There was stillness again. Riki stood mousy-quiet. _When she realizes what this means_, thought Bordman grimly, _she won't admire me so much. Her brother's built me up. But I've been a fool, figuring out excuses to hope. She'll see it._ "I think," said Riki, "that you're telling me that after all we can't store up heat to live on, down in the mine." "We can't," agreed Bordman. "Not much, nor long. Not enough to matter." "So we won't live as long as Ken expects?" "Not nearly as long," said Bordman. "He's hoping we can find out things to be useful back on Lani II. But we'll lose the power we can get from our grid long before even their new grids are useless. We'll have to start using our reserve power a lot sooner. It'll be gone--and us with it--before they're really in straits for living-heat." Riki's teeth began to chatter. "This sounds like I'm scared," she said angrily, "but I'm not! I'm just freezing. If you want to know, I'd a lot rather have it the way you say. I won't have to grieve over anybody, and they'll be too busy to grieve for me.... Let's go inside while it's still warm." He helped her back into the cold-lock, and the outer door closed. She was shivering uncontrollably when the warmth came pouring in. They went into Herndon's office. He came in as Riki was peeling off the top part of her cold-garments. She still shivered. He glanced at her and said to Bordman: "There's been a call from the grid-control shack. It looks like there's something wrong, but they can't find anything. The grid is set for maximum power-collection, but it's bringing in only fifty thousand kilowatts!" "We're on our way back to savagery," said Bordman, with an attempt at irony. It was true. A man can produce two hundred fifty watts from his muscles for a reasonable length of time. When he has no more power, he is a savage. When he gains a kilowatt of energy from the muscles of a horse, he is a barbarian, but the new power cannot be directed wholly as he wills. When he can apply it to a plow he has high barbarian culture, and when he adds still more he begins to be civilized. Steam-power put as much as four kilowatts to work for every human being in the first industrialized countries, and in the mid-twentieth century there was sixty kilowatts per person in the more advanced nations. Nowadays, of course, a modern culture assumed five hundred as a minimum. But there was less than half that in the colony on Lani II. And its environment made its own demands. "There can't be any more," said Riki, trying to control her shivering. "We're even using the aurora and there isn't any more power. It's running out. We'll go even before the people at home, Ken." Herndon's features looked pinched.