88 ROCHESTER ACADEMY OF SCIENCE. 



ably troilite nodules, which have since been eroded or decomposed 

 away. On the top of the front part of the foot is a deep cavity, due 

 to the folds in the iron, which passes nearly through to the sole. The 

 sole itself is very fiat, which has allowed a thin slice, ^ of an inch thick 

 and weighing 300 grammes, to be cut off, of same width from toe to 

 heel, and like thickness throughout, like the sole of a shoe. The 

 polished section is quickly etched by the use of dilute nitric acid, and 

 the Widmanstatten figures produced are both sharp and peculiar. 

 (Fig. 3, plate VIII.) The iron is typically octahedral. The etched 

 surface is composed mainly of short kamacite blades, with an average 

 thickness of about i mm. and from 5 to 10 mm. in length. These 

 depart from the ordinary rule defining the usual angular figures by 

 being largely curved or snake-like in form, giving a pattern like that of 

 floss or tangled yarn. Many of these kamacite blades are club-shaped 

 (rounded on both ends) as in the Augusta Co., Va. , iron. The 

 patches of plessite are minute, sometimes showing clearly the alternate 

 layers of taenite and kamacite. The taenite plates lying between the 

 kamacite blades are very narrow, but stand out in prominent relief on 

 the etched surface, and are faintly distinguishable by their bronze 

 yellow color from the tin- white kamacite. 



Two fissures, each about 25 mm. in length and averaging from 

 I to 2 mm. in width, cross the sole diagonally, and are filled with 

 troilite. No rounded nodules of this mineral were to be seen in 

 in the section made. Several patches of schreibersite, rudely repre- 

 senting cuneiform characters, are scattered throughout the etched 

 surface. These are brighter and with denser surface than the troi- 

 lite, the latter being granular and less lustrous. But the main 

 peculiarity of this iron is the extremely winding, vermiform 

 assembling of the kamacite plates, to which we have already 

 referred. In this respect the Bald Eagle iron is quite unique. 



