Then, stripped for action, the Sylph set out upon the trail of the German cruiser. "We are on the trail at last," said Lord Hastings, "and on the trail we'll remain until the Emden has been sent to the bottom." He turned to Jack. "Hereafter," he said, "I'll place faith in your premonitions." The Sylph kept just far enough in the rear of the Emden to be out of range. After three hours, it became apparent that the commander of the German cruiser was aware that he was being followed. He slowed down, waiting the Sylph to come within range and give battle. But while Lord Hastings was a brave man, he had no idea of accepting battle now. For had the day gone against him, the Emden would have been able to disappear once more. With the superior speed of the Sylph, Lord Hastings knew that he could remain on the trail, using his wireless to pick up some British vessel big enough to put an end to the "Terror of the Sea." Accordingly, the Sylph also slowed down. After waiting in vain for the little scout cruiser to approach closer, the Emden again set out on her course, at full speed. The Sylph also quickened her pace, and the Emden was unable to shake her off. Then the Emden slowed down again. So did the Sylph. The wireless operator approached Lord Hastings with a message. Lord Hastings read it aloud: "Remain where you are till I come up, or I shall sink you. Signed, von Mueller." Followed by the two lads Lord Hastings made his way to the wireless room, and ticked off this message himself: "The Emden is doomed. Signed, Hastings." CHAPTER XXI ON THE TRAIL A reply to this message was not long coming. It read: "Lord Hastings: Sorry you are aboard, but I must sink you." To this Lord Hastings replied: "It can't be done." Now the Emden put about and headed for the Sylph. Quickly also the Sylph came about and headed westward. "If he'll only follow long enough, we'll lure him into the path of some British vessel," said Lord Hastings. "Well," said Jack, "I don't believe he will. As soon as he finds he cannot overtake us, he'll continue on his way." "And he'll try to lose us in the night," said Frank. "That is my idea," said Lord Hastings. "To prevent that we must be on the alert continually. We'll follow him for months, if necessary. At nights we shall have to close up a bit, and take a chance that they cannot hit us." It was nearing dusk when the Emden finally gave up the chase of the Sylph as futile, and once more put about. Immediately also the Sylph's head came about, and she once more set out, to trail the German. Occasional messages were exchanged between Captain von Mueller and Lord Hastings. Night fell, and now the Sylph began to draw closer to her quarry. She closed up the distance gradually, until Lord Hastings decided that they were near enough; and this position the Sylph maintained, her searchlight playing upon the Emden and making her as light as day.