Dan laughed. "Of course nobody _knows_ anything. You just get what information you can through the windows of your five senses, and then make your guesses. When they're wrong, you pay the penalty." His mind was clear now save for a mild headache. "Listen," he said suddenly. "You can argue a reality away to an illusion; that's easy. But if your friend Berkeley is right, why can't you take a dream and make it real? If it works one way, it must work the other." The beard waggled; elf-bright eyes glittered queerly at him. "All artists do that," said the old man softly. Dan felt that something more quivered on the verge of utterance. "That's an evasion," he grunted. "Anybody can tell the difference between a picture and the real thing, or between a movie and life." "But," whispered the other, "the realer the better, no? And if one could make a--a movie--_very_ real indeed, what would you say then?" "Nobody can, though." The eyes glittered strangely again. "I can!" he whispered. "I _did_!" "Did what?" "Made real a dream." The voice turned angry. "Fools! I bring it here to sell to Westman, the camera people, and what do they say? 'It isn't clear. Only one person can use it at a time. It's too expensive.' Fools! Fools!" "Huh?" "Listen! I'm Albert Ludwig--_Professor_ Ludwig." As Dan was silent, he continued, "It means nothing to you, eh? But listen--a movie that gives one sight and sound. Suppose now I add taste, smell, even touch, if your interest is taken by the story. Suppose I make it so that you are in the story, you speak to the shadows, and the shadows reply, and instead of being on a screen, the story is all about you, and you are in it. Would that be to make real a dream?" "How the devil could you do that?" "How? How? But simply! First my liquid positive, then my magic spectacles. I photograph the story in a liquid with light-sensitive chromates. I build up a complex solution--do you see? I add taste chemically and sound electrically. And when the story is recorded, then I put the solution in my spectacle--my movie projector. I electrolyze the solution, break it down; the older chromates go first, and out comes the story, sight, sound, smell, taste--all!" "Touch?" "If your interest is taken, your mind supplies that." Eagerness crept into his voice. "You will look at it, Mr.----?" "Burke," said Dan. "A swindle!" he thought. Then a spark of recklessness glowed out of the vanishing fumes of alcohol. "Why not?" he grunted. He rose; Ludwig, standing, came scarcely to his shoulder. A queer gnomelike old man, Dan thought as he followed him across the park and into one of the scores of apartment hotels in the vicinity. In his room Ludwig fumbled in a bag, producing a device vaguely reminiscent of a gas mask. There were goggles and a rubber mouthpiece; Dan examined it curiously, while the little bearded professor brandished a bottle of watery liquid.