"Th-th-th—Never mind," he fumbled. "I was only g-going to ask about it myself."

"Well—" She yawned and stretched with breathtaking effect. "I suppose I'd better get back and—"

"Ah, why so, señorita?" replied Alemán. "If the work does not need your personal attention just now, come join me in a leetle drink. It is near dinnertime anyhow."

"All right," she said. "How about you, Tom?"

He merely nodded, for fear of stuttering, and accompanied them down the stairs and into the tunnel. Half of him raged at his own timidity—why hadn't he made that suggestion?

The passages connecting the domes were all alike, straight featureless holes lined with plastic. Behind lay insulation and the pipes of the common heating system, then more insulation, finally the Hill itself. That was mostly porous iron, surprisingly pure though it held small amounts of potassium and aluminum oxides. The entire place was a spongy ferrous outcropping. But then, Triton was full of geological freaks.

"How goes your work?" asked Alemán sociably.

"Oh, pretty well," said Catherine. "I suppose you know we've synthesized virus which can live outside. Now we're trying to build bacteria to do the same."

On a professional level, Gilchrist was not a bad conversationalist. His trouble was that not everyone likes to talk shop all the time. "Is there any purpose in that, other than pure research to see if you can do it?" he inquired. "I can't imagine any attempt ever being made to colonize this moon."

"Well, you never know," she answered. "If there's ever any reason for it, oxide-reducing germs will be needed."