"Open this door!" he summoned. As the door did not open Dick placed his shoulder against it. "Open the door, or I'll break it down," Dick insisted. There was still no answer. Thereupon Prescott proceeded to put his threat into execution. Harry bounded forward to help. Under their combined assault the door gave way. Lieutenant Prescott was the first to enter the dark little cabin. Poor as the light was his eyes caught sight of something that made him gasp. "This is the big capture of the season!" cried Dick jubilantly. CHAPTER XIX A NEW MYSTERY PEEPS IN "Get out of here, or you'll get something you don't want," roared an ugly voice at the farther end of the cabin. At sound of that voice Tom Reade started. He thrust his head in the open doorway. "Hullo, Evarts!" called the young chief engineer. "Get out of here!" came the furious order. "So you've openly joined the enemy, Evarts?" demanded Tom, as his eyes fell upon the object that had first claimed Lieutenant Dick Prescott's attention. "You've no business here! Get out, or I'll shoot," cried Evarts, defiantly. "Don't be too quick on the shoot," warned the Blixton policeman, who still had his own revolver in his hand. "This is a police party, and you're under arrest. Start any shooting trouble, and the air will be full of it." "Clear out, and I'll come outside and talk with you," proposed Evarts, for it really was the discharged foreman. "All right," nodded the policeman. "Gentlemen, let him step outside." The others left the entrance to the cabin, As Evarts, his pistol now back in his pocket, stepped sullenly outside, Harry Hazelton dropped back into the doorway. "Glad to meet you, Mr. Evarts," grinned the police officer, deftly slipping handcuffs on the fellow's wrists. "This is treachery!" stormed the prisoner. "I didn't surrender to you. I only came out to talk with you." "If you didn't surrender, then excuse me, and go ahead and put up a fight," laughed the policeman, handily removing Evarts's revolver from a hip pocket. "Now, look in here, Tom," urged Dick. "Do you see what caught my eye?" Prescott pointed to a sharp-nosed cylinder, some eight feet long. Just as it lay the propeller at the other end was invisible to one at the doorway of the cabin. "It's a home-made imitation of a Whitehead torpedo," Lieutenant Dick went on, in explanation. "If it proves to be charged with explosives then the mere having of it aboard this sloop will prove embarrassing to these two prisoners to explain in court. If it isn't loaded, that will be almost as bad, as such a torpedo can be rather easily loaded, and then set in operation by clock-work machinery that will control the propeller." "Young man, you seem to think you know a good deal about torpedoes," sneered Evarts. "He ought to," Harry retorted quietly. "He's a West Point man and an army officer. Therefore, he's a specialist in some kinds of explosives."