The three men watched the light breathlessly. At first it seemed steady, but now it began to waver slowly this way and that way, like a warning hand admonishing or threatening, a spiritual hand beckoning or blessing. It was not crimson, as the other flame had been, but pale yellow, like the early east. It was not fierce and dazzling, but lambent and soft. It was not light in darkness, as a zenith moon, but light against darkness, as a setting star. It was independent, absolute, taking or giving nothing. Space lay between it and the eyes that saw; infinity between it and the sightless vault. There was something in this cave that killed you, and yet in that place you must not die. "Heaven be merciful to us!" whispered a human voice. "To us," whispered the phantom voice against the men's hair. "It's the corpse-candle of the dead men of the Black Rock," whispered Phelan. "Of the Black Rock!" echoed the spirit. The words "Black Rock" acted like a charm, and broke the terrible spell of the place. Never before had the name of that fatal and hated shelf of land sounded grateful to human ears. The two boatmen had been often in that stupendous cave before, had seen its colossal glories in the ruby flare, and heard its reverberating thunders in the inexorable gloom. But never until now had they gazed upon this weird light; they were certain that if it had existed when they had been visitors on other occasions they could not have missed observing it. What they now saw made a profound impression on them, and powerfully excited their superstitious minds. They had never rowed to the end of that eastern shaft of the labyrinth, but they knew from the sharp turn it struck west, and the great depth to which it penetrated, that the onward limit of it must be near the rear of the Black Rock. This filled them with doubt--uneasy doubt. Owing to the darkness and the nature of the remote light, they could not form an exact notion of its position, but they guessed it to be no less than a mile from the Red Gap, and, allowing for everything, that would be the back of the Black Rock. Why should there be a light at the back of the Black Rock? How could a light be accounted for there? except it was a corpse-candle on that murderous reef. It was a thought to shudder at. With the other two men the effect was wholly different. Neither had ever been in this marvellous place before; neither had seen its sights, or heard its sounds, or endured its darkness until now, and their imaginations had been powerfully excited and exercised. At one time they were exalted by the visible--at another overawed by the unseen. Sobriety of thought and familiarity of experience were absent, and they were face to face with things undreamed of and enormous, and with phantoms and monstrous ideas that baffled investigation and pursuit.