302 MEMOIR ON METEORITES. 



late communcation to the British Association) which have been 

 ultimately drawn from their path by the attraction of the earth? 

 For more reasons than one this view is not tenable. Many of 

 our most distinguished astronomers do not regard the asteroids 

 as fragments of a shattered planet; and it is hard to believe if 

 they were, and the meteorites the smaller fragments, that these 

 latter should resemble each other so closely in their composi- 

 tion, a circumstance that would not be realized if our earth was 

 shattered into a million of masses large and small. 



If then we leave the asteroids and look to the other planets, 

 we find nothing in their constitution or the circumstances at- 

 tending them to lead to any rational suj)position as to their 

 being the original habitation of the class of bodies in question. 

 This leaves us then but the moon to look to as the parent of 

 meteorites; and the more I contemplate that body the stronger 

 does the conviction grow that to, it all these bodies originally 

 belonged. 



It can not be doubted from what we know of the moon that 

 it is in all likelihood constituted of such matter as compose 

 meteoric stones: and that its appearances indicate volcanic 

 action, which, when compared with the combined volcanic 

 action on the face of the globe, is like contrasting iEtna with 

 an ordinary forge, so great is the difference. The results of 

 volcanic throws and outbursts of lava are seen for which we 

 seek in vain any thing but a faint picture on the surface of our 

 earth. Again, in the support of the present view it is clearly 

 established that there is neither atmosphere nor water on the 

 surface of that body, and consequently no oxygen in those con- 

 ditions which would preclude the existence of metallic iron. 



Another ground in support of this view is based on the 

 specific gravity of meteorites, a circumstance that has not been 

 insisted on; and although of itself possessing no great value, 

 yet in conjunction with the other facts it has some weight. 



In viewing the cosmical bodies of our system with relation 

 to their densities, they are divided into two great classes — 

 planeta^ and cometary bodies (these last embracing comets 

 proper and shooting-stars) — the former being of dense and the 

 latter of very attenuated matter; and so far as our knowledge 

 extends there is no reason to believe that the density of any 

 comet approaches that of any of the planets. This fact gives 



