He answered Mitfpa's questions. "The power used was very small. You have heard of controlled space warps?" "What about it?" grumbled the soldier. "An interesting laboratory trick. But it also occurs in nature. As a youth I once saw the light of stars bent around the sun in a selector-scope; indeed, it was this very phenomenon that showed our scientists how to make their own warps." "Enough of your lecture, old one. What was the result of this scientific trickery?" "One as stupid as you would not understand the method," Thak replied levelly, "but the result of warping all of our power beams was a network of opaque lines that to an observer would be an obvious signal. And now, if you are quite ready to leave--?" * * * * * Grumbling, Mitfpa departed, taking his soldier-worker with him. Thak checked the placement of the telescope, finally nodding in satisfaction as he found everything in proper order. The four students crowded around, watching with interest. He gazed good-naturedly at them. "Our work is a great one," he declared. "We must communicate with the third planet by means of a system of signals that we shall work out--in time. But there is so little time...." His tentacles curled thoughtfully about him. "You have followed the work of our last great physicist, _Mor_ Gran?" "You mean," asked an alert youngster named Rofan, "the probability tables worked out by him? Showing that the end is near for our race?" Thak nodded sadly. "Indeed, lad, the future appears dark. War and its disorganization must inevitably strangle civilization. Even now our race is thinned in numbers, and the beasts of the desert multiply." "There," he went on, waving toward the blue planet, "is our only hope. If we can effect communication with them, and be guided by their superior wisdom, we may yet rally. They may have some secret--some way to prevent wars--" [Illustration: _"There!" Thak said. "There lies our only hope."_] "You continue to speak of their superior wisdom, _Mor_ Thak," said Rofan. "How can you be so very sure of that?" "It is obvious, lad. Their signal system consists of spots of light over the greater part of the land surface of their planet. I have shown you the old photographs, taken before the last war, showing these lights. Even with the small telescope I have been forced to use during these lean years, I have watched the lights. What a mighty science theirs must be that can make the night time light merely to signal another planet! For that can be the only purpose of the lights." Rofan let his tentacles curl about him as he concentrated. "You must be right," he finally agreed. "I was going to suggest that they might be the lights of cities. I noticed many of them were situated where a city would be likely--but there must be millions of beings to populate so many cities--"