parts of the web w can be moisturized differently from the middle parts of the web in the embodiment shown in fig1 the air float chamber 20 of the turning airborne type for the web is disposed in connection with the take out of the second nip 2 the air float chamber 20 in accordance with this embodiment is closed and extends across the entire width of the web w in the air float chamber 20 the run of the web w passes in the air conditioned passage of the air float chamber in which the web w is not in contact with the walls defining the passage and which is defined by an outer blow box 23 and an inner blow box 24 which both blow air or steam to the web the temperatures moisture contents and flow quantities of said air or steam being adjustable independently of one another in order to moisturize the web w it is advantageous that the feed of a medium in particular its feed pressure feed temperature and feed quantity into the outer blow box 23 is independent of the feed of a medium fed into the inner blow box 24 and vice versa in which connection regulation of the temperature of and evaporation from one side of the web w is independent of regulation of the temperature of and evaporation from the other side of the web w in order that the moisture content of and evaporation from the web w might also be regulated in the cross direction with respect to the machine direction of the paper machine it is advantageous that.