H. HAGA AND F. M. JAEGER. " ON THE SYMMETRY OF THE RöNTGEN-PATTERNS 



OF TRIGONAL AND HEXAGONAL CRYSTALS, AND ON NORMAL AND ABNORMAL 



DIFFRACTION- IMAGES OF BIREFRINGENT CRYSTALS IN GENERAL. 



Fig. 15 

 Pennine. Plate parallel to (0001). 



Fig. 16. 



Hambergite. Plate parallel to (QIC). 



(Normal Pattern). 



Fig. 17. 



Zinc-Sulphate Cleavage-lamella, exactly parallel to (010). 



(The 6-a.\is is 1« bissectrix). 



Proceedings of the Acad, of Sciences, Amsterdam. XVIII. A» 1915/1916. 



