trike over and try to pick up the frontiers of Savissa."

It was just at dusk that they saw white towers against the sky. They
rose out of the sea as Gerry turned the _Viking's_ blunt nose toward
them--the mighty battlements of a vast city. Closana, who was standing
on deck beside him at the time, rested her hands on the rail and stared
in utter amazement.

"But it isn't possible, Geree!" she gasped, "there isn't any
civilization out there on the islands of the Great Sea!"

"Could it be a mirage?" he suggested. "A reflection of some Savissan
city on the mainland?"

"No." The girl shook her head. "There are no cities of that sort in any
of these lands. Geree--there is something strange here. I do not like
it. There _cannot_ be any city ahead of us there!"

"But there it is!" Gerry said grimly. "We can't all be seeing things.
We'll go closer and get a better look."

It was sunset, the unspectacular Venusian sunset which was simply a
swift lessening of the golden glow from the cloud veiled sky above.
Lights were gleaming from most of the tall buildings of the towering
city as the _Viking_ drove toward it through a quiet sea. Sea birds
swooped low about the ship's wake. The watchers on deck could see the
low shore line of the island on which the city was built. Then they
heard distant bells, pleasant bells that seemed to be chiming a farewell
to the day and a welcome to the night. And then a red light flashed on
top of the tallest building and in an instant the entire city vanished.

* * * * *

One minute the strange city had been clearly visible before them, its
graceful towers agleam with lights as they notched the sky. The next
instant the whole place was gone. There was nothing in sight at all but
a low shoreline. It was as though a thick veil of concealing mist had
been suddenly drawn across between the ship and the city. Only--the air
was clear and without a trace of mist. Gerry walked across to the open
dome of the upper control room.

"Cut rockets!" he snapped. "Get some kind of an anchor overboard. We'll
just stay right here off shore until morning. There's something queer
going on."

Gerry and Steve Brent leaned on the rail together, peering through the
darkness toward the island. Nothing was visible in the faint
phorphor-glow that marked the Venusian night, but they could just hear a
distant singing as of many voices lifted in chorus.

"What do you think happened to the