30 



PROCEEDINGS OF THE AMERICAN ACADEMY 



V. 



THE CRYSTALLINE STRUCTURE OF THE COAHUILA 



IRONS. 



By Oliver W. Huntington. 



Presented October 10, 1888. 



In a previous paper on the crystalline structure of iron meteorites,* 

 the author described two cleavage crystals broken from a specimen of 

 the Butcher meteorite (Coahuila), but, from the compact nature and 

 softness of the iron, no further examples of cleavage were at that 

 time obtained. Recently, however, on examining a large number of 

 small sawed slabs of the same iron in the Harvard Collection, one slab 

 was found to be intersected by an angular crack, as shown of actual 

 size in Fig. 1. On taking the slab in the hand, it was found that the 

 two portions could be readily separated by a slight pressure, and the 



Fig. 1. 



surfaces, though considerably oxidized, showed sharply defined crystal 

 faces extending through the entire thickness of the plate (about six 

 millimeters) and forming angles of about 132° and 90°. 



As this cleavage was so very striking, an attempt was made to 

 break another slab artificially. It was mounted in a vice for the 

 purpose, and the projecting portion struck with rej^eated blows of the 



* American Journal of Science, 3d series, vol. xxxii. pp. 281-303. 



