Tunnels 03, Freefall

sharp turns in the channel. The ride was rougher than Will had expected. As the launch bounced along, both he and his father were very soon soaked to the skin by the spray from the icy-cold river and the occasional sheet of water that broke over the bows. Will was grateful for the woolly hat and the extra layers of clothing he'd donned for the journey.
    The river seemed to go on forever, snaking up through the guts of the Earth for kilometer and kilometer. The only sign that man had ever been there before came in the form of large white circles daubed on the rough walls -- these were markers to show which direction to go when the river forked, as it did many times. So as Dr. Burrows kept an eye out for them, Will steered the launch upwards, always upwards, to the source of the river.
    When Will was so tired he was finding it hard to control the outboard, his father swapped places with him at the helm. Although Will could have done with some sleep, this was impossible because someone needed to be at the bow with the lamp, or else they would be running blind in all the confusion of the spray. While it wasn't any warmer there, at least it gave him an opportunity to rest his aching arms.
    They carried on without stopping because there was nowhere they could stop that would give them protection from the continuous onrush of water. It must have been almost a day later, in which time Dr. Burrows had repeatedly managed to refuel the outboard engine as it still ran, when Will spotted a different type of sign -- a white circle but this time with a black square within it. He gestured to his father to steer towards it. As they followed more of these signs around a bend, they found that the channel widened out considerably, so that it was at least a hundred meters from side to side.
    In these less turbulent waters, they noticed something pale in the distance and Dr. Burrows made for it. It turned out to be a metal pontoon, which must once have been painted white, although it was now largely discolored by rust. Just beyond it, they spotted a pier jutting out into the water and a small, manmade quay. Dr. Burrows cut the engine and they drifted into the side.
    "Got it!" Will shouted as he caught hold of a metal railing, and brought the launch to a stop. After he'd tied up the bow rope, they clambered out.
    "Good to be back on dry land again," Dr. Burrows said, as he stamped his feet, taking pleasure in the solid ground beneath his feet. He pulled off his woolly hat and wrung it out, while Will took a quick look around. The quay was a fraction of the size of the one they'd departed from, and he was back within a few minutes.
    "Nothing much here, Dad. Just some fuel tanks and a small building that's completely empty except for a telephone."
    "Thought as much," Dr. Burrows said. "This is probably a refueling stop -- a kind of way station, where the barge and the boats could take on more petrol. Damned good thing too, as we've already gone through a couple of the spare cans. I was beginning to wonder if we'd have enough to make it to the top."
    "Better check if there's any fuel in the tanks, then," Will said, and began to go off when he stopped and turned. "Dad, are we nearly there?"
    Dr. Burrows chuckled, ramming a finger into his ear to try to get the water out. "You'd ask me that when we used to go on our fossil-hunting trips in the car. You couldn't wait to get there. Remember?"
    Will smiled. "Well, are we nearly there?"
    "Difficult to say, but I'd estimate we haven't gone a third of the distance yet," Dr. Burrows said. "Maybe less." He flapped his arms several times, and then jumped up and down.
    "Why are you doing that?" Will asked, intrigued.
    "Notice how when you move it feels sort of sluggish?" He took hold of his kitbag he'd brought with him from the launch, then slowly lifted it up. "Even this feels heavier. By the time we reach the surface, we're going to feel as if we're made of lead."
    "Yes, back to full gravity again. I hadn't thought of that," Will said, then sighed. "We're not going to have our super-powers anymore."
    They set up camp in the building, lighting a petrol stove in the doorway to warm themselves and dry their sopping clothing and boots. With some hot food in them, they crawled into their sleeping bags, and were sound asleep within minutes.
    Will was woken by his father passing a mess tin of steaming hot fluid in front of his nose.
    "Yuck! Not more of your tea ," Will said, then groaned. "Can't I have