Through his glasses Dennis could see a dull glow in the distance, which was soon left behind as Laval altered the course, and for some time their flight was through cloud-banks which hid everything. After a while the pilot passed him another message. "Look down; we cannot be far from the Rhine now, and it is important to know when we cross it. Keep a sharp look out." The depression of the point of the _nacelle_ told Dennis that the Aviatik was planing down to a lower altitude, and when, some distance ahead, he saw the milky gleam of a river winding away to right and left, he hung over the side with the powerful German glasses glued to his eyes. The moment it passed beneath them he touched Laval on the shoulder, and, swinging round again to the right, they flew almost due south, still coming down lower and lower. It was a clear night, and the visible difference in the blackness of the ground here and there told Dennis that they were traversing above mountainous country, while the little bright specks shining like glow-worms marked the existence of enemy towns and villages, whose inhabitants fancied themselves secure from the daring French airmen. With the exception of the historic raid upon Karlsruhe they had seldom journeyed so far afield. For a moment the engines ceased working, and Laval shouted to his companion: "We must be close to the place now. There should be a hill covered with pine trees in front of us, and the hangar lies within a league beyond it on a flat plain." "Then yonder it is!" cried Dennis. "There is no end of a strong light showing ahead. That ragged edge that looms against it must be your tree tops." "Good!" replied the pilot. "Get your bombs ready. When I shut off again we shall he as nearly above the spot as one can judge." He restarted the engines. In the distance a curious yellow glow outlined the hill, and as they sailed clear of the pines the glow resolved itself into a considerable illumination, for which the pilot steered. Rows of electric lamps formed a huge parallelogram, in the centre of which was a long black object, undoubtedly the airship hangar. "By Jupiter!" yelled Dennis; "we're in luck to-night! The Zeppelin's coming out!" He forgot that his words were completely drowned, and he received a sudden shock when the brilliant beam of a searchlight flashed up from the ground, and, after a circling swoop, found them and held them in its fierce eye. Every stay and rivet was as clearly visible to him as though it had been noonday, and it was a trying moment. As another light challenged them, and asked "Who are you?" he remembered Laval's previous instructions, and showing his signal lamp, replied in the Morse code, "Blumberger, returning from reconnaissance beyond Muelhausen."