Abstract: Cooling apparatus comprising an air humidifying element defining a plurality of liquid pathways and a plurality of parallel air pathways intersecting and communicating with the plurality of liquid pathways and apparatus for applying a pressure gradient across the plurality of parallel air pathways and, in another embodiment, air conditioning apparatus comprising a housing defining an inlet and an outlet, apparatus located within the housing for providing passage of air between the inlet and the outlet, apparatus located within the housing, upstream of the outlet, for cooling air passed between the inlet and the outlet and apparatus located within the housing for raising the relative humidity of the air passed between the inlet and the outlet, the apparatus for raising the relative humidity comprising an air humidifying element defining a plurality of liquid pathways and a plurality of parallel air pathways intersecting and communicating with the plurality of liquid pathways.