A medieval value for the circumference of the Earth
July 2020
| Journal article
| Early Science and Medicine
Geographic and astronomical texts from late-medieval Central Europe frequently give 16 German miles, or miliaria teutonica, as the length of a degree of terrestrial latitude. The earliest identifiable author to endorse this equivalence is the Swabian astronomer Heinrich Selder, who wrote about the length of a degree and the circumference of the Earth on several occasions during the 1360s and 1370s. Of particular interest is his claim that he and certain unnamed experimentatores established their preferred value empirically. Based on an analysis of relevant statements in Selder’s extant works and other late-medieval sources, it is argued that this claim is plausible and that the convention 1° = 16 German miles was indeed the result of an independent measurement.
medieval metrology, FFR, medieval geodesy, circumference of the Earth, Heinrich Sedler, medieval astronomy