216 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



and in one, instance was undoii})te(lIy crystallized, but, unfortunately, 

 the speciuKMi was so lu'ittle that it fell to pieces on attempting to 

 measure it. 



An analysis o-ave the following: 



Iron 64. 990 



Nickel 18. 905 



Ci>l)alt 105 



Pho.si)honis 15. 700 



Copper Trace. 



Tr'oilite occurs commonly associated with the black specular mate- 

 rial lining the cavities containing the olivnne in the nickel-iron con- 

 stituent. It varies in its dimensions from a coating aline in thickness 

 to masses 2 or more millimeters thick l)y l(» millimeters in length. 

 Grains and flakes of troilite are occasionally contained in masses of 

 the nickel-iron alio}" and may then be associated with schreibersite 

 areas. Further, it may occur as isolated grains or flakes and fllling 

 cracks in the olivine areas. 



The material analyzed was obtained by treating the metallic portion 

 with mercury bichloride, and after its solution separating the troilite 

 and schreibersite from carbon, silicates, etc., with the magnet and 

 from each other by lixiviation. The material thus obtained had a 

 specitic gravity of 4.759 at 18 C-. and th(^ following composition: 



Iron 62. 99 



Nickel \ 



Cobalt / 



Phosphorus Trace. 



Sulphur 86. ;i5 



The sj)eevlar inatcr/dl lining the olivine, cavities is essentially a 

 graphitic iron containing sulphur and chlorine. The material analyzed 

 was far from being homogeneous, as it was separated mechanically 

 with the aid of a glass. The composition was as follows: 



Iron 84. 900 



Nickel 



Cobalt 



Silica 2. 990 



Carbon 2. 810 



Sulphur 1. 750 



Phosphorus 1. 470 



Chlorine 100 



Alumina 940 



Chromite occurs quite abundantly, varying in size from microscopic 

 grains to a crystal 1 millimeter in diameter. The crystals are more 

 oi- less perfect octahedrons, rarely modified by other forms, and then 

 only by x () (110), as noted in one instance. The}' are brilliant black 



I 5.039 



