
"One hundred and nine light-years, Mr. Underhill."
That made the first point, but Underhill concealed his satisfaction. The new space liners were
pretty fast, but the velocity of light was still an absolute limit. Casually, he played for another point:
"My wife says you're a scientist, Mr. Sledge?"
"Yes."
The old rascal's reticence was unusual. Most of Au-rora's tenants required very little prompting.
Underhill tried again, in a breezy conversational tone:
"Used to be an engineer myself, until I dropped it to go into mechanicals." The old vagabond
straightened, and Underhill paused hopefully. But he said nothing, and Un-derhill went on, "Fission
plant design and operation. What's your specialty, Mr. Sledge?"
The old man gave him a long, troubled look, with those brooding, hollowed eyes, and then said
slowly, "Your wife has been kind to me, Mr. Underhill, when I was in desperate need. I think you
are entitled to the truth, but I must ask you to keep it to yourself. I am engaged on a very important
research problem, which must be finished secretly."
"I'm sorry." Suddenly ashamed of his cynical little game, Underhill spoke apologetically. "Forget
it." But the old man said deliberately, "My field is rhodomagnetics."
"Eh?" Underhill didn't like to confess ignorance, but he had never heard of that. "I've been out of
the game for fifteen years," he explained. "I'm afraid I haven't kept up.
The old man smiled again, faintly.
"The science was unknown here until I arrived, a few days ago," he said. "I was able to apply for
basic patents. As soon as the royalties start coming in, I'll be wealthy again."
Underhill had heard that before. The old rogue's solemn reluctance had been very impressive, but
he remembered that most of Aurora's tenants had been very plausible gentry.
"So?" Underhill was staring again, somehow fascinated by those gnarled and scarred and
strangely able hands. "What, exactly, is rhodomagnetics?"
He listened to the old man's careful, deliberate answer, and started his little game again. Most of
Aurora's tenants had told some pretty wild tales, but he had never heard anything to top this.
"A universal force," the weary, stooped old vagabond said solemnly. "As fundamental as
ferromagnetism or grav-itation, though the effects are less obvious. It is keyed to the second triad of
the periodic table, rhodium and ru-thenium and palladium, in very much the same way that
ferromagnetism is keyed to the first triad, iron and nickel and cobalt."
Underhill remembered enough of his engineering courses to see the basic fallacy of that.
Palladium was used for watch springs, he recalled, because it was completely non-magnetic. But he
kept his face straight. He had no malice in his heart, and he played the little game just for his own
amusement. It was secret, even from Aurora, and he always penalized himself for any show of
doubt.
He said merely, "I thought the universal forces were already pretty well known."
"The effects of rhodomagnetism are masked by nature," the patient, rusty voice explained. "And,
besides, they are somewhat paradoxical, so that ordinary laboratory meth-ods defeat themselves."
"Paradoxical?" Underhill prompted.
"In a few days I can show you copies of my patents, and reprints of papers describing
demonstration experi-ments," the old man promised gravely. "The velocity of propagation is infinite.
The effects vary inversely with the first power of the distance, not with the square of the distance.
And ordinary matter, except for the elements of the rhodium triad, is generally transparent to
rhodomag-netic radiations."
That made four more points for the game. Underhill felt a little glow of gratitude to Aurora, for