"We'll have to try them another way, since they have withstood the ordeal of powder," Ned heard the elder Pulsifer's heavy voice boom out, half-amusedly, as the inner door of the room banged open. At the same instant there came a low "chug" from the motor. "Speed up that spark," ordered the laboring inventor. "No, not that lever. There, that little attachment on the wheel. That's it." Chug-chug-chug! "Hurray! that did the trick!" shouted Mr. Varian, forgetting his dignity in the excitement of the moment. As he spoke, from inside the house they heard, above the roar of the now awakened motor, the shouts of dismay with which Pulsifer and his mercenaries greeted their discovery that their "birds had flown." "They can't be far off!" Ned heard the heavy voice boom out. "Scatter, boys! After them! One hundred dollars to the lad who bags the first one!" The front door burst open and out rushed the men who a few minutes ago had been so confident of bluffing out one of Uncle Sam's sailors and one of his brainiest citizens. "There they are!" yelled Pulsifer, as his eyes lit on the two figures as they lightly swung into the auto. "Don't let them get away! Five hundred dollars if you stop them!" "Shoot 'em down!" bawled the shrill tones of Schultz. As the inventor opened up the motor and threw in the clutch several dark figures leaped in front of the machine, and one jumped on to the seat beside Ned. This last figure--it was that of Kennell--raised a knife high and then brought it down with a vicious swoop. The blade seemed to strike full at Ned's heart. The inventor gave a cry of dismay. But at the same instant, like a thing instinct with life, the car leaped forward. "Stand from under!" bawled the inventor, as he threw in the third-speed clutch. Ned saw the figures of Schultz and Hank Harkins flung aside by the wheels and go rolling down the steep hillside. At the same time he drew back his fist and sent it crashing into Kennell's face. The knife fell clattering twenty feet away, as the treacherous bluejacket, with a howl of alarm, fell backward. "Take that from Herc Taylor!" shouted Ned. Forward into the darkness plunged the car, leaping and rolling over the rough road. "Hurt, Ned?" It was the inventor speaking. His voice was anxious. Already the shouts and cries behind them were dying out. "No, sir, why?" "That blow with the knife. I thought it would have killed you." "Well, it might have, sir, but for _this_. I carried it for a luck piece, and I guess it's earned its name!" The Dreadnought Boy held up a tiny silver coin. It had a big dent in it, where Kennell's blade had been turned. It was old Zack's parting present, the Canadian dime. CHAPTER XXVII. A STRANGE RETURN. "You say Seaman Strong made his way after the men you suspected, and that was the last you saw of him?"