Mahler gestured to them, and they led the jumper away. Amazed, Mahler watched the retreating figure, studying him until he could no longer be seen.

If they were all like that, Mahler thought. I could have gotten to like that one. He was a sensible man—one of the few. He knew he was beaten, and he didn’t try to argue in the face of absolute necessity. It’s too bad he had to go. He’s the kind of man I’d like to find more often these days. But I mustn’t feel sympathy. That would be unwise.

Mahler had succeeded as an administrator only because he had managed to suppress any sympathy for the unfortunates he had been compelled to condemn. Had there been any other place to send them—back to their own time, preferably—he would have been the first to urge abolition of the Moon prison. But, with only one course of action open to him, he performed his job efficiently and automatically.

He picked up the jumper’s time rig and examined it. A two-way rig would be the solution, of course. As soon as the jumper arrived, a new and better policy would be in force, turning him around and sending him back. They’d get the idea quickly enough. Mahler found himself wishing it could be so; he often wondered what the jumpers stranded on the Moon must think of him.

A two-way rig would change the world so completely that its implications would be staggering. With men able to move at will backward and forward in time the past, present, and future would blend into one broad and shining highway. It was impossible to conceive of the world as it might be, with free passage in either direction.

But even as Mahler fondled the confiscated time rig he realized that something was wrong. In the six centuries since the attainment of time travel, no one had yet developed a known two-way rig. And an unknown rig was pretty well ruled out. There were no documented reports of visitors from the future and presumably, if such a rig existed, such visitors would have been as numerous as were the jumpers from the past.