Relative determinants of birefringence of a biaxial crystalline substance

Abstract

The points on the proposed diagram (see article) constructed from the examples just presented are distributed, as at least directly visible, in some harmonious order, along an arc, and it becomes possible to predict from it the relationships between the properties of yet undiscovered biaxial minerals; it is very likely that for such minerals, the relative determinants of their birefringence will be given when plotting on a diagram by points distributed between already known points on the same arc of our diagram. Consequently, and vice versa: taking any point along with those already known on this arc, we can expect that it corresponds to an as yet unknown mineral, and from the found determinants we can calculate the value of the angle of the optical axes based on the known formulas that were given at the beginning of this articles.