Groups of Plane Symmetries

In the recent second edition of his Theorie der Gruppeu von endhcher Ordnung, A. Speiser directed attention to the fact that the study of symmetries may have been the source of the earliest developments in higher mathematics of which we now have only indirect records, and that these developments may have preceded most of those relating to what we now regard as elementary mathematics which are embodied in the noted Elements of Euclid.