They were powerful weapons, longer and of greater diameter than the British Whiteheads, while from the German characters engraved on parts of the mechanism the Sub concluded that they must be the formidable Schwartz-Kopff torpedoes. Moreover, they were intended to be fired from shore stations. Carefully screened from observation, torpedo-tubes had been placed in position, so that a direct hit at any hostile warship attempting to force The Narrows was almost a certainty. The Sub would dearly have liked to follow the narrow-gauge line of rails, but the risk was too great. No doubt he would be able to discover the exact locality of the firing-station, but realizing it would serve no useful purpose if he did so and was caught in the act, he resumed his way through the main archway. The doors were closed and barred by massive beams, but a wicket attracted his attention. Somewhat dubious as to what would be awaiting him on the other side, Dick cautiously shot the bolt and pushed open the means of exit. It was not perhaps in keeping with his role as a Prussian officer to open a door cautiously, but well it was that he did so. Ten feet from the door was a grey-painted sentry-box, in which stood a ferocious-looking Bashi Bazouk, his shawl simply bristling with weapons. Fortunately his face was turned away from the wicket-gate, and the noise it made was not sufficient to attract his attention. But it was not the Turkish irregular that caused Dick's heart to give a violent thump in spite of his usually cast-iron nerves. A little farther away a regiment of infantry was drawn up in quarter-column, while in front, and almost at the angle nearest the British officers, were seven or eight Germans, both of the line and of the artillery, all engaged in studying by the aid of a lantern a map which had been spread upon the ground. "Where's von Eitelheimer?" demanded one in the uniform of a colonel. "He ought to be here." "He and Lieutenant Schwalbe went to see the two cursed Englishmen, Herr Colonel," replied a German sergeant-major. "The Major said it was most important to get the prisoners' signatures before the regiment marches." "Quite right," assented the Colonel. "Nevertheless he ought to be here before this. Hurry, Schneider, and tell Major von Eitelheimer that----" Dick waited to hear no more. Softly closing the door, he gripped Farnworth by the arm and hurried him back under the archway until they reached the transverse passage. "We've precious little time," he explained hurriedly, at the same time lowering his voice to a whisper. "They're sending a fellow to look for our pal Ahmed and the fat subaltern. We'll risk it and try this way."