METEORITES OF NORTH AMERICA. 



43 



space. Small splinters were present on the inclusions, with apparently rectangular orientation 

 to one another. 



Analyses: 1 to 4, Troost iron; 5 and 6, Blake iron. 



6. 

 Cohen and 

 Weinschenk. 



96.92 



100. 00 



99. 85 



100. 70 



99.37 



86.30 



12.58 



1.66 



100.54 



Since, according to the statement of Brezina, the irons do not differ structurally, while 

 the analyses gave very various results, Cohen investigated sections from both ends of the Blake 

 iron. A few small fragments and a section weighing 392 grams, with a cut surface of 52.5 sq. 

 cm. were used from one end of the cigar-shaped mass ; and from the other end two sections 

 with cut surfaces of 8.5 sq. cm. and 10 sq. cm.; from the Troost iron two sections of 16 grams 

 weight together, and cut surfaces of 6 sq. cm. each were used. 



Structurally, all these sections corresponded exactly. By weak etching the nickel-iron 

 took on a varnish-like luster, characteristic for the most part of ataxites rich in nickel. The 

 etched surface appeared homogenous to the unaided eye. By strong magnification, however, 

 a structure made up of grains 0.01 mm. in size could be seen; moreover, tiny, glistening points 

 also appeared. By stronger etching the cut surface became dull, with a velvet-like sheen, 

 on account of the diffuse reflection of the light on the numerous small lumps which varied in 

 size from 0.01 to 0.03 mm. A division into distinct grains did not, however, occur, and in 

 general the etching surface remained of an unusually homogenous structure. The glistening 

 particles in question may, in reflected light, be somewhat enlarged and appear to be very 

 regularly distributed. Whether etching pits were present or whether it was the reflection 

 of an uneven surface which the etching has made manifest was not easily determined; but 

 the latter was the more probable. Disregarding the absence of etching bands, the etching sur- 

 face is suggestive of that of the Cape iron, as Reichenbach and Rose have previously shown. 



Of subsidiary material only a round kernel of graphite of 3 mm. in size occurs, in a section 

 of the Vienna mass. Of the needles which Reichenbach mentions, and the splinters which 

 Cohen thought he observed in the earlier investigation of this meteorite, nothing has been noted 

 in the later more comprehensive material examined. Troost also emphasized the absence of 

 all inclusions. Babbs Mill was the most homogenous nickel-iron and the poorest in subsidiary 

 material known to Cohen. 



The same sections of both lumps which were taken from near the original surface of the 

 meteorite contained fine cracks running out in very irregular directions from the neighbor- 

 hood of the surface, along which cracks rust formations occurred; these large sections had a 

 very characteristic appearance owing to the fine brown veins which were sharply marked off 

 from the other, perfectly fresh nickel-iron. Here again it was noted that iron chloride in 

 meteorites accumulates in those places where the structure is least compact, and that when 

 such places are present it is usually confined to them. The softness of this iron has already 

 been noted by Troost, Blake, and Brezina. 



