382 THE POPULAR SCIENCE MONTHLY. 



from their original bed. Like the lavas, they are composed chiefly of 

 silicates. 



We observe, in the first place, that most of the eruptive rocks differ 

 considerably from meteorites. The most important point of contrast 

 is that the latter contain nothing resembling the arenaceous or fossil- 

 iferous matters of which the stratified beds are constituted that is, 

 nothing suggesting the action and movement of an ocean or the pres- 

 ence of life. A great difference also appears in comparison with the 

 masses on which the sedimentary beds immediately rest. Thus, we 

 never find granite, or any of the minerals associated in it, in meteorites. 

 The analogies of meteorites must be sought in the silicate rocks, which 

 originate in deep regions, below the granite. 



A striking example of this similitude is afforded by the recent 

 lavas, which are formed from the association of two silicates, pyrox- 

 ene and anorthite feldspar, and which correspond exactly with the 

 meteorite picked up at Jonzac (Charente-Inferieure) on the 15th of 

 June, 1819, and with that one which fell at Juvinas, in the depart- 

 ment of Ardeche, on the 13th of June, 1821. Peridote, which is re- 

 markably constant in meteorites, also occurs in the eruptive masses, 

 often abundantly. 



An equally remarkable fact is the absence from meteorites of the 

 whole series of rocks which form an important part of the crust of the 

 globe. It may be explained by supposing that the meteoric stones that 

 reach us come exclusively from the internal parts of planetary bodies 

 constituted as our globe is, or that those bodies are destitute of quartz- 

 iferous silicates, like granite, as well as of the stratified beds. In the 

 latter case, those stars have suffered less complete revolutions than our 

 planet, and exhibit no traces of the co-operation of an ocean by which 

 most of the crust of the earth above the internal masses has received 

 its shaping. 



A recent unexpected discovery, made by M. Nordenskiold in Green- 

 land, has shown the resemblances we have just described to be closer 

 and more complete. It is worthy of remark that, notwithstanding the 

 abundance with which iron is diffused in all parts of the crust of the 

 earth, that metal has never been found in the native state. However 

 pure and rich may be the mineral, some kind of a process is neces- 

 sary to extract the metal contained in it. This peculiarity is due to 

 the sensitiveness of iron in the presence of chemical agents, particu- 

 larly of oxygen. Sir John Ross brought back from his arctic voyage, 

 in 1818, some knives with blades formed of pieces of iron which the 

 Esquimaux said came from scattered blocks not far from Cape York. 

 The analysis of this iron showing the presence of nickel, a meteoric 

 origin was attributed to it. Other samples of iron, offering similar 

 characteristics, were brought down from the North by other explorers. 

 M. Nordenskiold's attention was attracted to some of these specimens, 

 which had been deposited in the museum at Copenhagan, and prompted 



