﻿284 Huntington — Crystalline Structure of Iron Meteorites. 



Art. XXXIII. — On the Crystalline Structure of Iron Meteorites /* 

 by Oliver Whipple Huntington. 



The general octahedral structure of iron meteorites was ob- 

 served soon after the attention of mineralogists had been 

 directed to this remarkable class of bodies. 



In the year 1808, von Widmanstattenf of Vienna observed 

 the crystalline figures brought out on a polished section of the 

 Agram iron by tempering or etching, which have since been 

 known by his name. That these figures might be due to an 

 octahedral structure is said to have been remarked by Berze- 

 lius,f and as early as 1816 was inferred by Sommering from 

 definite measurements of angles between the lines of the fig- 

 ures. In the same year, Wollaston remarked that the iron 

 from Bemdego (Bahia) had an octahedral cleavage, § and later, 

 in 1839, still more striking evidences of octahedral structure 

 were described by C. U. Shepard in his paper on the Ashe- 

 ville meteoric iron.| Furthermore, in 1861, von Keichenbach 

 studied with great detail all the minute features which are pre- 

 sented by the Widmanstattian figures, and published his results 

 in a series of papers in Poggendorff's Annalen entitled " Ueber 

 das innere Gefiige der naheren Bestandtheile des Meteor- 

 eisens."^ He first made the distinction between the different 

 conditions of nickeliferous iron forming the material of the 

 crystalline plates of which the Widmanstattian figures are sec- 

 tions, and introduced into the descriptions of these bodies the 

 now familiar terms of Balkeneisen, Bandeisen and Fiilleisen, 

 which he also designated respectively as Kamacite, Teenite 

 and Plessite. 



In the year 1864, Gustav Rose, in his " Beschreibung und 

 Eintheilung der Meteoriten," distinctly pointed out the octa- 

 hedral arrangement of the plates which form the Widmanstat- 

 tian figures, and compared the structure of meteoric iron with 

 the lamellar structure of many leucite and magnetite crystals, 

 regarding the crystalline mass as consisting of scales or plates 

 of iron separated by laminae of the iron and nickel alloy which 

 Reichenbach called Taenite. 



In 1848, Neumann,** in studying the structure of the Haupt- 

 mannsdorf (Braunau) iron, concluded that the fine linear mark- 

 ings which appear on etching the faces of the remarkable cubic 

 forms obtained by fracture were essentially distinct from the 



* From the Proceedings of the American Academy of Arts and Sciences, May 

 12, 1886. f Schweigger's Journ., lii, 1*72. 



i This Journal, III, vi, 18. § Phil. Trans., 1816, p. 281. 



| Journal, I, xxxvi, 82. ^[ Poggendorff's Annalen, Ed. cxiv. 



** Naturwiss. Abhandlung ber. v. Haidinger, vol. iii, pt. ii, p. 45. 



