478 PROCEEDINGS OF THE AMERICAN ACADEMY 



XXVIL 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 

 HARVARD COLLEGE. 



ON THE CRYSTALLINE STRUCTURE OF IRON 

 METEORITES. 



By Oliver Whipple Huntingtox. 



Presented by invitation, May 12, 1886. 



The general octahedral structure of iron meteorites was observed 

 soon after the attention of mineralogists had been directed to this 

 remarkable class of bodies. 



In the year 1808, Von Widmanstatten * of Vienna observed the 

 crystalline figures brought out on a polished section of the Agrara 

 iron by tempering or etching, which have since been known by his 

 name. That these figures might be due to au octahedral structure 

 is said to have been remarked by Berzelius,t and as early as 1816 

 was inferred by Sommering from definite measurements of angles 

 between the lines of the figures. 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 octa- 

 hedral structure were described by C. U. Shepard in his paper on 

 the Ashville meteoric iron.§ Furthermore, inil861 Von Reichenbach 

 studied with great detail all the minute features which are presented 

 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 Meteoreisens." || 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 sections, and introduced into the de- 

 scriptions of these bodies the now familiar terms of Balkeneisen, 



* Schweigger's Journ., Bd. lii. p. 172. 



t American Journal, 3(1 series, vol. vi. p. 18. 



t Pliilos. Trans, for 1816, p. 281. 



§ American Journal of Science, 1st series, vol. xxxvi. p. 82. 



II Poggendorff's Annalen, Bd. cxiv. 



