Science of Discworld III

of tools by the stack; one was a rod with an end like a super-corkscrew.
    Carefully, he pushed it down the cannon, wincing at every clink . Twice he felt the curved springy bits engage with the ball, and twice it came away and rolled back with a thud.
    At the third attempt he was able to get the tapped ball almost outof the mouth of the barrel, and slid his fingers under it.
    Well, that wasn’t too hard, was it? He dropped it over the side, where the sea swallowed it with a ‘plomp!’
    This caused no stir anywhere. Job done, and nothing horrible had happened at all! He pulled a scrap of paper out of his pocket. It was important to get the words right.
    ‘Return—’ he began, and stopped. With a little metallic grinding noise, another ball rolled gently off the pile, across the deck, and leapt into the cannon’s mouth.
    ‘O-kay,’ said Rincewind slowly. Of course. Obviously. Why had he thought otherwise for even one second?
    Sighing, he picked up the ball grasper, rammed it down the barrel, caught the ball, and jerked it out so hard that it would have made a giveaway noise hitting the deck. Fortunately, it landed on Rincewind’s foot.
    A little metallic sound disturbed him while he was lying across the barrel making the traditional ‘gheeee’ noise of those who are screaming through clenched teeth.
    It was the noise of another cannon ball rolling across the deck. He jumped on it, picked it up, and felt a slight resistance trying to tug it out of his hands. He wrenched against the invisible force, spun around and the ball flew out of his hands and over the rail.
    This time the ‘plomp!’ caused an interrogatory mumble from below decks.
    The last remaining ball started to roll towards the cannon.
    ‘Oh no you don’t!’ snarled Rincewind, and grabbed it. Again the force tried to pull the ball away from him, but he clung on tightly.
    There was the sound of footsteps climbing stairs. Somewhere close, in the fog, someone sounded angry.
    Then in the billows in front of Rincewind there was … something. He couldn’t make out the shape, but it disturbed the fog, making an outline of sorts. It looked like—
    It let go as someone hurried closer. Rincewind growled in triumph, staggered backwards, tipped over the rail and, still clutching the cannon ball, went ‘plomp!’
    ‘Look at the red circles, sir!’ shouted Ponder.
    Erratically, in the drifting tangle of lights, the red circles were winking out. The yellow line was extending.
    ‘That’s the style, Mr Stibbons!’ the Archchancellor roared. ‘Keep pounding away!’
    Wizards were scuttling through the hall, getting fresh instructions, catching their breath and disappearing in the circle again.
    Ridcully nodded at the stretcher containing the screaming Pennysmart, as it was hurried away to the Infirmary.
    ‘Never seen that shade of purple on a leg,’ he said. ‘I told him to look where he was going. You heard me, didn’t you?’
    ‘He says he was dropped right on top of the fish,’ said Ponder. ‘I’m afraid Hex is running at the very limit of his power, sir. We’re bending an entire timeline. You’ve got to expect some accidents. A few of the returning wizards are reappearing in the fountain. We just have to accept that it’s better than them reappearing inside walls.’
    Ridcully surveyed the throng, and said: ‘Here comes one from the fountain, by the look of it …’
    Rincewind limped in, his face like thunder, water still streaming off him, with something grasped in his hands. Halfway across the hall a fish fell out of his robe, in obedience to the unbreakable laws of humour.
    He reached Ponder, and dropped the cannon ball on the floor.
    ‘Do you know how hard it is to shout underwater?’ he demanded.
    ‘But I see you were successful, Rincewind,’ said Ridcully.
    Rincewind looked up. All over the streaming lines, little pointy wizard symbols were appearing and disappearing.
    ‘No one told me it would fight back! It fought back! The cannon tried to load itself!’
    ‘Aha!’ said Ridcully. ‘The enemy is revealed! We’re nearly there! If they are breaking the—’
    ‘It was an Auditor,’ said Rincewind, flatly. ‘It was trying to be invisible but I saw it outlined in the fog.’
    Ridcully sagged a little. A certain exuberance faded from his face. He said, ‘Oh, darn,’ because an amusing misunderstanding in his youth had led him to believe that this was the worst possible word you could say.
    ‘We’ve found no evidence