MEMOIR ON METEORITES. 301 



1. That all meteoric masses have a community of origin. 



2. At one period they formed parts of some large body. 



3. They have all been subject to a more or less prolonged 

 igneous action, corresponding to that of terrestrial volcanoes. 



4. That their source must be deficient in oxygen. 



5. That their average specific gravity is about that of the 

 moon . 



From what has been said under the head of common char- 

 acters of meteorites, it would appear far more singular that 

 these bodies should have been formed separately from each 

 other than that they should have at one time or another con- 

 stituted parts of the same body; and from the character of 

 their formation that body should have been of great dimen- 

 sions. Let us suppose all the known meteorites assembled in 

 one mass, and regarded by the philosopher, mindful of our 

 knowledge of chemical and physical laws. Would it be con- 

 sidered more rational to view them as the great representatives 

 of some one body that had been broken into fragments, or as 

 small specks of some vast body in space that at one period or 

 another has cast them forth? The latter, it seems to me, is 

 the only opinion that can be entertained in reviewing the facts 

 of the case. 



As regards the igneous character of the minerals composing 

 meteorites, nothing remains to be added to what has already 

 been said. In fact, no mineralogist can dispute the great re- 

 semblance of these minerals to those of terrestrial volcanoes, 

 they having only sufficient difference in association to establish 

 that, although igneous, they are extra-terrestrial. The source 

 must also be deficient in oxygen, either in a gaseous condition 

 or combined as in water. The reasons for so thinking have 

 been clearly stated as dependent upon the existence of metallic 

 iron in meteorites; a metal so oxidizable that in its terrestrial 

 associations it is almost always found combined with oxygen, 

 and never in its metallic state. 



What then is that body which is to claim common parentage 

 of these celestial messengers that visit us from time to time? 

 Are we to look at them as fragments of some shattered planet, 

 whose great representatives are the numerous asteroids be- 

 tween Mars and Jupiter, and that they are "minute outriders 

 of the asteroids" (to use the language of R. P. Greg, jr., in a 



