CHAPTER XVII

THE CARNIVORE

As Forrester mounted higher into the chimney, he worked with ever increasing caution. To allow the rays to break a passage through before everything was ready for joint action with his friends above would be disastrous. Another possible mischance was even more alarming. The ground might cave in prematurely by its own weight, or the weight of somebody passing over it. The result might be to hurl him on to the frail screen below, and through it into the pit.

To guard against such accidents he listened intently at each ascent, before he brushed away the protective dust. Once he thought he heard distant footfalls; another time the sound of running water. He wished that Mackenzie had been more communicative about what he was doing, and what he had discovered; but reflected that if his friend was silent, it was because, with Scotch canniness, he was determined to risk as little as possible, for the sake of all.

He waited patiently for the sign by which he would know when darkness fell in the open. The bone, no doubt, could be dropped only at uncertain intervals, as opportunity offered. Even if he knew that it would be let down precisely at the hour of sunset, he could not be sure of being then on the watch at the cleft, for it was not his duty to enter the inner cavern at all; his secret work there had been done only when guards and prisoners were asleep, and that was probably much later than sunset.

One day, Beresford, just before he had finished his task at the pit, and while Forrester was awaiting him in the outer cavern, noticed a trickle of water running from the inner passage towards him. While he was still looking at it in surprise, wondering where it came from, it was reinforced by a sudden swell, which carried the tiny stream across the floor of the cavern in a direct course for the open pit. By the time it reached the brink it had almost exhausted its energy; but some of it flowed slowly on, and poured over. Instantly there was a terrific explosion, like the bursting of an immense inflated bag, accompanied by a flash of white light which for the moment wholly conquered the green. Beresford was hurled against the wall of the cavern, and when he picked himself up, he saw that the force of the concussion had shut the screen down upon the pit, gripping the gold chain to which was suspended the plate in process of transmutation.

It was all over in a moment; but Beresford had hardly recovered his senses when Forrester came hurrying into the cavern, through the cloud of dust which had followed the explosion, with Wing Wu and the priest in charge hard on his heels.

Forrester had just time to give a word of warning. When the priest arrived, Beresford had sufficient presence of mind to explain in Chinese that while the cover was lifted from the mouth of the pit there had been a loud bang. He did not mention the stream of water; it had now ceased to flow, and though its appearance had amazed him, and in his half-dazed condition he attached no definite meaning to it, he felt instinctively that it had a meaning for himself and his fellow prisoners.

The priest looked puzzled. The dust had set him coughing. He peered through it round the walls, remaining at a discreet distance from the pit, and thus failing to notice the dwindling trickle on the farther side. The atmosphere of the cavern, at all times unpleasant and oppressive, was stifling now. In a few moments everybody was retreating along the passage to the outer cavern, Beresford remaining only to release the chain, draw up the plate, and lower the apparently uninjured screen firmly into its place. The negritos were just bringing in the evening meal.

"Are you hurt?" Forrester asked anxiously.

"Slightly bruised, perhaps; nothing serious."

"What on earth caused the explosion?"

"A trickle of water into the pit. Where it came from----"

"That was the sign!" exclaimed Forrester aloud, knowing that the priest could not understand him. But Wing Wu understood.

"What sign, sir?" he asked eagerly.

"Shall we tell him?" said Beresford.

Forrester hesitated for a moment.

"Not yet," he answered.

Wing Wu sighed, and turned away.

The priest at the entrance was joined by a second, drawn by the noise from the guard-room beyond the lake. They talked together for a few minutes, then the second man departed.

"He will tell the Old Man, no doubt," said Forrester to his companion.

"Yes; things are coming to a crisis. The water was our sign, no doubt. It could hardly have been accidental. Mackenzie must have thrown a bucketful or two through the grating. It is dark outside at about the time of our last meal."

"Do you think the priests suspect us?"

"Who can say what goes on in their Chinese minds? The fellow didn't see the water: that is pretty certain. But I am troubled. In the chimney you heard running water above you, you said?"

"I am almost sure of it--perhaps the stream that runs across the plateau."

"If our chimney pierces its bed, we are doomed. There is not the ghost of a chance for us. The explosion you heard will be as a popgun to a whole Dreadnought armament in comparison with the result if the cavern is flooded. I take it that the water which fell into the pit was instantly decomposed by the rays. Only a little trickled over the brink; yet the explosion was powerful enough to hurl me against the wall. If water pours down in any volume, the whole place will be shattered, and we shall be cremated instantly in one enormous flame."

"Will you go up the chimney yourself presently, and see if I was right?" asked Forrester, aghast at the thought of this cataclysm.

"I will try. Thanks to you I am not nearly so much crocked as I was a few days ago. But we will wait a little longer than usual, to give the priest time to settle down if he is at all suspicious.... You were quite right, by the way, not to let me explain things to Wing Wu. He is so easily hypnotised that he might betray us at the first question. It will be time enough to tell him when our work is done."

Several hours later, they stole into the inner cavern, and when Forrester had placed the cross-bars in position, Beresford mounted the ladder, and climbed laboriously into the chimney from bar to bar. He carried the piece of pointed iron, with which he carefully probed the roof. Withdrawing the implement, he passed his fingers along it from the pointed end downwards.

"We are very near the surface," he called down softly. "You have destroyed all the rock. The iron has gone through two or three inches of clay, and then into loose earth. We can't risk employing the rays again. If the earth above collapsed en masse, it would smash through the screen and carry us with it into the pit. We must bore a hole gradually with the iron."

"What about the water?" Forrester asked.

Beresford listened intently, Forrester standing below with his hand on the ladder.

"Yes," said Beresford at length, "you are right. But it appears to be at one side, not directly overhead. Ah! there are footsteps. Listen!"

They kept absolute silence. The dull thud of footsteps overhead was clearly audible. Forrester looked up at his friend, dimly visible high above him. His attention was so fully concentrated that a slight sound behind caused him to jump round with a sudden start. And there, in the entrance to the cavern, he saw the priest, peering up towards the hole in which the ladder rested.

In after years Forrester often felt a quickening of the pulse as he tried to piece together the confused sequence of events in the next crowded minute. Whether he shouted to warn his companion before the Chinaman swung round and dashed back along the passage, or whether the Chinaman fled first and his cry followed, he could never distinctly recollect. All that he could remember was that, impelled by an instinctive feeling that the priest must be caught and silenced, he sprang like a tiger towards the intruder. Probably the fact was that the priest, being on the alert, had already turned before Forrester dashed after him, for he had a lead of several yards up the narrow passage.

Forrester was the younger and the fleeter of the two. Weeks of life in the mephitic atmosphere of the underworld, indeed, had slackened his muscles and lowered his nervous energy; his wind came short; but at this perilous crisis he seemed to regain all the athletic vigour which had served him so well on the football field in years gone by. When the priest dashed into the outer cavern, Forrester was only a few yards in the rear.

The former, feeling no doubt that he had now desperate men to deal with, rushed straight across to the entrance, where he might expect to find the negrito guards ready to support him. The little men, however, startled out of their wits by a sight which never, in all their years of servitude, had they beheld before, stood like stockfish, gazing amazedly at the two figures swiftly approaching them. When he reached them, the Chinaman appeared to realise instantly that he could place no reliance on men so palsied. He darted between them, turned to the right, and ran as fast as his long robe would allow along the ledge leading to the ward-room on the other side of the lake.

Crossing the cavern Forrester had gained on him. At the entrance he was barely two yards behind. He flashed past the astounded negritos, swung round on to the ledge, came up with his quarry just as he reached the plank bridge, and making a spring forward, caught him round the waist, as he had tackled many a man in pursuit of the oval ball. The Chinaman, however, although less agile, was of heavier build, and by sheer strength and weight he began to haul Forrester along the bridge towards the further ledge, at the end of which his colleague and the negrito guards were already massing.

Forrester clung to him desperately, tried to drag upon him by digging ineffectual heels into the plank; but with the cavern wall on his right, and only two feet of planking to manoeuvre on, he found that inch by inch he was being pulled into the jaws of danger. The Chinaman was clutching at the crazy handrail for purchase in hauling his tenacious grappler along. In a few seconds Forrester must either release him, or fall a captive into remorseless hands. Despair struck a spark in his darkening mind. There was one chance--one, and no more!

Bracing his right leg, he threw the whole weight of the Chinaman and himself against the balustrade. It creaked; there was the snap of breaking timber. Forrester released his man and drew quickly back. The priest fell with a great splash into the green oily waters of the lake.

By this time the startled company at the remote end of the ledge were beginning to advance. A spear whizzed past Forrester's ear. To protect himself, he wrenched away a piece of the broken handrail. With this club he could ward off a missile or crack a skull. Facing the enemy, he retreated with wary footsteps along the bridge. The priest, leading on his negritos, came striding along the ledge, his parchmenty features grimacing with rage.

Forrester was trembling in every limb. The sudden spurt, the muscular strain, had told heavily upon his debilitated body. And again despair seized upon his soul as he realised that his efforts after all had been made in vain. Before long the priest now menacing him would hurry to acquaint the Old Man with this revolt of the prisoners. They would be taken aloft, and then--the Eye!

But all speculation was suddenly shocked out of his mind by a tragic sequel, unlooked-for, terrible.

The Chinaman was still floundering beneath the bridge.

Swift and silent, from out the sombre spaces of the lake there slid a something huge and hideous--a Shape. A glint of greenish light in cruel eyes; a flash of gleaming teeth in jaws like those of a mammoth dog-fish; a shriek of terror and despair; then silence, and a slow heaving of the waters. The Monster had claimed his ancient right!