392 J. L. Smith — Carbon Compounds in Meteorites. 



he sees so vast a difference in the mineral constituents of the 

 different meteorites there enumerated ; and yet they represent 

 the two extremes of these bodies so far as their external proper- 

 ties are concerned. It is well known that three or four mine- 

 rals represent the great mass of the constituents of every meteor- 

 ite in various proportions, viz : nickeliferous iron, olivine, 

 pyroxene, and anorthite, especially the first three; and the 

 purely iron meteorites must be recognized as magnified masses 

 of the metallic particles to be found in every stony meteorite, 

 not excepting even the carbonaceous meteorites.* 



My object, however, in this paper is not to discuss at length 

 the general internal resemblances of these bodies, as I may have 

 occasion to do it more fully at another time. I wish simply to 

 note, that black and pulverulent as are the carbonaceous mete- 

 orites, they are not removed by their mineral constituents from 

 the so-called common meteorites. I now pass on to show that 

 even in their carbonaceous constituent they are strongly linked 

 even to the iron meteorites. 



2. Graphite carhon in the Iron Meteorites. — Ever since the inter- 

 nal structure of this class of meteorites has been examined by 

 sections through the center of these compact metallic masses, 

 nodular concretions have been noted in their interior, the most 

 common of which consist of troilite, a protosulphide of iron, and 

 filling ovoidal cavities. Sometimes these troilite concretions 

 have a thin coating of a lighter colored mineral known as 

 schreibersite ; and this last is also found alone in concretionary 

 masses which are usually angular or lamellar. 



Less frequent concretions than either of the above, and even 

 more remarkable, consist of carbon of the character of graphite : 

 these, like the troilite, usually fill irregular ovoidal cavities, and 

 are more or less contaminate"d with the latter mineral. 



The most important of the meteoric irons containing these 

 nodules, that have come under my immediate observation, are 

 the Toluca, the Cranbourne, the DeKalb, and the Sevier : the 

 last two have received my special study, the latter furnishing 

 much the larger part of the material in my hands. 



Character of the graphite nodules. — These concretions differ 

 more or less in appearance, while their general character is the 

 same. In this communication I call special attention to a large 

 nodule taken from the very center of the Sevier iron, the largest 

 that has come under my observation, and perhaps the largest 

 known. It was detached from the iron entire and perfect in 

 every respect Its greatest length is 60 ram. ; its dimensions in 



* At present, the OrgueU and Rhoda meteorites are the only t«ro in which no 

 positive evidence of the presence of nickeliferous iron has been traced; in the 

 Orgueil, however, we find nearly three per cent of oxides, nickel and cobalt, and 

 the fihoda has not been very criticaUy examined. 



