"Guess you'd better look after filling the tank, son, while I chase over to the house and get my goggles and my harness," referring to a leather brace the doctor had brought him a few days before to use until his shoulder grew stronger. Unfortunately, the thing was not properly made and it held the arm too stiffly, so Mr. Fulton used it only when he absolutely had to.

The boys all wanted to have a hand in this final operation and consequently it took twice as long as was necessary to fill the tank.

Enough was spilled, as Tod said, to run the _Skyrocket_ ten miles. In the meanwhile, one of the boys took the small can and went the rounds and filled all the torches with gasoline, while another came close behind him and started them going.

Tod finally left the rest to finish the job of filling the _Skyrocket_, and disappeared in the direction of the workshop. Within five minutes the boys heard the steady chugging of "Old Faithful" as they had named the shop motor. An instant later the whole field was suddenly lighted up as the twenty incandescent lights flashed up brightly.

"_Some_ illumination!" cried Jerry, delightedly, turning to Mr. Harris, who happened to be nearest him.

"Yes," agreed the man coldly, "but it's all on the ground."

"Sure. Because there's nothing up in the air to see. Wait till the old _Skyrocket_ shoots up," and Jerry walked over to where the boys were standing. "Old grouch," he said to himself. "You'd think he didn't want to see us win out."

Tod came hurrying back from the hangar. "Where's dad?" he asked.

"Hasn't got back yet."

"That's funny. I saw him leave the cabin as I went in to start up the dynamo. He called something to me about hurrying so as not to give those fellows any time to think up new tricks. Who's that over there with Mr. Harris?"

"Phil, I guess. Your dad hasn't come out yet or we'd have seen him--it's light as day."

"What's the cause of the delay now?" came from behind them. Mr. Lewis had approached the group un.o.bserved.

"Waiting for my father," answered Tod. "Guess he's having a hard time with his harness. I'd have stopped for him only I thought he'd have come back ahead of me. I'll chase over now and see if he needs any help with his straps."

Tod ambled off across the torch-lighted open. It was a weird sight, that flaring line of torches, the paler gleam of the electric lights hung high in the trees, the animated faces of the excited boys, the two stolid men, and the adventurous looking _Skyrocket_, its engines throbbing, the tiny searchlight ahead of the pilot's seat sending a fan-shaped road of white light into the trees. It was like a scene on the stage--just before the grand climax.

Tod furnished the climax for this scene. Hardly had he disappeared within the door of the cabin, before he came running out again, shouting at the top of his voice:

"Fellows! Quick!"

There was a note in his cry that went through the boys like an electric shock. It was anger and fear and a dozen other emotions at once. They fairly flew across the hundred yards or so to the cabin, crowding in till the main room was filled.

"What is it, Tod?" cried Phil, as his cousin flung open the door to the tiny lean-to bedroom. Tod's face was pasty white and his eyes bulged out.

"They've--_got_ dad! I'm afraid he's--killed!"

"No!" exclaimed Jerry, pushing past.

But the first look made him believe the worst. On the floor, toppled over in the chair to which he had been bound, lay Mr. Fulton, his injured shoulder twisted way out of place, his distorted face the color of old ivory. Gagged and tightly laced to the bed lay Mr. Billings, his features working in wildest rage.

But Mr. Fulton was not dead. He came to under the deft handling of Phil and his fellow Scouts, but it was Mr. Billings who told the story of the attack.

While Mr. Fulton had been struggling with the strap that held his shoulder-brace in place, two burly men had burst through the doorway and quickly overpowered him, handicapped as he was by his useless arm.

They had bound him to the chair, and then, after gagging and tying Billings, had calmly proceeded to ransack the room, one holding a pistol at Fulton's head while the other searched.

Papers scattered about on the floor, wrecked furniture and broken boxes, testified to the thoroughness of the hunt. But they had found nothing until they had thought to go through the bed on which Billings lay. Under the mattress was a portfolio packed with blueprints and plans. That was when Mr. Fulton had fallen; he had tried to free himself from his bonds and get at the two, no matter how hopeless the fight.

As Mr. Billings finished the story, Mr. Fulton opened his eyes weakly.

"Tod----" he gasped--"where's Tod?"

"Here, dad," coming close beside him where he lay on a big pile of blankets.

"Look quick and see if they found the little flat book--you know."

Tod rummaged hastily through the disordered mess of drawings littered over the bed and floor. "Not here," he confessed finally.

The man gave a deep groan. "We're done for, then. It had the contract folded up in it. And it had the combination to the safe at the house, and there was the list of the specifications Mr. Billings made out for me when we packed away the first draft of the _Skyrocket_."

"What difference does that make, if they've already got the blueprints'?" asked Jerry.

"Oh-h!" cried Mr. Fulton, despair in his voice, "don't you see? The aeroplane itself was made here; Billings did all the work on it. But Tod and I did all the experimental work at home. All the data concerning the invention is back there in the safe!"

"And they're already halfway there in their motorboat!" groaned Phil.

But Mr. Fulton made no answer. His eyes were closed; he had fainted dead away.

Tod jumped up from where he had been kneeling beside his father. "Look after him, Phil," he directed briskly. "Jerry, you come with me. Those villains have got the contract and they will soon have dad's secret--it means that we're cleaned out. There's only one thing to do in a tight place like this, and you and I are going to do it--if you've got the nerve!"

"I've got it," responded Jerry quickly. "What is it?"

"We're going after those crooks in the _Skyrocket_!"

CHAPTER XVIII

A CLOSE FINISH

The incidents of the next hour or so would be hard to picture from the standpoint of Jerry's emotions. As they half ran over to where the _Skyrocket_ stood ready, snorting like an impatient racehorse, his heart was filled with a kind of frightened determination. Once he was strapped into his seat, his pulses stopped galloping so fast, but as Tod began an endless fumbling with levers, plainly as nervous as his chum, Jerry's nerve oozed out at his fingertips; he might have climbed out had it not been for the straps--and the two men, who now came forward and insisted that the boys give up their hair-brained plan.

Jerry would have been killed by inches rather than give in to them.

A sudden terrifying lurch, a dizzy parting company with solid earth that almost made Jerry part company with his stomach. He yelled, but it might easily have been through excitement rather than fear. He hoped the two and Tod would think so. He dared not look down--all he could do was grip the rod before him with a death-defying clutch. Faster and faster, higher and higher they mounted, the air whistling by them like mad.

"Can't you slow her down a little?" he yelled in Tod's ear, but Tod gave no answer. He could hardly have heard above the roar of the motor and the sickening whine of the propellers--not to intention a steady drumming of taut wires and tightly stretched silk. "Can't you tune her down?" Jerry yelled, louder this time, "and get her level?"

"Can't!" shouted Tod. "I've forgotten which handle to pull, even if I knew which way to pull it!"

He tried first one and then another, but although they lurched dangerously, first this way and then that, they kept mounting into the sky. Finally there was but one chance left--Tod cautiously drew the lever toward him, then with an "Ah!" heard above all the noise, brought it all the way. The _Skyrocket_ quivered, dropped to an even keel, and then turned her nose earthward. But Tod was ready for that. Halfway back he shoved, the lever and once more the _Skyrocket_ rode level.

They had left Lost Island far behind, but in which direction they could not be sure. A long streak of flame to the left told them that a railroad lay there, and it could be none other than the Belt Line that ran into Watertown. Through a rift in the clouds a cl.u.s.ter of stars showed briefly--the Big Dipper. "See!" shouted Tod. "We're headed north, all right."

They were going much slower now, and the noise was not so deafening; they could talk without splitting their throats. Dimly they made out Plum Run directly beneath them, while a haze of lights indicated Watertown, the goal. Even as they watched it seemed to be drawing nearer.

"Were you scared?" asked Tod.

"Stiff," confessed Jerry. "You?"