"That's just what I did say. It sounds crazy, but let me finish, will you? I'm not kidding, and I'll show you proof later if necessary. "Anyway, this bird stepped straight out of the wall as if it had been a waterfall or something, but the wall itself was undamaged. The only proof I had that he had actually done it was the fact that he was in my office, but that was proof enough. "To put it mildly, I was thunderstruck. After jumping to my feet, I could only stand there like an idiot. I was so shaken that I couldn't speak a word. But he spoke first. "'General Garvers?' he asked, just as if he had run into me at a cocktail party or on the street. "I told him he was correct, and asked him who _he_ was and what he wanted. And how he got into my office. "He identified himself as a Henry Busch and explained that he was acting in behalf of a good friend of his, the late Dr. Hymann Duvall. Have you ever heard of Duvall, Max?" His friend twisted his face in thought. "Can't say that I have, off-hand. But the name seems to ring a bell somewhere." "Well, anyway, he said that Duvall had perfected an invention of great national importance shortly before his death and asked Busch to deliver it to the government if anything should happen to him. Then Duvall died suddenly of a heart attack." "And what was this invention?" "Isn't it obvious? A machine that would enable a man to walk through walls. And Busch has no idea how the thing works, other than the general explanation that Duvall gave him. And Busch was poles apart from Duvall. They were friends from college, but not because of professional interests. It seems they were both doublecrossed by the same girl. "Duvall was a brilliant but obscure nuclear and radiation physicist. He was one of those once-in-a-lifetime fellows like Tesla. He was so shy that he didn't bring himself to anybody's attention, save for a few papers he published in the smaller physical societies' magazines. It was only because he had inherited a considerable amount of money that he could do any research whatsoever." "Hm-m-m. I seem to remember a paper about wave propagation in one of the quarterlies. Quite unorthodox, as I recall," said Max. "Could be. But anyway, about Busch. "Busch majored in psychology at college, but took special courses after he graduated and took a Master's in English. He has written two novels and three collections of poems under various pen names. At the time of Duvall's death, he was working on the libretto of an opera. He has had no technical training, unless you want to count a year of high school general science. So he wasn't too much help in explaining how Duvall's instrument works. "And, just to make matters more juicy, Duvall kept no notes. He had total recall and a childlike fear of putting anything into writing that had not been experimentally verified." "And this machine, how is it supposed to work?"