"I'd be glad to. Can't sit here all day."

"These cuts on your head and hands aren't sealed yet. They'll sting like the devil when you get out into this cold."

"Got to get used to it, haven't I? Lead the way."

The airliner, crouching in the snow like some great wounded bird, was faintly visible in the twilight now, seven or eight hundred yards away to the north-east, port wing-tip facing us, lying at exactly right angles to our line of sight. There was no saying how often we might have to go out there, the quasi daylight would be gone in another hour or so, and it seemed pointless to follow in darkness the zigzag route we had been compelled to make the previous night, so with help from Zagero and Corazzini I staked out a route, with bamboo markers about five yards apart, straight out to the plane. Some of the bamboos I fetched from the tunnel, but most of them were transplanted from the positions where they had been stuck the previous night.

Inside the plane itself it was as cold as the tomb and as dark as the tomb. One side of the plane was already thickly sheeted in drift ice, and all the windows were completely blanked off, made opaque, by rime frost. In the light of a couple of torches we ourselves moved around like spectres, our heads enveloped in the clouds of our frozen breath, clouds that remained hanging almost stationary above our heads. In the silence we could faintly hear the crackling of our breath in the super-chilled air, followed by the curious wheezing noise that men make in very low temperatures when they were trying not to breathe too deeply.

"God, this is a ghastly place," Zagero said. He shivered, whether or not from cold it was impossible to say, and flashed his torch at the dead man sitting in the back seat. "Are we – are we going to leave them there, Doc?"

"Leave them?" I dumped a couple of attache-cases on to the pile we were making in the front seat. "What on earth do you mean?"

I don't know, I thought – well, we buried the second officer this morning, and – "Bury them? The ice-cap will bury them soon enough. In six months' time this plane will have drifted over and be vanished for ever. But I agree – let's get out of here. Give anyone the creeps."

As I made my way to the front I saw Corazzini, a doleful look on his face, shaking an ebonite and metal portable radio and listening to the rattling that came from inside.

"Another casualty?" I inquired.

"Afraid so." He twiddled some dials, without result. "Battery and mains model. A goner, Doc. Valves, I expect. Still, I'll tote it along – cost me two hundred dollars two days ago."

Two hundred?" I whistled. "You should have bought two. Maybe Joss can give you some valves. He's got dozens of spares."

"No good." Corazzini shook his head. "Latest transistor model – that's why it was so damn' expensive."

"Take it with you," I advised. "It'll only cost you another two hundred to get it repaired in Glasgow. Listen, there's Jackstraw now."

We could hear the barking of dogs, and we lost no time in lowering the odds and ends down to Jackstraw who loaded them on the sledge. In the forward hold we found about twenty-five suitcases of various sizes. We had to make two trips to bring all the stuff back, and on the second trip the rising wind was in our faces, already lifting the drift off the ice-cap. The climate on the Greenland plateau is one of the most unstable in the world, and the wind, which had all but stopped for a few hours, had now veered suddenly to the south. I didn't know what it presaged, but I suspected it wasn't anything good.

We were all chilled to the bone by the time the luggage had been lowered down into the cabin, and Corazzini looked at me, his eyes sober and speculative. He was shaking with cold, and his nose and one of his cheeks were white with frostbite, and when he pulled off one of his gloves the hand, too, Was limp and white and dead.

"Is this what it's like to be exposed to this stuff for half an hour, Dr Mason?"

"I'm afraid it is."

"And we're to be out in this for maybe seven days and seven nights! Good God, man, we'll never make it! And the women, old Miss LeGarde, and Brewster and Mahler, they're no chickens either – " He broke off, wincing – and I was beginning to suspect that it would take a great deal to make this man wince – as the circulation returned under the influence of vigorous rubbing. "It's nothing short of suicide."

"It's a gamble," I corrected. "Staying here and starving to death is suicide."

"You put the alternative so nicely." He smiled a smile that never touched the cold and determined eyes. "But I guess you're right at that."

Lunch that day was a bowl of soup and crackers, poor fare at any time, shockingly insufficient to stay and warm men who would have to work for the next few hours in these bitter sub-zero temperatures above. But there was no help for it: if it would take us a week to reach the coast, and in all optimism I couldn't count on less, rationing would have to start now.

In a matter of a couple of hours the thermometer reading had risen with astonishing speed – these dramatic temperature variations were commonplace on the ice-cap – and it was beginning to snow when we emerged from the hatch and moved across to where the tractor lay. The rise in temperature flattered only to deceive: the south wind brought with it not only snow but a rapidly climbing humidity, and the air was almost unbearably chill.

We ripped off the covering tarpaulin – it cracked and tore but I was no longer concerned with preserving it – and our guests saw for the first time the vehicle upon which all their lives were to depend. Slowly I played my torch over it – the dark shroud of the arctic night had already fallen across the ice-cap – and I heard the quick indrawn hiss of breath beside me.

"Drove it out when the museum attendant wasn't looking, I suppose." Corazzini kept his voice carefully expressionless. "Or did you just find it here – left over from the last ice-age?"

"It is a bit old," I admitted. "Pre-war. But all we can afford. The British Government isn't quite so lavish with its IGY expenditure as the Russians and your people. Know it? It's the prototype, the ancestor of the modern arctic tractor."

"Never seen it before. What is it?"

"French. A 10-20 Citroen. Underpowered, narrow-tracked as you can see, and far too short for its weight. Lethal in crevasse country. Plods along fairly well on the frozen ice-cap, but you'd be better with a bicycle when there's any depth at all of new-fallen snow. But it's all we have."

Corazzini said no more. As the managing director of a factory producing some of the finest tractors in the world, I suppose his heart was too full to say any more. But his disappointment made no difference to his drive, his sheer unflagging determination. For the next few hours he worked like a demon. So, too, did Zagero.

Less than five minutes after we had started work we had to stop again to rig up a canvas screen, lashed to aluminium poles brought up from the runnel, round three sides of the tractor: work had been impossible in that snow and knife-like wind that lanced through even the bulkiest layers of clothing – and most of them were now wearing so many that they could move only with difficulty – as if they were tissue paper. Behind this screen we placed a portable oil stove – the very illusion of warmth was better than nothing – two storm lanterns and the blow-torches without which we could have made no progress at all. Even with this shelter, practically everyone had to go below from time to time to rub and pound life back into his freezing body: only Jackstraw and I, in our caribou furs, could stay up almost indefinitely. Joss was below all the afternoon: after spending a couple of hours trying to raise our field party on the tractor's emergency radio he gave up and went doggedly back to work on the RCA.