This is an air volume test of a Viking Age type 'twin chamber' bellows - of a size potentially large enough for use with a 'short shaft' bloomery iron furnace. Focus is on the anemometer used to record delivery volumes (KPH across a 2.5 area) Full discussion of this test : https://warehamforgeblog.blogspot.com...
Test by Darrell Markewitz of the Wareham Forge (http://www.warehamforge.ca)