The Blacksmith's Coal Forge
This is the traditional blacksmiths' forge. A blast of air is blown through the burning coke, and the extra oxygen supplied by this blast raises the temperature in the fire's core to a white heat. This high temperature allows the forge to be used for fire welding.
Coke is a fuel derived from coal which has been preheated to drive off its volatile constituents, such as coal-gas and tar. This allows the fire to burn cleanly with very little fumes being given off.