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a 
% aes Obfervations on a Ma/s of Tron 
irregular and Yomewhet compreffed figure like a rough ais 
nite; was covered externally with a ferruginous kind of 
cruft ; andthe infide confifted of malleable iron, brittle when 
heated, porous like a large fea fponge, and having its inter- 
{tices filled with a brittle hard vitrified fubftance of an amber 
yellow colour. . This texture and thevitrified fubftance ap- 
peared uniformly throughout the whole mafs, and with- 
out any traces of flag or artificial fire. 
Dr. Chladni fhews with a great deal of ingenuity, that, 
this mafs neither originated by the wet method ; nor could 
have been produced by art, the burning of a foreft, by light- , 
ning, or bya volcanic eruption. It appears to him much 
“more probable that it is of the fame nature as the fo called 
fire-balls (dolides) or flying dragons, and he quotes a variety 
of obfervations made on thefe phenomena; from which he 
endeavours to prove that they do not arife from an accumu- 
lation of the matter of the aurora borealis; a tranfition of 
electricity from one part of the atmofphere to another; an 
accumulation of porous inflammable fubftances in the higher 
regions, or the catching fire of a long train of inflammable 
air; but that their component parts meft be confiderably 
denfe and heavy, as their courfe fhews in fo apparent a man- 
ner the effects of gravity; and becaufe their mafs, though iz 
diftends to a monftrous fize, retains fufficient confiftency 
and weight to continue an exceedingly rapid mo¥ement 
Abrough a very large fpace, without being decompofed or 
diffolved, notwithftanding the refiftance of the atmofphete, 
It feems to him probable, that this fubftance is by the effeé 
of fire reduced to a tough fluid condition; becatife its form 
appears fometimnes round and fomcetimes elongated, and as 
its extending till it “burits 3, as well as the burfting itfelf, 
allows us to fuppofe a previous capability of extention by 
elaftic fluidity. At any rate, it appears to: be certain, that 
fuch denfe matter at fo'great a height is’ not collected: from 
particles to be found in our atmofphere, or can be thrown 
dogether into large mafles by any power with which we are 
acquainted ; 
