"Well," he said at length, "it is probably plain to you that we cannot afford to be burdened with prisoners. For that reason, if given an opportunity, I had intended to set you adrift in one of the small boats when we were able to come to the surface and are close enough to shore for you to reach if safely." "You are kind captors, sir," said the German with a bow. "Until such a time, then, I shall return to the quarters you have assigned me. Also, I give my word that I shall make no attempt to escape, nor to interfere with your plans." "Your parole is accepted, sir," replied Lord Hastings. "The freedom of the ship is yours." The German bowed low and left the room. "Do you not fear to trust him?" asked Jack. "Remember the trouble we had with the other officer." "I am not afraid to trust this one," replied his commander. "Nor I," agreed Frank. "He is as different from the other as day from night." Lord Hastings rose and glanced at his watch. "If I have calculated correctly," he said, "we should by now be beyond the confines of the Kiel canal." "But," said Frank, "there are still German war vessels and mines in the bays at this end of the Baltic." "True," replied his commander, "but once out of the canal we will be safe enough, for we can submerge to a greater depth and continue under water until we are safe." He gave the command to bring the submarine to the surface, and when it floated upon the water, made his way to the bridge. The lads followed him. "As I thought," said the commander, looking about. "We have reached the Baltic--not the Baltic proper, perhaps, but still Baltic waters." It was true. Behind could be seen the narrow entrance to the Kiel canal, and ahead the broader expanse of the western arm of the Baltic Sea. There was not a vessel of any kind in sight. "Well," said Jack. "Looks like we were safe enough here." "Looks that way," agreed Frank, "but you never can tell, you know." CHAPTER XVI. IN TROUBLE AGAIN. "What's that?" asked Frank, as he gazed across the water. "Smoke," replied Jack. "It's plain enough." "I know that," replied the former, "but what I meant is, do you suppose it is a battleship?" "Looks like it might be," replied Jack briefly. "Russian or German?" asked Frank. "Can't tell," said Lord Hastings, who had been peering at the cloud of smoke through his glass. "I can make out that it is a battleship, but that's all. However, we shall know soon enough." Slowly the cloud of smoke came nearer and nearer, until at last the dim outline of a large battle cruiser of the second class was plainly visible to the naked eye. But still those aboard the D-16 were unable to make out her nationality, for she flew no flag. "We'd better get ready to dive in case she proves to be a German," said Lord Hastings. "Right you are, sir," replied Jack, and turning, went below. Frank and Lord Hastings remained upon the bridge.