"You listen to your mother, and don't study too hard," she warned, knowing how he was apt to "lose himself" in his books. "You need plenty of rest for tomorrow." "All right, Mom." But when she went into the control room long after dinner, he was still deep in his reelbook. She took it away from him. "Get to bed, Jon. You promised." "I'm sorry, Mom. Just got so interested I forgot time." He kissed her. "'Night, Mom. And don't worry. We'll make out swell." "I'm sure of it." Her words were brave but he could see the tears were perilously close. "You'd better ask Jak for some barbit, or you won't sleep any better than you did last night," he counseled. "Remember, he and I are going to take turns watching Pop." "Thank you, Son. Good night." He touched a switch and the glolights dimmed and went dark as he followed her out. All the next morning Mrs. Carver and her two sons were in the control room--except for their frequent trips to Mr. Carver's bunk, to see how their patient was getting along. They were studying through the telescopic visiplates the solar system they were rapidly approaching. Jon had figured the sun was a Type G Dwarf, much like Sol, but a little larger. It had, they now knew, only five planets. Three of these--Two, Three and Four--had seven satellites among them. From their distances from the sun, the boys figured that probably Two and Three would have climates that human colonists, with some adaptation, could stand. Now they were peering even more closely into their plates, as their ship circled the globe beneath them. Jon had maneuvered it into a spiral course about Planet Two, in such a manner that, from a height of about a hundred miles, they could get a good view of the world beneath them, in their telescopic plates. "Lots of plant life, but I haven't seen anything that looks like cities," Jak said at last. "Nor I," from their mother and, "Me neither," Jon added. Their first measurements of this new planet had shown it to be almost the size of Terra, and they had been delighted to see that there was a moon of considerable size, although not as large as Luna. It was about one hundred and fifty thousand miles out. "There's a number of large seas or oceans," Jak commented without taking his eyes from his visiplate. "Look at that plant life, though--it evidently coats the whole planet. From here it looks like jungle." "Lots of lakes and rivers on it, and in those plains we saw." Jon was excited. "It sure looks like a wonderful world where men can live." As they crisscrossed the planet from pole to pole, they saw small ice fields about each. "That means there'll be varied seasons here," Jon stated. "Not necessarily," Jak argued. "In fact, while possible, it's not even probable." "Says you," Jon sniffed. Then later, "I figure the year here at about three hundred days. Just an approximation, of course, but probably within five per cent. I'm not too good at such things."