When Robin Hood was about twenty years old,

mound of clothing, rode on the dog-sled while the others walked. The tractor was wide, the trail narrow and sometimes sloping outwards and downwards, and with a sideslip into the gaping crevasse that bordered our path nobody inside the cabin would have had any chance of escape. The first part was easy. The trail, sometimes not more than eight or nine feet broad, more often than not opened out into a shelf wide enough, almost, to be called the flat floor of a valley, and we made rapid progress. At noonI'd warned Hillcrest that we would be traversing the Vindeby Nunataks then and would have to miss our regular radio schedulewe were more than half-way through and had just entered the narrowest and most forbidding defile in the entire crossing when Corazzini came running up alongside the tractor and waved me down to a stop. I suppose he must have been shouting but I'd heard nothing above the steady roar of the engine: and, of course, I'd seen nothing, because they had all been behind me and the width of the tractor cabin made my driving mirror useless. Trouble, Doc," he said swiftly, just as the engine died. "Someone's gone over the edge. Come on. Quick!" "Who?" I jumped out of the seat, forgetting all about the gun I habitually carried in the door compartment as an insurance against surprise attack when I was driving. "How did it happen?" "The German girl." We were running side by side round a corner in the track towards the little knot of people forty yards back, clustering round a spot on the edge of the crevasse. "Slipped, fell, I dunno. Your friend's gone over after her." "Gone after her!" I knew that crevasse was virtually bottomless. "Good God!" I pushed Brewster and Levin to one side, peered gingerly over the edge into the blue-green depths below, then drew in my breath sharply. To the right, as I looked, the gleaming walls of the crevasse, their top ten feet glittering with a beaded crystalline substance like icing sugar, and here not more than seven or eight feet apart, stretched down into the illimitable darkness, curving away from one another to form an immense cavern the size of which I couldn't even begin to guess at. To the left, more directly below, at a depth of perhaps twenty feet, the two walls were joined by a snow and ice bridge, maybe fifteen feet long, one of the many that dotted the crevasse through its entire length. Jackstraw was standing on this pressed closely into one edge, holding an obviously dazed Helene in the crook of his right arm. It wasn't panasonic digital camera g-1 hard to work out Jackstraw's presence there. Normally, he was far too careful a man to venture near a crevasse without a rope, and certainly far too experienced to trust himself to the treachery of a snow-bridge. But, when Helene had stumbled over the edge, she must have fallen heavilyalmost certainly in an effort to protect her broken collar-boneand when she had risen to her feet had been so dazed that Jackstraw, to prevent her staggering over the edge of the snow-bridge to her death, had taken the near-suicidal gamble of jumping after her to stop her. Even in that moment I wondered if I would have had the courage to do the same myself. I didn't think so. "Are you all right?" I shouted. "I think my left arm is broken," Jackstraw said conversationally. "Would you please hurry, Dr Mason? This bridge is rotten, and I can feel it going." His arm broken and the bridge goingand, indeed, I could see chunks of ice and snow falling off from the underside of the arch on which he was standing! The matter-of-fact lack of emotion of his voice was more compelling than the most urgent cry could possibly have been. But for the moment I was in the grip of a blind panic that inhibited all feeling, all thought except the purely destructive. Ropesbut Jackstraw couldn't tie a rope round himself, not with an arm gone, the girl couldn't help herself either, both of them were helpless, somebody would have to go down to them, and go at once. Even as I stared into the crevasse, held in this strange motionless thrall, a large chunk of niv6 broke off from the side of the bridge and plummeted slowly down into the depths, to vanish from sight, perhaps two hundred feet below, long before we heard it strike the floor of the crevasse. I jumped up and raced towards the tractor sled. How to belay the man who was lowered? With only eight or nine feet between the edge of the crevasse and the cliff behind, not more than three men could get behind a rope, and, with perhaps two men dangling at the end of it what possible purchase could those three find on that ice-hard snow to support them, far less pull them up? They would be pulled over the edge themselves. Spikesdrive a spike into the ground and anchor a rope to that. But heaven only knew how long it would take to drive a spike into the icy surface with no guarantee at the end that the ice wouldn't crack and refuse to hold, and all the time that