Mathematische Geographie für Lehrerbildungsanstalten is the earth as mathematics: Erwin Eggert leads future teachers through the evidence for the globe’s shape and size, the celestial sphere, time and the seasons, latitude, longitude and map projection — everything a schoolmaster needed to explain why the world behaves as it does.
It is a fine specimen of the German teacher-training tradition at its most exact. Download the free EPUB, in German, and take the schoolmaster’s course in the mathematics of the sky and the globe.