"Fool! I want to go."
They made the box bigger.
Ten months from the day the crash program had been started, the job was completed. Jason Wall had spent the last few days watching the world at play. Happy children, contented people, folks who didn't have much, but who did have happiness. They would go right on enjoying themselves, after Jason Wall died. It wasn't fair, he told himself. And he would see to it that they didn't—by destroying their first ancestor, and his, so they would never be born, so the human race would never be....
"... all physical actions on the sub-microscopic level, on the level of molecules and atoms and sub-atomic particles and quanta of energy—all these actions," the chief physicist told Jason Wall, "are reversible. If you can control the reversal, you can return matter, energy, and space to its former state. Doing that, you travel through time. Therefore—"
"Never mind the details," Jason Wall snapped. "That's your department. I only want to know this: will it work. Will it take a man back through time."
"Yes, but—"
"Very well. I'll go."
"But we haven't figured out a way to return. If you go, you won't come back. You'll have to spend the rest of your life back there."
The rest of his life. Jason Wall smiled. The rest of his life could be measured in pain-wracked months, possibly only in weeks.
Fifteen minutes after his discussion with the chief physicist, he sat down in the time chair. Anthropologists had been consulted for the final stages of the project. There would be no mistakes. He would go where and when he had to go....