The two lads, Bill and Charlie, stared with undivided attention at the astonishing spectacle. Two large fins which evidently had been lying close to the submarine’s sides, were rising into the air. With a speed that seemed remarkable these fins reached a vertical position. For a moment they remained pointing straight toward the high blue arc of the heavens. Then they swung outward, lowering horizontally from the ship’s sides, to come to rest when level with the deck, and about five feet above the surface of the water—a complete set of airplane wings.