e. 
found in Siberia ; <). 
fequainted ; that no. power with which we are acquainted 
is able to give to'fuch bodies fo rapid a projeétile force in a 
direction siiaid parallel to the horizon; that the matter 
does not rife upwards from the earth, but exifts previoufly 
in the celeftial regions, and muft have been conveyed thence 
to ourearth, In the opinion of Dr. Chladni, the following 
_is the only theory of this: phenomenon that agrees with all 
the accounts hitherto given; which is not contrary to na- 
ture in any other refpect; and which befides feems to be 
confirmed by yarious majffes found on the fpot where they 
fell. 
As earthy, metallic and other particles form the principal 
component parts of our planets, among which iron is the 
prevailing part, other planetary bodies may therefore confift 
of fimilar, or perhaps the fame component parts, though 
combined and modified in a very different manner. ° There 
may alfo be denfe matters accumulated in fmaller mafles 
without being in immediate connexion with the larger 
planetary bodies, difperfed throughout infinite fpace, and 
which, being impelled either by fome projecting power 
or attraction, continue to moye until they approach the 
earth or fome other body; when being overcome by their 
attractive force, they immediately fall down. By their ex- 
ceedingly great velocity, {till increafed by the attraCtion of 
the eagth and the violent friétion in the atmofphere, a ftreng 
electricity and heat muft neceflarily be excited, by which 
means they are reduced to a flaming and melted condition, 
and great quantities of vapour and different kinds of gafes 
are thus difengaged, which diftend the liquid mafs to a mon- 
ftrous fize, till, by a full farther expanfion of thefe elaftic 
fluids, they muft at length burft. . Mr. Chladni thinks alfo, 
that the greater part of the fhooting-fiars as they are called, 
are nothing clfe than fire-balls, which differ from the latter 
only in this;, that their. peculiarly great velocity carries them 
paft the earth at a greater diftance, fo that they are not fo 
ftrongly attraéted by it as to fall down, and therefore in their 
Ba paflage 
