"Where is this human being you speak of?" he squeaked.

"In the lounge. It is located-"

"Don't bother. I shall follow the aura of moral decay. I think I have it. How do I identify the human being?"

"Sandy hair, pale eyes-"

"No, no. His mind."

"A fanatic."

"Ah, you might have said so at once. I have him-and I see I shall require a thorough steam-bath when I return home. He is worse than you are."

"Never mind that. Is he telling the truth?"

"About the saser? Which, by the way, is a clever conceit."

"Yes."

"Well, that is a difficult question. As I often say to a friend of mine who considers himself a great spiritual leader: What is truth? I'll tell you this; he considers it the truth. He believes it. What a human being believes, however, no matter with what ardor, is not necessarily objective truth. You have probably caught a hint of this in the course of your life."

"I have. But is there no way you can distinguish between belief that stems from objective truth and belief that does not?"

"In intelligent entities, certainly. In human beings, no. But apparently you consider this man an enormous danger. I can rearrange some of the molecules of his brain, and he will then be dead."

"No, no," I said. It may be a silly weakness on my part, but I do object to murder. "Couldn't you rearrange molecules in such a way that he will lose all memory of the saser?"

Azazel sighed in a thin, wheezing way. "That is really much more difficult. Those molecules are heavy and they stick together. Really, why not a clean disruption-"

"I insist," I said.

"Oh, very well," said Azazel, sullenly, and then he went through a whole litany of puffing and panting designed to show me how hard he was working. Finally, he said, "It's done."

"Good. Wait here, please. I just want to check it out, and then I'll be right back."

I rushed down hastily, and Hannibal West was still sitting where I had left him. The bartender winked at me as I passed. "No drinks necessary, sir," said that worthy person, and I gave him five dollars more.

West looked up cheerfully. "There you are."

"Yes, indeed," I said. "Very penetrating of you to notice that. I have the solution to the problem of the saser."

"The problem of the what?" he asked, clearly puzzled.

"That object you discovered in the course of your speleological explorations."

"What are speleological explorations?"

"Your investigations of caves."

"Sir," said West, frowning, "I have never been in a cave in my life. Are you mad?"

"No, but I have just remembered an important meeting. Farewell, sir. Probably, we shall never meet again."

I hastened back to the room, panting a little, and found Azazel humming to himself some tune favored by the entities of his world. Really, their taste in what they call music is atrocious.

"His memory is gone," I said, "and, I hope, permanently."

"Of course," said Azazel. "The next step, now, is to consider the saser itself. Its structure must be very neatly and precisely organized if it can actually magnify sound at the expense of Earth's internal heat. No doubt, a tiny disruption at some key point-something that may be within my mighty powers-could wipe out all saser activity. Exactly where is it located?"

I stared at him thunderstruck. "How should I know?" I said.

He stared at me, probably thunderstruck also, but I can never make out the expressions on his tiny face. "Do you mean to say you had me wipe out his memory before you obtained that vital piece of information? "

"It never occurred to me," I said.

"But if the saser exists, if his belief was based on objective truth, someone else may stumble upon it, or a large animal might, or a meteorite might strike it-and at any moment, day or night, all life on Earth may be destroyed."

"Good Lord!" I muttered.

Apparently my distress moved him, for he said, "Come, come, my friend, look at the bright side. The worst that can happen is that human beings will all be wiped out. Just human beings. It's not as though they're people!"

Having completed his tale, George said, despondently, "And there you are. I have to live with the knowledge that the world may come to an end at any moment."

"Nonsense," I said, heartily, "Even if you've told me the truth about this Hannibal West, which, if you will pardon me, is by no means assured, he may have been having a sick fantasy."

George looked haughtily down his nose at me for a moment, then said, "I would not have your unlovely tendency toward skepticism for all the loveliest saminis on Azazel's native world. How do you explain this?"

He withdrew a small clipping from his wallet. It was from yesterday's New York Times and was headed "A Dim Rumble." It told of a dim rumble that was perturbing the inhabitants of Grenoble, France.

"One explanation, George," I said, "is that you saw this article and made up the whole story to suit."

For a moment, George looked as though he would explode with indignation, but when I picked up the rather substantial check that the waitress had placed between us, softer feelings overcame him, and we shook hands on parting, amiably enough.

And yet I must admit I haven't slept well since. I keep sitting up at about 2:30 A.M., listening for the dim rumble I could swear had roused me from sleep.