Up Against It - M. J. Locke [147]
Xuan had to assume that the men watching him—and they were watching him, though more out of boredom than suspicion—were familiar with the process of measuring a stroid’s gravity. They had probably taken his students out on other claims.
Here was the tricky part. He had to take care not to deviate too much from what they were accustomed to seeing, while making the gravitometer lie about the stroid’s density—but only if the rock was highly porous. Otherwise, the device had to tell the truth, or the measured gravity would be higher now than when it had first been discovered. This, as a practical matter, wasn’t possible and it would clue his watchers into the fact that he had tampered with the instrument.
According to Xuan’s calculation, a fifty-seven-second period for the pendulum swing would put it at its original density. Anything between fifty-seven and about eighty seconds, he could leave alone. Any more than eighty seconds or more to complete an arc meant the rock had big pores, and he’d have to work fast.
The sun was sinking toward the horizon again. Once down, it would rise behind him again in less than two minutes. Time to act. Xuan drew a deep steadying breath, took his wrench and a large screw bolt from his field kit, and radioed Mills. “We’re almost ready. First I’ll do a calibration, then readjust the machine as needed and take the measurement.”
“All right. Fine,” Mills said. “Jesse, you copy?”
“Roger that,” the pilot replied.
“Report his findings as he receives them.”
“Will do.” The pilot moved over next to Xuan and looked over his shoulder at the device. He again touched a glove to his weapon in a mixture of bellicosity and anxiety. Jesse the pilot was obviously even more nervous than Xuan, who surmised that he was not used to his role as a thug.
Xuan released the pendulum and counted in his head as it arced lazily down: one, cryptocrystalline; two, cryptocrystalline, three … By the time he got to thirty … forty—choi oi! The pendulum had not even reached the halfway point! He stopped the test. His heart knocked insanely against his ribs. Sweat poured down his face and torso. Calm; stay calm.
This rock had to be more than half vacuum. Or ice.
“One last adjustment should do the trick,” he said. His voice quavered. Get it under control. He thought of Jane. Be like rock. He jumped over the table, opened the back of the gravitometer, and wrapped the pendulum wire many quick turns around the bolt. Quickly now, but calmly. Shorten it by half.
Sunrise could occur any second, and he needed to be done with this adjustment before it did. Damn it, Xuan. At this rate you’ll ruin everything, and not just for yourself. Focus! He eyeballed it as best he could, then closed the back of the instrument, as the sun rose again. It’d have to do.
“Time to measure,” he said. He returned to the front of the device, cocked and retriggered the pendulum. As it arc’d downward, on its now-much-shorter arc, he said, “What we are hoping for is a period of substantially greater than fifty-seven seconds. The longer it takes for the pendulum to complete its arc, the more likely we have a good sugar-rock candidate.”
While he talked, the others came over to watch.
“Please!” he snapped, and they all jumped. “Don’t touch the table. You’ll throw off the measurement. It’s a sensitive instrument.”
All of them edged nervously away.
They waited almost twenty minutes—the device required ten full arcs to complete its internal calculation. He counted in his head; it looked as though the average