﻿288 Huntington— Crystalline Structure of Iron Meteorites. 



appear to make various angles with each other ; but when the 

 etched surface is parallel to an octahedral face, the Widman- 

 stattian figures all make equilateral triangles, their sides being 

 parallel to the octahedral edges. 



De Kalb County. 



Such a section is shown in fig. 1, which is part of a surface 

 cut parallel to an octahedral face of the De Kalb specimen just 

 referred to. The figure is an exact sketch, representing the 

 plates of their natural size. The most noticeable character in 

 the figure is the system of broad bands which divide the mass 

 into equilateral triangles. These are cross-sections of the crys- 

 tal plates, which, in another part of the specimen, stand out so 

 markedly in forming the hollow-faced octahedrous. These 

 plates consist of the purer iron to which Reichenbach gave 

 the name of Balkeneisen, or Kamacite, and they are separated 

 from the groundmass by a thin layer of iron rich in nickel, 

 called by Reichenbach Bandeisen or Tasnite. This material is 

 not readily acted upon by acid, and therefore appears on the 

 etched surface as a bright silvery line along the edge of the 

 kamacite plates. In some meteorites, as in the Cocke County 

 and Sevier County, it occurs in sufficient mass to be easily 

 separable from the plates in the form of a thin elastic foil, 

 while in others it almost wholly disappears. The thin plates 

 of " bandeisen " resist the action of oxidizing agents, as they 

 resist the action of dilute acid, so that, when the surface of the 

 meteorite becomes disintegrated by air and moisture, these 

 plates not un frequently become loose, and are easily separated. 

 Dr. Lawrence Smith analyzed the material of some plates thus 

 obtained from the Sevier County meteorite, and found in them 

 27 per cent of nickel. The groundmass consists of what 

 Reichenbach calls Fiilleisen, or Plessite. In the present case, 

 the latter is filled with very thin plates, or u combs," in general 

 following the octahedral directions and appearing to be a sub- 

 sequent crystallization, as if the larger plates had first shot 

 through the mass when in a liquid state, and then, as the inte- 



