METEORITES OF NORTH AMERICA. 259 



Isolated schreiberaite of greatly differing size occurs abundantly in the nickel-iron; especially noteworthy is a 

 crystal from a small mold whose kernel of nickel iron possesses exactly the form of the host. Of troilite only grains 

 a few millimeters in size were observed, which lay sometimes in the nickel iron, sometimes in the carbon. Brezina 

 may, indeed, have taken many schreibersites for troilite, a mistake easily made when the former turns yellow. Black 

 veins of eisenglas run from the original surface into the interior. The Kendall County iron dissolves very easily in 

 dilute hydrochloric acid, with development of carburetted hydrogen. In this manner the following minor constit- 

 uents were isolated: Amorphous carbon, black veins, schreibersite, silicate grains, and a hitherto unnoted cristobalite- 

 like silica. 



The latter occurs by preference or exclusively in intimate union with the carbon and the carbon-echreibersite 

 concretions, since the pieces rich in the latter furnish the largest share, and the isolated constituents (carbon, schrei- 

 bersite, and black veins), according to the analysis, give a mixture of silicic acid found nowhere else in meteoric iron 

 and which can be referred to no mineral as yet observed in meteoric irons. The cristobalitelike crystals are small, 

 very sharply outlined, colorless, and isometric. Some are clear, others turbid. On strong magnification one recog- 

 nizes pointlike inclusions which are generally pretty uniformly distributed, though at times aggregated to cause 

 cloudiness. As a rule only the cube is present, but occasionally the octahedron appears in part subordinate, in part 

 equal with the cube. Most of the crystals are ideally formed, but occasionally prismatic through a stronger develop- 

 ment of four faces of the cube in one zone. 



Somewhat more common, but still rare, are cube faces indented by growth along the edges. Most of the crystals 

 are 0.03 to 0.04 mm. in size, but the dimensions rise to 0.09 and sink to 0.01 mm. The following properties were veri- 

 fied: Completely isotropic; index of refraction between 1.48 and 1.52; specific gravity, 2.3; no cleavage; not attacked 

 by concentrated HC1 or aqua regia; soluble in cold hydrofluoric acid; unchanged B. B. A few opaque grains (appar- 

 ently chromite), as well as cloudy, apparently very much disintegrated silicate grains, accompany the cristobalite- 

 like silica. Although the number of the cristobalitelike crystals was very considerable, it was not possible, on account 

 of their small dimensions, to obtain enough material for an analysis. 



The amorphous carbon behaves, under treatment with potassium chlorate and nitric acid, exactly as Moissan 

 describes. The oxidation proceeds with extreme slowness, but it develops no trace of carbonic acid. Without closer 

 investigation the carbon would be taken from its appearance for graphite, and this graphitic character may account 

 for the resistance to strong oxidizing agents. 



The dark fragments remaining after treatment of the insoluble residue with copper ammonium chloride, and 

 which disregarding the schreibersite inclusions have the appearance of a homogeneous substance, were analyzed 

 in the supposition that they were particles of eisenglas. They appeared, however, in the main to be a mixture of iron 

 hydroxide and carbon with abundant intermixture of cristobalitelike silicic acid. 



Kendall County takes on pretty strong permanent magnetism ; s the specific magnetism was determined by Leick 

 at 0.33 absolute units per gram. 



Analyses: 



I. Schreibersite; Scheerer and Fahrenhorst. la: After deducting insoluble residue. 



II. Complete analysis; Fahrenhorst. Ila: Composition of the nickel-iron after deducting accessory constituents. 



III. Amorphous carbon, specific gravity 2.24, Fahrenhorst. 



100.00 100.00 101.11 100.0 100.43 

 IV. Fahrenhorst gives the following analysis of the black veins: 



............... 47.57 



XiO+CoO .......................................................... 1. 29 



C ................................................................... 29.50 



SiO 2 ................................................................ 7. 21 



HjO ............................................................... 4.32 



Chromite ............................................................ 1. 17 



Schreibersite ........................................................ 6. 11 



91.77 



