would ask everyone to look at their watches, and say that the mayor had just written so and so on a sheet of paper, then burned it. Scotty would bring the mayor to the auditorium, and Barby would tell him what she had said, and at what time, and ask him if it was right. Of course it would be."

Rick looked at the girl with new respect. It was a very good gimmick indeed. He said as much.

Barby put her arm around Jan's waist. "We'll be sure to invite you to the show. Won't it be fun?"

"If it's safe for us to let people know where we are by then," Jan said somberly.

They fell silent at the reminder that Jan's presence was far more serious than a casual visit. Finally Rick said, "We'll get to work on the sets this afternoon."

"Make it tomorrow," Barby said quickly. "I sort of promised Jan something...."

Rick and Scotty exchanged glances.

"I said you and Scotty would teach her how to use the aqualungs."

Rick breathed a sigh of relief. That would be no hardship. He and Scotty needed practice, anyway. They had hardly used the lungs since returning from the Virgin Islands.

Mrs. Brant summoned them to breakfast and they walked in to find Steve and the scientists gathered at the big table.

"Got everything settled?" Rick asked.

"Just about," Steve replied. "We have a job for you, though."

Rick's pulse quickened. "What is it?"

"Your father and Weiss will need to pay a quick trip to Washington. I want you to take them in the Sky Wagon."

"When?" Scotty inquired.

"Tomorrow morning. You'll come back tomorrow afternoon."

Over breakfast, Rick tried to get more information from the agent. "Exactly what are we working on, Steve?"

Ames sipped steaming coffee thoughtfully. "Ever hear of a weapon system?"

Rick had. "It's a weapon so complicated, with so many parts, that it's actually a system instead of just a simple weapon. I think the term is used mostly for missiles."

"You think right. Well, Winston, Weiss, and your father will help Dr. Morrison do the basic design work on a system to go into a weapon system."

Scotty had been listening, too. "How complicated can you get?" he asked.

Dr. Morrison answered. "When it comes to missile work, you can get fantastically complicated. In fact, some missile systems are so complicated it's a wonder they ever work at all."

The telephone rang. Barby, who served when necessary as the island's switchboard operator, ran to answer. In a moment she returned. "It's for you, Steve. From Washington. I plugged it in on the library extension."

Steve excused himself. A few moments later he returned. "Hartson, I just took the liberty of ordering a scrambler placed on your phone switchboard, in case we need to hold any classified conversations between here and my offices. The phone man will install it today, if you have no objection."

"Of course not," Hartson Brant said. "I think it's a sensible precaution, especially with one member of the team remaining in Washington."

"What's a scrambler?" Barby asked.

"A special device that turns phone conversations into jumbled gibberish so no one can understand them. You talk normally, and sound normal to the person listening. But anyone tapping in on the line gets only sounds that mean nothing."

The agent's face turned grim. "Speaking of gibberish reminds me of the reason for the call. The Washington Post carried a story in one of its columns this morning hinting that two scientists working on a supersecret project had been driven insane. It also hinted that the insanity was an effect of the gadget they were working on!"

CHAPTER IV

A Haircut and a Wink

Rick held the Sky Wagon at the altitude to which he had been assigned by the control tower at Anacostia Naval Air Station in Washington. He was a little nervous because there was more air traffic around him than he had ever seen before.

Across the Potomac River, so close that the traffic patterns almost interlocked, was busy Washington National Airport. Below him along the Anacostia River were two military airports; Anacostia, at which he would land, and Bolling Air Force Base. And to complicate matters slightly, Andrews Air Force Base was only a short distance away.

A thousand feet above his head a tremendous Air Force Stratocruiser circled patiently. A thousand feet below him a flight of Navy Banshee fighters awaited clearance for landing. And climbing through the pattern came a division of Air Force F-80's.

Rick's neck ached from swiveling around. Scotty was helping him watch for other aircraft. But in the rear seat, Hartson Brant and Julius Weiss talked a steady stream, as they had ever since taking off from Spindrift. Rick wished he were as oblivious to the traffic. Actually, he didn't know what they were talking about. Good as his scientific training was, they were in a realm where his young mind hadn't even probed.

His earphones gave out: "Tower to Spindrift Flight. You are cleared to land. Approach from Northeast."

Rick glanced down in time to see the Navy fighters peel off in a precision maneuver that was lovely to watch. Then, on their heels, he stood the Sky Wagon up on a wing and slid down toward the muddy river below.

A short time later Rick called for instructions and was told to beach at Ramp Three. He located it without difficulty. Scotty climbed out on the pontoon and caught the rope thrown by a seaman. In a few moments they were beached.

A stocky young man who might have been a government clerk approached and introduced himself as Tom Dodd. The identification folder he held out bore the familiar JANIG imprint. "Steve phoned ahead," he said. "Do you need anything for your plane?"

"We'd better top off the tank," Rick said. "Everything else is all right." He described the kind of gas his plane used, fearful that the Navy might use either a higher or lower octane that would not be suitable.

Dodd gave instructions to a Navy petty officer, then led the Spindrifters to a waiting sedan. Rick got into the back seat and slumped back between his father and Weiss. The little mathematician looked at him in some alarm.

"Rick! You look done in. What on earth is wrong?"

He smiled feebly. "I'm a sissy, Professor. The only other times I've flown into Washington I landed at light-plane airports outside the city. This morning I got right into the middle of the big kids. Honest, the traffic was worse than Times Square. I was so scared I'd lose position and bang into someone that I almost swiveled my head off."

Tom Dodd looked back and grinned sympathetically. "Don't feel badly. Even the commercial pilots sit up straight and keep bright-eyed on the Washington approach. Airwise, it's one of the most crowded cities in the world."

As Tom steered the big sedan expertly through the traffic en route to downtown Washington, Rick asked his father, "What were you and Professor Weiss talking about? You lost me just about the time we got air-borne."

The scientist shook his head. "This time, Rick, I can't help much. Ask me again when you've completed your undergraduate work in college."

"I'm afraid your father is right," Weiss agreed. "When one gets deeply into the physical sciences there are no longer simple mechanical analogies; there are only equations that I'm afraid are beyond you for now, Rick."

Rick sighed. "A lot of help I'm going to be on this project!"

"You're not supposed to help," his father corrected. "The project is entirely for the purpose of developing principles for the system. The final