﻿Huntington — Crystalline Structure of Iron Meteorites. 285 



Widmanstattian figures, and such lines have since been known 

 as Neumann lines, and have been supposed to indicate a cubic 

 structure, just as the Widmanstattian figures had been sup- 

 posed to mark solely an octahedral structure. 



On this basis, iron meteorites are now generally classified 

 under two chief groups, as the octahedral and the cubic. This 

 distinction, originally made by Grustav Rose, has been brought 

 into prominence by Dr. Brezina in his recent catalogue of the 

 collection of meteorites at the Vienna Museum, and in this 

 catalogue both the cubic and octahedral meteorites have been 

 further subdivided by him into numerous sub-groups, marked 

 solely by the width and other features of the figures or lines. 



That such a classification cannot be natural or fundamental 

 is shown by the disagreement of equally competent observers 

 in regard to the character of the figures or lines in special 

 cases, and also by the circumstance that the figures may appear 

 very differently on separate masses of the same fall, and even 

 on different parts of the same section. For example, the iron 

 from Ovifak, Greenland, in regard to whose meteoric origin 

 there has been so much question, is described both by Dr. J. 

 Lawrence Smith and Daubree as yielding distinct well-marked 

 Widmanstattian figures, while Dr. Brezina insists that it shows 

 absolutely none. In like manner, the well-known iron of 

 Santa Catarina is described by Daubre'e, Damour and others, as 

 exhibiting distinct Widmanstattian figures, while Dr. Brezina 

 not only asserts that no figures could be developed on any 

 specimens which have come under his notice, but even calls in 

 question the discrimination of the eminent mineralogists just 

 quoted. Again, Dr. Brezina, in criticising some observations 

 of Dr. Walter Flight of the British Museum, includes the iron 

 of Babb's Mill among those which exhibit no Widmanstattian 

 figures ; but the specimens, of unquestionable authenticity, in 

 the collection of Harvard College show well-marked figures. 

 Furthermore, an etched surface on a mass of Nelson County 

 iron weighing 6,800 grams, and measuring 13 inches in its 

 longest dimension, presents perfectly distinct figures near the 

 centre of the section, which grow indistinct near the edges, and 

 entirely fade out at one end. On the other hand, the iron of 

 LaCaille, classed by Dr. Flight with the irons giving no figures, 

 shows, as Dr. Brezina truly remarks, very well developed fig- 

 ures when the sections are made in most directions ; but we 

 have etched surfaces of this meteorite which over several 

 square inches of area show no figures whatever. 



In view of such differences of observation and opinion as 

 the above examples indicate, it seemed desirable to make a 

 still further study of the crystalline structure of iron meteorites, 

 and Professor Cooke placed at my disposal for this purpose the 



