Lon drove the tractor the rest of the morning and all afternoon with a very peculiar expression on his face. He understood what he had done. Now that he had done it, it seemed the most obvious of expedients. He felt inclined to be incredulous that nobody had ever happened to think of this particular device before. But they very plainly hadn't. It was a source of all the electric power anybody could possibly want. The voltage would depend on the number of turns of copper wire around a suitably forked stick. The amperage would be whatever that voltage could put through whatever was hooked to it. He no longer needed a new generator for his tractor. He had one. He didn't even need a Diesel. With adequate power--he'd been having to nurse the Diesel along, too, lately--Lon Simpson ran his tractor late into the twilight. He cultivated all the ground that urgently needed cultivation, and at least one field he hadn't hoped to get to before next week. But his expression was amazed. It is a very peculiar sensation to discover that one is a genius. * * * * * That night, in Cetopolis, he told Cathy all about it. It was a very warm night--an unusually warm night. They walked along the plank sidewalks of the little frontier town--as a new colony, Cetis Gamma Two was a frontier--and Lon talked extravagantly. He had meant to explain painfully to Cathy that there was no use in their being romantic about each other. He'd expected to have to tell her bitterly that he was doomed to spend the rest of his life adding to the profits of the Cetis Gamma Trading Company, with all the laws of the human race holding him in peonage. He'd thought of some very elegant descriptions of the sort of people who'd worked out the system in force on Cetis Gamma Two. But he didn't. As they strolled under the shiver trees that lined the small town's highways, and smelled the _chanel_ bushes beyond the town's limits, and listened to the thin violinlike strains of what should have been night birds--they weren't; the singers were furry instead of feathered, and they slept in burrows during the day--as they walked with linked fingers in the warm and starlit night, Lon told Cathy about his invention. He explained in detail just why wires wound in just that fashion, and combined with bits of sheet iron twisted in just those shapes, would produce power for free and forever. He explained how it had to be so. He marveled that nobody had ever thought of it before. He explained it so that Cathy could almost understand it. "It's wonderful!" she said wistfully. "They'll run spaceships on your invention, won't they, Lon? And cities? And everything! I guess you'll be very rich for inventing it!" He stopped short and stared at her. He hadn't thought that far ahead. Then he said blankly: "But I'll have to get back to Earth to patent it! And I haven't got the money to pay one fare, let alone two!" "Two?" asked Cathy hopefully. "Why two?"