"Come now," said the ober-leutnant irritably. "What do you make of it?" "It is a vessel of some kind, Herr Kapitan," replied Eitel von Loringhoven. "Of course it is," snapped von Preugfeld. "Any fool could see that. What I want to know is: what sort of craft is it? Stand aside if you cannot do better than that." "It is a long, low-lying craft painted black," resumed Loringhoven, retaining his place at the periscope in order to ingratiate himself in the eyes of his commanding officer. "There are men standing aft. Amidships I can see a small sail--it may be that there is a sailing boat alongside." "That's better," remarked von Preugfeld, literally pushing the unter-leutnant aside. "Port helm fifteen degrees," he ordered. "A touch ahead with both motors." The U-boat shuddered under the beats of the twin screws, then forging slowly ahead approached the puzzling object. "Stop!" A bell clanged somewhere in the confined recesses of the modern pirate craft. At a curt nod from the kapitan the quartermaster pulled over a lever which had the effect of actuating the twin horizontal rudders. Once more the periscope reared its sinister head above the waves. "Ach! I see men in uniform," exclaimed von Preugfeld. "We must be cautious. Men in khaki," he continued, scratching his closely cropped head in perplexity. "I cannot understand it. Look again, Eitel: can you see if she carries any guns or torpedo-tubes?" "None, as far as I can see, Herr Kapitan," replied von Loringhoven after a careful scrutiny. "To me it looks as if she is sinking. Her stern is well down. Yes, there is a sailing-boat alongside or close to her. The boat is moving ahead." "We will submerge and come up again on the other side," declared von Preugfeld. "We may then solve the mystery. Down to ten metres," he ordered. Bubbling with latent insubordination, Furst and Krauss at their posts at the auxiliary ballast-tank valves obeyed promptly. In spite of all their revolutionary tendencies and expressions of general "fed-uppedness," they realised that their lives depended upon the prompt execution of their hated superior's orders. Knowing nothing of what was going on without, they submitted to discipline as the only remedy for their present predicament. After a period of ten minutes' total submergence the periscope shoved its squat snout above the surface--like a reluctant puppy about to receive a hiding. When a periscope is in danger of getting a blinding blow in the shape of a six-pounder shell, or the hull to which it belongs is liable to be pulverised by a trio of torpedoes, the need for extreme caution becomes apparent. "They have not observed us," muttered von Preugfeld with fervent gratitude to the providence that looks after Hun submarines. "There's 'X 5' painted on her bows. Know what that means, Eitel?"