96 Meteoric Stones. 



masses, and if the other parts of the moon are riot so full of iron, 

 then we see a reason why that point turns continually towards 

 the magnetic globe of the earth. 



The mineral ])ortion of meteoric stones consists of various min- 

 erals. 1. Olivine. It contains magnesia and protoxyd of iron, 

 is colorless or grayish, but is sometimes streaked with yellow or 

 green like all the terrestrial olivine. This shows that oxygen 

 is wanting for a higher oxidation of the iron. Like the terres- 

 trial, it is soluble in acids, and leaves the silicious earth in the 

 form of gelatine. It cmitains like some of the terrestrial, a trace 

 of oxyd of tin and oxyd of nickel. Olivine, however, in the me- 

 teoric iron found by Pallas, makes an exception to this, for it is 

 without nickel, and its color is yellow approaching to green ; but 

 it contains tin. OHvine comprises about one half the quantity of 

 the unmagnetic minerals. Olivine separates by treating with 

 acids, and the silicious earth is then set free by boiling in car- 

 bonate of soda. 



Then there remain, 2. silicates of magnesia, lime^ protoxyd 

 of iron ^ protoxyd of manganese, alumina, potash^ and soda, which 

 are not separated by acids and in which the siHcious earth con- 

 tains two species of bisilicates. These are probably blended with 

 morC; which I was not able to separate. We may conjecture 



M 



fy 



a species of pyroxene / J> S^ and a species of leucite where 

 hme and magnesia in the first terras replace a portion of potash 



Mo- 

 O 



and soda. iv / S^ -[-SAS^. The pyroxene not having so much 



K 



color as the terrestrial, is to be attributed to the same cause as the 

 want of color in meteoric olivine. 



3. Chrome-iron, — This is contained in both kinds of meteoric 

 stones, in both in like small quantity, is never wanting, and is the 

 source of the chrome in meteoric iron. It can be obtained unde- 

 composed if the unmagnetic portion of the meteoric stone is sepa- 

 rated with hydro-fluoric acid, and is then, after all the silicious earth 

 is removed, treated with sulphuric acid, after which the sulphates 

 and the gypsum are boiled out, when the chrome iron remains in 

 the form of a black burnt powder. This is the cause of the grey- 

 ish color in meteoric stones when thev are seen in the mass. 



