X-RAYS AND ORIENTATION OF QUARTZ CRYSTALS 317 



ASTU IS SIMILAR TO ASVW 

 Q = l 



Fig. 3.17 — Derivation of intercepts on orthogonal axes from intercepts on hexagonal axes 



Fig. 3.18 — Orientation of vectors (j'a — ii) and {i^ — i-:) with respect to ortiiogonal axes 



