And now came the question of what to do with him, but Mike left that to Ish.

He turned back to the precession panel a bit more convinced that perhaps the captain had been right--perhaps there were enemies aboard.

The precession controls, though operational, had not to date been required. Carefully, Mike switched the sequence that would put them into active condition but not operate. That was left to the Cow.

Turning to the vocoder panel, he directed the Cow to take over control of the now active precession equipment; to use the sun as a referrant for the axis of precession, and to move the pole ninety degrees in a clockwise direction around that axis of precession.

Under these directions, the big wheel began to turn, not as it had been turning, but sideways. The operation would take ten minutes, and the axis of this new turn would be aligned directly on Sol by the computer.

The Cow's help in such a maneuver was required, because the precession could only be accomplished by switching valves between the tanks of the rim in such a manner that water was switched north on one side of the wheel, and south on the opposite side of the wheel, and the points of this switching between the tanks must remain in a stable position relative to the spin of the wheel. The valves that accomplished this, seventy-two of them, were s.p.a.ced at intervals of five degrees around the rim, but only two out of the seventy-two could be active at any time; and these must be selected by the computer's controls so that always the precessive force was properly aligned to produce the required precession.

When the precession was finished, the rim of the wheel would be aligned, still with the sun, but also with Project Hot Rod which had been to their south.

As a third thought, Mike switched off the Confuser.

Having set up the necessary factors, Mike turned back to the problem of the Security guard, or saboteur, whichever he might be, but found this problem had already been well taken care of. Not satisfied with simply tying the man up, Ishie had bound him with wire to somewhat the resemblance of an Egyptian mummy, and then for added good measure, given him two sleepy shots with his own needle gun; put electrician tape across his mouth; and taken from him everything he could possibly use either as a method of communication or as a weapon.

At least, Mike thought, Ishie is a thorough workman when he sets his mind to it.

Having parked the Security man in a nearby tool locker, with the feeling that he would keep for a while there, Ishie turned back to Mike with a grin.

"Confusion say those who play with firearms should be cautious! Mike, this convinces me. I've heard s.n.a.t.c.hes of what's going on on Earth, and it looks like somebody is putting over a fast one down there.

Seems like maybe our own Security boys are part of it. They would be the ones the captain saw going out to Hot Rod. And that means they've got a purpose out there. Is good to know they can't shoot us now, at least in a few minutes now, without getting themselves shot back. But they can shoot at Earth. Any ideas?"

"Well ... I thought some time ago that there was a little fallacy involved in that project when I saw how they hung the beam-director way out in front on those little old balloon-poles. They've got 'em bent, and if any one or two of 'em should happen to get punctured, the other two would move the mirror complete out of the laser beam focus.

Then the only thing they could shoot would be the sun--and I don't think it'd care.

"Ishie, you stay here just to keep the home fires burning and make sure that n.o.body fiddles with anything we don't want 'em to. All of the bulkheads leading into this section can be locked from the inside--a feature I haven't seen fit to point out to other people who really don't need to know."

Walking around the floor, Mike carefully secured the four bulkheads, two leading back to the morgue; two leading forward to the north pole end of the hub. And then, jumping catlike upward and grasping the access ladder to the central axis tube, he carefully bolted that one, too.

[Ill.u.s.tration]

Dropping back to the floor he stepped over to the intercom and switched in Captain Nails' circuit.

"Mission accomplished, sir. And you were quite right. One of our _Security_ servos is off balance. I'm attending to the matter."

"Thank you, Mr. Blackhawk." The captain's voice was calm, quite unlike the voice he'd used to them on the bridge. "You would do well to listen for the ... sound ... of those servos." The captain's voice stopped but the intercom continued to hum, alive from his end.

"Ishie," said Mike, "the captain's in trouble, and he's asking us to listen in on what goes on the bridge. He's left his intercom open.

"Now I've got a mission to accomplish; and you can't leave here, because this post's got to be operational. But you can listen and do whatever the captain tells you.

"And, Ishie--if anybody takes the bridge away from the captain, you tell the Cow not to obey any orders or answer any questions unless they come from here."

With that, Mike leaned over, loosened an inspection plate in the floor, and climbed down a ladder through the inspection tube that led through the six feet of normal-shield water directly beneath the floor into the seventeen-foot flare-shielding chamber beyond. This was the tank which surrounded the hub and held all of the waters of the rim during flare conditions; but was now holding only the air supply which, during a flare, was pumped to the rim.

Making his way back towards the center of the hub, Mike considered his luck in being one of the people most familiar with the entire structure of the ship. It would be unlikely that enemies operating aboard would think to cut off the air and water pa.s.sages, or even keep them under surveillance. Nevertheless, he would be cautious.

He must now get to the machine shop, and enter it without triggering any more of those--he laughed quietly to himself--Security servos.

The particular tank he was in he had selected carefully. Of the twenty-one possible combinations, this one he knew would bring him into the water under the north hall that circled the outer rim.

In a few strides he reached the three-foot-diameter spoke tube through which the flood of water would pour during a draw-in action such as that they had had during the flare; let himself over the side head first, let go and began falling down the seventy-nine foot length of the tube, accelerated by the light pseudo-gravity of the spin. Even so, he spread his legs and arms against the walls of the tube to act as a brake, so as not to arrive with too much impact at the bottom of the tube.

As he hit the water at the bottom, the tube swung around the circ.u.mference of the rim to the point at its far side at which it entered its particular river.

The course of his dive carried Mike to the bottom of the curve, and he started crawling up its far side to where the tunnel entered the rim-river. There the motion of the fluorescent-lighted water caught him, and he was swirled quickly to his target, twenty-five feet along, inspection plate B-36. He grabbed the hand-hold by the plate before he swirled past, loosened the plate, lifted it only enough to be sure that the room was empty, and then pushed it off, pulled himself through, and emerged into the whining dimness of Compressor Room 9, next to the machine shop. The low whine a.s.saulting his ears was that created by the air compressors that fed the jets that drove the waters through the rim.

Stepping over to the wall locker, Mike took out a dry pair of shorts, a T-shirt, and moccasins, kept there for the purpose of making changes after such swimming inspections of the rim tanks.

Before entering the machine shop, Mike spotted the Security man through the open bulkhead--just standing there while Paul and Tombu grimly worked on; and Millie sat idle, watching.

Mike entered the machine shop casually, as though intent on business, brushed past the Security man, and stepped over to the tape-controlled, laser-activated milling machine as though to inspect its progress.

Then, as though finding an error, he halted its operation and swung the laser-head back away from the work piece.

The head swung free in his hand, attached to the machine but nevertheless free. Casually, without even looking at the Security man, he had somehow centered the laser directly on him. Just as casually, he stepped to one side.

"The beam from this machine is quite capable of milling the hardest materials," he said, still casually, as though to himself. "Even a diamond can't withstand it."

Now he looked directly at the Security guard. "It's capable," he said in an even tone, "of milling a hole right through your guts if you even to much as breathe too deep."

Then to Chernov, "Move around behind him, out of range of this beam, and secure the man please. Millie, is there any thing in your department that will make sure he won't talk for while?"

"Yes, Mike, but I don't think I'd better go there right now. There aren't many of them, but these boys seem to be spread out all over."

Chernov had the gun now; and the personal communicator from the Security man as well.

"O.K.," said Mike. "I don't think he can give us much trouble in there," pointing at the air-lock bulkhead through which he had just entered. "We can go in and out through the physics lab," he said.

"Best we shut that off now before some more of these boys wander along."

When both the lab and the Security man were under control, Paul Chernov turned to Mike. "That milling-laser," he said. "It's got a focus of about six inches maximum. How did you fix it so it could burn the guard at that distance?"

"I didn't," said Mike briefly. "He already knows that lasers can reach from here to Earth. Why should I bother to tell him any different?"

Turning to Tombu he handed him the Security man's radio. "See if you can rig this," he said, "to broadcast everything they say over the general intercom channel. It's about time we let people know what's happening."

It took Tombu only minutes to hook in the radio. As he turned it on, Elbertson's voice came over the loud-speaker system. A roll call of Security men was apparently being completed. The last three man responded as called.

The Elbertson's voice, crisp but somewhat labored, came over the Security beam, booming throughout the ship. "It is obvious that the renegade scientists and engineer of the wheel have replaced the men guarding their sectors.

"As we were informed, the captain had put them in charge. Since they struck the first blow, it is now up to Security to converge on them and eliminate them.