"Well, old pals," said Fuller, "at least I have traffic blocked fairly well if I feel like it, so eventually you'd have to help me. However--" He floundered clumsily as he removed one of his foam-rubber space-boots, "--my brains tell me that action is equal and opposite to reaction!" And he threw the boot with all possible velocity toward Morey! The reaction of the motion brought him slowly but surely to a handhold in the wall. In the meantime, the flying boot caught Morey in the chest with a pronounced _smack_! as he struggled vainly to avoid it. Handicapped by the lack of friction, his arms were not quite powerful enough to move his mass as quickly as his legs might have done, for his inertia was as great as ever, so he didn't succeed in ducking. "Round one!" called Arcot, laughing. "Won by Kid Fuller on a TKO! It appears he has brains and knows how to use them!" "You win," laughed Morey. "I concede the battle!" Arcot had cut off the space-strain drive by the time Fuller reached the control room, and the men set about making more observations. They took additional photographs and turned on the drive again. Time passed monotonously after they had examined a few stars. There was little difference; each was but a scene of flaming matter. There was little interest in this work, and, as Fuller remarked, this was supposed to be a trip of exploration, not observation. They weren't astronomers; they were on a vacation. Why all the hard work? They couldn't do as good a job as an experienced astronomer, so they decided to limit their observations to those necessary to retrace their path to Earth. "But we want to investigate for planets to land on, don't we?" asked Morey. "Sure," agreed Fuller. "But do we have to hunt at random for them? Can't we look for stars like our own sun? Won't they be more apt to have planets like Sol's?" "It's an idea," replied Morey. "Well, why not try it then?" Fuller continued logically. "Let's pick out a G-0 type sun and head for it." They were now well out toward the edge of the Galaxy, some thirty thousand light years from home. Since they had originally headed out along the narrow diameter of the lens-shaped mass of stars that forms our Island Universe, they would reach the edge soon. "We won't have much chance of finding a G-0 this far out," Arcot pointed out. "We're about out of stars. We've left most of the Galaxy behind us." "Then let's go on to another of the galactic nebulae," said Morey, looking out into the almost unbroken night of intergalactic space. Only here and there could they see a star, separated from its nearest neighbor by thousands of light years of empty space. "You know," said Wade slowly, "I've been wondering about the progress along scientific lines that a race out here might make. I mean, suppose that one of those lonely stars had planets, and suppose intelligent life evolved on one of those planets. I think their progress would be much slower."