As the men swept their flaming fire around, the savages fell back in shrilling panic. Scores of them were burned down, but more of the creatures kept surging in. The Earthmen knew it would be only a matter of seconds before the sheer mass of the creatures overwhelmed them. Still they pressed forward, slowly burning a way through. For some foolish reason Devries remembered shouting at Janus: "These flame-pistols are all right as toys. Wish I had an atom-blast!" Then the shrilling coppery devils were closing around, clawing. Janus brought down some more with a sweeping blast, and Devries did the same, but the flame-charges were getting very weak. Then the Earthmen stared. The savages were no longer pressing around them; they were fleeing away! For no reason at all they saw the space ahead of them open up. They saw a long, clean swath of Proktols topple like grain cut down by a mower. Those that did not fall fled frantically, shrilling in thin terror at a strangely invisible death. The men couldn't quite understand what had happened, but they took swift advantage of the miracle and darted across the now open square. But the larger Proktols weren't so superstitious. A dozen of them, now unimpeded, came leaping to intercept them. But before these Proktols could raise their flame-pistols, they toppled too, cut clean in two! All was clear around the men now, and they paused to catch a breath. "What the devil was it, Janus? What happened?" "Pure luck! I knew that lucky piece of mine couldn't fail!" But just then a figure emerged from the dark shadow of a building, and ran toward them. It was a familiar figure, and it held two atom-blasts, one of which it thrust into Devries' hands. "Luck nothing!" Devries yelled, recognizing him. "It's Ross! How did you escape? We thought you died on the _Wasp_!" * * * * * "Not quite," Ross said. "Come on, this is no picnic! Let's get out of here before those devils stop wondering what an atom-blast is." The men turned and sprinted for the open street ahead of them. But they hadn't taken five steps when Devries felt a crushing, numbing weight upon his brain. He staggered, fell to his knees; tried to rise but couldn't. Then he fell flat, as a force hit him like a giant invisible hand. Agonizingly he wondered why the others didn't help him; then he saw that they too were lying flat, dazed and panting heavily. With a tremendous effort Devries twisted his head around and looked across the square. He saw the huge Brain under its glass dome. It was pulsing with a fiery, angry red radiance. And Devries knew it was the Brain's tremendous thought-force that was reaching out and crushing them there.