"Garret! Garret Jackson!" cried Tom as he struggled through the hedge of bushes and ran after the men. "Where are you, Garret? Come on and help me chase these men!"

But there came no answer to Tom's hail. He could not hear the sound of the retreating footsteps of the men now and concluded that they had made their escape. Still he would not give up, but dashed on, slipping and stumbling, now and then colliding with a tree.

"What can they be doing here?" thought Tom in great anxiety. "Are they after some more of dad's inventions because they didn't get his turbine motor?"

"Hello! Who's there? Who are you?" called a voice suddenly.

"Oh, Garret! Where have you been?" asked the young inventor, recognizing the tones of his father's keeper. "I've been calling you. Some of those scoundrels are around again!"

"Why if it isn't Tom!" ejaculated the engineer. "However in the world did you get here? I thought you were at Sandport."

"I'll explain later, Garret. Just now I want to catch those men, if I can."

"Which men?"

"Happy Harry and another one. I saw them hiding down by the orchard path. Come on, they're right ahead of us."

But though they hunted as well as they were able to in the fast- gathering darkness, there was no trace of the intruders. They had to give up, and Tom, after going to the boathouse to see that the Arrow was all right, returned to the house, where he told the engineer and housekeeper what had brought him back and how he had surprised the two men.

"Is everything all right, Garret?" he concluded. "Dad is nervous and frightened. I must telephone him at the hotel to-night and let him know, for I promised to come back. I can't, though, until to-morrow."

"Everything is all right as far as I know," answered Jackson. "I've kept a careful watch and the burglar alarm has been in working order. Mrs. Baggert and I haven't been disturbed a single night since you went away. It's curious that the men should be here the very night you come back. Maybe they followed you."

"I hardly think so, for they didn't know I was coming."

"You can't tell what those fellows know," commented the engineer. "But, anyhow, I don't suppose they could have gotten here from Sandport as soon as you did."

"Oh, yes they could, in their automobile," declared Tom. "But I don't believe they knew I was coming. They knew we were away, however, and thought it would be a good time to steal something, I guess. Are you sure nothing has been taken?"

"Perfectly sure, but you and I will take a look around the shop."

They made a hasty examination, but found nothing disturbed and no signs that anyone had tried to break in.

"I think I'll telephone dad that everything is all right," decided Tom. "It is as far as his inventions are concerned, and if I tell about seeing the men it will only worry him. I can explain that part better when I see him. But when I go back, Garret, you will have to be on your guard, since those men are in the neighborhood."

"I will, Tom. Don't worry."

Mr. Swift was soon informed by his son over the telephone that nothing in the shops had been disturbed, and the inventor received the news with evident satisfaction. He requested Tom to come back to the hotel in the morning, in order that the three of them might go for a ride about the lake in the afternoon, and Tom decided to make an early start.

The night passed without incident, though Tom, who kept the gun Mr. Duncan had given him in readiness for use, got up several times, thinking he heard suspicious noises. After an early breakfast, and having once more cautioned the engineer and housekeeper to be on their guard, Tom started back in the Arrow. As it would not be much out of his way, the young inventor decided to cut across the lake and stop at the sanitarium, that he might inquire about Mr. Duncan. He thought he could speed the Arrow up sufficiently to make up for any time he might lose, and, with this in mind, he headed out toward the middle of Lake Carlopa. The engine was working splendidly with the new spark plugs, and Tom was wondering if there was any possible method of getting more revolutions out of the motor. He had about come to the conclusion that a new propeller might answer his purpose when he heard the noise of an approaching boat. He looked up quickly and exclaimed:

"Andy Foger again, and Pete and Sam are with him. It's a wonder he wouldn't go off on a trip instead of cruising around so near home. Guess he's afraid he'll get stuck."

Idly Tom watched the Red Streak. It was cutting through the water at a fast rate, throwing up curling foam on either side of the sharp bow. "He seems to be heading this way," mused Tom. "Well, I'm not going to race with him to-day."

Nearer and nearer came the speedy craft, straight for the Arrow. The young inventor shifted his helm in order to get out of Andy's course, but to his surprise he saw that the red haired lad changed the direction of his own boat.

"Guess he wants to see how close he can come to me," thought our hero. "Maybe he wants to show how fast he's going."

The Red Streak was now so close that the features of the occupants could easily be distinguished. There were grins on the faces of Andy and his cronies.

"Get out of the way or we'll run you down!" cried the bully. "We've got the right of way."

"Don't you try anything like that!" shouted Tom in some alarm, not that he was afraid of Andy, but the Red Streak was getting dangerously near, and he knew Andy was not a skillful helmsman. The auto-boat was now headed directly at the Arrow and coming on speedily. Andy was bending over the wheel and Tom had begun to turn his, in order to get well out of the way of the insolent, squint-eyed lad and his friends.

Suddenly Andy uttered a cry and leaped up.

"Look out! Look out!" he yelled. "My steering gear has broken! I can't change my course. Look out!"

The Red Streak was bearing right down on Tom's boat.

"Shut off your power! Reverse!" shouted Tom.

Andy seemed confused and did not know what to do. Sam Snedecker sprang to the side of his crony, but he knew even less about a motor-boat. It looked as if Tom would be run down, and he was in great danger.

But the young inventor did not lose his head. He put his wheel hard over and then, leaping to his motor, sent it full speed forward. Not a moment too soon had he acted, for an instant later the other boat shot past the stern of the Arrow, hitting it a severe but glancing blow. Tom's boat quivered from end to end and he quickly shut off the power. By this time Andy had succeeded in slowing down his craft. The young inventor hastily looked over the side of the Arrow. One of the rudder fastenings had been torn loose.

"What do you mean by running me down?" shouted Tom angrily.

"I---I didn't do it on purpose," returned Andy contritely. "I was seeing how near I could come to you when my steering gear broke. I hope I haven't damaged you."

"My rudder's broken," went on Tom "and I've got to put back to repair it. I ought to have you arrested for this!"

"I'll pay for the damage," replied Andy, and he was so frightened that he was white, in spite of his tan and freckles.

"That won't do me any good now," retorted Tom. "It will delay me a couple of hours. If you try any tricks like that again, I'll complain to the authorities and you won't be allowed to run a boat on this lake."

Andy knew that his rival was in the right and did not reply. The bully and his cronies busied themselves over the broken steering gear, and the young inventor, finding that he could make a shift to get back to his boathouse, turned his craft around and headed for there, in order to repair the damage.