"He didn't!" rasped the professor. "Perhaps, in a dim, primitive fashion, he showed the way, but I — I, van Manderpootz — am the first to seize time, drag it into my laboratory, and perform an experiment on it."

"Indeed? And what sort of experiment?"

"What experiment, other than simple measurement, is it possible to perform?" he snapped.

"Why — I don't know. To travel in it?"

"Exactly."

"Like these time-machines that are so popular in the current magazines? To go into the future or the past?"

"Bah! Many bahs! The future or the past — pfui! It needs no van Manderpootz to see the fallacy in that. Einstein showed us that much."

"How? It's conceivable, isn't it?"

"Conceivable? And you, Dixon Wells, studied under van Manderpootz!" He grew red with emotion, then grimly calm. "Listen to me. You know how time varies with the speed of a system — Einstein's relativity."

"Yes."

"Very well. Now suppose then that the great engineer Dixon Wells invents a machine capable of traveling very fast, enormously fast, nine-tenths as fast as light. Do you follow? Good. You then fuel this miracle ship for a little jaunt of a half million miles, which, since mass (and with it inertia) increases according to the Einstein formula with increasing speed, takes all the fuel in the world. But you solve that. You use atomic energy. Then, since at nine-tenths light-speed, your ship weighs about as much as the sun, you disintegrate North America to give you sufficient motive power. You start off at that speed, a hundred and sixty-eight thousand miles per second, and you travel for two hundred and four thousand miles. The acceleration has now crushed you to death, but you have penetrated the future." He paused, grinning sardonically. "Haven't you?"

"Yes."

"And how far?"

I hesitated.

"Use your Einstein formula!" he screeched.