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 website with Rights Managed and Royalty Free stock photos, images, illustrations and footage available for download immediately for commercial and editorial uses. Aflo is a leading independent supplier and producer of stock pictures and visual content. Search and find high quality images and video for design, print, web-use and publishing. Buy photos from our extensive collection of model released and property released sports images. Search some of the most beautiful travel and landscape pictures from our own photographers and license from our large collection of content, modern and archive, focusing on Japan. We provide free research. Register for personal account management and for full use of our Stock Photography website and start to download images now.