92 THE ROYAL SOCIETY OF CANADA 



PLATE X 



Xo. 11. — Etched with bromine water X125. Lamellar 38% nickel alloy in 

 characteristic eutectic position at junction of ground mass areas, joining with lines 

 of massive phosphide (black, in very low relief at bottom and left) which penetrate 

 between areas of ground mass. The 38% pickel alloy shows a black area as a result 

 of etching, which may be either graphite or the black phosphide decomposition 

 product desfcribed by Stead. 



No. 12. — Etched with bromine water X125. 38% nickel alloy at top and 

 fractured phosphide at bottom apparently not quite in contact though a very 

 thin line of phosphide (black) may continue and join the high nickel alloy. 



PLATE XI 



No. 13. — Etched with bromine water X125. Lamella of 38% nickel alloy with 

 black boundary due to high relief in ground mass showing typical ferrite grain 

 boundaries. Flocks of phosphide crystals arranged parallel to lamella, some lying 

 across the boundary of adjacent grains. 



No. 14. — Etched with bromine water X500. Lamella of 38% nickel alloy to 

 left showing projection on left side penetrating between grains. On the right 

 phosphide crystals in parallel and normal positions. 



PLATE XII 



No. 15. — LTnetched X500. Sections of phosphide crystals. 



No. 16. — Etched with bromine water X500. Sections of phosphide crystals 

 showing sharp crystal faces and cross fracturing. The long crystal is doubly termin- 

 ated with the base on one end, domes or pyramids on the other. 



PLATE XIII 



No. 17. — Etched with bromine water X1200. Phosphide crystals apparently 

 tetragonal in form with good terminal faces. The one in long section occurs at the 

 distorted junction of grains of ground mass represented by the dark vertical line. 

 The distorted grain boundary appears to be indicative of plastic movement in the 

 ground mass. 



No. 18. — Deeply etched with 2 per cent, picric acid in alcohol. Indications 

 of crystalline structure developed in Kamacite ground mass by deep etching. 



PLATE XIV 



No. 19. — Unetched X 125. Troilite showing parallel lines of cleavage or parting 

 at left. Graphite-troilite mixture at the right. 



No. 20. — Unetched X125. Troilite-graphite mixture in outer zone of nodule 

 Troilite white, graphite black. 



