The William Branchell—dubbed Brainchild—fled Earth at ultralight velocity, while officers, crew, and technical advisers settled down to routine. The only thing that disturbed that routine was one particularly restless part of the ship’s cargo.

Snookums was a snoop.

Cut off from the laboratories which had been provided for his special work at Chilblains, he proceeded to interest himself in the affairs of the human beings which surrounded him. Until his seventh year, he had been confined to the company of only a small handful of human beings. Even while the William Branchell was being built, he hadn’t been allowed any more freedom than was absolutely necessary to keep him from being frustrated.

Even so, he had developed an interest in humans. Now he was being allowed full rein in his data-seeking circuits, and he chose to investigate, not the physical sciences, but the study of Mankind. Since the proper study of Mankind is Man, Snookums proceeded to study the people on the ship.

Within three days the officers had evolved a method of Snookums-evasion. Lieutenant Commander Jakob von Liegnitz sat in the officers’ wardroom of the Brainchild and shuffled a deck of cards with expert fingers.

He was a medium-sized man, five-eleven or so, with a barrel chest, broad shoulders, a narrow waist, and lean hips. His light brown hair was worn rather long, and its straight strands seemed to cling tightly to his skull. His gray eyes had a perpetual half-squint that made him look either sleepy or angry, depending on what the rest of his broad face was doing.

He dealt himself out a board of Four Cards Up and had gone through about half the pack when Mike the Angel came in with Lieutenant Keku.

“Hello, Jake,” said Keku. “What’s to do?”

“Get out two more decks,” said Mike the Angel, “and we can all play solitaire.”

Von Liegnitz looked up sleepily. “I could probably think of duller things, Mike, but not just immediately. How about bridge?”

“We’ll need a fourth,” said Keku. “How about Pete?”

Mike the Angel shook his head. “Black Bart is sleeping—taking his beauty nap. So Pete has the duty. How about young Vaneski? He’s not a bad partner.”

“He is out, too,” said von Liegnitz. “He also is on duty.”

Mike the Angel lifted an inquisitive eyebrow. “Something busted? Why should the Maintenance Officer be on duty right now?”

“He is maintaining,” said von Liegnitz with deliberate dignity, “peace and order around here. He is now performing the duty of Answerman-in-Chief. He’s very good at it.”

Mike grinned. “Snookums?”

Von Liegnitz scooped the cards off the table and began shuffling them. “Exactly. As long as Snookums gets his questions answered, he keeps himself busy. Our young boot ensign has been assigned to the duty of keeping that mechanical Peeping Tom out of our hair for an hour. By then, it will be lunch time.” He cleared his throat. “We still need a fourth.”

“If you ask me,” said Lieutenant Keku, “we need a fifth. Let’s play poker instead.”

Jakob von Liegnitz nodded and offered the cards for a cut.

“Deal ’em,” said Mike the Angel.

A few minutes less than an hour later, Ensign Vaneski slid open the door to the wardroom and was greeted by a triune chorus of hellos.

“Sirs,” said Vaneski with pseudo formality, “I have done my duty, exhausting as it was. I demand satisfaction.”

Lieutenant Keku, upon seeing Mike the Angel dealt a second eight, flipped over his up cards and folded.

“Satisfaction?” he asked the ensign.

Vaneski nodded. “One hand of showdown for five clams. I have been playing encyclopedia for that hunk of animated machinery for an hour. That’s above and beyond the call of duty.”

“Raise a half,” said Mike the Angel.

“Call,” said von Liegnitz.

“Three eights,” said Mike, flipping his hole card.

Von Liegnitz shrugged, folded his cards, and watched solemnly while Mike pulled in the pot.

“Vaneski wants to play showdown for a fiver,” said Keku.

Mike the Angel frowned at the ensign for a moment, then relaxed and nodded. “Not my game,” he said, “but if the Answerman wants a chance to catch up, it’s okay with me.” The four men each tossed a five spot into the center of the table and then cut for deal. Mike got it and started dealing—five cards, face up, for the pot.

When three cards apiece had been dealt, young Vaneski was ahead with a king high. On the fourth round he grinned when he got a second king and Mike dealt himself an ace.

On the fifth round Vaneski got a three, and his face froze as Mike dealt himself a second ace.

Mike reached for the twenty.

“You deal yourself a mean hand, Commander,” said Vaneski evenly.

Mike glanced at him sharply, but there was only a wry grin on the young ensign’s face.

“Luck of the idiot,” said Mike as he pocketed the twenty. “It’s time for lunch.”

“Next time,” said Keku firmly, “I’ll take the Answerman watch, Mike. You and this kraut are too lucky for me.”

“If I lose any more to the Angel,” von Liegnitz said calmly, “I will be a very sour kraut. But right now, I’m quite hungry.”

Mike prowled around the Power Section that afternoon with a worry nagging at the back of his mind. He couldn’t exactly put his finger on what was bothering him, and he finally put it down to just plain nerves.

And then he began to feel something—physically.

Within thirty seconds after it began, long before most of the others had noticed it, Mike the Angel recognized it for what it was. Half a minute after that, everyone aboard could feel it.

A two-cycle-per-second beat note is inaudible to the human ear. If the human tympanum can’t wiggle any faster than that, the auditory nerves refuse to transmit the message. The wiggle has to be three or four octaves above that before the nerves will have anything to do with it. But if the beat note has enough energy in it, a man doesn’t have to hear it—he can feel it.

The bugs weren’t all out of the Brainchild, by any means, and the men knew it. She had taken a devil of a strain on the take-off, and something was about due to weaken.

It was the external field around the hull that had decided to goof off this time. It developed a nice, unpleasant two-cycle throb that threatened to shake the ship apart. It built up rapidly and then leveled off, giving everyone aboard the feeling that his lunch and his stomach would soon part company.

The crew was used to it. They’d been on shakedown cruises before, and they knew that on an interstellar vessel the word “shakedown” can have a very literal meaning. The beat note wasn’t dangerous, but it wasn’t pleasant, either.

Within five minutes everybody aboard had the galloping collywobbles and the twittering jitters.

Mike and his power crew all knew what to do. They took their stations and started to work. They had barely started when Captain Quill’s voice came over the intercom.

“Power Section, this is the bridge. How long before we stop this beat note?”

“No way of telling, sir,” said Mike, without taking his eyes off the meter bank. “Check A-77,” he muttered in an aside to Multhaus.

“Can you give me a prognosis?” persisted Quill.

Mike frowned. This wasn’t like Black Bart. He knew what the prognosis was as well as Mike did. “Actually, sir, there’s no way of knowing. The old Gainsway shook like this for eight days before they spotted the tubes that were causing a four-cycle beat.”

“Why can’t we spot it right off?” Quill asked.

Mike got it then. Fitzhugh was listening in. Quill wanted Mike the Angel to substantiate his own statements to the roboticist.

“There are sixteen generator tubes in the hull—two at each end of the four diagonals of an imaginary cube surrounding the ship. At least two of them are out of phase; that means that every one of them may have to be balanced against every other one, and that would make a hundred and twenty checks. It will take ten minutes if we hit it lucky and find the bad tubes in the first two tries, and about twenty hours if we hit on the last try.

“That, of course, is presuming that there are only two out. If there are three....” He let it hang.

Mike grinned as Dr. Morris Fitzhugh’s voice came over the intercom, confirming his diagnosis of the situation.

“Isn’t there any other way?” asked Fitzhugh worriedly. “Can’t we stop the ship and check them, so that we won’t be subjected to this?”

“’Fraid not,” answered Mike. “In the first place, cutting the external field would be dangerous, if not deadly. The abrupt deceleration wouldn’t be good for us, even with the internal field operating. In the second place, we couldn’t check the field tubes if they weren’t operating. You can’t tell a bad tube just by looking at it. They’d still have to be balanced against each other, and that would take the same amount of time as it is going to take anyway, and with the same effects on the ship. I’m sorry, but we’ll just have to put up with it.”

“Well, for Heaven’s sake do the best you can,” Fitzhugh said in a worried voice. “This beat is shaking Snookums’ brain. God knows what damage it may do unless it’s stopped within a very few minutes!”

“I’ll do the best I can,” said Mike the Angel carefully. “So will every man in my crew. But about all anyone can do is wish us luck and let us work.”

“Yes,” said Dr. Fitzhugh slowly. “Yes. I understand. Thank you, Commander.”

Mike the Angel nodded curtly and went back to work.

Things weren’t bad enough as they were. They had to get worse. The Brainchild had been built too fast, and in too unorthodox a manner. The steady two-cycle throb did more damage than it would normally have done aboard a non-experimental ship.

Twelve minutes after the throb started, a feeder valve in the pre-induction energy chamber developed a positive-feedback oscillation that threatened to blow out the whole pre-induction stage unless it was damped. The search for the out-of-phase external field tubes had to be dropped while the more dangerous flaw was tackled.

Multhaus plugged in an emergency board and began to compensate by hand while the others searched frantically for the trouble.

Hand compensation of feeder-valve oscillation is pure intuition; if you wait until the meters show that damping is necessary, it may be too late—you have to second-guess the machine and figure out what’s coming before it happens and compensate then. You not only have to judge time, but magnitude; overcompensation is ruinous, too.

Multhaus, the Chief Powerman’s Mate, sat behind the emergency board, a vernier dial in each hand and both eyes on an oscilloscope screen. His red, beefy face was corded and knotted with tension, and his skin glistened with oily perspiration. He didn’t say a word, and his fingers barely moved as he held a green line reasonably steady on that screen.

Mike the Angel, using unangelic language in a steady, muttering stream, worked to find the circuit that held the secret of the ruinous feedback tendency, while other powermen plugged and unplugged meter jacks, flipped switches, and juggled tools.

In the midst of all this, in rolled Snookums.

Whether Snookums knew that his own existence was in danger is problematical. Like the human brain, his own had no pain or sensory circuits within it; in addition, his knowledge of robotics was small—he didn’t even know that his brain was in Cargo Hold One. He thought it was in his head, if he thought about it at all.

Nonetheless, he knew something was wrong, and as soon as his “curiosity” circuits were activated, he set out in search of the trouble, his little treads rolling at high speed.

Leda Crannon saw him heading down a companionway and called after him. “Where are you going, Snookums?”

“Looking for data,” answered Snookums, slowing a little.

“Wait! I’ll come with you!”

Leda Crannon knew perfectly well what effect the throb might have on Snookums’ brain, and when something cracked, she wanted to see what effect it might have on the behavior of the little robot. Like a hound after a fox, she followed him through the corridors of the ship.

Up companionways and down, in and out of storerooms, staterooms, control rooms, and washrooms Snookums scurried, oblivious to the consternation that sometimes erupted at his sudden appearance. At certain selected spots, Snookums would stop, put his metal arms on floors and walls, pause, and then go zooming off in another direction with Leda Crannon only paces behind him, trying to explain to crewmen as best she could.

If Snookums had been capable of emotion—and Leda Crannon was not as sure as the roboticists that he wasn’t—she would have sworn that he was having the time of his life.

Seventeen minutes after the throb had begun, Snookums rolled into Power Section and came to a halt. Something else was wrong.

At first he just stopped by the door and soaked in data. Mike’s muttering; the clipped, staccato conversation of the power crew; the noises of the tools; the deep throb of the ship itself; the underlying oddness of the engine vibrations—all these were fed into his microphonic ears. The scene itself was transmitted to his brain and recorded. The cryotronic maze in the depths of the ship chewed the whole thing over. Snookums acted.

Leda Crannon, who had lost ground in trying to keep up with Snookums’ whirling treads, came to the door of Power Section too late to stop the robot’s entrance. She didn’t dare call out, because she knew that to do so would interrupt the men’s vital work. All she could do was lean against the doorjamb and try to catch her breath.

Snookums rolled over to the board where Multhaus was sitting and watched over his shoulder for perhaps thirty seconds. The crewmen eyed him, but they were much too busy to do anything. Besides, they were used to his presence by this time.

Then, in one quick tour of the room, Snookums glanced at every meter in the place. Not just at the regular operating meters, but also at the meters in the testing equipment that the power crew had jack-plugged in.

Mike the Angel looked around as he heard the soft purring of the caterpillar treads. His glance took in both Snookums and Leda Crannon, who was still gasping at the door. He watched Leda for the space of three deep breaths, tore his eyes away, looked at what Snookums was doing, then said: “Get him out of here!” in a stage whisper to Leda.

Snookums was looking over the notations on the meter readings for the previous few minutes. He had simply picked them up from the desk where one of the computermen was working and scanned them rapidly before handing them back.

Before Leda could say anything, Snookums rolled over to Mike the Angel and said: “Check the lead between the 391-JF and the big DK-37. I think you’ll find that the piping is in phase with the two-cycle note, and it’s become warped and stretched. It’s about half a millimeter off—plus or minus a tenth. The pulse is reaching the DK-37 about four degrees off, and the gate is closing before it all gets through. That’s forcing the regulator circuit to overcompensate, and....”

Mike didn’t listen to any more. He didn’t know whether Snookums knew what he was talking about or not, but he did know that the thing the robot had mentioned would have had just such an effect.

Mike strode rapidly across the room and flipped up the shield housing the assembly Snookums had mentioned. The lead was definitely askew.

Mike the Angel snapped orders, and the power crewmen descended on the scene of the trouble. Snookums went right on delivering his interpretation of the data, but everyone ignored him while they worked. Being ignored didn’t bother Snookums in the least.

“... and that, in turn, is making the feeder valve field oscillate,” he finished up, nearly five minutes later.

Mike was glad that Snookums had pinpointed the trouble first and then had gone on to show why the defect was causing the observed result. He could just as easily have started with the offending oscillation and reached the bit about the faulty lead at the end of his speech, except that he had been built to do it the other way around. Snookums made the deduction in his superfast mind and then reeled it off backward, as it were, going from conclusion to premises.

Otherwise, he might have been too late.

The repair didn’t take long, once Snookums had found just what needed repairing. When the job was over, Mike the Angel wiped his hands on a rag and stood up.

“Thanks, Snookums,” he said honestly. “You’ve been a great help.”

Snookums said: “I am smiling. Because I am pleased.”

There was no way for him to smile with a steel face, but Mike got the idea.

Mike turned to the Chief Powerman’s Mate. “Okay, Multhaus, shut it off. She’s steady now.”

Multhaus just sat there, surrounded by a wall of concentration, his hands still on the verniers, his eyes still on the screen. He didn’t move.

Mike flipped off the switch. “Come on, Multhaus, snap to. We’ve still got that beat note to worry about.”

Multhaus blinked dizzily as the green line vanished from his sight. He jerked his hands off the verniers, and then smiled sheepishly. He had been sitting there waiting for that green line to move a full minute after the input signal had ceased.

“Happy hypnosis,” said Mike. “Let’s get back to finding out which of those tubes in the hull is giving the external field the willies.”

Snookums, who had been listening carefully, rolled up and said, “Generator tubes three, four, and thirteen. Three is out of phase by—”

“You can tell us later, Snookums,” Mike interrupted rapidly. “Right now, we’ll get to work on those tubes. You were right once; I hope you’re right again.”

Again the power crew swung into action.

Within five minutes Mike and Multhaus were making the proper adjustments on the external field circuits to adjust for the wobbling of the output.

The throb wavered. It wobbled around, going up to two-point-seven cycles and dropping back to one-point-four, then climbing again. All the time, it was dropping in magnitude, until finally it could no longer be felt. Finally, it dropped suddenly to a low of point-oh-five cycles, hovered there for a moment, then vanished altogether.

“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.”