Dr, Reynolds on Meteors, 267 



gions of the air. Doctor Halley ascribes them to a fortuitous 

 concourse of atoms, which the earth meets in her annual track 

 through the ecliptic ; and Sir John Pringle seems to regard 

 them as bodies of a celestial character, revolving round cen- 

 tres, and intended by the Creator for wise and beneficent pur- 

 poses, perhaps to our atmosphere, to free it of noxious quali- 

 ties, or supply such as are salutary. Many other theories, as 

 ingenious as fanciful, might be enumerated ; but without com- 

 menting on their comparative merit, I must acknowledge that 

 none of them have yet impressed my mind with a conviction of 

 their truth. A series of observations, however, have enabled 

 the moderns to ascertain, with apparent accuracy, several par- 

 ticulars relative to these stupendous bodies, which add much 

 to our knowledge of their general character : — their velocity, 

 equal to 30, and even 40 miles in a second of time ; their alti- 

 tude, from 20 to 100 miles ; and their diameter, in some instan- 

 ces, more than a mile, are facts we derive from respectable 

 authority, and may aid us, essentially, in forming just concep-. 

 tions of their nature and properties. 



I believe meteoric stones to result from all meteoric explo- 

 sions ; limiting, however, the term meteor to those pheno- 

 mena, in the higher regions of the air, denominated fire-balls, 

 shooting-stars, &c. That these bodies move in a resisting 

 medium, must be evident to every attentive observer ; and 

 that this medium is our atmosphere, is pretty certain, 1st. Be- 

 cause we know of no other resisting medium round the earth ; 

 2dly. Because the same kind of resistance is apparent at every 

 intermediate altitude, from their greatest to their least, which 

 last we know to be far within our atmospheric bounds ; and, 

 3dly. Calculation has, in no instance, assigned them an eleva- 

 tion beyond the probable height of the atmosphere. 



That meteors proceed from the earth, that they arise from 

 certain combinations of its elements with heat, and that me- 

 teoric stones are the necessary result of the decompositions of 

 these combinations, are opinions I will endeavour to support, 

 by the following considerations. 



1st. The properties and habitudes of matter, viader certain 

 conditions and combinations, 



