312 Prof. W. H. Bragg on the Structure of 



Fig. 3 b. — Diagram illustrating structure of magnetite, 



Oxygen tetrahedra shown correctly as regards form and position, 



but not as regards size. 



/ \H 





A 



'"' 1^. 



vi? "Divalent iron atom. 

 ®|Trivalent iron atom. 

 O Oxygen atom. 



AB=3-60A.U. 



BD=DH = BE=EJ=BF=FK = BG = 5-40 A.U, 



BH, BJ, BK, BG are trigonal axes. 



