"I'm trying to talk to you as if you were an adult," Raymond said, "but if you will persist in these childish interruptions—"
"I'm sorry," Martin said.
But he wasn't, for by now he had little respect left for any of his descendants. They were all exceedingly handsome and cultivated young people, with superior educations, smooth ways of speaking and considerable self-confidence, but they just weren't very bright. And he had discovered that Raymond was perhaps the most intelligent of the lot. Somewhere in that relatively short span of time, his line or—more frightening—his race had lost something vital.
Unaware of the near-contempt in which his young ancestor held him, Raymond went on blandly: "Anyhow, Conrad took it upon himself to feel particularly guilty, because, he decided, if it hadn't been for the fact that our great-grandfather discovered the super-drive, we might never have reached the stars. Which is ridiculous—his feeling guilty, I mean. Perhaps a great-grandfather is responsible for his great-grandchildren, but a great-grandchild can hardly be held accountable for his great-grandfather."
"How about a great-great-grandchild?" Martin couldn't help asking.
Raymond flushed a delicate pink. "Do you want to hear the rest of this or don't you?"
"Oh, I do!" Martin said. He had pieced the whole thing together for himself long since, but he wanted to hear how Raymond would put it.
"Unfortunately, Professor Farkas has just perfected the time transmitter. Those government scientists are so infernally officious—always inventing such senseless things. It's supposed to be hush-hush, but you know how news will leak out when one is always desperate for a fresh topic of conversation."
Anyhow, Raymond went on to explain, Conrad had bribed one of Farkas' assistants for a set of the plans. Conrad's idea had been to go back in time and "eliminate!" their common great-grandfather. In that way, there would be no space-drive, and, hence, the Terrestrials would never get to the other planets and oppress the local aborigines.