THE AIRSPE METEORITE. 85 



Structure clear across, that it had afterwards cracked into three pieces, 

 and that these pieces had swung around and reunited with different 

 sides together than those which at first existed. This must needs have 

 been done at a time when the iron was still in a somewhat plastic 

 state, and before the troilite had cooled to its fusion point! Whether 

 such mobility is conceivable in a mass pressed inward from all sides 

 is, perhaps, open to question. Another view is that each of these 

 three divisions is an area of original crystalization. 



In speaking of the above structure of Arispe, I should not omit 

 mention of the fact that a somewhat similar changed-about (umge- 

 wandelt) phenomenon has been noticed in the iron meteorite Mukerop 

 from southwestern Africa, and described by Prof. Frederick Berwerth 

 in a paper read before the Imperial Academy of Sciences, of Vienna, on 

 the 20th of February, 1902. In this paper, which is, unfortunately, 

 unaccompanied by any cut or photograph, there are four distinct areas 

 mentioned, each defined, as in Arispe, by differently directed figures. 

 These are in two pieces, with sharp lines of demarcation, which, 

 Berwerth says, "appear to be brought out by the changing of the 

 system of lamellae on the plane of contact". Here then, are no 

 fissures, as those in Arispe, which have once separated the mass into 

 parts, but those are held by him to be a twinning of two supposed 

 original crystals. The African and Mexican meteorite thus present 

 two entirely distinct phenomena. Both undoubtedly owe their inner 

 structural framework to the time when they existed as a crystalizing 

 magma in some incandescent celestial body. The opportunities there 

 present for variation in ultimate structure were large, and the outcome 

 will be different in different masses, while all are held firmly in unison 

 with primal laws of composition and of crystalization which have 

 fashioned the phenomena of these earth-wandered fragments which 

 we to-day have under our inspection. They announce no new laws, 

 but they tell us new and unexpected stories. 



^Prof. J. E. Whitfield, of Philadelphia, has analyzed Arispe and 

 finds : 



Iron, ------ 92.268 



Nickel, ------ 7.040 



Specific Gravity, - - - 7.853 



Mr. John M. Davison, of Reynolds Laboratory, of the University 

 of Rochester, writes : 



