MEMOIR ON METEORITES. 285 



proved ; and meteorites when looked upon as bringing these 

 proofs acquire additional interest. 



Meteorites studied in the way just mentioned lead us to the 

 inference that the materials of the earth are exact represen- 

 tatives of the materials of our system, for up to the present 

 time no element has been found in a meteorite that has not its 

 counterpart on the earth ; or, if we are not warranted in making 

 such a broad assumption, we certainly have the proof, as far as 

 we may ever exj)ect to get it, that materials of other portions 

 of the universe are identical with those of our earth. 



Meteorites also show that the laws of crystallization in bodies 

 foreign to the earth are the same as those affecting terrestrial 

 matter, and in this connection we may instance pyroxene, 

 olivine, and chrome iron, affording in their crystalline form 

 angles identical with those of terrestrial origin. 



But perhaps of all the interesting facts under this head 

 developed by meteorites is the universality of the laws of 

 chemical affinity, or the truth that all the laws of chemical 

 combination and atomic constitution are to be equally well 

 seen in extra-terrestrial and terrestrial matter; so that were 

 Dalton or Berzelius to seek for the atomic weights of iron, 

 silica, or magnesia, they might learn them as well from me- 

 teoric minerals as from those taken from the bowels of the 

 earth. The atomic constitution of meteoric anorthite or of 

 pyroxene is the same as that which exists in our own rocks. 



Keeping in view then the physical and chemical characters 

 of meteorites, I propose to offer some theoretical considerations 

 which to be fully appreciated must be followed step by step. 

 These views are not offered because they individually possess 

 particular novelty. It is the manner in w T hich they are com- 

 bined to which especial attention is called. 



Physical Characteristics to be noted in Meteorites. 



The first physical characteristic to be noted is their form. 

 No masses of rock, however rudely detached from a quarry, or 

 blasted from the side of a mountain, or ejected from the mouth 

 of a volcano, would present more diversity of form than 

 meteoric stones. They are rounded, cubical, oblong, jagged, 

 flattened, and in fine they present a great variety of fantastic 

 shapes. Now the fact of form I conceive to be a most im- 



