one hand and upon the other the sun, which changes appreciably only in
millions upon millions of years. In equilibrium at last--with our bodily
and atmospheric temperatures finally constant at their present values,
which seem as low to you as yours appear high to us. Truly, an evolution
astounding to contemplate!"

"But how about power?" asked Stevens. "You seem to have all you want,
and yet it doesn't stand to reason that there could be very much
generated upon a satellite so old and so cold."

"You are right. For ages there has been but little power produced
upon Titan. Many cycles ago, however, our scientists had developed
rocket-driven space-ships, with which they explored our neighboring
satellites, and even Saturn itself. It is from power plants upon Saturn
that we draw energy. Their construction was difficult in the extreme,
since the pioneers had to work in braces because of the enormous force
of gravity. Then, too, they had to be protected from the overwhelming
pressure and poisonous qualities of the air, and insulated from a
temperature far above the melting point of water. In such awful heat,
of course, our customary building material, water, could not be
employed...."

"But all our instruments have indicated that Saturn is _cold_!" Stevens
interrupted.

"Its surface temperature, as read from afar, would be low," conceded
Barkovis, "but the actual surface of the planet is extremely hot, and
is highly volcanic. Practically none of its heat is radiated because of
the great density and depth of its atmosphere, which extends for many
hundreds of your kilometers. It required many thousands of lives and
many years of time to build and install those automatic power plants,
but once they were in operation, we were assured of power for many tens
of thousands of years to come."

"Our system of power transmission is more or less like yours, but we
haven't anything like your range. Suppose you'd be willing to teach me
the computation of your fields?"

"Yes, we shall be glad to give you the formulae. Being an older race, it
is perhaps natural that we should have developed certain refinements as
yet unknown to you. But I am, I perceived, detaining you from your time
of rest--goodbye," and Barkovis was wafted back toward his mirrored
globe.

"What do you make of this chemical solution blood of theirs, Steve?"
asked Nadia, watching the placidly floating form of the Titanian
captain.

"Not much. I may have mention