The mechanism of the bloomery process in shaft furnaces was investigated experimentally. It was found that the furnace was capable of producing metal ranging from 0-1.8% C (wrought iron and cast iron). Steel (0.3-0.8% C) could be produced but reworking was necessary to remove slag. Easily reducible ores of low sulphur content are best; fine grinding improves the reducibility of the lower grade ores. Yields were also discussed and the use of induced blast. -- AATA