They were bound hand and foot. At a piping cry from the leader, several of the gangling figures picked them up in reedy arms and began to walk across the square, away from the ship. Brand noticed that his bearers' arms trembled with his weight: and sensed the flabbiness of the substance that took the place in them of good solid muscle. Physically these things were soft and ineffectual indeed. They had only the ominous tubes with which to fight.

The eery procession, with the bound Earthmen carried in the lead, wound toward a great building fringing the square. In through the high arched entrance of this building they went, and up a sloping incline to its tower-top. Here, in a huge bare room, the two were unceremoniously dumped to the floor.

While three of the things stood guard with the mysterious tubes, another unbound them. A whole shower of high pitched, piping syllables was hurled at them, speech which sounded threatening and contemptuous but was otherwise, of course, entirely unintelligible, and then the creatures withdrew. The heavy metal door was slammed shut, and they were alone.

Brand drew a long breath, and began to feel himself all over for broken bones. He found none; he was still nerve-wracked from that last terrific shock, but otherwise whole and well.

"Are you hurt, Dex?" he asked solicitously.

"I guess not," replied Dex, getting uncertainly to his feet. "And I'm wondering why. It seems to me the brutes were uncommonly considerate of us—and I'm betting the reason is one we won't like!"

Brand shrugged. "I guess we'll find out their intentions soon enough. Let's see what our surroundings look like."

They walked to the nearest window-aperture, and gazed out on a startling and marvelous scene.

Beneath their high tower window, extending as far as the eye could reach, lay the city, lit by the reddish glare of the peculiar metal with which its streets were paved. For the most part the metropolis consisted of perfectly square buildings pierced by many windows to indicate that each housed a large number of inmates. But here and there grotesque turrets lanced the sky, and symbolic domes arched above the surrounding flat metal roofs.

One building in particular they noticed. This was an enormous structure in the shape of a half-globe that reared its spherical height less than an eighth of a mile from the building they were in. It was situated off to their right at the foot of a vast, high-walled enclosure whose near end seemed to be formed by the right wall of their prison. They could only see it by leaning far out of the window; and it would not have come to their attention at all had they not heard it first—or, rather, heard the sound of something within it: for from it came a curious whining hum that never varied in intensity, something like the hum of a gigantic dynamo, only greater and of a more penetrating pitch.

"Sounds as though it might be some sort of central power station," said Brand. "But what could it supply power for?"

"Give it up," said Dex. "For their damned shock-tubes, perhaps, among other things—"

He broke off abruptly as a sound of sliding bolts came from the doorway. The two men whirled around to face the door, their fists doubling instinctively against whatever new danger might threaten them.