MEMOIR ON METEORITES. 289 



although all four of them have strong affinity for this element, 

 and are never found (except copper) in the earth uncombined 

 with it, except where some similar element (as sulphur, etc.) 

 supplies its place.* 



The inference of the absence of oxygen in a gaseous condi- 

 tion, or in water, is drawn from such substances as iron and 

 nickel being in their metallic state, as has been just mentioned. 

 But it must not be inferred that oxygen is absent in all forms 

 at the place of origin of meteorites, for the silica, magnesia, 

 protoxide of iron, etc., contain this element. The occurrence 

 of one class of oxides and not another would indicate a limited 

 supply of the element oxygen, the more oxidizable elements, 

 as silicon, magnesium, etc., having appropriated it in preference 

 to the iron. 



Many other elements worthy of notice might be mentioned 

 here, and some of them, for aught we know, may be constant 

 ingredients ; but in the absence of strong presumption at least 

 on this head they will be passed over, as those already men- 

 tioned suffice for the support of all theoretical views to be 

 advanced. 



I can not, however, avoid calling attention to the presence 

 of carbon in certain meteorites ; for although its existence is 

 denied by some chemists, it is nevertheless a fact that can be as 

 easily established as the presence of the nickel. The interest 

 to be attached to it is due to the fact that it is so commonly 

 regarded in the light of an organic element. It serves to 

 strengthen the notion that carbon can be of pure mineral 

 origin, for no one would be likely to suppose that the carbon 

 found its way into a meteorite either directly or indirectly from 

 an organic source. 



Having thus noted the predominant physical, mineralogical, 

 and chemical characteristics of meteorites, I pass on to the next 

 head. 



Marked Points of similarity in the Constitution of Me- 

 teoric Stones. 

 Had this class of bodies not possessed certain properties dis- 

 tinguishing them from terrestrial minerals, much doubt would 



*The traces of iron found in basaltic rock already alluded to form too 

 insignificant an exception to "be insisted on. 



