“And what about the stability of the brain?”

The mathematician thrust out his lips, “Decreased, naturally. But it’s within the border of safety. The first Nestors were delivered to Hyper Base nine months ago, and nothing whatever has gone wrong till now, and even this involves merely fear of discovery and not danger to humans.”

“Very well, then. We’ll see what comes of the morning conference.”

Bogert saw her politely to the door and grimaced eloquently when she left. He saw no reason to change his perennial opinion of her as a sour and fidgety frustration.

Susan Calvin’s train of thought did not include Bogert in the least. She had dismissed him years ago as a smooth and pretentious sleekness.

Gerald Black had taken his degree in etheric physics the year before and, in common with his entire generation of physicists, found himself engaged in the problem of the Drive. He now made a proper addition to the general atmosphere of these meetings on Hyper Base. In his stained white smock, he was half rebellious and wholly uncertain. His stocky strength seemed striving for release and his fingers, as they twisted each other with nervous yanks, might have forced an iron bar out of true.

Major-general Kallner sat beside him, the two from U.S. Robots faced him.

Black said, “I’m told that I was the last to see Nestor 10 before he vanished. I take it you want to ask me about that.”

Dr. Calvin regarded him with interest, “You sound as if you were not sure, young man. Don’t you know whether you were the last to see him?”

“He worked with me, ma’am, on the field generators, and he was with me the morning of his disappearance. I don’t know if anyone saw him after about noon. No one admits having done so.”

“Do you think anyone’s lying about it?”

“I don’t say that. But I don’t say that I want the blame of it, either.” His dark eyes smoldered.

“There’s no question of blame. The robot acted as it did because of what it is. We’re just trying to locate it, Mr. Black, and let’s put everything else aside. Now if you’ve worked with the robot, you probably know it better than anyone else. Was there anything unusual about it that you noticed? Had you ever worked with robots before?”

“I’ve worked with other robots we have here—the simple ones. Nothing different about the Nestors except that they’re a good deal cleverer—and more annoying.”

“Annoying? In what way?”

“Well—perhaps it’s not their fault. The work here is rough and most of us get a little jagged. Fooling around with hyper-space isn’t fun.” He smiled feebly, finding pleasure in confession. “We run the risk continually of blowing a hole in normal space-time fabric and dropping right out of the universe, asteroid and all. Sounds screwy, doesn’t it? Naturally, you’re on edge sometimes. But these Nestors aren’t. They’re curious, they’re calm, they don’t worry. It’s enough to drive you nuts at times. When you want something done in a tearing hurry, they seem to take their time. Sometimes I’d rather do without.”