Schröder  discusses Das Buch der Natur (The Book of Nature), written by Konrad von Megenberg between 1348 and 1350. The Buch was the first encyclopedia of natural phenomena written in German. (For a contemporary German translation, see Schulz ; for definitions of Megenberg's astronomical terminology, see Deschler ). Megenberg translated the Liber de Natura Rerum, written by Thomas of Cantimpre between 1225 and 1240.
Descriptions of optical atmospheric phenomena are found in chapters 12 and 14 of Book 2. My discussion rests largely on Deschler's translation. Chapter 12, entitled “About fire in the air,” contains descriptions of phenomena such as meteors and fireballs, and concludes with a description of a ball or sphere, whose periphery is brighter and less dense than its middle, so that it looks like a crown. Here Deschler (p. 305) considers that Megenberg may be thinking of an auroral form.