"I'm not so sure about that," said Jack. "Frank is rather hot headed at times, you know, and he is likely to chase him clear aboard a German warship." "I give him credit for more sense than that," said Lord Hastings. "So do I," said Jack, "at times. At other times he loses his head altogether." "Well, the best thing we can do is to wait and see what happens," said Lord Hastings. "The only thing that worries me is that the German may prove more than a match for him should he overtake him." "I'll leave it to Frank to get himself out of any trouble like that," said Jack. "The only thing that I am afraid of is his hot-headedness." In the meantime, exert himself as he would, Frank realized that he was not lessening the distance between himself and the fugitive; but the lad was not one to give up the chase so easily. He gritted his teeth and muttered to himself: "I'll get him if I have to chase him all around the world." After a time Frank's hopes arose, for a quick look ahead showed him that he had gained a trifle. This encouraging sign lent strength to his arms. He struck out more vigorously than before, as he realized that it was only a question of time until he overtook his quarry. But what the lad did not know was that at that very instant the lookout on the nearest German warship had caught sight of the two swimmers. A shouted command aboard the German vessel, and a launch put off over the side and dashed rapidly toward the German officer in the water. This Frank did not see, and so swam on in ignorance of the danger that threatened. Raising his eyes, a couple of minutes later he saw the German officer as he was picked up by the boat, and for the first time realized that he was in a ticklish situation. "Great Scott!" he muttered to himself. "Why didn't I keep my eyes open? I hope they are satisfied with saving him and let me alone." He turned quickly, and made for the D-16 as fast as he could swim. But his hopes were to prove fruitless, as a quick glance over his shoulder told him. In the launch he perceived the German commander gesticulating violently and pointing in his direction. "I guess it's up to me to hustle," he told himself. Now the German launch started after him, gaining at every stroke the lad made. Lord Hastings and Jack perceived the turn of affairs, and Jack cried out: "Get the launch over quick and man it. Unless we can lick these fellows, Frank is a goner." The crew acted with promptness, and in a twinkling the launch of the D-16 also was racing toward the swimming lad. CHAPTER XII. CAPTURED. Frank, literally the bone of contention between the two forces in the launches, swam as swiftly as possible in the direction of safety; but the furtive glances he cast over his shoulder showed him that the Germans were nearer than his friends, and that in spite of the fact that he was swimming toward the latter, the former would come up with him first.