NEWTON COUNTY (ARK.) METEORITE. 341 



Chrome Iron. — This is found in small quantity in minute 

 particles, some of them showing distinct faces of crystals; but 

 I failed to find any complete octahedron. The quantity was 

 too small for analysis, but was readily recognized by the blow- 

 pipe. 



Sulphuret of Iron. — This also is discernible only in minute 

 quantity, and could not be collected for analysis. I would 

 remark, with reference to the sulphuret of iron found in mete- 

 orites, that it can not be classed with the terrestrial magnetic 

 pyrites, whose formula is considered Fe 7 S 3 , having always 

 found the sulphur too small for this formula; in which con- 

 clusion I believe that I am sustained by Eammelsberg and 

 others. My results point to the formula FeS; and if the com- 

 positions of these two kinds of pyrites are correctly made out, 

 then the meteoric "variety has no terrestrial representative. 



Hornblende. — This mineral is easily separated, and is of a 



greenish-gray color, more or less soiled by iron. With some 



care it can be detached unmixed with other constituents. It 



has a very distinct cleavage in one direction and an imperfect 



one in another. On analysis it gave 



Silica 52.10 



Alumina 1.02 



Protoxide of iron 16.49 



Protoxide of manganese 1.25 



Magnesia 29.81 



Alkalies (potash, soda, lithia) 24 



100.91 



The oxygen relations of the silica and protoxides furnish the 



formula E4 Si3 — the formula of hornblende. In structure and 



composition it is not unlike some varieties of anthophyllite. 



Olivine. — This mineral is diffused through the mass. Some 



of the smaller pieces are almost colorless; others again are 



more or less yellow, being stained with oxide of iron. Some 



of the fragments are iridescent, like varieties of oligoclase, 



which I at first took it to be. Sufficient of it was detached 



in a pure state for analysis, and was found to be composed as 



follows : 



Silica 42.02 



Alumina 46 



Protoxide of iron 12.08 



Magnesia 47.25 



101.81 

 23 



