The raygun in his hand gushed a livid flame as Kang, tightening his worn, exhausted body for one final effort, pitched forward convulsively. The random shot missed the old man, and Borisu screamed a cry like that of a stricken animal, as in a last futile moment he realized Kang's intention. Kang, already living on borrowed time, was yet the scientist. He alone, of all in the room, had seen what could and _must_ be done. He alone, of all those who stood helplessly trapped, was close enough to do it. Three strides he stumbled forward ... then Borisu's second blast caught him squarely in the chest. If he should have been dead before, he was _surely_ so now. But it did not matter. Understanding had come too late to the mad-man of Magog. For sheer impetus carried Kang's body forward to that which Kang had planned. His body plunged full length and sprawling upon the gleaming busbars of the wave cannon. There burst from Borisu's lips a last and frightful scream. The atmosphere crackled. For a moment the biting odor of ozone was horribly mingled with the charnel stench of searing flesh. "_Down!_" roared Gary. "_Down on the floor, for God's sake! Short circuit--!_" As one, the watching four fell flat on their faces just as the gigantic machine before them, quivering and trembling to its very roots, rocked itself from its moorings ... and in a roaring fountain of flame exploded into a million fragments! CHAPTER XXI "Journey's End...." "So," said Tsalnor regretfully, "you will not change your mind? You will not stay?" Gary Lane shook his head. "No, Tsalnor. Someday we may return. But now our duty is to go to our own system, there tell them what we have here learned." Tsalnor nodded. "Yes, man uff Earth, I suppose that is best. But you will send others uff your people to see us? You will teach us, as you promised, your method uff travel? That there may be friendship and amity between the people uff our worlds?" "We will," pledged Gary. "Dr. Bryant has said that now the ultrawave cannon is destroyed the solar universe will not only stop its dwindling but will, indeed, begin to return to the true and greater universe from which it was exiled. "But before this happens our races will have forged bonds of friendship so close that when Sol returns to take its place amongst its sister stars there need never again be war between our worlds." Muldoon said, "And you, Tsalnor, you've got an even more important job than we have. Keeping the Magogeans under control. You've got to see to it that they never try to build another one of those cannon." Tsalnor said softly, "We shall be careful. But I think we need never again fear the construction uff such a weapon. The _kraedars_ of Magog have been overthrown. It was never the common people who conspired against us. When we haff taught them the benefits of freedom and democracy, they too shall take their place in a new and better universe."