J. L. Smith— Carbon Compounds in Meteorites. 439 



teristic constituents of the nodules are here found. Then 

 again, in the case of the troilite concretions, this sulphide has 

 been separated from the mass of iron, and a phosphide of iron 

 and nickel has been concreting along with it; and yet, there 

 seems to be so great an incompatibility between these two 

 minerals that they could not commingle, but the phosphuret 

 was thrust, as it were, to the exterior of the nodule, there to 

 form a thin covering to the sulphide, like the skin of an orange 

 over the internal pulp. 



Again, the graphitic concretions bear no resemblance to the 

 scaly graphite found in the slag of iron furnaces and between 

 the crystals of cast iron, either in structure or appearance ; the 

 fractured surface is more like that of the Borrowdale graphite, 

 but the oxidizing action of the nitric acid and potash chlorate 

 on this last differs somewhat from the action on the meteoric 

 graphite. Many and varied have been the hypotheses formed 

 in my mind to account for the foimation and accumulation of 

 this graphite, but I must admit that I have been forced at last 

 to abandon them all, as none covers all the facts of the case. In 

 appearance this graphite is more like the amorphous carbon 

 that is separated from cast iron, but the oxidizing action of 

 nitric acid and chlorate of potash at once points out their great 

 difference as shown by Berthelot's experiments.* And although 

 it differs in appearance from the scaly graphite of iron, the oxid- 

 ation of the two are very similar. I am more inclined to 

 adopt the suggestion of Berthelot, that it may be formed by 

 the reaction of bisulphide of carbon upon incandescent iron, 

 as this reaction is known to give rise to an amorphous 

 graphite analogous to the one under consideration, and its asso- 

 ciation with sulphide of iron would lend some support to this 

 hypothesis ; and still further the presence of free sulphur and a 

 carbon compound, either a hydrocarbon, or sulph-hydrocarbon, 

 points also in that direction for a solution. 



It is very clear from the present accumulated knowledge of 

 the geological occurrences of graphite that we must abandon 

 all attempt to account for its formation by any one series of 

 reactions on the interior of our globe ; for it is to be found in 

 basaltic rocks, in the older crystalline rocks, and through all 

 the series of rocks up to the recent Tertiary formations ; and 

 when we add to this the laboratory experiments of Berthelot 

 that I have so frequently quoted, 'this view of the subject is 

 strengthened. But on this point I may have something more 

 to say in a paper on the Ovifak iron, and the graphite m the 

 basalt in which this iron is found. 



The carbon from the black meteorites, as the Orgueil, Alais, 

 etc., I consider as having a similar origin to that found in the 



