"By the beard of my sainted maiden aunt," said Chief Multhaus in awe. "A three-tube offbeat solved in less than half an hour! If that isn"t a record, I"ll dye my uniform black and join the Chaplains" Corps."

Leda Crannon, looking tired but somehow pleased, said softly: "May I come in?"

Mike the Angel grinned. "Sure. Maybe you can--"

The intercom clicked on. "Power Section, this is the bridge." It was Black Bart. "Are my senses playing me false, or have you stopped that beat note?"

"All secure, sir," said Mike the Angel. "The system is stable now."

"How many tubes were goofing?"

"Three of them."

"_Three!_" There was astonishment in the captain"s voice. "How did you ever solve a three-tube beat in that short a time?"

Mike the Angel grinned up at the eye in the wall.

"Nothing to it, sir," he said. "A child could have done it."

13

Leda Crannon sat down on the edge of the bunk in Mike the Angel"s stateroom, accepted the cigarette and light that Mike had proffered, and waited while Mike poured a couple of cups of coffee from the insul-jug on his desk.

"I wish I could offer you something stronger, but I"m not much of a drinker myself, so I don"t usually take advantage of the officer"s prerogative to smuggle liquor aboard," he said as he handed her the cup.

She smiled up at him. "That"s all right; I rarely drink, and when I do, it"s either wine or a _very_ diluted highball. Right now, this coffee will do me more good."

Mike heard footsteps coming down the companionway. He glanced out through the door, which he had deliberately left open. Ensign Vaneski walked by, glanced in, grinned, and went on his way. The kid had good sense, Mike thought. He hoped any other pa.s.sers-by would stay out while he talked to Leda.

"Does a thing like that happen often?" the girl asked. "Not the fast solution; I mean the beat note."

"No," said Mike the Angel. "Once the system is stabilized, the tubes tend to keep each other in line. But because of that very tendency, an offbeat tube won"t show itself for a while. The system tries to keep the bad ones in phase in spite of themselves. But eventually one of them sort of rebels, and that frees any of the others that are offbeat, so the bad ones all show at once and we can spot them. When we get all the bad ones adjusted, the system remains stable for the operating life of the system."

"And that"s the purpose of a shakedown cruise?"

"One of the reasons," agreed Mike. "If the tubes are going to act up, they"ll do it in the first five hundred operating hours--except in unusual cases. That"s one of the things that bothered me about the way this crate was hashed together."

Her blue eyes widened. "I thought this was a well-built ship."

"Oh, it is, it is--all things considered. It isn"t dangerous, if that"s what you"re worried about. But it sure as the devil is expensively wasteful."

She nodded and sipped at her coffee. "I know that. But I don"t see any other way it could have been done."

"Neither do I, right off the bat," Mike admitted. He took a good swallow of the hot liquid in his cup and said: "I wanted to ask you two questions. First, what was it that Snook.u.ms was doing just before he came into the Power Section? Black Bart said he"d been galloping all over the ship, with you at his heels."

Her infectious smile came back. "He was playing seismograph. He was simply checking the intensity of the vibrations at different points in the ship. That gave him part of the data he needed to tell you which of the tubes were acting up."

"I"m beginning to think," said Mike, "that we"ll have to start building a big brain aboard every ship--that is, if we can learn enough about such monsters from Snook.u.ms."

"What was the other question?" Leda asked.

"Oh.... Well, I was wondering just why you are connected with this project. What does a psychologist have to do with robots? If you"ll pardon my ignorance."

This time she laughed softly, and Mike thought dizzily of the gay chiming of silver bells. He clamped down firmly on the romantic wanderings of his mind as she started her explanation.

"I"m a specialist in child psychology, Mike. Actually, I was hired as an experiment--or, rather, as the result of a wild guess that happened to work. You see, the first two times Snook.u.ms" brain was activated, the circuits became disoriented."

"You mean," said Mike the Angel, "they went nuts."

She laughed again. "Don"t let Fitz hear you say that. He"ll tell you that "the circuits exceeded their optimum randomity limit.""

Mike grinned, remembering the time he had driven a robot brain daffy by bluffing it at poker. "How did that happen?"

"Well, we don"t know all the details, but it seems to have something to do with the slow recovery rate that"s necessary for learning. Do you know anything about Lagerglocke"s Principle?"

"Fitzhugh mentioned something about it in the briefing we got before take-off. Something about a bit of learning being an inelastic rebound."

"That"s it. You take a steel ball, for instance, and drop it on a steel plate from a height of three or four feet. It bounces--almost perfect elasticity. The next time you drop it, it does the same thing. It hasn"t learned anything.

"But if you drop a lead ball, it doesn"t bounce as much, and it will flatten at the point of contact. _The next time it falls on that flat side, its behavior will be different._ It has learned something."

Mike rubbed the tip of an index finger over his chin. "These ill.u.s.trations are a.n.a.logues of the human mind?"

"That"s right. Some people have minds like steel b.a.l.l.s. They can learn, but you have to hit them pretty hard to make them do it. On the other hand, some people have minds like gla.s.s b.a.l.l.s: They can"t learn at all.

If you hit them hard enough to make a real impression, they simply shatter."

"All right. Now what has this got to do with you and Snook.u.ms?"

"Patience, boy, patience," Leda said with a grin. "Actually, the lead-ball a.n.a.logy is much too simple. An intelligent mind has to have time to partially recover, you see. Hit it with too many shocks, one right after another, and it either collapses or refuses to learn or both.

"The first two times the brain was activated, the roboticists just began feeding data into the thing as though it were an ordinary computing machine. They were forcing it to learn too fast; they weren"t giving it time to recover from the shock of learning.

"Just as in the human being, there is a difference between a robot"s brain and a robot"s mind. The _brain_ is a physical thing--a bunch of cryotrons in a helium bath. But the _mind_ is the sum total of all the data and reaction patterns and so forth that have been built into the brain or absorbed by it.

"The brain didn"t have an opportunity to recover from the learning shocks when the data was fed in too fast, so the mind cracked. It couldn"t take it. The robot went insane.

"Each time, the roboticists had to deactivate the brain, drain it of all data, and start over. After the second time, Dr. Fitzhugh decided they were going about it wrong, so they decided on a different tack."

"I see," said Mike the Angel. "It had to be taught slowly, like a child."

"Exactly," said Leda. "And who would know more about teaching a child than a child psychologist?" she added brightly.

Mike looked down at his coffee cup, watching the slight wavering of the surface as it broke up the reflected light from the glow panels. He had invited this girl down to his stateroom (he told himself) to get information about Snook.u.ms. But now he realized that information about the girl herself was far more important.