"Heart of all evil," murmured the shaykh, "how many princes died for thee in the Beginnings of Happenings? Surely the blood of kings throbs in thee. The sultans and the princesses and the generals who wore thee, they are dust and are forgotten, but thou blazest with majesty undimmed, fire of the world----" Nureddin seized the stone. A shuddery wail broke from the Arabs, cut through by a sharp inhuman cry. To Steve it seemed, horribly, that the great jewel had cried out like a living thing! The stone slipped from the shaykh's hand. Nureddin might have dropped it; to Steve it looked as though it leaped convulsively, as a live thing might leap. It rolled from the dais, bounding from step to step, with Nureddin springing after it, cursing as his clutching hand missed it. It struck the floor, veered sharply, and despite the deep dust, rolled like a revolving ball of fire toward the back wall. Nureddin was close upon it--it struck the wall--the shaykh's hand reached for it. A scream of mortal fear ripped the tense silence. Without warning the solid wall had opened. Out of the black wall that gaped there, a tentacle shot and gripped the shaykh's body as a python girdles its victim, and jerked him headlong into the darkness. And then the wall showed blank and solid once more; only from within sounded a hideous, high-pitched, muffled screaming that chilled the blood of the listeners. Howling wordlessly, the Arabs stampeded, jammed in a battling, screeching mass in the doorway, tore through and raced madly down the wide stairs. Steve and Yar Ali, lying helplessly, heard the frenzied clamor of their flight fade away into the distance, and gazed in dumb horror at the grim wall. The shrieks had faded into a more horrific silence. Holding their breath, they heard suddenly a sound that froze the blood in their veins--the soft sliding of metal or stone in a groove. At the same time the hidden door began to open, and Steve caught a glimmer in the blackness that might have been the glitter of monstrous eyes. He closed his own eyes; he dared not look upon whatever horror slunk from that hideous black well. He knew that there are strains the human brain cannot stand, and every primitive instinct in his soul cried out to him that this thing was nightmare and lunacy. He sensed that Yar Ali likewise closed his eyes, and the two lay like dead men. * * * * * Clarney heard no sound, but he sensed the presence of a horrific evil too grisly for human comprehension--of an Invader from Outer Gulfs and far black reaches of cosmic being. A deadly cold pervaded the chamber, and Steve felt the glare of inhuman eyes sear through his closed lids and freeze his consciousness. If he looked, if he opened his eyes, he knew stark black madness would be his instant lot. [Illustration: "If he looked, if he opened his eyes, he knew that stark black madness would be his instant lot."]