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. 9. 

 Beryl. Plate parallel to (0001). 



Fig. 10. 

 Beryl. Plate parallel to (lOFo). 



Fig. ;/. 

 Beryl. Plate parallel to (72To). 



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



LlOTYPE.VAN LEER.AMSTeRDAM, 



