Abstract: Water, in the form of a mist, is delivered to cutting beds and the like through a plurality of nozzles attached to one or more pipes in which the flow of water is controlled by a valve, the opening and closing of which is regulated by a control device which operates in response to the atmospheric condition surrounding the cutting beds. The control device is provided with a liquid collecting-and sensing element, the movement of which actuates an electrical switch, which, in turn, activates and deactivates the circuit regulating the flow of water to the misting system. The control device is of simple construction, yet operates in a completely consistent and reliable manner.