This improved operating conditions within the reverberatory furnace. The granulated iron was then heated in pots in a reverberatory furnace. Roasting and reverberatory furnace smelting dominated primary copper production until the 1960s. Both reverberatory furnace and electric furnace can be used. A second reverberatory furnace at Tsumeb remained inactive, pending renovation. This included a novelty for France at the time, a reverberatory furnace. Sometimes the reverberatory furnace rotated and thus was called a "revolver". Hagi also contains a reverberatory furnace which has been designated a World Heritage Site. The Siemens-Martin oven in open hearth steelmaking is also a reverberatory furnace. One reverberatory furnace seems to have been installed in 1844, with more in 1851.