42 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



Blake goes on to say: 



It weighed 290 pounds (G39.36 kg.), its original weight having been probably 300 pounds. It was reduced by 

 cutting small portions from the ends of the iron and by exfoliation. Its form was its most striking visible peculiarity, 

 it being an extremely regular long ellipsoid, tapering at each end to a flattened point, but having throughout its length 

 an ellipsoidal section. It thus resembled somewhat the form of a flattened cigar. 



Its dimensions were: 



Inches. Meters. 



Length 36 0.9144 



Breadth 10 0. 2540 



Thickness 6 0. 1524 



Circumference 24 0.5991 



It had probably been shortened about 3 to G inches by cutting off pieces from the ends. The surface was scaly 

 and rusty, but is in general smooth and evenly curved, with the exception of several cup-shaped indentations or 

 depressions, one of which, near one edge, gives the inward curvature in an elliptical outline. One of the depressions 

 was nearly 3 inches broad and 1 inch in depth. These depressions did not seem to be due to the weathering out of 

 more or less globular inclusions, such as troilite or schreibersite, but rather to the unequal exfoliation. The mass when 

 struck by a hammer was remarkably sonorous and seems to be very compact and sound throughout. 



The oxidized crust was in some places very thin, and a few strokes of a file developed the unchanged bright iron 

 below; but in other parts of the mass the crust was found to be much thicker, especially after the meteorite had stood 

 unmoved for several years. Flakes as broad as the hand and nearly 0.25 inch in thickness have been scaled off from 

 the lower side. This scaling was the result of the gradual oxidation of the surface of the iron by the deliquescence 

 of included iron protochloride, as shown by the abundant reactions for chlorine and the constant accumulations of 

 moisture, especially upon the under surface of the iron. This deliquescence for several years was sufficient to cause 

 drops of perchloride of iron to form and fall off at times upon the support below. The heavier of the oxidized crusts 

 exhibited thin successive layers with smooth mammillated surfaces like the surface of limonite. They consisted of a 

 mixture of hydrous sesquioxide of iron and magnetic oxide. They affected the magnetic needle and exhibited feeble 

 polarity, as some fragments of the bright iron also did, but this might have been in consequence of the presence of an 

 invisible scale of the magnetic oxide. The exudation of moisture seemed to be greatest from small seams, which on 

 cutting into the iron were found to extend for 0.5 inch or more below the surface and were filled up with dark and 

 hard magnetic oxide. Freshly cut surfaces of the iron, when laid upon a sheet of white paper, soon caused rusty spots, 

 and moisture accumulated upon the surface, particularly in damp weather. This constant exfoliation of the mass 

 perhaps gives an explanation of its peculiar symmetrical form. It maybe regarded as the kernel or residuary nodule 

 of a much larger and probably much more irregularly shaped mass. 



The iron could be readily cut by a saw with oil and it works well under a file, giving a uniform dense surface 

 without any signs of inclusions or of crystalline structure. The surface of fracture exhibited a fine granular structure, 

 but with no crystalline facets. It was perfectly malleable; thin, fin-shaped projections could be readily bent back 

 and forth repeatedly without cracldng. A fragment heated to redness and quenched in cold water was not percept- 

 ibly hardened, and could be, as before, spread into thin sheets under the hammer, without impairing its malleability. 

 The metal took a high mirrorlike polish, but yielded no structural markings on etching. The iron dissolved equally 

 on all sides leaving a delicate velvety or frosted surface indicating a very even and fine granular structure. 



According to Brezina 23 the iron was already known in 1818, but was lost sight of until 

 1876. Upon its arrival at Vienna the block weighed 131 kg.; the portions cut off from the 

 pointed ends being estimated at 5-10 kg. In this publication Brezina holds that from its form 

 the iron must have been an inclusion in a large meteorite, and instances a cylindrical inclusion 

 in Bolson de Mapimi. He emphasizes the fact that the form can not be accounted for on the 

 ground either of fusion in the atmosphere or of weathering by lying on the ground. The in- 

 terior is compact, with insignificant scattered lumps and needles. 



In 1895, Brezina 27 added that the Blake iron and Troost iron correspond perfectly. 

 Both were referred by him to the ataxites, and, indeed, to the rather heterogeneous group of 

 Babbs Mill. The very soft iron becomes dull by etching, with a velvetlike luster; the Blake 

 iron is distinguished by many irregularly directed, straight or less frequently crumpled cracks, 

 which appear to be due to weathering. 



Cohen and Weinschenk 23 published in 1891 a new analysis, which gave an essentially dif- 

 ferent result from that obtained by Blake; among other things, it showed that cobalt was never 

 wanting, as was especially emphasized by the latter. On a very small quantity of material, 

 small angular rust spots appeared which were renewed quickly on a perfectly compact-appear- 

 ing, freshly polished surface, and indeed always occupied the same spot and exactly the same 



