Steve paused. "That is quite a barn. No hay, no oats, no horses. But it has the loveliest dish antenna in it you've ever seen."

"A microwave dish?" Rick gasped.

"Exactly. It's mounted on a truck, and I suspect the electronic gear is inside. I couldn't get a good look. There are also little cubicles inside the barn, probably horse stalls, and I could hear a man snoring in one of them. There wasn't much light, and I couldn't use my little flashlight beam too freely, but I did get a look at several gas bottles racked along one wall. They were big ones, of the kind used for commercial gases like propane or oxygen."

"Or hydrogen?" Scotty asked quickly.

"Or hydrogen," Steve agreed. "And that's probably what they contain, for inflating the balloons."

He got up, turned off the coffee, and poured three cups. "Along about that time, I heard rifleshots. You can imagine what I thought. I had a vision of two bodies sinking slowly into the mud. If I'd had a weapon, I think I'd have run down to see what was going on. But common sense got the better of me, and I figured it was highly unlikely that a pair of divers could be picked off with rifles if they were underwater. I was sure you had sense enough to stay down. So I left the barn and went to the house."

"You actually went in?" Rick asked, his eyes wide.

"Sure. It was safe enough. The gang was sleeping upstairs and the two guards were interested in you and Orvil. No papers were left where I could get them. There's a built-in safe, but I'm no Jimmy Valentine who sandpapers his fingers and opens boxes by touch. I couldn't do anything with it. Finally, I figured all had been seen that could be seen, and left the house. I could hear a motor racing, and I recognized the runabout, so I knew you were still alive. I retired to the woods behind the barn and headed for the riverbank. I saw Scotty hurl his homemade bomb."

Scotty shook his head. "I didn't see you."

"You weren't supposed to. I decided Scotty must be creating a diversion, and that meant you, Rick, were still diving in the cove. I took off for the cove, keeping a weather eye out for the guards. There was plenty of cover along the bank, so it wasn't hard. I got a good view of the festivities. After the fire was stamped out, the two guards walked up to the bank of the cove and waited until Orvil got close, then they pointed their rifles at him and invited him to come closer still. He didn't have much choice."

Rick thought that was an understatement.

"They questioned him for a while. Who were the divers and what were they after? Orvil played dumb. He said he knew nothing about divers and of course he had seen bubbles. He always saw bubbles. Marsh gas was rising all the time. He couldn't understand what all the shooting was about."

"Good for Orvil," Scotty muttered.

"He put on a pretty good act, saying he didn't know what they were shooting at, but the guards weren't having any. They finally made him pull up his lines, throw his bait overboard, and get everything shipshape. Then one of the guards invited him to step ash.o.r.e. Orvil balked and took a swing at the nearest one and got a rifle across the head. He dropped to the deck. That must be how the stain got there. They slapped him back into consciousness and made him get out. One guard held a rifle on him while the other put his weapon down and got in the boat.

He took the boat out into the middle of the cove, aimed it toward the river, and put it in gear, then dove over the side and swam ash.o.r.e. The boat headed out and the guards walked Orvil back."

"So he's alive," Rick said with relief.

"Probably. I waited until the parade went by, then fell in line. They took Orvil into the barn, and I managed to get a look through a window.

They tossed him into one of the horse stalls and locked the barn door. I decided it was time to leave."

Steve sipped his coffee and made a face as it burned his tongue. "You can imagine how I felt. If one had gone away, I could have jumped the other. But two with guns, and me with not even a rock--I was dead certain to end up with Orvil. Besides, I couldn't take the chance."

Rick stared. If Steve felt he couldn't take a chance on rescuing Orvil, there had to be a good reason. The only reason Rick could think of was that Steve had decided there was more at stake than Orvil himself.

"We know where Orvil is," Scotty pointed out. "We can go after him. This time we'll be armed."

Steve shook his head. "Sorry. I wish it could be like that, but we're not engaged in a personal vendetta. Orvil may be out of there by tonight, or he may not. He'll have to take his chances."

One thing had been bothering Rick, aside from Steve's untypical att.i.tude about rescuing Orvil. "You haven't accounted for all your time. You could have reached here before we did if you had started back right away."

Steve shook his head. "I didn't. I went to the airport and used a public phone booth by the side of the road to call Patuxent Naval Air Station.

In twenty minutes I had a Navy jet fighter on the Cambridge field. I handed the pilot the pictures you took and told him what to do with them, then I made another call to my office in Washington to tell them the pictures were on the way and to look them over and take action accordingly. We'll be seeing the results pretty soon."

The young agent stopped smiling. "Your little mystery has turned into a case for JANIG, kids. I'm pretty sure of my facts, but I'll know definitely before noon. Right now, you'd better finish your coffee and get into bed. You'll need sleep if things start to pop. That rockoon idea of yours about cinches things."

Rick blurted, "If it's a case for JANIG, there must be security involved somewhere. Is Wallops Island involved somehow?"

"Go to bed," Steve said sternly. "By the time you wake up, I'll have a lot more than guesses, and I'll give you the details then."

CHAPTER XVII

Crowd at Martins Creek

Rick and Scotty awoke to find four newcomers at Steve's house. Steve introduced them to Dave Cobb, electronics specialist; Joe Vitalli and Chuck Howard, JANIG agents; and Roy McDevitt from Wallops Island.

McDevitt, who had just driven over from the rocket range, was a tall, lean engineer dressed in slacks and a spectacular sport shirt emblazoned with tropical flowers. He shook hands cordially. "You're Hartson Brant's boys. We've certainly enjoyed having your family over at the island.

When Barby and Jan leave, the whole base will go into mourning."

Rick grinned. "Somebody loses, somebody wins. We're anxious to have them back with us again."

Vitalli and Howard greeted the boys as old comrades. Although they had had no chance to become well acquainted, the two agents had been part of the JANIG team during the case of _The Whispering Box Mystery_.

Dave Cobb, who was scarcely older than the boys, had been hastily borrowed from the Naval Research Laboratory in Washington. He spared no time for greetings other than a cordial wave, and immediately got to work on the rocket Rick had found in the cove.

The group pulled chairs up to the kitchen table on which Cobb was working, and watched.

Cobb studied the rocket for a few minutes, then took a pointed tool and pressed it into a spot five inches below the rounded nose. He rotated the cylinder and pressed a similar spot on the other side. Rick saw a thin line appear around the rocket below where Cobb had pressed.

The electronics specialist gripped the cylinder above and below the thin line and twisted. The nose of the rocket came off. Cobb pointed to a pair of metal p.r.o.ngs that extended out of the nose into the rocket casing. "Contacts," he said. "They press against strips inside the rocket casing. The whole a.s.sembly acts as a dipole antenna."

No one commented. Cobb took a tiny screwdriver and removed two screws from a metal plate in the bottom of the nose cone. The screws were long ones, holding the entire nose a.s.sembly in place. With the screws laid carefully aside, Cobb tapped the cone and the a.s.sembly dropped into his hand.

"A terrific job of miniaturization," he commented. "First-rate design."

He pointed with a screwdriver to a segment about the size of two silver dollars stacked together. "Tape recorder. It acc.u.mulates data, then plays it back in a single high-speed burst."

Rick watched, fascinated, as the electronics expert identified components and circuits. The whole unit, scarcely larger than a common soup can, contained receiver, tape recorder, transmitter, batteries, and command circuits that could be triggered from the ground. It was a highly complex and beautifully engineered package for receiving data, storing it, then retransmitting it.

"But why?" Rick demanded. "Why send up a rockoon at all? What data does it receive and transmit, and what do the people at the mansion do with it?"

"What Rick is asking," Scotty observed, "is the question that has puzzled us since we got here. Why do the stingarees fly?"

Steve waved a hand. "Patience for just a few more minutes. Anything else, Cobb?"

The electronics expert shook his head. "Not unless you have specific questions. In summary, this is a very elegant little a.s.sembly of receiver, data recorder, transmitter, and command circuits."

"Fine. McDevitt, what about the rocket?"

The man from Wallops Island shrugged. "Nothing very complex about it.

It's a simple solid-fuel rocket with star grain, fired by a squib that is commanded from the ground. A squib is simply an igniter to start the fuel burning. Battery power makes it glow red hot when turned on."

"How high an alt.i.tude would the rocket reach?" Steve asked.