The visitor sat unmoved through the silence. He had been caught inside the old sawmill and flown to the hidden base the night before. His credentials said he was an agent of the United States Bureau of Internal Security, that his name was David Lyle. Morrow glanced at him, speculatively.
"I've told you all I dare about our group, here," he said. "I've told you some of the things we've done—"
"Without explaining them," Lyle interjected wryly.
Morrow smiled. "You wouldn't grasp the technical end of it if I had told you. It's as if I were the first man to invent the wheel and had gathered a few others about me who were now developing the propellor, the fly-wheel, gear-ratios and the piston engine. We can generate enough electrical power in this canyon site to light a large metropolitan city, and we're now working on a means of using broadcast power and perhaps harnessing atomic energy. We already suspect some of the chemical and medical possibilities inherent in gravitor-field conditions—"
"And you have the answer to interplanetary travel at your fingertips!" Lyle muttered dourly.
"Yes, but without the financial means to do it," Morrow agreed. "Interplanetary travel won't be important for another hundred years anyway—if it is at all—since it will take that long for the world's population to reach any dangerous numbers."
"What's that got to do with it?"
"Mankind is due to reach the stage of population where he can no longer feed himself on Earth," Morrow explained. "He simply won't be able to raise enough food on this one planet to feed such numbers. Either that, or there'll be three or four atomic wars in the next few generations—if there's one, there'll be several wars—and population will cease to be a problem.
"There's been some talk of birth-control as the only logical answer to this overpopulation. It may be used, but I doubt its logic. You'll have to tell some people they simply can't have children, and on a world-wide scale you're going to have many cases where they disregard authority and have children anyway. Then, to make your authority stick, you'll have to take those unauthorized children away from their parents and kill them. You'll need a world dictatorship to do that.
"The only answer that's really logical is when this world gets too small to support mankind, go out and settle a couple more. That's where interplanetary travel becomes important, and not before. The astronomers claim there is very little likelihood of any native species of intelligent beings living on either Mars or Venus. I only hope they're right!