Harry lay quite still; fear at last possessed him. The loud report of his revolver was still singing in his ears; and, before silence reigned again, it was as if the whole place, even the very walls, were possessed of life.

Dark shadows were moving everywhere. All about the boy were yellow, staring eyes, that dilated and grew smaller in the darkness. And then Harry became conscious of a fierce, growling sound.

As far as he was able to make out, this proceeded from the largest pair of eyes, immediately before him. And it was this that gave him the first inkling as to the solution of the mystery: he had crept into a den of savage beasts.

The largest pair of eyes drew nearer, and suddenly dropped lower, almost to the level of the ground. The brute was about to spring.

There was a snarl. As quick as lightning Harry sprang aside.

The great beast collided with the wall with such force that the roof-or as much of it as remained-came down with a crash upon the ground, and Harry found himself buried in a mass of debris and dust.

He tried to move, but found he was unable to do so. A heavy beam lay across his chest. With the exception of his head and shoulders he was buried in the wreckage.

As the dust cleared, the place became illumined by the moonshine. On the sudden disappearance of the roof, the light from without had been admitted to the darkened chamber. At once Harry was able to see quite distinctly, and the sight that he beheld was sufficiently alarming to shake the nerves of even the strongest man.

Pinned to the ground, unable to move, he found himself in the midst of a family of leopards. Quite near to him, also half buried in the wreckage, lay the beast that he had shot-evidently the father of the family. Six cubs, half-grown, growled and snarled on the other side of the chamber, and in front of them, her white fangs gleaming in the moonlight, was the mother leopard, fiercely guarding her young.

It was she who had hurled herself at the wall, who had brought down the roof, and who now snarled repeatedly at the boy. It was apparent that the sudden collapse of the building had given the animal a fright. Twice she made as if she would advance, and twice drew back towards her young.

Harry was not able to fire again. The hand which held his revolver was pinned down beneath the fallen beam. He could not move his eyes from the leopard. At the same time, the brute feared to advance.

A sharp jet of fire-it seemed not two paces from the boy's face-a loud report, and the leopard rose upon its hind legs, rampant, terrible and glorious, fighting the air with its fore feet as if in the throes of a struggle with an invisible, all-powerful foe.

Then the brute came down and lay quite still, shot through the brain by a bullet from Jim Braid's rifle.

Quick upon Jim's heels, through the narrow opening in the wall, came the two guides, Cortes leading the way.

"Are you hurt?" asked Jim.

"No," said Harry. "I am not hurt. But get me out of this; I can't move."

With quick hands they lifted the beams and rafters that pinned the boy to the ground, and, a moment after, Harry was on his feet.

The young leopards gathered together in a corner of the chamber. Then, one after the other, they sprang over the ruined wall like cats, and disappeared into the night.

"The sheikh!" cried Fernando. "Where is he?"

"I have not seen him," answered Harry.

"He came here to-day," said Cortes, "and pitched his camp. Look here, what's that?"

He pointed to the ground, where lay something that was white as snow. It was a bone.

The two boys drew back in horror. Fernando was undismayed. He calmly picked up the bone and examined it in the moonlight.

"This is the shin-bone of a camel," said he. "Moreover, of a camel that was killed to-day. As my brother says, the Black Dog was here."

"See this!" cried Cortes. "The ground is charred. It was here he lit his fire."

All four searched the chamber. Besides the shin-bone, they found other evidence that could not be disputed: four hoofs and a piece of the Arab's white flowing robe.

"Has the man been killed?" cried Jim.

"It seems that that is so."

"But the Sunstone!" Harry exclaimed.

"This evidence," said Fernando, "is indisputable. The Black Dog came here by day, pitched his camp, and lit his fire. When his fire burned out he fell asleep. He had had no sleep for forty-eight hours, and must have been exhausted. It was whilst he was asleep that the leopards entered. It seems I have been robbed of my revenge."

Harry looked at the man.

"So you think," said he, "that the sheikh is dead?"

Fernando pointed to the strip of the Arab's clothes, and shrugged his shoulders. "At all events," said he, "the camel he purchased in the village fell a prey to the leopards."

"But," exclaimed Harry, "how could the camel have got here. We were obliged to crawl in on hand and knees."

Fernando laughed.

"The leopards slew the camel outside," said he. "They tore it to pieces, which they dragged in here to play with. Have you never watched a cat?"

"Then," cried Harry, "the Sunstone has been lost!"

"Have patience," said Fernando. "We may find it yet. We will get out of this place and wait for dawn. When the daylight comes we will search the ruins. There is no need as yet to despair."

This advice was good. They went out together, leaving by way of the little archway half-hidden by the cactus plant. On the sand of the desert they lay down side by side, and, whilst one acted as sentry, the others slept.

As soon as the sun began to rise in the east, Fernando rose to his feet.

"Come," said he, "we will search."

They looked everywhere. Under the palm-trees, the sand was all disturbed where the eight leopards had flung themselves upon the camel. Around the trunk of one of the trees was a rope which had been gnawed in half. In the inner chamber of the temple no further evidence was forthcoming, and this was in part due to the fact that the ground was covered with the wreckage of the roof. It was the younger guide who discovered in the outer chamber a drop of blood upon the stones.

The man evidently considered that he had found a clue of great importance; but to the two boys it seemed quite obvious that this was the blood of the camel that had been dragged piecemeal through the narrow opening.

"No," said Cortes, shaking his head. "These are small drops of blood. It is possible the Black Dog is still alive."

At that he turned upon his heel and set off at a jog-trot across the plain. When he was a long way off, they saw him waving his arms frantically, in the highest state of excitement.

They ran to the place where he was, and found him pointing to the ground.

"Look there!" he cried. "I was right. The sheikh has escaped!"

Sure enough, upon the soft sand was a line of footmarks, leading in the direction of the plateau. Every now and again the trail was marked by a small drop of blood.

Harry asked for an explanation.

"It is very simple," answered Cortes. "The leopards first attacked the camel, which was tethered to a palm-tree outside the temple. The Black Dog was awakened from his sleep and endeavoured to escape. As he fled from the entrance he must have encountered a leopard. His cloak was torn, but he escaped, bearing the marks of the leopard's teeth or claws, probably in his thigh. Wounded, he has gone back to the hills, knowing that there lies his only chance of safety."

The man was certain of his facts. Moreover, the evidence of the foot-marks and the blood spoor was too strong to be denied.

"Come!" cried Fernando. "He is as good as ours, unless he is only slightly hurt."

CHAPTER XXXI-The Fox in View

Before the heat of the day had arisen, Harry, Jim Braid, and the two guides had covered many miles across the desert, leaving the Arab village to their left. All this time it was easy to follow the track of the sheikh. The Black Dog evidently suffered pain, and progressed only with the greatest difficulty; for, as they went on, his footsteps became more irregular, as though he staggered when he walked.

Indeed, the whole thing was like the hunting of a wounded deer. It is a well-known fact that all wounded animals take to higher ground, because there they know they are more likely to be safe, since there are usually hiding-places in the mountains-crannies in the rocks, and caves. And besides, it is good to lay down one's life a little nearer to the stars.

The desert ended suddenly in a great expanse of scrub, bordering the plateau, where the ground was stony, and where the foot-marks of the sheikh were no longer visible. For some miles the two guides held the track, until they came to a place where the fugitive had halted by the side of a little stream. Here he had washed and bathed his wounds; he had torn strips from his clothing, making bandages for himself. He had gone down upon his knees at the side of the stream and had drunk the fresh water from his hands. Then he had continued on his way, invigorated and refreshed, making straight towards the Maziri mountains.

Soon after that they were obliged to leave the camel to browse upon the hill-side. The ground had become so steep and broken that the animal could advance but slowly. They off-loaded the provisions and ammunition and divided these equally among the party.

Presently they climbed the lower slopes of the mountains, where the country was much intersected by strips of forest and dried-up watercourses, with here and there a patch of sand-a kind of offshoot of the desert. There was no longer any trail to follow.

The Black Dog had chosen his way with sagacity, walking upon stony ground, where his sandals left no marks. For all that both Cortes and Fernando were confident that they would overtake him. However, to make the more sure of their victim, they decided to divide their forces, Harry and the elder man going one way, and Jim and Cortes another.

Late that afternoon, Harry and his companion had attained a great height on the ridge of the mountains. Before them extended a great valley, and it was on the other side of this that they beheld a white figure moving rapidly from rock to rock, bearing steadily towards the east.

The guide lifted his rifle and fired in the air.

"That is to warn my brother," said he. "He will know the signal. This time it is you and I who lead the chase."

He set off running down the mountain-side, springing from boulder to boulder. There was no foot-path, and the way was almost precipitous; but the man, though not so sure of foot as his brother, was as agile as a panther. In fact, it was as much as Harry could do to keep up with him. The half-caste was all impatience to overtake the fugitive.

The sheikh was no longer in sight, nor was there any sign of Jim and the younger guide, when the sun sank beyond the mountains, and the shadows of night crept into the valleys with the mists. For all that, Fernando held upon his way until long after dark, until at last Harry was obliged to call upon him to halt. The boy was utterly exhausted. Since daybreak that morning they had travelled without a halt, and must have covered nearly forty miles, over country that was rugged, wild, and pathless.

The guide agreed to halt, but would permit no fire. Harry appeased his appetite with some wild fruit he had procured on the margin of the desert, and then lay down to sleep. In less than a minute he was buried in the deepest slumber.

It seemed to him he had not been sleeping for more than an hour when the guide took him by the shoulder and shook him lightly.

Harry Urquhart looked about him.

"It is still dark," said he.

"The dawn comes," said the man, as if that clinched the matter once and for all.

"Have you not slept?" asked Harry.

"Does the hound sleep," said Fernando, with a grim smile, "with the fox in view? Remember, I have sworn to the saints."

When they had eaten such of the desert fruit as remained over from the previous day, they set forward on their journey, the guide leading as before.

They traversed valley after valley, the guide selecting the route, as it seemed, by some kind of natural instinct similar to that which will lead a cat to find its way across unknown country. Though during that morning they saw nothing of the Arab, Fernando was certain that the Black Dog was not many miles ahead. Every time they reached a hill-top, he screened his eyes with a hand and examined the surrounding country for signs of the fugitive, who, they were convinced, was making back to the Caves of Zoroaster.

They were returning to the hills of Maziriland by a route that lay far to the south of that of their former journey. The mountains here were not so high as those farther to the north. For all that, they were exceedingly desolate and rugged. They were in a land where nothing appeared to live. There were no villages; neither cattle nor sheep grazed upon the lowlands.

At midday the guide caught sight of the sheikh, still bearing towards the south-east. His white robes were conspicuous at a distance.

On the opposite side of the valley in which they found themselves, the man was hurrying forward along a ledge that did not appear to be more than a few feet across, that hung-as it were-between earth and sky. Beneath this ledge, the smooth face of a precipice dropped sheer to the depths of the valley; above, the same inaccessible cliff continued, rising upward to the clouds.

"If Cortes were only here," said the half-caste, "the task would be easy; the Black Dog would be ours."

"Where is your brother?" asked Harry.

"I am inclined to think he is somewhere toward the north. For the last three days the wind has been blowing from that direction. Had he been to the south he must have heard the shot I fired, in which case he would have caught us up."

"Perhaps," said Harry, "he returns by the way we came."

"It may be," said the guide. "Sooner or later, he will discover his mistake. Then he will come south; but he and Braid will be many miles in rear of us. If Cortes were with me now, I could capture the sheikh before sunset."

"How?"

"You see where he is," said the guide, pointing across the valley. "He walks on the brink of one precipice and at the foot of another. He can turn neither to the right nor to the left. He must either go straight on or else turn back. My brother can run faster than you or I. If he were with us, I would send him down the valley in all haste, to ascend the mountain-path in advance of the sheikh; whilst I would mount to the path at this end of the valley. Thus the Black Dog would be caught between us two."

Harry looked at the great, yawning abyss that arose before them like a mighty wall. The figure of Bayram was not more than two miles away. In mid-valley was a stream that flowed through a narrow strip of grassland, upon which it would be possible to run.

"I may not be able to run as fast as your brother," said he, turning to the guide, "but I think I can overtake the sheikh."

Fernando laughed.

"I think so too," said he. "As for me, though I can climb for many hours, I am no runner on the flat. Do you, therefore, set forth upon your way. At the foot of the valley you will see that the precipice ends; a spur of rock juts out. If you reach that place before the sheikh, you will be able to climb up to the path at the top of the precipice. There you will lie in wait for him. I will follow in his rear. He will be caught between two fires."

As there was little time to lose, Harry was not slow to obey the man's injunctions. Side by side they climbed down into the valley, and there they separated, Fernando going to the north, Harry Urquhart setting out in the opposite direction.

CHAPTER XXXII-Between Two Fires

In less than an hour Harry drew level with the Arab. The progress of the Black Dog was necessarily slow. In the first place, he still suffered from his wound; in the second place, the path he followed was in places so narrow as to be dangerous, and he was obliged to proceed with the utmost caution. Harry, on the other hand, had been able to run as fast as his legs could carry him by the side of the stream that rushed down from the mountains.

The boy paused for breath and looked about him. Though he and the sheikh were making for the same point, in regard to which they were level with one another, there was more than a mile between them. In other words, that was the distance that separated the precipice from the stream in mid-valley. Harry looked up and saw Fernando far in rear. He had already gained the path at the top of the abyss, and was following with all dispatch upon the heels of the fugitive.

The Black Dog stopped. His small white figure seemed to be crouching. Harry, with the aid of his field-glasses, tried to make out what the man was doing.

At that moment there came a quick, hissing sound within a fraction of an inch of the boy's ear, and a bullet buried itself deep in the ground not fifteen yards away.

Without a doubt, the sheikh now realized to the full the danger in which he stood. He saw that he was rapidly being cut off from all means of escape. There was nothing that could save him but his surety of aim, and at that distance it was no easy matter to hit a mark several hundred feet below him.

When a rifle is fired downward from a great height, what is known as the "trajectory", or flight, of the bullet is affected, and in consequence the line of sight is not wholly accurate. This may have been sufficient to account for the failure of the Arab's shot; but in any case, to put a bullet within an inch of the target at so great a range proved him a marksman of the greatest skill.

When he saw that he had missed he hurried on his way, hoping against hope to reach the spur in advance of Harry Urquhart.

The boy was determined that the fugitive should not escape. He cared little or nothing for the life of Bayram, but at all costs he meant, if possible, to recover the Sunstone. He was never able to forget that, all this time, von Hardenberg was shut up alive in the silent vault, in the very heart of the mountain.

Running as if his life depended on his efforts, he dashed down the valley. Three times the Black Dog fired, and each time the bullet flew within a hand's-breadth of its mark.

On gaining the spur, Harry clambered to the southern side, where he was out of sight of the fugitive, who was now too far away to fire. Slinging his rifle across his shoulder, hand over hand the boy climbed up the rocks, and at last gained the pathway which formed a little ledge, or terrace, upon the face of the great abyss.

He walked forward stealthily. On his right hand a rock arose, inaccessible and smooth as a plate of steel, whilst on the left it dropped sheer into the shadowy depths of the valley from which he had come. Far below him, the stream that he had followed looked like a little silver thread glittering in the sunlight.

He knew that he must find some kind of cover. If he came face to face with Black Dog on that narrow path he would have little chance of living. A rifle in the sheikh's hands, at a point-blank range, was more an implement of execution than a weapon of defence; and, besides, the Black Dog was known to be a man of prodigious strength.

As the boy went upon his way he looked forward eagerly, hoping to find some rock or boulder behind which he could hide and await the approach of the Arab. But the path was bare, not only of vegetation, but of stones and fragments of rock. It was as if some mighty hurricane had swept the mountain-side, brushing all obstacles from the narrow ledge, sweeping the place as clean as the pavement of a street.

Presently the path turned a sharp angle. The cliff stood folded back in the shape of the letter W. From the corner, Harry was able to see, not only the other extremity of the W, but also the smaller salient which formed the centre of the letter. It was then that the complete success of their enterprise was made apparent.

At the corner of the southern extremity was Harry, and at the northern stood the guide, his rifle in his hand. Between them the face of the precipice was folded back in two re-entrant angles. Everywhere the abyss was smooth and perpendicular, both above and below the pathway. It was possible to climb neither up nor down. Escape was beyond all question. And midway between Harry Urquhart and the half-caste guide, standing upright at the central angle, was Sheikh Bayram, the Black Dog of the Cameroons, like a great bird of prey perched above its eyrie. Whatever the issue of this business was to be, it was certain that for the present the fugitive was caught.

Neither was it possible for him to conceal himself. If he turned back, he was exposed to fire from the guide; if he went forward, he was covered by the rifle of Harry.

He stood motionless for some seconds, as if deliberating in his mind what was best to do. Then, with a slow and measured step, he walked towards the boy.

Harry waited till the man had come within twenty yards of him; then he raised his rifle to his shoulder and directed the sights full upon the Arab's heart. To his amazement, the Black Dog stood stock-still.

Harry was about to press the trigger when, for two reasons, he desisted. Firstly, the thing smacked of a cold-blooded murder, since the sheikh had made no show of resistance; secondly, if he fired and killed the man, his lifeless body would pitch headlong into the abyss. In that case they might not be able to recover it, and thus the Sunstone would be lost.

Suddenly the sheikh raised his rifle above his head, and cried aloud to the boy in English.

"Fire," said he, "and kill me! I am at your mercy; my life is in your hands. See here, this rifle-it has served me well for twenty years. It is known from Lagos to Port Stanley, even as far south as the Kasai. Behold, there goes my best and truest friend."

At that he cast the weapon to the depths below.

"You surrender?" cried Harry, coming forward.

"I can do nothing else," replied the sheikh. "As you ran in the valley I fired my last cartridge. Still, I am not yours so long as I am alive."

With these last words, he turned sharply and looked behind him, as if he had heard something. There, sure enough, was Fernando, crawling on hands and knees, his head and shoulders just appearing around the central angle.