Professor Jacob Berzelius on Meteoric Stones. 3 



might be supposed that they were broken from one piece. They 

 contain ductile metallic iron in variable quantities. There are 

 examples of enormous blocks, consisting of one single connected 

 mass of iron, whose crevices are filled by mineral matter, and 

 which have been preserved during the fall, owing to their being 

 held together by the including iron. Others are composed more 

 of mineral matter, with less iron, and they have therefore less 

 cohesion. These are modified by the heat resulting from the 

 immense pressure exercised during the few minutes of their pas- 

 sage through the atmosphere, a pressure produced by the unre- 

 strained and increasing rapidity of motion of the aerolites towards 

 the earth ; and in consequence, their external surface is always 

 melted to a black slag, which is finer than the thinnest post paper. 

 We may hence say that meteoric stones, it being assumed that 

 they are derived from the moon, come from only two different 

 volcanoes, of which the one has either more abundant ejected 

 masses, or the masses go in such a direction that they reach us 

 more frequently. Such a state of things corresponds perfectly 

 with the idea, that a certain portion of the moon has the earth 

 constantly in the zenith, and that all its ejected masses which 

 are thrown out in a straight line are directed by it towards the 

 earth, whither, however, they do not proceed in a straight direc- 

 tion, since they are also subjected to that motion which they 

 previously possessed as parts of the moon. If it is this portion 

 of the moon that sends us meteoric blocks of iron, and if the 

 other parts of the moon do not abound so much in iron, we see 

 a reason why this point should be constantly turned towards the 

 magnetic terrestrial globe. 



The mineral matter of meteoric stones is composed of differ- 

 ent mineral species. These are, 



1. Olivine. It contains magnesia and oxide of iron, and is 

 colourless or greyish, seldom yellow or green like all terrestrial 

 olivine. This proves that there is no oxygen present further to 

 oxidise the iron. Like the terrestrial, it is soluble in acids, 

 leaving behind the gelatinised silica. Like it, also, it contains 

 traces of oxide of tin and oxide of nickel. The olivine of the 

 Pallas iron is an exception, for it contains no nickel, and its co- 

 lour is greenish yellow ; but it contains tin. The olivine con- 

 stitutes about half of the non-magnetic mineral matter. We 

 separate the olivine by treating it with acids, and then after- 



