Brave New Worlds

tunnel. It was necessary to pack the blocks into the space at the rear with an absolute minimum of gaps, in exactly the way they had been cut, like pieces of a puzzle; they all got very good at the craft of this, losing only a few inches of open space in every mile they dug. This work was the hardest both physically and mentally, and each shift of it left Oliver more tired than he had ever been while mining. Because the truth was all of them were working at full speed, and for the middle team it meant almost running, back and forth, back and forth, back and forth. . . . Their little bit of open tunnel was only some sixty yards long, but after a while on the midshift it seemed like five hundred.
    The three people not working on the rock tended the air and the livestock, ate, helped out with large blocks and the like, and snatched some sleep. They rotated one at a time through the three stations, and worked one shift (timed by detonator timer) at each post. It made for a routine so mesmerizing in its exhaustiveness that Oliver found it very hard to do his calculations of their position in his shift off. "You've got to keep at it," Jakob told him as he ran back from the robot to help the calculating. "It's not just anywhere we want to come up, but right under the domed city of Selene, next to the rocket rails. To do that we'll need some good navigation. We get that and we'll come up right in the middle of the masters who have gotten rich from selling the blue to Earth, and that will be a very gratifying thing I assure you. "
    So Oliver would work on it until he slept. Actually it was relatively easy; he knew where they had been in the moon when they struck out on their own, and Jakob had given him the surface coordinates for Selene: so it was just a matter of dead reckoning.
    It was even possible to calculate their average speed, and therefore when they could expect to reach the surface. That could be checked against the rate of depletion of their fixed resources—air, water lost in the recycler, and food for the livestock. It took a few shifts of consultation with mute Elijah to determine all the factors reliably, and after that it was a simple matter of arithmetic.
    When Oliver and Elijah completed these calculations they called Jakob over and explained what they had done.
    "Good work," Jakob said. "I should have thought of that. "
    "But look," Oliver said, "we've got enough air and water, and the robot's power pack is ten times what we'll need—same with explosives—it's only food is a problem. I don't know if we've got enough hay for the cows. "
    Jakob nodded as he looked over Oliver's shoulder and examined their figures. "We'll have to kill and eat the cows one by one. That'll feed us and cut down on the amount of hay we need, at the same time. "
    "Eat the cows?" Oliver was stunned.
    "Sure! they're meat! People on Earth eat them all the time!"
    "Well. . . . " Oliver was doubtful, but under the lash of Hester's bitter laughter he didn't say any more.
    Still, Jakob and Freeman and Naomi decided it would be best if they stepped up the pace a little bit, to provide them with more of a margin for error. They shifted two people to the shaft face and supplemented the robot's continuous drilling with hand drill work around the sides of the tunnel, and ate on the run while moving blocks to the back, and slept as little as they could. They were making miles on every shift.
    The rock they wormed through began to change in character. The hard, dark, unbroken basalt gave way to lighter rock that was sometimes dangerously fractured. "Anorthosite," Jakob said. "We're reaching the crust. "After that every shift brought them through a new zone of rock. Once they tunneled through great layers of calcium feldspar striped with basalt intrusions, so that it looked like badly made brick. Another time they blasted their way through a wall of jasper as hard as steel. Only once did they pass through a vein of the blue; when they did it occurred to Oliver that his whole conception of the moon's composition had been warped by their mining. He had thought the moon was bursting with promethium, but as they dug across the narrow vein he realized it was uncommon, a loose net of threads in the great lunar body.
    As they left the vein behind, Solly picked up a piece of the ore and stared at it curiously, lower eyes shut, face contorted as he struggled to focus his third eye. Suddenly he dashed the chunk to the ground, turned and marched to the