Often the 'roller would cruise through grass tall as a man's knee. Then suddenly it would pass onto one of those tremendous lawns which seemed so well kept. Green had never ceased puzzling about them, but all he could get from anyone was one or more variations of the fable of the _wuru_, the herbivore bigger than two ships put together. One day they passed a wreck. Its burned hulk lay sideways on the ground, and here and there bones gleamed in the sun. Green expressed surprise that the masts, wheels and cannon were gone. He was told that those had been taken away by the savages who roamed the plains. "They use the wheels for their own craft, which are really nothing but large sailing platforms, land-rafts, you might say," Amra told him. "On these they pitch their tents and their fireplaces, and from them they go forth to hunt. Some of them, however, disdain platforms and make their homes upon the 'roaming islands.'" Green smiled but said nothing about that fairy story because disbelief excited these people, even Amra. "You'll not see many wrecks," she continued. "Not because there aren't many, for there are. Out of every ten 'rollers that leave for distant breaks, you can expect only six to get back." "That few? I'm amazed that with such a casualty ratio you could get anybody to risk his fortune and life." "You forget that he who comes back is many times richer than when he sailed away. Look at Miran. He is taxed heavily at every port of call. He is taxed even more heavily in his home port. And he has to split with the Clansmen, though he does get a tenth of the profit of every cargo. Despite this, he is the richest man in Quotz, richer even than the Duke." "Yes, but a man is a fool to take risks like these just for the remote chance of a fortune," he protested. Then he stopped. After all, for what other reason had the Norsemen gone to America, and Columbus to the West Indies? Or why were so many hundreds of thousands of Earthmen daring the perils of interstellar space? What about himself, for instance? He'd left a stable and well-paying job on Earth as a specialist in raising sea crops to go to Pushover, a planet of Albireo. He'd expected to make his fortune there after two years of not-too-hard work and then retire. If only that accident hadn't happened...! Of course, some of the pioneers weren't driven by the profit motive. There was such a thing as love of adventure. Not a pure love, however. Even the most adventurous saw Eldorado gleaming somewhere in the wilds. Greed conquered more frontiers than curiosity. "You'd think the ruins of 'rollers would not be rare, even if these plains are vast," said Amra, breaking in on his reflections. "But the savages and pirates must salvage them as fast as they're made."