﻿Huntington — Crystalline Structure of Iron Meteorites. 299 



the physical properties of iron. According to the analysis of 

 Eeichenbach already cited, the tsenite plates of the Cosby 

 Creek meteorite contain 0*295 per cent of phosphorus, while 

 the mass only contains 0*089 per cent, and it is well known 

 that schreibersite, which is a phosphuret of iron containing 

 fourteen per cent of phosphorus, constantly appears on sections 

 of meteoric iron, in lines along the bands of kamacite. But 

 our knowledge of the amount of phosphorus in the different 

 meteorites is even less complete than our knowledge of the per 

 cent of nickel. We do not know, in regard to any of the im- 

 purities, either the average amount in any considerable portion 

 of the meteoric mass, or to what extent the amount varies in 

 different portions of the same mass. The most we know, in 

 any case, is the composition of one or more fragments selected 

 for analysis, and, as we have shown, even these data are so dis- 

 cordant as to be wholly untrustworthy. It is impossible to 

 infer with certainty from the descriptions whether the disagree- 

 ment arises from faulty methods of analysis, or from actual 

 difference of composition in the fragments selected ; and no 

 satisfactory conclusions can be reached in regard to the influ- 

 ence of impurities on the crystalline structure, until an ex- 

 tended series of systematic analyses has been made of the iron 

 meteorites, by processes which have been well considered, and 

 the limits of whose accuracy have been carefully determined. 

 In such a chemical investigation, regard should be paid to the 

 probable variation in composition of different parts of the mass. 

 This is a subject to which we hope to return at a future time. 

 The action of the process of crystallization in eliminating 

 impurities produces effects with many minerals not unlike 

 those of the Widmanstattian figures. Yery striking exhibi- 

 tions of such effects may be seen with the microscope in rock- 

 sections containing crystals of leucite, nosean, nepheline and 

 other minerals. Illustrations of these phenomena have been 

 given in works on lithologj^, and it is only necessary to allude 

 to them here, in order to make clear their analogy with the 

 phenomena we are studying. But a far more striking illustra- 

 tion of this similarity is shown by a large specimen of fluorite 

 in the Harvard collection, which has been cut through a mass 

 of compacted crystals. The polished surface imitates very 

 closely the features of the Widmanstattian figures. There are 

 distinct bands, marked by difference of color instead of differ- 

 ence of luster, separated from the groundmass of the mineral 

 by definite layers of less pure material. The bands are about 

 the width of those in the Glorieta meteorite, and they all ap- 

 pear alike, bordered in every case by the same layers of impuri- 

 ties arranged in a definite order, and these bands, crossing at 

 various angles, with a predominance of right angles, bear a 



