﻿Huntington — Crystalline Structure of Iron Meteorites. 287 



This specimen shows six faces of a rough octahedron, one of 

 the faces having an area of seven square inches. One half of 

 this octahedron has been partially torn apart into numerous 

 smaller crystals, some of them an inch or more in diameter ; 

 but though the crevasses between the individuals are in some 

 places nearly a quarter of an inch in breadth, yet they are 

 bound firmly together by a network of plates, which in some 

 parts raggedly jut out from the octahedral faces. The general 

 appearance of the exterior of the specimen reminds one some- 

 what of a rough mass of galena crystals, only of octahedral 

 form. The rough crystal is evidently the result of fracture, 

 probably caused during the passage of the mass through the 

 air, and the octahedral faces are cleavage planes, if the term 

 cleavage may be applied to such fractures, which cannot be re- 

 produced by splitting in the ordinary way on account of the 

 malleability of the mass. The specimen further exhibits a 

 fused crust over the octahedral faces, which must have formed 

 after the partial breaking up of the large mass, giving a rounded 

 appearance to the edges. On a polished surface, cut nearly 

 parallel to the largest octahedral face, the figures produced by 

 etching appear very strikingly. They are perfectly distinct 

 and regular, being typical Widmanstattian figures ; but when 

 they come to the cracked portion of the iron, they appear as 

 separate plates, some having been broken by the rupture, 

 others separated, while the greater number appear bent and 

 strained, but still coherent and binding the mass firmly to- 

 gether. The whole appearance on the etched surface gives at 

 once the idea of a forcible explosion, and yet all the cracks, 

 even the most ragged, follow directions parallel to the octahe- 

 dral faces. 



A second specimen of the same iron, measuring twelve and 

 a half inches in its longest dimension, and weighing 9,980 

 grams, is a very remarkable mass of cleavage octahedrons, 

 loosely packed together and piled on top of each other, not un- 

 like crystals of alum, and almost as sharply defined. The 

 largest octahedral face measures five inches in diameter, but is 

 made up of numerous smaller crystals, in some places jutting 

 out and in others receding, forming numerous triangular pro- 

 jections and depressions. 



Another striking octahedral mass is a fragment of the well- 

 known De Kalb County meteorite. One specimen of this 

 iron shows hollow octahedral faces, two inches in diameter, like 

 hopper crystals, consisting of skeletons built up of a series of 

 plates about half an inch wide and one-sixteenth of an inch 

 thick. These plates, when cut transversely, constitute the 

 Widmanstattian figures. When the section is cut at random, 

 the figures may differ somewhat in character, and the plates 



