Brent still held the stone in air and his thoughts of hidden treasure vanished at the horrible spectacle below him. Should he drop the stone upon the enraged reptile? Suppose it should not fall right? And how long would this frightful thing, hated by man and bird and beast--how long would it wait? It was angry at the flashlight, not at Brent. But if Brent moved, stirred ... And, meanwhile, the seconds passed. A crumbling bit of plaster fell. The hissing continued. The little ball of light burned brightly and cast a luminous circle on the dank, oppressive débris. Six, seven, eight seconds. And Brent Gaylong did not stir--not a hair. He stood like a statue. But his blood was cold. Nine, ten, eleven seconds. We are all subject to insane impulses. Who has not felt the impulse to jump off a roof? For a moment Brent was in the spell of a strange impulse to stoop leisurely, lay down the stone and pick up his flashlight. But he did not do that. He did not budge. He still held the stone above his head, like a piece of Roman statuary. The reptile did not budge either, but he rattled and hissed, and his tongue darted like lightning. And meanwhile the seconds passed--twelve, thirteen, fourteen.... CHAPTER XV—The Trap Now something happened, trivial and barely perceptible, but it relieved the frightful situation of the moment. The flashlight flickered; it was less than a flicker; a scarcely visible flutter of the light for the fraction of a second. But the alert reptile projected its head like lightning. Its appalling rattle sounded in the hollow shaft; it hissed and its tongue darted. Brent Gaylong knew what that suggestion of a flicker meant; he had tinkered often enough with the defective connection in that troublesome flashlight. Should he cast the stone down on the horrible thing’s head? Suppose he should miss? Again the light flickered. Fortunately, that hideous, flat head was in the circle of brightness cast by the flashlight. It was poised menacingly a few inches above a flat bit of rock. Like lightning, Brent raised his right foot and planted it on the reptile’s neck. He had intended to crush the head but missed it, and there was the dreadful writhing thing pinned down but not killed. Though Brent’s foot had missed its mark and left him in a terrible predicament, still, the move had been well considered. Considering all the chances, it was better than casting down the rock.