Then something soughed past him. A whispering—dim, distant, fainter than a breath. Before him, like heat-waves in the air, a shimmer swept across the tunnel-mouth.
Instantly all sound ceased. Raft's ears rang with the dead, intense silence. He reached out into empty air, and it was not empty.
Across the mouth of the tube stretched the same glass-smooth barrier that were walls and roof and floor to him. The doorway was closed. The gate—the Gate to Paititi?
A trap? Had Pereira set this snare?
Raft patted the stock of his rifle. All right, a trap, then. But he wasn't exactly unarmed. He'd go ahead, since that had been his intention anyway. Only he would not go it blind. He would be ready.
There was no sign of the jaguar. He put the pack on his shoulders and started walking. The footing was smooth, but not slippery. Something seemed to hold his feet down. This wasn't glass. It was, perhaps, a force-field, an invisible screen of pure energy. Da Fonseca had spoken of the unseen road.
Check.
He hiked on, across the clearing, into the forest, not letting himself wonder too much yet. There was plenty to mink about. Raft had long ago learned the trick of shutting his mind to thoughts which he was not yet ready to entertain.
He had closed his mind time after time in these twenty days to one recurring vision—the gay, solemn, radiant face of the girl in the mirror, seen impossibly in one glance, and never to be forgotten.
It was not exactly a path. Had Raft not known that he walked in a tunnel, and had it not been for the utter, dead stillness, there would have seemed no reason for alarm. The jungle still rose solid and shadowy about him.
Butterflies fluttered brilliantly past. Birds trailed their fantastic plumage through the leaves. Now and then a cloud of tiny stinging puims blew past outside the stuff that was not glass.
Magellan, very long ago, had written of Brazilian trees that gave soap and glass, distorted versions of the hevea that flows rich latex. There was often truth in legends. The Seven Cities of Cibola—they were real, even though they had never been paved with gold.
Vespucci, Raft recalled from some dark cranny of memory, had mentioned a Lake Doirada, somewhere in the sertao, with shining cities on its banks. And the kingdom of Paititi, that da Fonseca had spoken of. In the old days bands of mamelucos had gone out on more than one expedition to find Paititi.
He could recall only fragmentary scraps. Paititi, where some of the natives were dwarfs and some were giants, some had their feet turned backwards, and others had legs like birds. The usual legendary yarns.
Nobody had ever found Paititi.
Raft got the torch out of his pack. The path had been sinking deeper and deeper below ground level. Now, a few yards ahead, the black depths of a tunnel loomed. The tube .was plunging underground. It was impossible to keep one's footing on that breakneck slant, and Raft advanced very cautiously, wondering how Pereira and Craddock had managed it.
The light stabbed out. There was nothing to see but the compressed earth walling him in. The tunnel angled down steeply. Too steeply. Raft realized abruptly that he had gone too far. Something had tricked him, a shifting of balance, a—a warping of gravity, it seemed. For, he realized unmistakably, an unknown force was keeping him upright as a fly keeps its footing on perpendicular walls.
For an instant giddiness made his head swim. This ramp was not perpendicular, of course, but he had no suction cups on his feet. Nevertheless he maintained his balance on a slope of at least forty-five degrees.
Pure energy, he thought. Walls of force!
He went on down, though now he had no way of telling whether he was climbing or descending. Only logic showed that, since it was dark, he was probably going deep into the earth.
Then, after a long time, came a sudden change. Light glowed curiously from around a curve ahead. Dim light, more like a darkness alive with twisting, coiling refractions. Raft went on warily.
It was water.
It went over and around the tunnel in a smooth, swift, glassy current, foam-marbled, perfectly silent, gleaming in the beam of the torch.
Raft thought, The Children of Israel went upon dry land in the midst of the sea, and the waters were a wall unto them.
Still another miracle occurred on a journey beginning to be laden with miracles. Raft's jaw set a bit harder. He went ahead, vaguely hoping that what had happened to the Egyptians wouldn't happen to him. If that wall should break, it would be unfortunate.
The wall did not break. He went forward into a long period of blackness, broken only by the light beam. He was, he realized, very far down now. For all he knew he might be descending a completely perpendicular path, the warped gravity of the tunnel making such a fantastic descent possible.
A faint glow warned him to switch off the light. Darkness closed in, but it did not last for long. His eyes adjusted them-selves to a dim violet glow that seemed to come from all sides, above, below, everywhere. Vertigo made Raft's head spin sickeningly.
Far, far below him, but at an impossible, angle, seen slantingly through the transparent floor, was the jagged curve of an immense cavern.
In a moment more logic asserted itself and the vertigo grew even worse, for Raft saw now that it was he himself who stood at that incredible angle, not the apparently tilted cave. It was bathed in faint violet light. The walls were crags, the roof, high above, dripped with stalactites that glittered wanly in the dimness.
The cave was narrow and curved right and left out of sight. The tunnel swept down in a dizzying arc and vanished into a spot of darkness in a distant wall. Raft knew that he should be totally unable to keep his footing on that tremendous slide. But as he advanced gingerly on the invisible flooring, it seemed the cavern and not himself was defying gravity.
Far down in the violet darkness something moved. Something alive. Raft could not see it clearly. Beyond it was another motion, and up among the crags of the walls, still more motion. The high, narrow, violently tilted cavern was coming alive all around him with those moving shadows which converged upon him as he stood frozen there in midair.
Devils of Paititi!
Biologically they were impossible. He could see only their outlines, but there were shadows that looked like wings—and great talons—and—and other things. No two of them were alike. The logic of anatomy had gone wrong, somehow, and Raft's mouth felt dry and sour.
They had seen him, obviously. They were moving sluggishly toward him, with a slowness more disturbing than any speed—as if they knew they could afford to take their time.
A shudder shook Raft. Though he knew that Pereira and Craddock had come this way, suddenly his footing did not seem so secure on that airy bridge. He had the sensation of toppling on the brink of a pit thronging with monsters from pure nightmare. If there were a break in this tunnel of glass, disaster would overwhelm him.
Biological sports, he told himself, and went on.
Ten minutes further along the dark tunnel he came to a fork of the way, the first one he had encountered. There was no clue as to which way he should turn. At random Raft took the right-hand branch, and this time luck was with him.
The ending of the tunnel was an anti-climax. He saw the circle of light long before he reached it. It was a deep, clear radiance which seemed to block the passage. Another force-wall, Raft thought, like the substance of the tube itself. But it was different in that it reflected light, or glowed with a cool brilliance of its own.
He touched the smooth glossy surface of it. Nothing. Simply light made tangible. Light that was, he saw, growing paler as he watched.