290 MEMOIR ON METEORITES. 



even now be entertained of their celestial origin, and various 

 would be the explanations made even in those cases where the 

 bodies were seen to fall, and afterward collected. . Chemistry 

 has entirely dissipated all doubts in the matter, and now an 

 examination in the laboratory of the chemist is entitled to more 

 credit than evidence from any other source in pronouncing on 

 the meteoric origin of a body. No question need be asked as 

 to whether it was seen to fall, or whether this or that rock or 

 mineral exists in the neighborhood where it may have been 

 collected. The reagents of the chemist alone are unerring 

 indications that suffice to set aside all caviling in the matter. 



It is the object of this part of the paper to explain more 

 prominently perhaps than has yet been done how it is that 

 chemistry pronounces with such unerring certainty on the 

 celestial origin of certain bodies ; and I propose to go even a 

 step farther, and see if the chemical constitution of the mete- 

 orites can indicate from what part of the heavens they may 

 have come. 



When the mineralogical and chemical composition of these 

 bodies are regarded, the most ordinary observer will be struck 

 with the wonderful family likeness running through them all, 

 however unlike at first sight. There will be seen to be three 

 great divisions of meteoric bodies (omitting three or four); 

 namely, metallic, stony with small particles of metal, and a 

 mixture of metallic and stony, in which the former predomi- 

 nates, as in the Pallas and Atacama meteorites. 



As regards external appearances, these three classes differ in 

 a very marked manner from each other. The meteoric iron 

 being ordinarily of a compact structure, more or less corroded 

 externally, and when cut showing a dense structure with most 

 of the peculiarities of pure iron, only a little harder in texture 

 and whiter in color. The stony meteorites are usually of a gray 

 or greenish -gray color, granular structure, readily broken by a 

 blow of the hammer, and exteriorly are covered with a thin 

 coating of fused material. The mixed, meteorite presents char- 

 acters of both of the above; a large portion of it is constituted 

 of the kind of iron already mentioned, cellular in its character, 

 and the cells filled up with stony materials, similar in appear- 

 ance to those constituting the second class. 



Although there are some instances of bodies of undoubted 



