Hartson Brant and Julius Weiss produced notebooks. Rick and Scotty relaxed as best they could in the uncomfortable chairs and prepared to listen.

"You are, of course, aware of the problems inherent in the development of inertial systems," Marks began. "Perturbations are many, and both predictable and random. Consider our missile. We set its little brain for a given pattern. We depend on its inertia to inform the brain when perturbations are pulling it off course. The brain then takes the necessary corrective action. This, of course, is oversimplification."

It wasn't very simple to Rick. He squirmed uncomfortably on the hard chair.

"Now, we have dealt primarily with the perturbations one would expect.

The equatorial bulge, for example. The result? We still have a probable error of several miles in hitting the target. This is not to be borne, gentlemen. We must have precision. Now, what information do we have that allows such precision? We have the effects of perturbation of the other planetary bodies and of the sun itself.

These we may calculate closely. We shall use them to guide our missile, as they interact with the missile's own inertia."

Marks broke off to glare at Rick. He inquired acidly, "Do I perhaps bore you? Or have you a serious itch? If so, scratch it, for heaven's sake. You are squirming so, I can see only a blur through the corner of my eye."

Hartson Brant came to his son's rescue. He looked at Dodd. "May the boys be excused? I'm sure this discussion will be of no value to them, and probably they have some things they would like to do."

Dodd nodded. "If you decide to leave the vicinity, let Sam know."

"We'll be in the lobby," Rick said. He motioned to Scotty. His feelings were of mixed relief at getting out of there and irritation at Marks for what amounted to summary dismissal.

As they walked to the elevator, Rick asked, "What did you make out of that?"

"Not much. How about you?"

"A little," Rick admitted. "Enough to know what the project is aiming at."

"Which is?"

"A guidance system for the intercontinental missile, and a fantastic one that uses the moon and the sun, and maybe Venus and Mars as guideposts."

Scotty whistled. "As you said, a lot of good we'll be to this project.

Well, what do we do now?"

Rick ran a hand through his hair. "Follow Barby's instructions." His sister had said bluntly that both he and Scotty were getting as s.h.a.ggy as Dismal, and please get haircuts. He knew why, of course. Barby wanted them to be at their best, because she liked Jan Morrison very much and wanted Jan to like the boys, too.

Sam nodded to them as they walked to the elevator. Rick noted that the guard could watch the stairs as well as the elevator doors. He also noted that the guard's coat was loose, and that the b.u.t.t of a Magnum revolver was within easy reach of his hand. Knowing how Steve Ames operated, Rick also suspected that other, less visible, methods had been taken to guard the fourth floor, but there was nothing he could see.

It was still early in the day and the barbershop in the lobby was not crowded. Rick and Scotty both were able to get chairs.

Rick browsed through a magazine as the barber worked, but found nothing of interest. He put it down and looked around him. The shop was like any other shop, anywhere. He thought that barbershops may vary in the number of chairs, the luxuriousness of the appointments, and the size of the mirrors, but they all have about the same smell, and the same collection of bottles for the barber's use.

However, one item attracted Rick's attention, because it seemed out of place. It looked for all the world like the hair driers one finds in beauty shops. There was a stand, and a metal hood.

He gestured toward it. "What's that?"

"It's for treating dry hair," the barber answered. "Special oil treatment, with electric ma.s.sage. Very good."

Rick's hair was dry from frequent immersion in both salt and fresh water. Being inquisitive about everything in the world, he thought about trying it.

"Maybe I'll have time for a treatment," he said.

The barber ran a hand through the boy's light-brown hair. "You don't need one. Your hair is healthy, and not especially dry. I wouldn't give you a treatment you don't need."

"Have it your way," Rick said. The barber was either too lazy or too honest for his own good. In all probability the machine would do nothing Rick couldn't do for himself with his own two hands.

There was a good view of the elevators through the barbershop windows.

Rick watched people coming and going, and speculated for his own amus.e.m.e.nt on who they might be, and their business in the building.

Speculation was idle, of course. Take Tom Dodd. No one, without inside knowledge, would suspect that he was a federal agent engaged in guarding a hush-hush project on the fourth floor. Or Dr. Marks. Who would suspect that he carried a vital secret? Or, more accurately, that he was working on one?

As the barber was brushing Rick off, the boy saw his father step out of the elevator, stop, and look around. He saw the elevator operator step from the car, look into the barbershop, and wink. Rick almost winked back, then he realized that the operator was winking at the barber and not at him.

The scientist saw Rick at almost the same moment and walked into the barbershop. "Julius will be busy for another half hour," he said. "I think I'll follow your example, Rick." He climbed into the chair Rick had just vacated.

Scotty was through, too. The boys took seats and busied themselves reading magazines.

Hartson Brant's hair had needed only tr.i.m.m.i.n.g, not complete cutting, so he was finished in a short time. The barber shook out his cloth, then put it back on for the finishing touches. Rick glanced up as the barber spoke.

"Your hair's pretty dry, sir, and I have an excellent treatment here.

I'd like to give you one. It would make your hair look better, and make it easier to handle."

Tension swept through Rick as though someone had turned on an electric current. The tension had no focus. It was just that something deep within him had reacted. He stood up and dropped his magazine.

"Dad," he said hastily, "I just saw Julius go through the lobby."

"Where did he go?" Hartson Brant demanded. "I didn't see him."

"I think he went through the front door," Rick said. "Better hurry.

I'll try to catch him."

Outside the barbershop he stopped, to let Scotty catch up with him.

"Why should Weiss run out through the front door?" Scotty demanded.

"He didn't. It was a stall, to get Dad out of there in a hurry."

"But why?"

"I don't know," Rick said slowly. "For some reason, I just didn't want him to have that dry-hair treatment!"

CHAPTER V

JANIG Runs a Security Check

There wasn't much evidence on which to base his reaction, Rick admitted. But when he reacted, he just reacted and that's all there was to it. Call it a hunch, or call it nonsense. That's how it was, and he couldn't change it.

The barber had practically refused him a dry-hair treatment--and his hair was rather dry. The same barber had tried to sell a treatment to Hartson Brant--whose hair was not dry at all. And the elevator boy who had carried the scientist down from the fourth floor had winked at the barber.

Even admitting that it added up to no evidence of anything, it bothered him. He had asked Tom Dodd how much JANIG knew about the barber.