"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 will handle five thousand people a minute. It is only very rarely, on such occasions as this, that they are ever loaded to capacity. Some of the channels in the middle of the city have as many as twenty tubes, so that it is always possible to go from one end of the city to the other in less than ten minutes."
"Don't they ever jam?" asked Dorothy curiously. "I've been lost more than once in the New York subway, and been in some perfectly frightful jams, too—and they weren't moving ten thousand people a minute either."
"No jams ever have occurred. The tubes are perfectly smooth and well-lighted, and all turns and intersections are rounded. The controlling machines allow only so many persons to enter any tube—if more should try to enter than can be carried comfortably, the surplus passengers are slid off down a chute to the swim-ways, or sidewalks, and may either wait a while or swim to the next intersection."
"That looks like quite a jam down there now." Seaton pointed to the receiving pool, which was now one solid mass except for the space kept clear by the six mighty streams of humanity-laden water.
"If the newcomers can't find room to come to the surface they'll swim over to some other pool." Carfon shrugged indifferently. "My residence is the fifth cubicle on the right side of this channel. Our custom demands that you accept the hospitality of my home, if only for a moment and only for a beaker of distilled water. Any ordinary visitor could be received in my office, but you must enter my home."