And still the weapon waited until the snarling faces of the enemy were close. Then the pistol cracked once, and the roar of its exploding shell came thundering after. For an instant all motion ceased; the very wings of the flying beasts seemed frozen rigid in mid-flight. Then the whole of the vast room was in motion. * * * * * A rush of escaping air whirled upward the black-winged monsters in an inverted maelstrom of shrieking winds. And, falling to meet them, came an enormous pendant whose rioting colors seemed glorying in their own death. And with that came the swift disintegration of the vaulted arches where the one central supporting point of their intricate maze had been shattered; till, with a crashing avalanche of sound that obliterated the thundering echoes of the detonite charge, the entire ceiling, that seemed now like the roof of a mighty world, roared down to destruction. The pyramidal rostrum was at one side. A cascade of shattered rock fell like a curtain before it--a kindly curtain that hid from human sight the hideous slaughter of a demoniac mob. It was still falling; the imprisoned air was gathering added force to rush upward, screaming as if the very winds were insane with joy at their release, when the great arms of Frithjof Haldgren closed about the others of the group and half carried them, half hurled them, down the slope. * * * * * The echoing clang of great doors was still with them as the bellowing voice of Haldgren was heard. "Get into your suits! The internal pressure is lost." Even as he spoke the big man was clutching at his throat, though the closing doors of the sacred room had given them respite. "Quick! They have emergency doors. They will close them--but this part is cut off. In only minutes there will be no air!" But it was Chet who snapped shut the closure of Anita Haldgren's suit before he pulled on his own. And he grinned happily through the glass of his helmet as he saw the others safely encased, while their suits slowly bulged as the pressure of the air about them went down and their own tanks of oxygen took up the task of maintaining one atmosphere of pressure. In silence the great doors of the sacred room swung back; in silence, as before, the Earth-folk passed through where chaos had reigned. Chet checked them; he threw one arm clumsily around the figure of Anita Haldgren while he turned to her brother. "The door is open, Frithjof Haldgren," he said, and pointed upward at the black vault of the heavens where a massive ceiling had been. In that immensity of space, framed in the torn outlines of a shattered world, shone a great globe--a globe like a giant moon. The Earth, unbelievably bright, was beckoning them once more. "The door is open," Chet repeated; "do you still wish to go home?" CHAPTER XI _"Bullard, of the I.B.C.!"_