And now faces were bending over her.

Gerald Black was gasping, "Are you hurt, Dr. Calvin?"

She shook her head feebly. They pried the arm off her and lifted her gently to her feet, "What happened?"

Black said, "I bathed the place in gamma rays for five seconds. We didn’t know what was happening. It wasn’t till the last second that we realized he was attacking you, and then there was no time for anything but a gamma field. He went down in an instant. There wasn’t enough to harm you though. Don’t worry about it."

"I’m not worried." She closed her eyes and leaned for a moment upon his shoulder. "I don’t think I was attacked exactly. Nestor 10 was simply trying to do so. What was left of the First Law was still holding him back."

Susan Calvin and Peter Bogert, two weeks after their first meeting with Major-general Kallner had their last. Work at Hyper Base had been resumed. The trading ship with its sixty-two normal NS-2’s was gone to wherever it was bound, with an officially imposed story to explain its two weeks’ delay. The government cruiser was making ready to carry the two roboticists back to Earth.

Kallner was once again a-gleam in dress uniform. His white gloves shone as he shook hands.

Calvin said, "The other modified Nestors are, of course, to be destroyed."

"They will be. We’ll make shift with normal robots, or, if necessary, do without."

"Good."

"But tell me – you haven’t explained – how was it done?"

She smiled tightly, "Oh, that. I would have told you in advance if I had been more certain of its working. You see, Nestor 10 had a superiority complex that was becoming more radical all the time. He liked to think that he and other robots knew more than human beings. It was becoming very important for him to think so.

"We knew that. So we warned every robot in advance that gamma rays would kill them, which it would, and we further warned them all that gamma rays would be between them and myself. So they all stayed where they were, naturally. By Nestor 10’s own logic in the previous test they had all decided that there was no point in trying to save a human being if they were sure to die before they could do it."

"Well, yes, Dr. Calvin, I understand that. But why did Nestor 10 himself leave his seat?"

"AH! That was a little arrangement between myself and your young Mr. Black. You see it wasn’t gamma rays that flooded the area between myself and the robots – but infrared rays. Just ordinary heat rays, absolutely harmless. Nestor 10 knew they were infrared and harmless and so he began to dash out, as he expected the rest would do, under First Law compulsion. It was only a fraction of a second too late that he remembered that the normal NS-2’s could detect radiation, but could not identify the type. That he himself could only identify wavelengths by virtue of the training he had received at Hyper Base, under mere human beings, was a little too humiliating to remember for just a moment. To the normal robots the area was fatal because we had told them it would be, and only Nestor 10 knew we were lying.

"And just for a moment he forgot, or didn’t want to remember, that other robots might be more ignorant than human beings. His very superiority caught him. Good-by, general."

"Last night I dreamed," said LVX-1, calmly. Susan Calvin said nothing, but her lined face, old with wisdom and experience, seemed to undergo a microscopic twitch.

"Did you hear that?" said Linda Rash, nervously. "It’s as I told you." She was small, dark-haired, and young. Her right hand opened and closed, over and over.

Calvin nodded. She said, quietly, "Elvex, you will not move nor speak nor hear us until I say your name again."

There was no answer. The robot sat as though it were cast out of one piece of metal, and it would stay so until it heard its name again.

Calvin said, "What is your computer entry code, Dr. Rash? Or enter it yourself if that will make you more comfortable. I want to inspect the positronic brain pattern."

Linda’s hands fumbled, for a moment, at the keys. She broke the process and started again. The fine pattern appeared on the screen.

Calvin said, "Your permission, please, to manipulate your computer."

Permission was granted with a speechless nod. Of course! What could Linda, a new and unproven robopsychologist, do against the Living Legend?

Slowly, Susan Calvin studied the screen, moving it across and down, then up, then suddenly throwing in a key-combination so rapidly that Linda didn’t see what had been done, but the pattern displayed a new portion of itself altogether and had been enlarged. Back and forth she went, her gnarled fingers tripping over the keys.

No change came over the old face. As though vast calculations were going through her head, she watched all the pattern shifts.

Linda wondered. It was impossible to analyze a pattern without at least a hand-held computer, yet the Old Woman simply stared. Did she have a computer implanted in her skull? Or was it her brain which, for decades, had done nothing but devise, study, and analyze the positronic brain patterns? Did she grasp such a pattern the way Mozart grasped the notation of a symphony?

Finally Calvin said, "What is it you have done, Rash?" Linda said, a little abashed, "I made use of fractal geometry."

"I gathered that. But why?"

"It had never been done. I thought it would produce a brain pattern with added complexity, possibly closer to that of the human."

"Was anyone consulted? Was this all on your own?"

"I did not consult. It was on my own."

Calvin’s faded eyes looked long at the young woman. "You had no right. Rash your name; rash your nature. Who are you not to ask? I myself, I, Susan Calvin, would have discussed this."

"I was afraid I would be stopped."

"You certainly would have been."

"Am I," her voice caught, even as she strove to hold it firm, "going to be fired?"

"Quite possibly," said Calvin. "Or you might be promoted. It depends on what I think when I am through."

"Are you going to dismantle El – " She had almost said the name, which would have reactivated the robot and been one more mistake. She could not afford another mistake, if it wasn’t already too late to afford anything at all. " Are you going to dismantle the robot?"

She was suddenly aware, with some shock, that the Old Woman had an electron gun in the pocket of her smock. Dr. Calvin had come prepared for just that.

"We’ll see," said Calvin. "The robot may prove too valuable to dismantle."

"But how can it dream?"

"You’ve made a positronic brain pattern remarkably like that of a human brain. Human brains must dream to reorganize, to get rid, periodically, of knots and snarls. Perhaps so must this robot, and for the same reason. Have you asked him what he has dreamed?"

"No, I sent for you as soon as he said he had dreamed. I would deal with this matter no further on my own, after that."

"Ah!" A very small smile passed over Calvin’s face. "There are limits beyond which your folly will not carry you. I am glad of that. In fact, I am relieved. And now let us together see what we can find out."

She said, sharply, "Elvex."

The robot’s head turned toward her smoothly. "Yes, Dr. Calvin?"

"How do you know you have dreamed?"

"It is at night, when it is dark, Dr. Calvin," said Elvex, "and there is suddenly light, although I can see no cause for the appearance of light. I see things that have no connection with what I conceive of as reality. I hear things. I react oddly. In searching my vocabulary for words to express what was happening, I came across the word ‘dream.’ Studying its meaning I finally came to the conclusion I was dreaming."

"How did you come to have ‘dream’ in your vocabulary, I wonder."