﻿298 Huntington — Crystalline Structure of Iron Meteorites. 



cubic irons ; but in the first case the process of crystallization 

 determines the elimination of the various materials which form 

 the Widmanstattian plates, while in the second case no such 

 elimination takes place, and between these extremes there is 

 every gradation. The element of time may also be an import- 

 ant, and perhaps the chief, condition in determining the result, 

 for we should naturally expect that, during a very slow crys- 

 tallization, foreign material would be more completely elimi- 

 nated than during a process which was comparatively rapid. 

 That the crystalline structure is equally definite in both cases, 

 is shown by the fact that cleavage forms may be developed 

 with equal readiness in either class of irons. 



Though there are no very definite data in regard to the crys- 

 tallization of nickeliferous alloys, yet it has been suggested 

 that the presence of nickel in the meteoric iron might deter- 

 mine its crystallization. It has been thought that between cer- 

 tain limits in the per centage of nickel present octahedral struct- 

 ure might result, while with a different amount of nickel the 

 crystallization would be cubic. With an idea of deciding this 

 point if possible, the analyses of eighty meteoric irons, as given 

 in various scientific journals, were tabulated according to their 

 per cent of nickel, and at the same time the size and character 

 of the figures produced by etching were noted. Unfortunately, 

 these results appeared so discordant that no trustworthy con- 

 clusion could be drawn from them, for it was frequently the 

 case that the composition of the same meteorite as given by 

 equally competent analysis differed by several per cent. Thus 

 the per centage of nickel in the Babb's Mill meteorite has been 

 variously stated as 14*7, 17*1, 4*7 and 12'4, and yet this appears 

 to be a perfectly homogeneous iron. 



Dr. Flight of the British Museum has made the remark, that 

 Widmanstattian figures seldom appear in irons containing more 

 than nine per cent of nickel, and it appears to be true that 

 most of the irons giving well-marked Widmanstattian figures 

 contain from five to nine per cent of nickel, though they vary 

 all the way from 3*12 to 17*37 per cent. On the other hand, 

 the irons giving well-marked Neumann lines contain generally 

 only five or six per cent of nickel, but the data at present are 

 insufficient to afford any basis for generalization. 



Moreover, it is by no means as yet established that the 

 amount of nickel present is the cause which determines the 

 difference of feature in the crystallization of meteoric irons, 

 nor should we be led to infer that such would be the case from 

 the behavior of alloys of metals so closely allied as nickel and 

 iron. It is certainly quite as probable that the effect may be 

 due to some other impurity, — for example, to the presence of 

 phosphorus, which is known to produce such marked effects on 



