62 Mr. T. Andrews. 



Table I. Secondary Micro- crystallisation of Metallic Iron. 



In the case of both the primary and secondary crystals the pre- 

 dominant well-defined angles of the facets of the crystals hovered more 

 or less about the angle of 120. The majority of the angle readings, 

 made with the goniometer attached to the microscope, indicated 

 generally a hexagonal structure or form of crystallisation. There 

 were, however, also perfect cubical crystals observed. 



The observations were made with a floss' first-class microscope. 

 The micro-measurements afford an indication of the comparative size 

 of the primary and secondary crystals. These measurements were 

 carefully taken by a Jackson micrometer and in some cases by a 

 Bamsden screw micrometer, both accurately calibrated with a standard 

 stage micrometer. The wrought-iron forgings on which the observa- 

 tions were made were constituted of practically pure hammered 

 wrought iron, the dimensions of the mass being about 10 feet long 

 and about 12 inches square. The great length of time required for 



