophical Tninfaftions 1801. 



+ Piin. Hift. Nat. lib. ii. cap. s8- § Cometographie, p. 156. 



II PUilofophical Magazine, vol. ii. 



fall 



