alternated with another, a
stone of intense blue. They were hard, and the colors made a very
striking pattern, pleasingly different from what they had been
accustomed to, but common to Venus, as they later learned.

At last the party had crossed the great hall, and stopped beside a large
doorway. The officer halted for a moment, and gestured toward two of his
men, who remained, while the others walked quickly away. The diminished
party stepped through the doorway into a small room whose walls were
lined with copper, and an instant later, as the officer pushed a small
button, there was a low hiss of escaping air, and a copper grating
sprang quickly up across the opening of the elevator. He touched another
button, and there was the familiar sinking feeling as the car rose, a
low hum seeming to come from its base.

The elevator rose swiftly through a very considerable distance--up--up,
endlessly.

"They must have some wonderfully strong cables here on Venus!" Morey
exclaimed. "The engineers of Terrestrial buildings have been wondering
for some time how to get around the difficulty of shifting elevators.
The idea of changing cars doesn't appeal to me, either--but we must have
risen a long way!"

"I should say so--I wonder how they do it. We've been rising for a
minute and a half at a very fair clip--there we are; end of the line--I
want to look at this car!" Arcot stepped over to the control board,
looked at it closely, then stepped out and peered down between the car
and the shaft as the copper grating fell, simultaneously pulling down
with it the door that had blocked off the hallway.

"Come here, Morey--simple system at that! It would be so, of course.
Look--they have tracks, and a regular trolley system, with cog rails
alongside, and the car just winds itself up! They have a motor
underneath, I'll bet, and just run it up in that way. They have never
done that on Earth because of the cost of running the car up without too
much power. I think I see the solution--the car has electro-dynamical
brakes, and descending, just slows itself down by pumping power into the
line to haul some other car up. This is a mighty clever scheme!"

As Arcot straightened, the officer beckoned to him to follow, and
started down the long corridor which was lined on either side with large
doorways, much like a very exotic earthly office building. Passing
through a long series of branching corridors they at last reached one
that terminated