But he, Zurk, would be powerless to help.
Through the long hours of the day and night, Zurk sat there watching the two youngsters at their toil. They were working against time now, struggling for the right of freedom and happiness.
But Zuldi might come. He might come before the gun was finished. Or he might come before the arrival of the black ship.
Hours later, Bob made the final adjustments on the machine and stepped back to look at it. His face was pale and his hands trembled slightly with excitement.
"Now to test it!" he told Marene. "And ... and I hope it works!"
He turned the long snout of the gun toward the open window, connected the electrodes and made final adjustments.
"Wait!" Marene placed a hand upon his arm. A sudden fear had come into her sparkling eyes. "If the gun makes a flash or a vibration of any kind, Zuldi will be sure to know. He will come here immediately!"
Bob paused. "That's right," he said finally. Then, "But we've got to test it! We can't wait until the black ship comes! We've got to be sure!"
They stood there for a moment gazing into each other's eyes. Then Bob put his arm about her and drew her to him. "It doesn't matter so much about us," he told her. "We are doomed anyway. It's your father and my father and all the others in the city that we must think about! It is they...."