indicated
stark puzzlement. "Its breached hull makes the ship incapable of flight.
Apparently it is used only to supply power to the outlying hamlets."

The mechanical put a flexible gray finger upon an indicator graph
derived from a composite section of detector meters. "The power
transmitted seems to be gross electric current conveyed by metallic
cables. It is generated through a crudely governed process of continuous
atomic fission."

* * * * *

Farrell, himself appalled by the information, still found himself able
to chuckle at Stryker's bellow of consternation.

"_Continuous fission?_ Good God, only madmen would deliberately run a
risk like that!"

Farrell prodded him with cheerful malice. "Why say mad _men_? Maybe
they're humanoid aliens who thrive on hard radiation and look on the
danger of being blown to hell in the middle of the night as a
satisfactory risk."

"They're not alien," Gibson said positively. "Their architecture is
Terran, and so is their ship. The ship is incredibly primitive, though;
those batteries of tubes at either end--"

"Are thrust reaction jets," Stryker finished in an awed voice.
"Primitive isn't the word, Gib--the thing is prehistoric! Rocket
propulsion hasn't been used in spacecraft since--how long, Xav?"

Xavier supplied the information with mechanical infallibility. "Since
the year 2100 when the Ringwave propulsion-communication principle was
discovered. That principle has served men since."

Farrell stared in blank disbelief at the anomalous craft on the screen.
Primitive, as Stryker had said, was not the word for it: clumsily ovoid,
studded with torpedo domes and turrets and bristling at either end with
propulsion tubes, it lay at the center of its square like a rusted relic
of a past largely destroyed and all but forgotten. What a magnificent
disregard its builders must have had, he thought, for their lives and
the genetic purity of their posterity! The sullen atomic fires banked in
that oxidizing hulk--

Stryker said plaintively, "If you're right, Gib, then we're more in the
dark than ever. How could a Terran-built ship eleven hundred years old
get _here_?"

Gibson, absorbed in his chess-player's contemplation of alternatives,
seemed hardly to hear him.

"Logic or not-logic," Gibson said. "If it's a Terran artifact, we can
discover the reason for its presence. If not--"

"_Any problem posed by one group of human beings_," Stryker quot