"By every right. I am the Guardian of the Cave. I have lived five score years, and never once have I ventured beyond the entrance of the Caves of Zoroaster. Come, deliver up the Sunstone."
"And if I refuse?" asked von Hardenberg.
"If you refuse," said the man, "you die!"
Von Hardenberg looked about him with a quick, furtive glance. Softly his hand crept to his belt, where he carried the holster of his revolver.
What happened next was the work of a few seconds. Those in the gallery had no time to interfere. As for the sheikh, he evidently intended that the tragedy should be played out to its end, to the falling of the curtain.
The old man, seeing von Hardenberg"s action, lifted his great two-handed sword and flourished it on high. Then, with a spring like that of a tiger, he hurled himself upon the Prussian.
Three shots rang out in quick succession. There were three flashes of fire, like jets of flame, and then three puffs of smoke. The cave was filled with an echo that went on and on as if it would never cease.
And when the smoke cleared, there was the old man lying upon his face upon the floor, silent and still. A century had rolled above his head, for a hundred years he had stood guardian of the Caves of Zoroaster--and now his task was ended.
Harry sprang to his feet, and would have fired then and there at von Hardenberg had not Cortes held him down by force.
"It was murder!" he whispered.
"If you fire, we are lost," cried Cortes. "It is too dark to shoot straight, and the Black Dog will escape us."
Harry resumed his kneeling position and waited.
A horrid silence reigned in the great, domed chamber. The scene was more tragic, more fantastic than ever. The shafts of light from above struck the body of the murdered man; the lamp still flickered before the altar. Even yet, the echoes of the shots were murmuring in the deeper recesses of the place.
Captain von Hardenberg stood stock-still, his revolver in his hand, thin wreaths of smoke issuing from the muzzle. From out of the heart of the stillness there came a chuckle: the Black Dog was pleased to laugh.
Murder was nothing to him. He had dealt for years in human lives. He was implacable, relentless. And even at that same moment he himself contemplated a greater crime, for the commission of which he was hiding in the darkness like a snake, biding his time to strike.
Captain von Hardenberg took two steps towards the body and turned it over with his foot.
"He is dead," said he in German.
The old man, who had been so terrible in life by reason of his madness, now looked sane and beautiful in death. The worn, agonized expression had gone altogether from his features, which were now calm and wholly at peace. With his white hair and ragged clothes, he was like one of the patriarchs of old.
Captain von Hardenberg was not himself. It was plain to see that it was all that he could do to control within him a feeling that was akin to terror. He looked about him with widely opened eyes--at the vast pillars, at the darkened corners of the aisles, at the shafts of sunlight that pierced the darkness like the blades of swords.
With trembling hands he attempted to unb.u.t.ton his coat. His nerves were so shaken, and he in such feverish haste, that he could not at first succeed. In the end, as if grown desperate, he took a knife from his pocket, opened the largest blade, and cut off the b.u.t.tons one by one.
Then he ripped open his waistcoat, and, a moment after, drew forth the Sunstone and placed it on the altar by the side of the burning lamp.
And next he did a strange thing indeed. He burst suddenly into loud laughter--laughter that was hysterical, delirious.
He had gone through so much; he had faced so many dangers; he had been guilty of a score of crimes; he had lost everything--good name and honour and position--in order to possess himself of the treasure that lay beyond the red granite rock.
And now that all this wealth was as good as his, he could do little else but laugh, in a kind of wild delirium, whilst tear-drops in quick succession coursed down his cheeks.
After a while he mastered himself a little, but not completely. He went to the nine wheels and turned them all ways in a fever of excitement.
Then he remembered what he had to do. He studied the wheels and took notice of the cuneiform writing on the "tyres". At that he returned for the Sunstone and brought it to the Bramah lock.
But, since it was too dark there to see the writing on the stone, he took it back to the altar, and laid it down once more before the lamp.
Then he studied the character in the first segment, and, having committed it to memory, he went back to the wheels.
Slowly he turned the first wheel, noting each character as it appeared above the golden bar. At last he appeared satisfied. The cuneiform figure, or character, which lay immediately above the golden bar corresponded to that upon the Sunstone.
Then, in a like manner, he turned the second wheel. Always when he got the wheel in the correct position he compared the two characters--that upon the Sunstone and that upon the wheel--to make sure they were the same.
Finally, he came to the ninth wheel. His excitement was now so great that those in the gallery could see that he was trembling violently in every limb.
He troubled no longer with the Sunstone. He turned the wheel very slowly, with his eyes fixed upon the red granite rock. Presently there was a "click" like the sound of the turning of an enormous lock. Captain von Hardenberg held the wheel quite still.
There came another "click" even louder than that which had gone before.
And then slowly, like some great living monster, the rock began to turn, as if it revolved upon a pivot.
It turned evenly, slowly, noiselessly, and, as it turned, the light from the lamp caused the quartz and mica and felspar in the granite to glisten like a thousand fire-flies on a summer"s evening.
And then, in the moving rock itself, appeared a narrow archway about four feet across; and when this was immediately opposite the altar there was another "click" and the whole rock was still.
Those in the gallery sprang to their feet and looked on with bated breath. The thing was like a miracle. As for von Hardenberg, he gave vent to a cry that was half a cheer and half a sob. Then, s.n.a.t.c.hing the lamp from the altar, he rushed through the archway into the darkness beyond.
From the gallery they could see the light grow smaller and fainter as the Prussian descended a narrow flight of steps. Then the light went out, and there came up from the vault beyond a faint cry of exultation.
Captain von Hardenberg had attained the treasure of Zoroaster.
And it was at that cry that the Black Dog glided from his hiding-place.
Now that the lamp had gone, the cave was darker than before. But by the light that came from above, and through the entrance, those in the gallery could see his white robes as the man glided noiselessly across the hall.
He went straight to the altar, picked up the Sunstone, raised it to his lips, and kissed it. For a moment he gazed at it, long and lovingly, before he thrust it into a pocket.
He moved on tiptoe towards the wheels. As he did so he pa.s.sed through one of the shafts of light, and his features were illumined. On his face there was an expression that was diabolical. It was the face of a beast of prey, a tiger that stalks its victims. His white robes contrasted strangely with the swarthiness of his countenance. His eyes were very bright and now looked yellow like those of a cat.
When he reached the wheels, he let out a great shout that filled the vastness of the cave.
"Die!" he cried. "Die the death you merit!"
At that he set the wheels in motion, and immediately the great granite rock revolved again. And Captain Carl von Hardenberg was buried alive in the midst of the treasure that was his.
The sheikh pa.s.sed rapidly down the centre aisle. Half-way to the entrance he stopped, looked back, and shook his fist at the rock.
"Lie there," he cried, "and rot! In my own good time I will return."
Before the last word was from the man"s lips, Fernando had lifted his rifle and fired. The bullet flattened itself against a pillar not three inches from the Arab"s head. The Black Dog glanced up at the gallery and then dashed out of the entrance, so swift and agile in his movements that it would have been sheer folly to fire again.
"You hit him?" cried Harry.
"No," cried the man, with a sullen oath. "I missed. It was too dark to see."
"Too dark to see!" repeated Harry. "But he is gone! Make haste, or he"ll escape!"