"If we cut for Terra right away, without waiting to go on to Four and Five, Bogin couldn't possibly build up speed enough to beat us in, could he?" Jon questioned anxiously. "Not unless his ship's a lot faster than ours. It probably is, because his crew can undoubtedly stand more acceleration, and he'll drive to the limit. But if he stops to change those other signals, I don't see how he can do it. Go ahead, change course, and let's hike for home." "Right. Let's see, now. Terra's behind and down from where we are and the way we're heading. I'll set us into a circle while we're figuring out our course." "Make it just an approximation for now. We can refine it as we go." "Right." Jon worked swiftly at his computer, then at his controls, and they could feel the gallant little ship begin to strain toward the right. "Don't try too short a turn," his father warned. "OK, I'll let up a bit. I was figuring on a two million radius." "Better make it three for safety." In time their circling was completed, the new homeward bound course figured. For days the little ship and its anxious crew were on their way. Three times each day their acceleration was stepped up to two Earth-gravities for a period of four hours, then back to one and a quarter for the same period--four on and four off continually, to give them a rest from the burden of doubled weight, and to make it easier to prepare and eat their meals, and to do what personal and ship's chores had to be done. In between times, as they could, they slept. Jon had set their receptor and analyzer to react to atomics. It was now fanning out behind them in a cone-shaped funnel of force. He hoped by this to be able to tell if Bogin began overtaking them. Of course, space was so vast, and the distance to Sol and Terra so great, and their points of trajectory so different, that the pirate ship might be taking an entirely different course, and not come anywhere near them until the two ships were almost home. On the other hand, Jon was taking the most direct route--and he was sure Bogin would undoubtedly do the same--so they were quite apt to converge sooner or later. And since Jon's receptors covered an ever-larger sphere of space the farther away they reached, he and his father hoped they would be able to tell if and when their enemy began catching up with them. Meantime, the two studied almost continuously together the problem of that supposedly new fuel-metal they had discovered on the planet Marci--hoping it could be used in their engines. They were sadly handicapped, both because neither was an atomic physicist, and because their little ship--well-stocked and provided with many instruments as it was--did not contain anywhere near all the testing equipment needed for such a delicate and complex and dangerous task. Yet they learned much.