"Come back here, you rat!" Koerber shrieked, swinging the big atom-ray around. But he had no need to fire, a glowing globe fully six feet in diameter, already was pursuing the doomed, fear-maddened creature with vertiginous speed. Koerber saw it suddenly descend and envelop the running figure, and in seconds the outlaw was a shrunken mass that dropped to the ground like a squeezed fruit. [Illustration: _The spheres rolled down in a deadly wave._] Koerber's eyes were blazing as he whirled around and screamed at his men: "Fight ... fight you lousy rats!" Uncontrollable passion twisted his features in a fiendish snarl at the thought of losing the supreme power and unimaginable wealth he had thought to be within his grasp. His voice rose piercingly above the concussions of the atomite capsules that at his command had been brought into action. But unknown to him, stealthily, a growing fear was creeping into his brain as all his efforts and the deadly fire of atom-blasts, atom-ray and atomite capsules failed to even destroy a single globe. The unearthly, macabre appearance of the luminous globes was already playing havoc with the men's minds, and one by one the outlaws fled shrieking into the darkness, to be consumed by the glowing spheres. * * * * * In the impenetrable blackness of the cave, Dennis Brooke had stopped building the emotion of fear. With part of his mind he sought to dispel the stubborn auto-hypnosis, and slowly, he was able to regain a measure of normalcy. The thought of Marla helped, as with the growing destruction of Koerber's men, he deliberately forced himself to see her safe, in his arms. And slowly he came back out of the abyss of fear into which he had purposely pushed his courageous mind. It took patience, infinite patience and time, but time was growing short. He rubbed the frayed bonds that bound his arms back of him, against the jagged outcroppings of radio-active rock, until he burst them with herculean strength, then it took a matter of seconds to free his legs. Painfully he stood up, and let the blood course with exquisite torture through his semi-paralyzed limbs. Then he sought the tiny atom-blast Marla had given him to conceal.