Übersetzen...
Automatische Übersetzung:
Mine ventilation shaft topped with a device to extract the stale air from the mine. H is a vane to make the barrel revolve so that is always facing in the optimum wind direction. From "De re metallica", by Agricola, pseudonym of Georg Bauer (Basle, 1556). Woodcut. (Photo by: Universal History Archive/UIG via Getty Images)