A paddle wheel used to operate the blast furnace blower is reconstructed at the Metallurgic Park in Dommartin-le-Franc (Haute-Marne). With a diameter of 4 metres and a width of 2 metres, it is of the “lateral” type, i.e. it receives the water not from below, but at an intermediate level. A drop in the sub-bay allows the water to be evacuated very quickly after its working phase. Developed from 1830 onwards, this type of water wheel made it possible to increase the efficiency of the furnaces, which could reach 60% instead of 40% previously.