"No, it is not impossible," said Lord Hastings. "We shall go." At this moment Jack came in, and when he learned what Lord Hastings proposed to do, he attempted to dissuade him. So did the commander of the _Queen Elizabeth_ when he came to visit Lord Hastings that afternoon. But the commander of the D-16 was not to be dissuaded. "I am the commander of this vessel," he said grimly, "and when I give an order I want it obeyed. Mr. Templeton, you will get under way an hour after nightfall." Jack saluted. He said nothing, for he knew that to say anything would be useless. He had never seen his commander in just this frame of mind before, but he was smart enough to realize that Lord Hastings meant what he said. Night fell. An hour later, in accordance with his orders, Jack gave the signal, and the D-16 sank slowly from sight. Lord Hastings called Frank. "Help me to my place at the periscope," he said quietly. "But, sir," protested Frank. "There are no buts," said Lord Hastings. "Help me to my post." Frank said nothing further, but obeyed. Seated in a chair beside the periscope, Lord Hastings took a long breath. Then he called to Jack. "I'll do the watching here," he said. "You run the ship in response to my signals." Jack saluted. Frank took the lookout, as usual, and once more the huge searchlight lighted up the water under the Dardanelles. The time wore on, still all stood at their posts. Morning came and Lord Hastings said: "According to my calculations we should now be in the Sea of Marmora. We will go up for a look about, Mr. Templeton." The D-16 rose until her periscope showed Lord Hastings the signs about her. "Very good," he said slowly. "You may go down to your previous depth." The D-16 sank again. "See anything, sir?" asked Frank. "Enough to know that my calculations were correct and that we are in the Sea of Marmora." "Any vessels in sight, sir?" "Couple of merchantmen, as nearly as I could make out." "Did they see us, sir?" "I think not. In fact I am sure of it." "That's good, sir." "So it is. You may proceed at twenty-five knots." The D-16 gathered headway and soon was traveling along under the water at a great rate. "Won't we have to be careful of mines along here, sir?" asked Jack. "I do not believe they have mined much as yet. They figure that there is little danger of the Allies forcing an entrance for some time to come. However, we may as well be careful. Take the lookout, Mr. Chadwick." Frank saluted and returned to his post. "The only place we shall have to be really careful," said Lord Hastings, "is when we near Constantinople. No matter how safe the Turks may have felt, it is hardly possible they have not taken all emergency precautions." "If not," said Jack, "the German officers who have been put in charge of their forces will have done it for them." "I guess there is no doubt about that," was the reply. "The Germans are thorough in everything they do." "Shall we land in Constantinople, sir?"