MEMOIR ON METEORITES. 287 



MlNERALOGICAL AND CHEMICAL POINTS IN METEORITES. 



The rocks or minerals of meteorites are not of a sedimen- 

 tary character, nor such as are produced by the action of water. 

 This is obvious to any one who will examine these bodies. A 

 mineralogist will also be struck with the thin dark-colored 

 coating on the surface of the stony meteorites. The coating, 

 in most if not in all instances, is of atmospheric origin, being- 

 acquired after the meteorite enters the atmosphere, and as 

 such no further notice will be taken of it; but I will proceed 

 at once to notice the most interesting peculiarities under this 

 head. First of all, metallic iron, alloyed with more or less 

 nickel and cobalt, is of constant occurrence in meteorites, with 

 but three or four exceptions — in some instances constituting 

 the entire mass, at other times disseminated in fine particles 

 through stony matter. The existence of this highly oxidizable 

 mineral in its metallic condition is a positive indication of a 

 scarcity or total absence of oxygen (in its gaseous state or in 

 the form of water) in the locality whence it came. 



Another mineralogical character of significance is that the 

 stony portions of the meteorites resemble the older igneous 

 rocks, and in even a more striking manner the volcanic rocks 

 belonging to various active and extinct volcanoes. It is useless 

 to dwell on this fact, as it is one well known to all mineralogists 

 who may have examined this matter; and none have given 

 more especial attention to it than Eammelsberg, who in a paper 

 published in 1849 details his examination of a great variety 

 of lavas, and traced the perfect parallelism between them and 

 stony meteorites. He showed that the Juvenas stone has the 

 same constitution as the Thjorsa lava of Heckla, both con- 

 sisting substantially of augite and anorthite, even in nearly 

 the same relative proportions; while the Chateau Renard and 

 Nordhausen stones have labradorite replacing the anorthite ; and 

 the Blansko, Chantonnay, and Utrecht stones have oligoclase 

 as the feldspar, and resemble the lavas of iEtna, Stromboli, and 

 the newer lavas of Heckla. 



The inference to be drawn from the last character is very 

 evident. It is highly significative of the igneous origin of 

 these bodies, and of an igneous action similar to that now 

 existing in our volcanoes. 



