Prof. Berzelius on Meteoric Stones. 439 



3rd. Magnetic Ore of h-on. — Although the iron in meteoric 

 stones is principally either in the metallic state, or at the mini- 

 mum of oxidation, nevertheless it is certainly found in the 

 state of deutoxide ( oxide f err oso-fcrri que) in the meteorites 

 of Loutolox and Alais : the magnetic portion of the first is 

 wholly composed of it, and in great part, that of the second. 



4th. Meteoric Olivine, — This constitutes about half of that 

 which remains after the separation of the magnetic portion; it 

 is decomposed by acids, leaving a siliceous residue. Its for- 

 mula is exactly the same as common olivine, /. e. -v^ \ S, in 



which M and f vary in their relative proportions: it contains 

 as isomorphous substitutes small quantities of the silicates of 

 oxide of nickel and protoxide of manganese, as well as a por- 

 tion of oxide of tin, like terrestrial olivine : it is worthy of 

 remark that it scarcely ever contains lime. 



5th. Silicates of magnesia, lime, protoxide of iron, prot- 

 oxide of manganese, alumina, potash, and soda, insoluble in 

 acids, in which the oxygen of the silica is double that of the 

 bases : these probably constitute another mineral, analogous 

 to pyroxene, 



Ml ^1 



C rS-; and nnother, analogous to leucite, ^j rS' + SAS-. 



^ ^ kJ 



The black crust tliat covers the surface of meteoric stones 

 is owing to the fusibility of their silicates : these also contri- 

 bute to the fusion of the olivine, which by itself is infusible. 



That which deserves particular attention is, that if meteoric 

 stones were formed of terrestrial olivine and pyroxene, their 

 colour would be green, or even black, in consequence of 

 the higher degree of oxidation of the iron : this is a sufficient 

 proof that the fused black crust has not been formed in the ter- 

 restrial atmosphere. 



6th. Alloy of Chromium arid Iron. — It is very remarkable 

 that this mineral so constantly accompanies meteoric stones, 

 considering that it always occurs in such very small quantity. 

 The preceding experiments show that it separates from the 

 meteorites without alteration, yet it is always partially decom- 

 posed, when it must be sought for in the separated oxide of iron. 



7lh. Ore of Tin. — The tin of meteoric stones partly pro- 

 ceeds from the native iron they contain, and partly from a small 

 portion of oxide of tin which is disseminated through the chro- 

 miron, and which on analysis dissolves or remains undissolved 

 with the latter body. The oxide of tin is mixed with copper. 



M. Berzelius considers that a more profound study of meteo- 



