“It looks just like a piece of the ocean, doesn’t it?” said Ikey eagerly. “But there are no ships----” He broke off with a startled cry. Mr. MacMasters and Whistler echoed the ejaculation. Everybody on deck who had paid any attention to the mystery in the sky showed increased interest. Rising slowly and distinctly upon the reflective surface of the reflected sea was an object which the onlookers watched with growing excitement and wonder. It was the outlines of a ship--but not an ordinary ship! It had upperworks and the two stacks of a steam freighter. It was of the color of the sea itself--gray; yet its outlines--even the wire stays--were distinct! The sea shown in the mirage had been absolutely empty. Now, of a sudden, this ghostly figure had risen upon it. Whistler Morgan caught Mr. MacMasters by the arm. He was so excited that he did not know he touched the officer. “Look at it! Do you know what it is?” he gasped. “That’s a submarine--a huge submarine. She’s just risen to the surface.” “It’s the sub we’re looking for!” cried Ikey, hoarsely. “My goodness, see it sailing up there in the sky!” CHAPTER XV--COMBING THE SEA Suddenly the red edge of the sun appeared above the eastern sea line. He had not forgotten to rise! For an instant--the length of the intake of the breath the two astonished boys drew--the mirage painted by nature against the western sky was flooded with the rising glory. Then the wonderful picture was erased, disappearing like a motion picture fade-out, and there no longer remained any sign of the startling vision in the sky, save a mass of formless and tumbled cloud. “What do you know about that?” murmured Ikey Rosenmeyer, in amazement. “You’ll never see the like of it again, boys--not in a hundred years,” Ensign MacMasters said with confidence. “That was a wonderful mirage!” “But, Mr. MacMasters,” cried Whistler Morgan, “that vision was the reflection of something real, wasn’t it? An actual picture of a part of the sea?” “So they tell us.” “Where do you suppose that piece of water lies?” demanded the youth eagerly. “I have no idea. ‘Somewhere at sea’! It may be north, east, south, or west of the _Colodia’s_ present position. As I tell you, there is no means of making sure--that I know anything about,” he added, shaking his head. “Oi, oi!” exclaimed Ikey. “Then we don’t know any more than we did before where that super-submarine is.” “If that was a picture of her,” said Whistler thoughtfully. “It is truly ‘all in the air’, boys,” laughed Ensign MacMasters. “We saw something wonderful. Every mirage is that. But it is a mystery, too.” “Maybe that wasn’t the picture of the submarine, after all,” Ikey suddenly suggested. “Maybe that was the mirage of a real freighter we saw. Two stacks and as long as this old destroyer, I bet! Maybe it only looked as though it rose from the sea.” “I’d wager money on it’s being a picture of a huge German submarine,” said Whistler with confidence.