Abstract
The procedure for a perfect, rapid and accurate determination of orientations of trigonal bismuth single crystals by the use of light figures produced by their etched {111} and {uuv} planes was worked out.Full accounts are given of the geometrical relationships, procedure, etching directions, directly measurable range and kind of angles, representation of crystal orientations, accuracy, and actual examples. Though bismuth crystals show complex light-figure phenomena, different from cubic crystals and from hexagonal zinc crystals and,consequently,the procedure of orientation determination by the light-figure method becomes somewhat complicated, the perfect determination of crystal orientations can be made with an accuracy within ±0.2.°
