The stuff that dreams are made of is steam! So now you know how these waltzing-in-the-clouds film scenes are done. These ballet dancers are in a dream sequence in the film "Melba." This is what happens. First they take up their swooning poses against a cloudy backcloth - and in front of huge trays of dry ice. "Action," the producer cries. Propmen pour buckets of hot water on the ice, a fan blows the resulting steam in a deep layer across the floor and there they are - waltzing in the clouds... Brings you down to earth, doesn't it The scene is being shot, by Horizon Pictures, at Covent Garden. October 8, 1952. (Photo by Daily Mirror).