"Walk," replied the ape-man. "Turn her over, Andua!" he directed one of the blacks. A moment later the ship was bumping over the veldt, from which, directly, it rose in smooth and graceful flight; circled, climbing to a greater altitude, and then sped away in an air line, while on the ground below the six strained their eyes until the wavering speck that it had dwindled to disappeared entirely from their view. "Where do you suppose he is going?" asked Meriem. Korak shook his head. "He isn't supposed to be going anywhere in particular," he replied; "just making his first practice flight alone; but, knowing him as I do, I wouldn't be surprised to learn that he had taken it into his head to fly to London and see mother." "But he could never do it!" cried Meriem. "No ordinary man could, with no more experience than he has had; but then, you will have to admit, father is no ordinary man." For an hour and a half Tarzan flew without altering his course and without realizing the flight of time or the great distance he had covered, so delighted was he with the ease with which he controlled the ship, and so thrilled by this new power that gave him the freedom and mobility of the birds, the only denizens of his beloved jungle that he ever had had cause to envy. Presently, ahead, he discerned a great basin, or what might better be described as a series of basins, surrounded by wooded hills, and immediately he recognized to the left of it the winding Ugogo; but the country of the basins was new to him and he was puzzled. He recognized, simultaneously, another fact; that he was over a hundred miles from home, and he determined to put back at once; but the mystery of the basins lured him on--he could not bring himself to return home without a closer view of them. Why was it that he had never come upon this country in his many wanderings? Why had he never even heard of it from the natives living within easy access to it. He dropped to a lower level the better to inspect the basins, which now appeared to him as a series of shallow craters of long extinct volcanoes. He saw forests, lakes and rivers, the very existence of which he had never dreamed, and then quite suddenly he discovered a solution of the seeming mystery that there should exist in a country with which he was familiar so large an area of which he had been in total ignorance, in common with the natives of the country surrounding it. He recognized it now--the so-called Great Thorn Forest. For years he had been familiar with that impenetrable thicket that was supposed to cover a vast area of territory into which only the smallest of animals might venture, and now he saw it was but a relatively narrow fringe encircling a pleasant, habitable country, but a fringe so cruelly barbed as to have forever protected the secret that it held from the eyes of man.