XIV
"Leave the fire alone," Charles said sharply to Kennedy. The little man was going to douse it for the night.
There was a flash of terrified sense: "They beat you. If the fire's on after dark they beat you. Fire and dark are equal and opposite." He began to smile. "Fire is the negative of dark. You just change the sign, in effect rotate it through 180 degrees. But to rotate it through 180 degrees you have to first rotate it through one degree. And to rotate it through one degree you first have to rotate it through half a degree." He was beaming now, having forgotten all about the fire. Charles banked it with utmost care, heaping a couple of flat stones for a chimney that would preserve the life of one glowing coal invisibly.
He stretched out on the sand, one hand on the little heap beneath which five pounds of smokeless powder was buried. Kennedy continued to drone out his power-series happily.
Through the chinks in the palisade a man's profile showed against the twilight. "Shut up," he said.
Kennedy shivering, rolled over and muttered to himself. The spearman laughed and went on.
Charles hardly saw him. His whole mind was concentrated on the spark beneath the improvised chimney. He had left such a spark seven nights running. Only twice had it lived more than an hour. Tonight—tonight, it had to last. Tonight was the last night of the witch-girl's monthly courses, and during them she lost—or thought she lost, which was the same thing—the power of the goddess.
Primitive aborigines, he jeered silently at himself. A life time wasn't long enough to learn the intricacies of their culture—as occasional executions among them for violating magical law proved to the hilt. His first crude notion—blowing the palisade apart and running like hell—was replaced by a complex escape plan hammered out in detail between him and Martha.
Martha assured him that the witch girl could track him through the dark by the power of the goddess except for four days a month—and he believed it. Martha herself laid a matter-of-fact claim to keener second sight than her sister because of her virginity. With Martha to guide him through the night and the witch-girl's power disabled, they'd get a day's head start. His hand strayed to a pebble under which jerked venison was hidden and ready.
"But Martha. Are you sure you're not—not kidding yourself? Are you sure?"