Bibliothek geographischer Handbücher. Herausgegeben von ... F. Ratzel
A volume from the German-language series of geographical handbooks edited by Friedrich Ratzel, published 1885 for students and teachers of mathematical and physical geography. The plates are numbered line diagrams of spheres, arcs and sightlines — circles crossed by dotted rays, lettered vertices, spherical triangles and small angle marks — usable as clean geometric figures, technical ornament, or lettered schematic detail.
