Suddenly, through night glasses, Dan, who had been called to the bridge, discovered what was taking place. On the quiet waters of this night the two craft had managed to get near enough to each other to attempt to transfer mines from one to the other. Then it was that the "Reed" had opened fire with her guns, had turned on her searchlight and had rushed in. As soon as the German commanders found their boats punctured into helplessness they had signalled their surrender. "But I was glad indeed when I saw you bearing down on us," Dan announced, when he visited his chum a little later. "The enemy had surrendered, but I know enough of German treachery to realize that they might let me drive in close and then try to torpedo me. I needn't have worried, but of course I could not afford to take chances." Sending for Boatswain's Mate Runkle, Dave inquired: "Do you speak German?" "I know about six words, sir; not as many as eight." "Then you are the man for the job, Runkle. Go down among the prisoners that have been sent on board, the seamen, I mean, not the officers. Act as though you were there on duty, but not very busy. Use your six words of German and make English do for the rest. The German sailors won't understand you, unless some of them speak English. That will be all the better, for as soon as you discover that some of the men don't know what you are saying you will be able to judge which of those who speak no English are the most stupid, or the most likely to talk and tell us the truth. Spot three or four of these stupid ones, and then bring one of them here to the chart-room." "Now, what on earth does the 'Old Man' want?" wondered Runkle, as he started away on this errand. "But never mind. Even if I can't guess what he wants it's a cinch that he knows. The stupidest one, eh? I wonder why any Fritz wouldn't do, then!" Runkle found his man within five minutes, detached him from the other prisoners, and led him to the chart-room. Darrin tried his own German on the fellow, asking: "Your craft had just arrived from the base port?" The man stared, then slowly nodded. "How many mines did you have on board when you left the base port?" "Thirty, I heard." "You planted some on the way?" "A few, so I heard." "Most of the mines you were to deliver here tonight?" "Yes." "How many trips a week has your craft been making between here and the base port?" "Usually about four." "Did you always deliver, here, to the same mine-layer?" "No; that was as it happened. Sometimes to one boat, sometimes to another." "How many mines could your craft carry?" "Thirty." As this agreed with the information supplied by Ensign Andrews, Dave believed that the seaman was telling the truth. "Did your craft always come to these same waters to deliver mines to mine-layers?" "Always, since I have been aboard, to some one of the shoals in this stretch of them," replied the sailor.