tip of one claw, and began squeezing the fluid on to the wall in a slow, painstaking fashion. As Rakesh manoeuvred himself into a better vantage point, he saw that a complex pattern of intersecting lines was already present, marked on the wall with a thinner, paler version of the bladder’s dark contents. Line by line, this Arkdweller was repainting a faded sign.
Parantham caught up with him, then hovered beside him, watching in silence. When the signwriters had finished the two travelers remained, gazing at the strange symbols.
16
Zak called out, “Just a few more spans, and I’m there!”
He sounded exhausted, but utterly determined to complete the arduous climb. Roi circled anxiously around the edge of the crack. When she’d helped him up to the entrance, he’d struggled to maintain his hold on the steep, jagged surface, and she had doubted that he would make it all the way through the outer wall. She had underestimated his reserves of strength. He hadn’t taxed himself needlessly on the journey; he hadn’t even forced himself to stay awake to make polite conversation with his bearers when he’d felt like resting instead. He had been saving everything for this moment, and now it seemed that his strategy was about to prove its worth.
The light machine stopped chugging but it was out of reach, so Roi left the darkness undisturbed. On Zak’s instructions she and Ruz were clinging to the ceiling, the idea being that if whatever had killed those who’d ventured out before was present in the void as well as the Incandescence, they would be less exposed to it here than anywhere on the floor nearby. In fact, as Roi had helped Zak into the entrance, she had seen by the glow of the light machine that the crack was twisted in a way that allowed no direct line of sight. Still, during the shomal dark phase some light from the Incandescence had nonetheless made its way right down to the floor, so she couldn’t fault Zak’s logic.
Zak exclaimed suddenly, “I’m outside!” A moment later he added, “There’s an arc of light. I don’t understand this.”
“An arc?” What did he mean? “Zak?”
There was a long silence, then he replied in a labored voice, “I need to take some measurements. I’ll explain everything when I get back down.”
“All right.” Roi was desperate to hear exactly what he’d witnessed, but she knew it was unfair to expect a running commentary. Zak didn’t have much time, and he needed to concentrate on setting up the instruments and collecting the crucial data.
Whatever else there might be to discover in the void, the one possibility in which they had invested the most hope—and planning—was that Zak would be able to locate a distant object that he could track for a while, in order to obtain an independent measurement of the Splinter’s motion. From inside the Splinter, there were really only two distinct numbers that could be measured: the ratio of the garm-sard and shomal-junub weights, and the ratio between the periods of the shomal-junub cycle and the turning of the plane of the Rotator’s spinning bar. Those numbers were in agreement with Zak’s principle, but beyond that they revealed nothing about the geometry through which the Splinter was moving. If the simple geometry that the team had found in their calculations was the right one, then the time it took the Splinter to orbit the Hub would be identical to the period of the shomal-junub cycle. If all orbits at a given distance from the Hub were the same, regardless of their angle of inclination—the assumption of symmetry on which the simple geometry was based—then a stone moving shomal and junub of the Null Line would take the same time to complete its orbit as the Splinter itself, and so it would return to its greatest distance shomal of the Null Line after exactly one orbit for both.
How could you mark a fixed point on an orbit, though, in order to measure the time it took to return to it? The idea that two orbits at an angle to each other always intersected at the same two points was the very assumption they were trying to test, so it could not provide the signposts. The only method anyone on the team had been able to come up with was to rely on a different assumption—that objects far from the Hub moved on slower orbits—and then to hope that, with the Incandescence out of the way, it would be possible to observe something in the void so distant that it was as good as fixed. The apparent motion of that distant beacon would then be due—in the most part—to the Splinter’s motion around the Hub.
While Roi had paced, Ruz had been still, but now she heard him shifting, consulting his clock. “Zak?” he called. “It’s halfway through the dark phase!”
A few heartbeats passed, then the reply came back, “I know.”
Roi said, “We should have tied a rope around him. Then if he cut it too fine we could have just dragged him down.”
Zak hadn’t taken the light machine, because of its weight, but they had never imagined that such a device would be available. Ruz had made three clocks that could easily be read by touch, and Zak had practiced in total darkness setting up the most important instrument, the one that would allow him to measure the passage of an object across his field of view. Once that was in place, then so long as there was a beacon worth aiming at, he only had to be able to time the moments when it passed behind a series of metal wires. However dim or bright an object might be, whatever the color of its light, you always knew when it passed behind metal.
“An arc of light?” Roi said. “Do you know what that could be?”
“No,” Ruz replied. “But be patient. We’ll have the whole journey back in which to interrogate him. In fact, we should extract every detail and write it all down, so if the Splinter sinks back into the Incandescence and never leaves it again, we’ll have a record of what lies beyond.”
Roi struggled to imagine what it could be like, looking out into the void. “If the Splinter really did break in two, long ago, do you think we could ever find the other half? Ever see it, even if we couldn’t reach it?”
Ruz pondered the question. “It’s hard to know how far away its orbit might be. Until we know,
Roi waited for his reluctant assent.
There was nothing.
“Zak?” She pressed her body against the rock, straining to hear anything, a word or a footstep. “
She climbed up into the mouth of the crack. “I’m going up there. Something’s happened to him, I need to bring him back.”
Ruz said, “If the void’s harmed him, it will do the same to you.”
“You know what his health is like! He’s been sick even back at the Null Line. The effort of the climb would have been enough to weaken him.”
“When we planned this trip,” Ruz insisted, “we all agreed that only Zak would take the risk—”
Roi seethed with frustration. He was right, they had agreed, but she didn’t care. She said, “I’m not going to waste time arguing.”
She clambered up the inside of the crack as quickly as she could, forcing herself to ignore the instinctive urge to feel her way slowly through the darkness. The rock was sharp in places, and slippery with weeds, but she kept her footing, and kept advancing. She didn’t try to judge the distance or the passage of time, she just willed herself forward.
When a hint of light appeared ahead, she made no effort to make sense of it. Moments later, she tumbled on to the surface of the Splinter.
A band of light was wrapped across the blackness of the void, an arc that stretched from a point high above the rock and swept around a quarter-circle before the Splinter interrupted it. The color of the light varied smoothly across the band from inner to outer rim; within it, small points of brightness slowly drifted, changing color as they moved. Roi looked away; the spectacle was baffling and hypnotic, but this was not the time to sink into the morass of questions that it posed. The illumination it cast on the rock around her was weak and shallow, barely more than that cast by the light machine, but she had no trouble spotting Zak.
