He built up the fire again. His stock of fuel was dwindling. He opened one of his bundles, ate some cheese and drank from the jug. The box, which had been in the same bundle, lay on the floor of the basket at his feet.
"Box," he said, "how much farther is it to the cavern you showed me?"
"It is less than ten ells."
As the box spoke, Thorinn became aware of a red glow, like the glare from an oven at night but much dimmer and darker. Seized by fear, he was at the edge of the basket ready to leap out before he mastered himself. There was no heat in the steady red glare; he felt nothing when he held out his hand to it. "Box, why is it red?" he called.
"It is red because the engines see by red light."
Now, as the bladder rose, he could see the rim of the shaft, with unfamiliar tall shapes beyond it. He strung his bow, made sure the sheaf of arrows was lying ready to hand. Now the lip of the shaft dropped away, and he saw that they were rising through a vast red-lit gulf in which a confusion of tall ovoid shapes rose one on another, with slender pedestals between them. Here and there were dots of brighter red, some so distant that they were like grains of dust. In the sullen gloom the walls and ceiling of the cavern were invisible; he could not rid himself of the conviction that he was in a great furnace, about to crisp and burst into flame. "Box, how high is this cavern?"
"It is seventy ells high."
"And the shaft goes straight through it?"
"Yes, Thorinn."
Now, as his eyes grew more accustomed to the dimness, he saw a distant movement through the aisles between the columns; a red eye winked on. It was coming closer. He reached for the box, turned it.
"Box, what is that?"
"It is an engine."
"What sort of engine?"
"It is an engine that tends other engines."
Now he could see the spidery shape behind the light, looming nearer. Another red eye winked on in the distance, then another. The first engine was so near that he could see its skeletal arms outstretched, the sheen of something round and water-bright in its belly. He felt a sudden chill around his ankles, and looked down to see that the yellow flames of his fire had magically vanished. Even the embers were not alight; there was nothing but blackened wood and sullen red ash. Incredulous, he passed his hand over the charred sticks, then touched them. They were as cool as if the fire had gone out days ago.
"Box!" he cried.
"Here am I."
But he had no time for questions. The second and third engines were soaring past the bladder; the first had disappeared below. He felt a jolt, and the bladder dipped toward the nearest columns; another, and it moved again. He leaped to the other side of the basket, and saw that two engines were pushing the bladder above, half visible beyond its bulge. Another jolt, and a hiss; the bladder was moving, dropping. Thorinn leaned over the edge of the basket and saw the shaft below drifting away out of reach. "Box!"
"Here am I."
Feverishly Thorinn piled tinder and kindling under the dead fire, got out his fire stick, saw the yellow flames curl up. After a moment there was another wave of cold, and the flames vanished. He turned to see an engine soaring by, no more than two ells away.
Trembling with fear and anger, he seized an arrow, nocked it, let fly. He saw the arrow strike fair in the center of the engine, saw the pitch-smeared cords spring out and wrap themselves around it. He heard a shriek and a clatter; the engine drifted away aslant between the columns. Another jolt came, and another. Thorinn nocked an arrow, fired at one of the engines above. He saw the pitch burst on the tail of the engine, but nothing more happened. The bladder was still drifting steadily downward away from the shaft; now it was passing between two columns of the tall shapes that stood one above another like gigantic beads on a wire. A hundred ells away, the forest ended and he glimpsed a broad open space with other shapes beyond it.
Thorinn slung his bow over his shoulder, seized two arrows and put them between his teeth. He sprang for the rigging, pulled himself up along the fat bulge.
Now he could see the two engines with their noses against the bladder, and the water-bright disks in their bellies. He jammed his foot under one of the cords of the rigging, forced his bow arm under another, and took aim at one of the engines. He struck it as he had the other, heard it shriek. Slowly it tilted, came drifting down. In the dazzle of its red eye, he saw the spidery arms reaching for him, saw the round place in its belly no longer a bright disk but four curved blades like the petals of a flower, tangled and still. He drew his sword, struck at the reaching arm, heard a clang. The engine, slowly tumbling, passed on.
Thorinn put his sword away, nocked another arrow, and shot the third engine. It died in its turn, drifting downward, its spidery arms vainly reaching. In the silence, he heard the hiss of escaping air above. He climbed higher to look, and found two long rents in the fabric; the bladder around them was crinkling, collapsing. Filled with fury, he climbed down to the basket again. He gave the box one burning glance, but did not speak to it. He tore open a bundle, found his patches, stuffed a handful of them into his belt. He dropped the bow, seized his pitch-pot and brush, and sprang up through the neck of the bladder. In the stifling red dimness, he pulled himself up by grasping folds of the bladder, found the first hole. Gripping the handle of the pitch-pot between his teeth, he dipped his brush, painted the edges thickly, then got a patch from his belt and pressed it over the rent. He climbed higher, dealt with the other hole in the same way, then lowered himself again and dropped into the basket. Below, one of the engines was drifting into the stem between two of the tall ovoids of a column. It struck with a distant clang, rebounded, slowly tumbled in the air, and resumed its gradual motion toward the floor of the cavern.
Thorinn lighted his fire again. The flames flickered up yellow, spread, caught. But the bladder had already passed through the metal forest and was slowly settling into the open space. What was to be done now? The only way to get back to the shaft was to descend and go afoot, dragging the bladder after him. He separated the burning sticks a little; the bladder continued its gentle descent. At length the basket touched the floor, scraped a little, and was still. Thorinn stepped out of the basket; relieved of his weight, it began to rise. Thorinn caught the trailing cord and felt its tug lift him almost but not quite off his feet. To be safe, he knotted the cord around his waist, but when he tried to walk, he found that his feet had no purchase on the floor; the most he could do was to hop straight upward, whereupon the bladder ponderously bobbed upward, too, then as gradually settled.
While he was puzzling over this, the shapes beyond him caught his eye. At a little distance there were four slender curving tracks of pinkish metal suspended high in the air; in the red gloom, they seemed to be aimed at two cavernous doorways in the wall beyond. Along the wall, past the metal tracks, he could make out lines of bulbous objects like metal eggs, as big as the bladder. As he watched, an egg detached itself from the row, was lifted to one of the tracks, and disappeared rapidly into a doorway. Presently another egg emerged from the other doorway in a cloud of steam, traveled along another track, and moved out of sight. Whatever these things were, they seemed to be paying no attention to him. He turned away and stared out over the tops of the forest of columns. The best thing, perhaps, would be to build up his fire again, rise to the top of the cavern, then discharge one of his arrows at the ceiling with a cord tied to it. If the pitch held, he could draw the cord in and thus pull the bladder along; then pull the arrow free, shoot it again, and so on... Out there, where the opening of the shaft must be, a tiny dot of red had winked into being. It drifted a little, then hung steady; but now he saw that it was growing brighter. It was coming toward him, and it was moving too fast to be one of the little engines he had slain. Thorinn climbed hurriedly into the basket. "Box," he said bitterly, "what is that engine?"