440 Prof. Berzeliiis on Meteoric Stones. 



rites in the point of view from whence he has set out would 

 undoubtedly make known a much larger proportion of their 

 principal constituents. 



If we consider meteoric stones as niineralogical specimens, 

 and compare them with those of our earth, we shall find essen- 

 tial differences, even putting out of the question the existence 

 of the native iron. The abundance of magnesia which is 

 in all the chief constituent, the poverty in silica, and the 

 small proportion of the silicates of alumina and of the alkalies, 

 distinguish the meteoric minerals. On this earth it is just the 

 contrary : here silica is the predominant substance, and the 

 silicates of alumina and the alkalies form everywhere its prin- 

 cipal constituents. Magnesia is rare. 



The fineness of grain and feeble cohesion of meteoric stones 

 would lead one to suppose that they are projected in a fused 

 state, and consequently resemble the products of terrestrial 

 volcanos, yet this does not appear to be the case. If we 

 carefully examine the texture of a large fragment of a mete- 

 oric stone, it will be found to be split, and the fissures filled 

 with another kind of mineral, for the most part of a deeper 

 colour, which indicates a slower and calmer formation. If 

 olivine is found amongst the products of terrestrial volcanos, 

 and rarely in other minerals, it is no proof that it must always 

 be a volcanic product. It is infusible, and is found inclosed 

 in volcanic minerals, because it could not be fused with them. 

 On the contrary, in meteoric stones it is so uniformly mixed 

 with the other constituents, that its presence in these is evi- 

 dently owing to another cause which does not exist in lava 

 and basalt. 



The Alais meteorite proves that in their original situation 

 rocks are altered by the influence of some geognostic ac- 

 cident, and are converted into a kind of earth, and that even 

 this mass, resembling olivine and mixed with native iron, con- 

 stitutes the rock from which it is broken. The presence, in 

 this earth, of salts soluble in water would seem to prove that 

 this phasnomenon had occurred either without the presence of 

 water, or in water which contained such large quantities of 

 these salts that they remained after desiccation. The car- 

 bonized substance that this earth contains, in a state of mix- 

 ture, would not authorize the conclusion that in its oi'iginal 

 habitat, this earthy substance was of an organic nature. This 

 property of the earth a})pears, more than any other circum- 

 stance, to show that these meteoric stones have not been pro- 

 jected in a state of fusion and afterwards cooled, for under 

 such circumstances such a formation could not have occurred. 



The preceding remarks apply to the majority of meteoric 



