Captain Smith guided his "guests" down the ladder, and out through the ship's air-lock. They entered an elevator. Three minutes later they stepped off upon the side of the great cylinder that housed the City, and entered a low building with a broad concrete road curving up before it. As they stepped out, it gave Bill a curious dizzy feeling to look up and see busy streets, inverted, a mile above his head. The road before them curved smoothly up on either hand, bordered with beautiful trees, until its ends met again above his head.
The centrifugal force that held objects against the sides of the cylinder acted in precisely the same way as gravity on the earth—except that it pulled away from the center of the cylinder, instead of toward it.
A glistening heliocar came skimming down upon whirling heliocopters, dropped to rubber tires, and rolled up beside them. A young man of military bearing, clad in a striking uniform of red, black, and gold, stepped out, saluted stiffly.
"Captain Smith," he said, "the Prince desires your attendance at his private office immediately with your guests."
Smith motioned Bill and Captain Brand into the richly upholstered body of the heliocar. Bill, gazing up at the end of the huge cylinder with a city inside it, caught sight, for the first time, of the exterior of the Red Rover, the ship that had brought them to the City of Space. It lay just beside the massive machinery of the air-lock, supported in a heavy metal cradle, with the elevator tube running straight from it to the building behind them.
"Look, Brand!" Bill gasped. "That isn't the blue globe. It isn't the ship we fought at all!"
Brand looked. The Red Rover was much the same sort of ship that the Fury had been. She was slender and tapering, cigar-shaped, some two hundred feet in length and twenty-five in diameter—nearly twice as large as the Fury. She was cylindrical, instead of octagonal, and she mounted twenty-four motor tubes, in two rings fore and aft, of twelve each, instead of eight.
Brand turned to Smith. "How's this?" he demanded. "Where is the blue globe? Did you have two ships?"
A smile flickered over Smith's stern face. "You have a revelation waiting for you. But it is better not to keep the Prince waiting."
They stepped into the heliocar. The pilot sprang to his place, set the electric motors whirring. The machine rolled easily forward, took the air on spinning helicopters. The road, lined with green gardens and bright cottages, dropped away "below" them, and other houses drew nearer "above." In the center of the cylinder the young man dextrously inverted the flier; and they continued on a straight line toward an imposing concrete building which now seemed "below."