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PROCEEDINGS OF THE AMERICAN ACADEMY 



Fig. 1. 



are to be found in all the large museums of the world, I was inter- 

 ested in examining specimens of " Spiegel Eisen," which contains so 

 large an impurity of manganese, and is at the same time so strikingly 

 crystalline. In the first place, the fracture somewhat resembles that 

 of the Mexican irons which we have been discussing, as it shows cube 

 faces, although the octahedron is dominant. Moreover, thin plates 

 of " Spiegel Eisen " can in some cases be detached from the mass which 

 would make it appear still more like meteoric iron, were it not for 

 its great hardness. On a polished surface, however, the resemblance 

 is far more striking, since etching or tempering brings out well de- 

 fined Widmanstattian figures. These figures are shown of natural 

 size in Figure 1, which is an exact sketch of the etched surface on a 

 piece of this iron. 



