Graphic representation and nomenclature of the four-dimensional crystal classes. II. The individual symmetry operations

The nature of the four-dimensional crystallographic symmetry operations is clarified by representation of their effects in hyperstereograms presented in the form of stereo-pairs. Appropriate graphical symbols have been devised to indicate the orientations of the corresponding symmetry elements. Typographical symbols have been devised for the operations themselves, and for their symmetry elements, which are adaptable for use in a system of symbolic nomenclature of the four-dimensional classes following the general principles of the Hermann-Mauguin notation.