ighest speed he could use and
still hold the beam.

"I'd like to be up above watching us. I bet we're making the water boil
behind us," remarked Dorothy.

"Yeah, we're kicking up quite a wake, I guess. It sure takes power to
drive the old can through this wetness."

"Slow down!" commanded Crane. "I see a submarine ahead. I thought it
might be a whale at first, but it is a boat and it is what we are aiming
for. You are constantly swinging with it, keeping it exactly in the
line."

"O.K." Seaton reduced the power and swung the visiplate over in front of
him, whereupon the detector lamp went out. "It's a relief to follow
something I can see, instead of trying to guess which way that beam's
going to wiggle next. Lead on, Macduff--I'm right on your tail!"

The _Skylark_ fell in behind the submersible craft, close enough to keep
it plainly visible in the telescopic visiplate. Finally the stranger
stopped and rose to the surface between two rows of submerged pontoons
which, row upon row, extended in every direction as far as the telescope
could reach.

"Well, Dot, we're where we're going, wherever that is."

"What do you suppose it is? It looks like a floating isleport, like what
it told about in that wild-story magazine you read so much."

"Maybe--but if so they can't be fish," answered Seaton. "Let's go--I
want to look it over," and water flew in all directions as the _Skylark_
burst out of the ocean and leaped into the air far above what was in
truth a floating city.

Rectangular in shape, it appeared to be about six miles long and four
wide. It was roofed with solar generators like those covering the island
just visited, but the machines were not spaced quite so closely
together, and there were numerous open lagoons. The water around the
entire city was covered with wave-motors. From their great height the
visitors could see an occasional submarine moving slowly under the city,
and frequently small surface craft dashed across the lagoons. As they
watched, a seaplane with short, thick wings curved like those of a gull,
rose from one of the lagoons and shot away over the water.

"Quite a place," remarked Seaton as he swung a visiplate upon one of the
lagoons. "Submarines, speedboats, and fast seaplanes. Fish or not,
they're not so slow. I'm going to grab off one of those folks and see
how much they know. Wonder if they're peaceable or warlike?"

"They look peaceable, but you know the proverb," Crane cautioned hi