The boys reached the anch.o.r.ed motorboat, and soon were racing down toward Bayport. Frank was tense as he gripped the steering wheel; his mind was in a turmoil of worry over the fate of his brother. He could still see that shadowy, sinister figure rising out of the darkness and enveloping Joe in the folds of that eerie cloak.

"I guess I'll go home," Chet said as they put the Sleuth Sleuth back in the boathouse, "unless back in the boathouse, "unless there's something I can do to help.''

"Not now," Frank replied. "I'll drive you home. But first of all, I want to stop in at the telegraph office."

There Frank wrote an urgent message to his father, addressing him at the hotel in Washington. He was glad his mother had sent him the change of address.

"Have seen flickering torch and may have clues in your case," he wrote. he wrote. "Wire "Wire instructions."

"Aren't you going to tell him about Joe?" asked Chet.

117 Frank shook his head. "No use worrying Dad and Mother until I'm sure there's something to worry about. There's just a bare possibility that it wasn't Joe."

Chet left him at the telegraph office and set out for home, declining a ride. As Frank drove the car back toward the Experimental Farm, he felt sure the captured boy was his brother.

Frank swung into the main road and stepped on the gas. He saw the headlights of a truck overhauling him, the lights shining brightly in his rear-vision mirror. The boy pulled well over to the side of the road to give the big machine plenty of room to pa.s.s.

Its lights shone brighter. The truck was pulling close behind, and was well over on Frank's side of the road. The boy slowed down, pulled over farther. The wheels of the car b.u.mped on the soft shoulder of the highway.

Now the truck was abreast of him, crowding him over. Frank wrenched desperately on the wheel, stepping hard on the brake. His car lurched, slipped sideways and came to rest in a ditch, stuck fast.

The Hardy boy heard a sardonic laugh as the truck flashed past and vanished down the road.

"That fellow did it on purpose!" thought Frank angrily. "Guess he recognized the Hardy license number! And I didn't even get his!"

CHAPTER XIV.

JOE'S ADVENTURE.

in the meantime, what of Joe?

After Frank had left him at Trumper's that evening, the boy had walked over to the road construction project to look for d.i.c.k Ames. He was confident that he would find the young engineer near the job, and in this he was correct. After the experience with the scarecrow, d.i.c.k was keeping a close watch on things.

"But so far," he told Joe, "I'm up against a blank wall."

"How about Hefty Cronin?" Joe asked.

d.i.c.k grinned ruefully. "Either Hefty is an honest man, or he is too smart for me. I checked on all his order slips and they tally perfectly-even that order for wire."

"Who put up the scarecrow? That might give us a clue. If the thief who hid the power drill set up the hiding place-----"

"No good. The scarecrow is honest, too. The farmer who owns the field told me he erected it himself. I've questioned the workmen, and no one on this job admits having gone into the grounds. n.o.body knows anything about the power drill that disappeared. Nothing more has been taken so far as I know.''

118.

119 Joe was thoughtful. The scarecrow clue had evidently petered out for the moment.

"How about the watchman?" he asked.

'' He had been drinking and fell asleep down the road. He was fired this morning. The new one comes with fine references. I've been observing him, and he's certainly on the job.

Where's Frank?"

'' He went into Bayport,'' said Joe. '' A little later I'm going out to the cliff to investigate.

But in the meantime, I think I'll take a look at the Grable greenhouses. How about coming along?"

"What's doing over there?" asked d.i.c.k.

"It's the case we've been working on," Joe said. '' I want to look around the place a little.''

"If you think I can help, I'll be only too glad to go along. I feel I can leave here safely with the new watchman in charge."

They drove off in d.i.c.k's car. When they were in sight of the greenhouses, he parked his automobile on the side road and they cut across the fields. There was still enough light to enable them to distinguish the various buildings.

"What do we do now?" whispered d.i.c.k.

Joe gripped his arm, signaling for silence. At that moment he saw a man approaching the entrance to the office. Instead of opening the door and going inside, he sat down on the low step. The boys saw that he carried some object which he now placed across his knees.

120 It was a rifle!

The fellow on the steps made himself comfortable. It was evident that he was there to stay.

"I ought to get back to the cliff," thought Joe. "Frank will be out on the bay soon. But I certainly can't leave here until I find out what's going on."

The boys remained in the shadows for some time. Then Joe saw that the armed man had made himself too comfortable. His head drooped. His chin sank on his chest.

"He's asleep," whispered d.i.c.k five minutes later.

Joe nodded. "I'm going to get that gun," he murmured quietly.

The boy tiptoed forward. He had gone only a few paces before the man on the steps roused. Joe heard a gasp of apprehension from d.i.c.k Ames. He stood stock-still. But the sleeper had not awakened entirely. A moment later he was sound asleep again.

Step by step, Joe advanced stealthily toward the greenhouse doorway. It was dark by this time. In the gloom the Hardy boy tried to distinguish the sleeper's features. But the man's face was in shadow.

Joe reached for the rifle. His hand closed around the stock. Gently he lifted the weapon.

The man stirred uneasily, but he did not awake. With a quick movement the boy stepped away.

He felt more at ease now about exploring the 121 greenhouse property. If the guard should awaken and detect intruders, there would be no danger of his shooting them in the darkness.

Joe crossed the yard and made his way quietly toward the closed area where Asa Grable's private laboratory was located. There he saw a crack of light beneath the door. The boy's first impulse was to go up and knock.

Then caution restrained him. He knew the scientist was the only man supposed to have access to the laboratory, but in view of the robberies and the strange events that had been taking place, he could not take too much for granted.

Joe tiptoed back across the yard to the place where he had left d.i.c.k. At least he would get help before investigating further.

"I'll watch this sleeper," he whispered to his chum. "Will you go across the lawn to the house and inquire if Mr. Grable is there, and if not, where he is? I don't want to be seen up there myself."

"Right!" whispered d.i.c.k promptly.

"You'll probably meet an Archibald Jenkins. He's Grable's a.s.sistant. Don't let him bluff you!" Joe warned him in a whisper, as his friend moved off.

The Hardy boy withdrew into the shadows by the fence. He kept his eyes fixed on the man by the office door.

Suddenly there was a sound of movement. The fellow straightened up abruptly.

122 "My rifle!" he exclaimed aloud. "Where is it?"

He leaped to his feet, searched about him, then wheeled quickly and ran across the yard. Joe was able to identify him.

The man was Archibald Jenkins!

He hurried toward the house, where d.i.c.k Ames was proceeding up the walk. Joe did not expect trouble, so he did not follow.

The young engineer had just reached the porch when he heard running footsteps. He turned. Jenkins grabbed him.

"Now I got you!" gasped Grable's a.s.sistant triumphantly. "What are you doing, prowling around here? Who are you, anyway? And where's my rifle?"

d.i.c.k was quick-witted. "Hold on, now," he said. "I just came here to see Mr. Grable.

Who are you?"

"You can't see him."

"Isn't he in the house?"

"It's none of your business where he is. And he wouldn't see you at this time of night anyway!'' Then Jenkins remembered the missing rifle. "It must have been you who stole my gun. Where is it?"

"I didn't take it, but I saw one a few minutes ago that may be yours," replied d.i.c.k.

"How do I know you're telling the truth?" stormed Jenkins. "You give me back that rifle, or I'll go into the house and call the police.5'

123 "I'll make a trade with you," said d.i.c.k. "Tell me where I can find Mr. Grable, and I'll see that you get the rifle back."

Jenkins thought it over. "I want the rifle first."

"Come along, then."

d.i.c.k saw no way out of the situation but to return to Joe and persuade him to give up the weapon. The Hardy boy certainly could think of some excuse for having it in his possession.

Jenkins kept a tight grip on d.i.c.k's arm as they retraced their steps down the walk and crossed the yard to the greenhouse.

"There's something funny about this," muttered Grable's a.s.sistant. "I think I ought to call the police anyway. And if you can't produce that rifle------"

"You'll get your rifle. The person with it was right here-why, he's gone!''

d.i.c.k stared in consternation, for Joe was no longer at the fence where he had said he would wait.

"Are you trying to make a fool of me?" demanded Jenkins. "There's no one here."

"But I saw him at this very spot not three minutes ago. Unless he went------"

d.i.c.k wheeled and gazed toward the laboratory. Perhaps Joe had gone there looking for Asa Grable after all.

But the laboratory was in utter darkness. Even the beam of light that had shone beneath the door had vanished.

CHAPTER XV.

TORCH HANDLES.

shortly after Archibald Jenkins had disappeared up the walk, hidden from view by the angle of the house, Joe had seen the laboratory door open. Framed momentarily in the light from the room beyond was the familiar figure of Asa Grable.

The scientist switched off the light and came out. Joe set the rifle against the fence and hurried across the yard.

"Mr. Grable," he said in a low voice.

The scientist looked up, startled, and peered at the boy.

"Yes?"

"I'm Joe Hardy. I Ve been looking for you.'' Joe Hardy. I Ve been looking for you.''

Asa Grable turned and opened the laboratory door.

"Come in," he invited. He switched on the light. "Did anyone see you come here?"

Joe shook his head. He stepped inside and the man closed the door quickly.

"Mr. Grable," said Joe, "I want to ask you about Jenkins. He was sitting out there with a rifle a little while ago. Are you sure he can be trusted?"

The scientist blinked at the boy over the rims 124.

125 of his spectacles. "Don't get any ideas about Archibald," he said. "He's a fine young man. A very fine young man. I wouldn't have him here if I didn't trust him."

Joe saw that nothing would be gained by arguing this point with Asa Grable. He was just about to leave, to keep his appointment at the cliff, when the man looked happily at him and smiled. "Would you like me to show you a secret?"