I thought I understood that blast furnaces were for smelting ore to get contained metal out. Actually, most smelting furnaces I know of have some means of forcing air into the charge of ore, flux, etc. to achieve needed high temperatures to extract metal from ore and do a measure of extraction of unwanted impurities from metal.
Forges, so far as I know, always have some means of forcing air into the hearth so as to get highest temperatures, especially on demand, to heat metal that is to be worked by hammer. The piston "bellows" in the photo are called "blow machines", in direct translation from Swedish Blåsmaskin. There are no actual "bellows" in them. They are purely for getting higher temperatures in the hearth. NO smelting is done in this building.
Niklas
