The Collected Stories of Arthur C. Clarke by Arthur C. Clarke Page A

really annoyed or excited. Many people thought him lazy but that was a libel. He would spend weeks working out a theory until it was absolutely watertight—and then would put it away for two or three months to have another look at it later.
    Yet once at the controls of a cat this quiet and peaceloving astronomer became a daredevil driver who held the unofficial record for almost every tractor drive in the northern hemisphere. More than likely the explanation lay in a boyhood desire to be a spaceship pilot, a dream that had been foiled by physical disability.
    They shot down the last foothills of the Alps and put into the Sea of Rains like a miniature avalanche. Now that they were on lower ground Wheeler began to breathe again, thankful to have left the vertiginous slopes behind. He was not so pleased when with a colossal crash Jamieson drove the tractor off the road and out into the barren plain.
    ‘Hey, where are you going?’ he cried.
    Jamieson laughed at his consternation. ‘This is where the rough stuff begins. The road goes southwest to Aristillus here and we want to get to Pico. So from now on we’re in country where only half a dozen tractors have ever been before. To cheer you up I might say Ferdinand is one of them.’
    ‘Ferdinand’ was now plunging ahead at twenty miles an hour with a swaying motion Wheeler found rather disconcerting. If he had lived in an age that had known of ships he might have been familiar with it.
    The view was disappointing, as it always is at ‘sea’ level on the Moon, owing to the nearness of the horizon. Pico and all the more distant mountains had sunk below the skyline and the plain ahead looked uninviting as it lay in the blazing sun. For three hours they forged steadily across it, passing tiny craterlets and yawning crevasses that seemed of indefinite depth.
    Once Jamieson stopped the tractor and the two men went out in their space-suits to have a look at a particularly fine specimen. It was about a mile wide and the Sun, now nearly at the zenith, was shining straight into it. The bottom was quite flat as though, when the rock had split, lava had flowed in from the depths beneath and solidified. Wheeler found it very difficult to judge just how far away the floor was.
    Jamieson’s voice came over the suit radio. ‘See those rocks down there?’
    The other strained his eyes and could barely make out a few markings on the apparently smooth surface far below.
    ‘Yes, I think I see the ones you mean. What about them?’
    ‘How big would you say they are?’
    ‘Oh, I don’t know—maybe a yard across.’
    ‘Hmmm. See the smaller one near the side?’
    ‘Yes.’
    ‘Well, that isn’t a rock. That was a tractor that missed the bend.’
    ‘Good Lord! How? It’s plain enough.’
    ‘Yes, but this is midday. Toward evening, when the Sun’s low, it’s the easiest thing in the world to mistake a shadow for a crevasse—and the other way round.’
    Wheeler was very quiet as they walked back to their machine. Perhaps, after all, they had been safer in the mountains.
    At length the great rock mass of Pico came once more into sight until presently it dominated the landscape. One of the most famous landmarks on the Moon it rose sheer out of the Sea of Rains, from which, ages ago, volcanic action had extruded it. On Earth it would have been completely unclimbable. Even under one-sixth of Earth’s gravity only two men had ever reached its summit. One of them was still there.
    Moving slowly over the jagged terrain the tractor skirted the flanks of the mountain. Jamieson was searching for a place where the cliffs could be scaled so they could get a good view out over the Sea. After travelling several miles he found a spot that met with his approval.
    ‘Climb those cliffs? Not on your life!’ expostulated Wheeler when Jamieson explained his plan of action. ‘Why, they’re practically vertical and half a mile high!’
    ‘Don’t exaggerate,’ retorted the other. ‘They’re quite