Before the Master could reply, a shuddering concussion shivered through the solid gold all about them. The tremor of this shock, like that of an earthquake, trembled the cressets on the walls and made the huge ebony door, ajar into a dim-lighted hall, groan on its hinges. Stupefied, Legionaries and Arabs alike, stared silently under the vague gleam of the torches. Then, far and faint, as though coming along tortuous passages from distances above, a muffled concussion smote their ears. The shock of the air-wave was distinctly felt, eloquent of the catastrophe that in a second of time had shattered every plan and hope. As if an echo of that thunderous, far explosion, a faint wailing of voices--echoing from very far above--drifted eerily along the passage; voices in blended rage and fear, in hate, agony, despair. "God above--!" the major gulped. "Captain Alden" whipped her pistol from its holster, not a fraction of a second before the Master's leaped into his hand. The torchlight flickered on Leclair's service-revolver, and was reflected on the guns of every Legionary. "If that's the explosive," Bohannan cried, "faith, we're in for it! _Is_ it the explosive that's blown Hell out o' the Black Stone?" A wild cry echoed down the passage. The Olema, his face suddenly distorted with a passion of hate, snatched a pistol from beneath his burnous. "The dogs of Feringistan have spat on all Islam!" he screamed, in a shrill, horrible voice. "The Black Stone is no more! Vengeance on the unbelieving dogs! _Allah il Allah!_ Kill, kill, and let no dog escape! "Sons of the Prophet! Slay me these dogs! Kill!" CHAPTER XLIII WAR IN THE DEPTHS Horrible, unreal as a fever-born nightmare in its sudden frenzy, the Arab's attack drove in at them. The golden passageway flung from wall to wall screams, curses in shrill barbaric voices, clangor of steel whirled from scabbards, echoes of shots loud-roaring in that narrow space. Bara Miyan's pistol, struck up by the woman's hand, spat fire over the Master's head just as the Olema himself went down with blood spurting from a jugular severed by the major's bullet. The Olema's gaudy burnous crimsoned swiftly. "Got _him_!" shouted Bohannan, firing again, again, into the tangle of sub-chiefs and Maghrabi men. Adams pitched forward, cleft to the chin by a simitar. The firing leaped to point-blank uproar, on both sides. The men of Jannati Shahr numbered more pistols, but the Legionaries had quicker firers. Arabs, Legionaries, Maghrabis alike falling in a tumult of raw passions, disappeared under trampling feet. Deafening grew the uproar of howls, curses, shots. The smell of dust and blood mingled with the aromatic perfume of the cressets. The Master was shouting something, as he emptied his automatic into the pack of white-robed bodies, snarling brown faces, waving arms. But what he was commanding, who could tell?