as the temperature difference between the water and air has decreased in the preferred combination fill assembly of the invention however maximum use is made of the more expensive film fill in the regions of the overall fill where it is most effective i e where it has the greatest cooling potential for simplicity this will be explained as if each 34 cube 34 of fill has the same height and air travel dimensions even though this is not true in reality consider the case wherein there are three increments of fill height and three increments thereof in the air travel direction at the top all of the water has the same temperature so that the greatest cooling potential is immediately adjacent the tower air inlet where the air is coldest this therefore locates the film fill in the uppermost and outboardmost 34 cube 34 and the remainder of the fill in the air travel direction would contain splash type fill at the second vertical level the water falling from the uppermost and outermost film fill has been cooled significantly while the remainder of the water from the splash fill section has cooled much less the latter results from the fact that the splash is.