summarize the important facts
and give our conclusions, which may not be worth an inflated franc. It's
hard to judge this dried-up world by earthly standards.

"We took pictures of everything possible; I even tried to photograph
that gigantic mural in the library, but unless Tweel's lamp was
unusually rich in actinic rays, I don't suppose it'll show. And that's a
pity, since it's undoubtedly the most interesting object we've found on
Mars, at least from a human viewpoint.

"Tweel was a very courteous host. He took us to all the points of
interest--even the new water-works."

Putz's eyes brightened at the word. "Vater-vorks?" he echoed. "For vot?"

"For the canal, naturally. They have to build up a head of water to
drive it through; that's obvious." He looked at the captain. "You told
me yourself that to drive water from the polar caps of Mars to the
equator was equivalent to forcing it up a twenty-mile hill, because Mars
is flattened at the poles and bulges at the equator just like the
earth."

"That's true," agreed Harrison.

"Well," resumed Jarvis, "this city was one of the relay stations to
boost the flow. Their power plant was the only one of the giant
buildings that seemed to serve any useful purpose, and that was worth
seeing. I wish you'd seen it, Karl; you'll have to make what you can
from our pictures. It's a sun-power plant!"

Harrison and Putz stared. "Sun-power!" grunted the captain. "That's
primitive!" And the engineer added an emphatic "_Ja!_" of agreement.

"Not as primitive as all that," corrected Jarvis. "The sunlight focused
on a queer cylinder in the center of a big concave mirror, and they drew
an electric current from it. The juice worked the pumps."

"A t'ermocouple!" ejaculated Putz.

"That sounds reasonable; you can judge by the pictures. But the
power-plant had some queer things about it. The queerest was that the
machinery was tended, not by Tweel's people, but by some of the
barrel-shaped creatures like the ones in Xanthus!" He gazed around at
the faces of his auditors; there was no comment.

"Get it?" he resumed. At their silence, he proceeded, "I see you don't.
Leroy figured it out, but whether rightly or wrongly, I don't know. He
thinks that the barrels and Tweel's race have a reciprocal arrangement
like--well, like bees and flowers on earth. The flowers give honey for
the bees; the bees carry the pollen for the flowers. See? The barrels
tend the works and Tweel's people build