"Yes. I learned a curious thing about Amaterasu. Do you know why that planet was so extensively colonized by the Federation, when there don't seem to be any fissionable ores? The planet produced gadolinium." Gadolinium was essential to hyperdrive engines; the engines of a ship the size of the _Nemesis_ required fifty pounds of it. On the Sword-Worlds, it was worth several times its weight in gold. If they still mined it, Amaterasu would repay a second visit. When he mentioned it, Harkaman shrugged. "Why should they mine it? There's only one thing it's good for, and you can't run a spaceship on Diesel oil. I suppose the mines could be reopened, and new refineries built, but...." "We could trade plutonium for gadolinium. They have none of their own. We could charge our own prices for it, and we wouldn't need to tell them what gadolinium sells for on the Sword-Worlds." "We could, if we could do business with anybody there, after what we did to Eglonsby and Stolgoland. Where would we get plutonium?" "Why do you think the Beowulfers don't have hyperships, when they have everything else?" Harkaman snapped his fingers. "By Satan, that's it!" Then he looked at Trask in alarm. "Hey, you're not thinking of selling Amaterasu plutonium and Beowulf gadolinium, are you?" "Why not? We could make a big profit on both ends of the deal." "You know what would happen next, don't you? There'd be ships from both planets all over the place in a few years. We want that like we want a hole in the head." He couldn't see the objection. Tanith and Amaterasu and Beowulf could work up a very good triangular trade; all three would profit. It wouldn't cost men and ship-damage and ammunition, either. Maybe a mutual defense alliance, too. Think about it later; there was too much to do here on Tanith at present. There had been mines on the Moon of Tanith before the collapse of the Federation; they had been stripped of their equipment afterward, while Tanith was still fighting a rearguard battle against barbarism, but the underground chambers and man-made caverns could still be used, and in time the mines were reopened and the steel mill put in, and eventually ingots of finished steel were coming down by shuttle-craft. In the meantime, the shipyard had been laid out and was taking shape.