"Well, there are two controls, anyway. Now then, how do they steer this thing? That is the next problem we must solve." But though he touched this instrument and that, producing weird effects, their course continued in the direction set. And meanwhile, they were hurtling outward through space at a rate of speed he knew would presently carry them beyond the gravitational pull of the earth. Then, as he grasped and swung down a curious lever that worked in a quadrant, they felt a violent lunge to the left, and for a moment it seemed they would shoot to the ceiling. "Good God!" gasped Stoddard. "What's happened?" "Nothing--only that I've found how to steer this wild steed!" cried the professor, exultantly. * * * * * It was really quite simple, he explained, as he eased up on the lever. In application, it was a development of the gyroscope principle, that a wheel revolving freely within a freely suspended frame tends to make the frame revolve in the other direction. "You see, the rocket is the freely suspended frame," he went on, "while this lever controls a gyroscopic wheel somewhere. To set it spinning to the right causes us to turn to the left, and vice versa." "But you almost stood us on our heads, a moment ago! How did that happen?" "Simply because I threw the lever too far to the right. We are in interstellar space, obviously, where every change of direction involves an adjustment of equilibrium." And if Stoddard didn't exactly understand, being first a secret service man and only secondarily a scientist, at least he showed his ignorance no further. If the professor could bring this astounding machine back to Earth, that was all he wanted. Prescott said he could, he thought, providing they had fuel enough left. So for the next few minutes, while the younger man held his breath, the professor labored with the various instruments on that complicated dial. "Now then, I think we're headed back," he said at length, relaxing. "But we've got to have visibility, otherwise we will land with a velocity of about twenty thousand miles an hour, which is what I figure we're making at the present time." "Good Lord!" gasped Stoddard. "I'll say we've got to have visibility! Wait a minute! Let me look around!" He searched the room for further instruments--to find nothing that in any way met the purpose. But even as he returned dejected, the professor cried out: "Here--I've got it! Take a look at this!" Bending over a small table beside the dial, Stoddard saw mirrored, in its ground-glass surface a hazy circular panorama that at first had no significance. But as he continued to peer down upon the scene, certain familiar aspects loomed out. It was the Earth--and what he was looking at was a view of the North and South American continents! * * * * *