STRUCTURE AND NATURE OF TROOSTITE 



115 



Figs. 9 and 10— Mag. 3500X. Figs, 9 and 10 show two typical nodules along 

 grain boundaries or crystallographic planes. The excess constituent, the radial 

 grains, some practically irresolvable and others fully resolved, and the center of 

 growth (in Fig. 9) are clearly revealed. 



