New crystallographic projections

Abstract

Strictly speaking, projections can be constructed as many as geometric systems of the second stage, that is, an unlimited number, and if I now want to mention such as new crystallographic ones, it is solely because they represent a kind of convenience for solving certain crystallographic problems not delivered by other projections. Here I mean those projections that are obtained from the linear and gnomonic ones if they are subjected to transformation by inverse radii, which is why they can be called grammatic and gnomocyclic, respectively.