He turned to Maria. "I'll be okay now. It's time for you to get back to the radio station. Tell them what has happened and get their reports. I'll see you tonight." It seemed a long time since he had last been in the laboratory. The workers were once more in the midst of their thousands of trials and failures to produce a colloidal, non-poisonous form of the decontaminant, which could be infused in the atmosphere of the world to destroy the comet dust. He stayed until his father left at 7 o'clock, and they went home together. He still had to depend on someone else for assistance on the steep and slippery hill. When they reached home Maria had a lengthy report ready from the Pasadena people, and one from Schenectady. Professor Maddox read the reports at the dinner table. He passed the sheets to Professor Larsen as he finished them. Ken saw he was not reading with his usual thorough analysis. When he had finished he returned to his eating with perfunctory motions. "Anything new?" Ken asked. "The same old story. A thousand hours of experiments, and no success. I feel we're all on the wrong track, trying to perfect a chemical colloid, based on the decontaminant, which will destroy the dust. I feel that nothing's going to come of it." Ken said, "I had a crazy dream the other day while Dr. Adams had me under drugs. I had almost forgotten it. I dreamed I was walking along the street and had a special kind of flashlight in my hand. When I came to a car that wouldn't run, standing by the curb, I turned the beam of the flashlight on it. Then whoever owned it could step in and drive away. After I had done that to all the cars in Mayfield I turned it on the sky and just kept flashing it back and forth and the comet dust fell down like ashes and the air was clean." Professor Maddox smiled. "A nice dream! I wish we could make it come true. I'm afraid that idea will have to go back to the pages of your science fiction, where it probably came from in the first place." "Dad, I'm serious!" Ken said earnestly. "About making a magic flashlight?" His father was almost sarcastic, which revealed the extent of his exhaustion, Ken thought. He was never like that. "What I'm trying to say is that there are other ways to precipitate colloids. We haven't even given any thought to them. Colloids can be precipitated by heat, by pressure, by vibration. Maybe a dozen other ways that I don't know anything about. "Maybe some kind of physical means, rather than chemical, is the answer to our problem. Why don't we let Pasadena and the other labs go on with the chemical approach but let us do some work on possible physical means?" Professor Maddox sat very still. His glance passed from Ken to Professor Larsen. The latter nodded. "I think we have indeed been foolish in ignoring this possibility up to now. I wonder if Ken hasn't got a very good thought there." "Have you anything specific to suggest?" Ken's father asked.