Kay gripped Ruth's arm tightly. He held his breath. The crowd, of whom only a small part knew what was taking place, was screaming with terror as the mass of jelly on the other side pressed them inexorably backward. And Cliff had almost vanished. Would the machine work? Was it possible that the psenium emanations would succeed where the Millikan rays, the W-ray had failed? Then of a sudden the air grew dark as night. Kay began to sneeze. He gasped for air. He was choking. He could see nothing, and he strained Ruth to him convulsively, while the terrified multitudes behind him set up a last wail of despair. He could see nothing, and he stood with the ax ready for the onset of the monsters, more terrible now, in their invisibility, than before. Then of a sudden there sounded subterranean rumblings. The ground seemed to open almost under Kay's feet. He leaped back, dragging Ruth with him. Slowly the dust was settling, the darkness lessening. A faint, luminous glow overhead revealed the sun. Kay was aware that Cliff had swung the top, so that the psenium rays were being brought to bear upon the second mass of the monsters on the other side. The sun vanished in appalling blackness. Again the dust-choked air was almost unbreathable. The shrieks of the crowd died away in wheezing gasps; and then a wilder clamor began. "The earthquake! The earthquake!" a girl was shrilling. "God help us all!" Kay stood still, clutching Ruth tightly in his arms. He dared not stir, for all the world seemed to be dissolving into chaos. * * * * * Slowly the dust began to settle again. Perhaps five minutes passed before the sunbeams began to struggle through. A cloud of grey dust still obscured everything. But the wall of protoplasm was gone! Cliff's voice came moaning out of the murk, calling Kay's name. Kay moved forward cautiously, still holding Ruth. He seemed to be skirting the edge of a vast crater. At the edge of it he found the top, revolving slowly. And Cliff's voice came from beside the top. "Kay, we've won. Don't look at me. Don't let Ruth see me! Look down!" Kay looked down into the bottomless pit, extending clear across the plain to the distant jungle. An enormous canyon cloven in the earth, filled with the slowly settling cloud of dust. "They're there, Kay. Don't look this way!" But Kay looked--and could see nothing except a pile of debris, from the bottom of which Cliff's voice issued. "Cliff, you're not hurt?" "A--a little. You must listen while I tell you how to clean up the monsters. It's the psenium emanation. It has the same effect when our method is applied to it. It disintegrates everything inorganic--not organic.