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 /. 

 Tarmaline. Plate parallel to (OlTo). 



Fig. ■■;■ 

 Turmaline. Plate parallel to (01 TO). 





Fig. 3. 

 Turmaline Plate parallel to (T2T0). 



Fig. ■/. 

 Phcnakite. Plate parallel to (OlTo). 



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



