On the experimental evidence of the mosaic structure of Bi single-crystals

It is known that the description of the structure of a normal crystal as given by the theory of the atomic and molecular lattices is not complete without taking into account a certain kind of irregularities, the presence of which is dependent on the imperfection of the crystal. Thus the conception of the mosaic crystal rose, first given by Ewald and Smekal and others. In two recent papers, Zwicky (1,2) gave theoretical reasons for the assumption that the mosaic structure in a crystal is a regular one, its period depending on the character of the substance and the lattice. Thus, he obtains the aspect that a crystal has a definite structure - a kind of a secondary lattice-superposed to the molecular or atomic arrangement in the primary lattice.