fall, into the lagoon.
Each pipe was lighted in the interior, and each was full of people,
heads almost touching feet, unconcernedly being borne along, completely
immersed in that mad current. As the passenger saw daylight and felt the
stream begin to drop, he righted himself, apparently selecting an
objective point, and rode the current down into the ocean. A few quick
strokes, and he was either at the surface or upon one of the flights of
stairs leading up to the platform. Many of the travelers did not even
move as they left the orifice. If they happened to be on their backs,
they entered the ocean backward and did not bother about righting
themselves or about selecting a destination until they were many feet
below the surface.

"Good heavens, Dick! They'll kill themselves or drown!"

"Not these birds. Notice their skins? They've got a hide like a walrus,
and a terrific layer of subcutaneous fat. Even their heads are protected
that way--you could hardly hit one of them enough with a baseball bat to
hurt him. And as for drowning--they can out-swim a fish, and can stay
under water almost an hour without coming up for air. Even one of those
youngsters can swim the full length of the city without taking a
breath."

"How do you get that velocity of flow, Carfon?" asked Crane.

"By means of pumps. These channels run all over the city, and the amount
of water running in each tube and the number of tubes in use are
regulated automatically by the amount of traffic. When any section of
tube is empty of people, no water flows through it. This was necessary
in order to save power. At each intersection there are four stand pipes
and automatic swim-counters that regulate the volume of water and the
number of tubes in use. This is ordinarily a quiet pool, as it is in a
residence section, and this channel--our channels correspond to your
streets, you know--has only six tubes each way. If you will look on the
other side of the channel, you will see the intake end of the tubes
going down-town."

Seaton swung the visiplate around and they saw six rapidly-moving
stairways, each crowded with people, leading from the ocean level up to
the top of a tall metal tower. As the passengers reached the top of the
flight they were catapulted head-first into the chamber leading to the
tube below.

"Well, that is some system for handling people!" exclaimed Seaton.
"What's the capacity of the system?"

"When running full pressure, six tubes w