Conservation recently carried out on the baths of the Cisiarii has resulted in excavations in various parts of the complex, in particular the southern wing, related to the enlargement of the service areas carried out in the third century. Here a room was found to have been adapted to contain a water wheel, while the wheel itself was preserved in the silts on the floor. Two sides of the room reused the walls of the earlier complex of the Magazzini Repubblicani, while the northwest wall and the stairs formed part of the third century additions, designed to create the space for the water wheel and its operation. The continuously high water table has allowed the preservation of the wheel and other parts of the structure which supported it, including planks from the shuttering of the walls, joists, struts, and a wooden structure which might be interpreted as an earlier well head. The whole system may be related to the passage from Vitruvius which describes water wheels, or nouria, designed to lift water up to the height of the diameter of the wheel. The wheel itself was of light construction, with troughs to gather and lift the water. It turned on an axel held by bearings whose sockets are still visible in the wall. Among the wooden fragments are found spokes, the wedges that reinforced the joints, pivots, iron nails, and other still unidentified elements. Among the materials of the fill were found coins of Gordian III, Philip the Arab, marble and wooden statuettes, pottery, a leather sole, hairpins and so on.
(Margherita Bedello Tata)