over his shoulder. "There's a planet with some tens of millions of square miles on it. You know there's a ship down. You've no idea where. You assume the survivors have power—no civilized man will be without power very long, so long as he can smelt metals!—but making a space beacon calls for high-precision measurements and workmanship. It's not to be improvised. So what will your shipwrecked civilized man do, to guide a rescue ship to the one or two square miles he occupies among some tens of millions on the planet?"

Roane fretted visibly.

"What?"

"He's had to go primitive, to begin with," Roane explained. "He cooks his meat over a fire, and so on. He has to make a strictly primitive signal. It's all he can do without gauges and micrometers and very special tools. But he can fill all the planet's atmosphere with a signal that searchers for him can't miss. You see?"

Roane thought irritably. He shook his head.

"He'll make," said Huyghens, "a spark transmitter. He'll fix its output at the shortest frequency he can contrive—it'll be somewhere in the five-to-fifty-meter wave-band, but it will tune very broad—and it will be a plainly human signal. He'll start it broadcasting. Some of those frequencies will go all around the planet under the ionosphere. Any ship that comes in under the radio roof will pick up his signal, get a fix on it, move and get another fix, and then go straight to where the castaway is waiting placidly in a hand-braided hammock, sipping whatever sort of drink he's improvised out of the local vegetation."

Roane said grudgingly:

"Now that you mention it, of course—"

"My space phone picks up microwaves," said Huyghens, "I'm shifting a few elements to make it listen for longer stuff. It won't be efficient, but it will pick up a distress signal if one's in the air. I don't expect it, though."

He worked. Roane sat still a long time, watching him. Down below, a rhythmic sort of sound arose. It was Sourdough Charley, snoring. He lay on his back with his legs in the air. He'd discovered that he slept cooler that way. Sitka Pete grunted in his sleep. He was dreaming. In the general room of the station Semper, the eagle, blinked his eyes rapidly and then tucked his head under a gigantic wing and went to sleep. The noises of the Loren Two jungle came through the steel-shuttered windows. The nearer moon—which had passed 

 Prev. P 15/44 next