The temperature was dropping down into the minus thirties, but it was a perfect night for arctic travel – a moonlit, windless night under a still and starry sky. Visibility was phenomenal, the ice-cap was smooth and flat, the engine ran sweetly with never a falter: had it not been for the cold, the incessant roar and body-numbing vibration of the big engine, I think I would almost have enjoyed it.

With the wide tractor body blocking off the view behind, it was impossible for me to see what was happening there: but every ten minutes or so Jackstraw would jump off and stand by the side of the trail. Behind the tractor body and its shivering occupants -because of the tractor fuel tank beneath and the spare fuel drums astern the stove was never lit while we were in motion – came the sledge with all our stores: 120 gallons of fuel, provisions, bedding and sleeping-bags, tents, ropes, axes, shovels, trail flags, cooking utensils, seal meat for the dogs, four wooden bridging battens, canvas sheets, blow-lamps, lantern, medical equipment, radiosonde balloons, magnesium flares and a score of minor items. I had hesitated over including the radio sondes, especially the relatively heavy hydrogen cylinders for these: but they were ready crated with tents, ropes, axes and shovels and – this was the deciding factor – had saved lives on at least one occasion when a trail party, lost on the plateau with defective compasses, had saved themselves by releasing several balloons in the brief daylight hours thereby enabling base to see them and send accurate radio bearings.

Behind the heavy transport sled was towed the empty dog-sled, with the dogs on loose traces running astern of it, all except Balto who always ran free, coursing tirelessly backwards and forwards all night long, one moment far ahead of us, the next ranging out to one side, the next dropping astern, like some destroyer circling a straggling convoy by night. When the last of the dogs had passed by him, Jackstraw would run forward to overtake the tractor and jump in alongside me once more. He was as tireless, as immune to fatigue, as Balto himself.

The first twenty miles were easy. On the way up from the coast, over four months previously, we had planted big marker flags at intervals of half a mile. On a night such as this, with the moonlight flooding the ice-cap, these trail flags, a bright luminous orange in colour and mounted on aluminium poles stuck in snow beacons, were visible at a great distance, with never less than two and sometimes three in sight at the same time, the long glistening frost feathers stretching out from the poles sometimes twice the length of the flags themselves. We counted twenty-eight of these flags altogether – about a dozen were missing – then, after a sudden dip in the land, completely lost them: whether they had blown away or just drifted under it was impossible to say.

"Well, there it is, Jackstraw," I said resignedly. "This is where one of us starts getting cold. Really cold."

"We've been cold before, Dr Mason. Me first." He slid the magnetic compass off its brackets, started to unreel a cable from a spool under the dashboard, then jumped out, still unwinding the cable, while I followed to help. Despite the fact that the magnetic north pole is nowhere near the north pole – at that time it was almost a thousand miles south of it and lay more to the west than north of us – a magnetic compass, when proper variation allowances are made, is still useful in high latitudes: but because of the counter-acting magnetic effects of a large mass of metal, it was quite useless when mounted on the tractor itself. Our plan, therefore, was that someone should He with the compass on the dog-sled, fifty feet behind the tractor, and, by means of a switch which operated red and green lights in the tractor dashboard, guide the driver to left or right. It wasn't our original idea, it wasn't even a recent idea: it had been used in the Antarctic a quarter century previously but, as far as I knew, had not been improved upon yet.

With Jackstraw established on the sledge, I walked back to the tractor and pushed aside the canvas screen at the back of the wooden body. What with the faces of the passengers, drawn and pinched and weirdly pale in the light of the tiny overhead bulb, the constant shivering, the chattering of teeth and the frozen breath drifting upwards to condense and freeze on the wooden roof, it was a picture of utter and abject misery: but I was in no mood to be moved at that moment.

"Sorry for the delay," I said. "Just off again now. But I want one of you for a lookout."

Both Zagero and Corazzini volunteered almost in the same breath, but I shook my head.

"You two get what sleep or rest you can – I'm liable to need you very much later on. Perhaps you, Mr Mahler?"

He looked pale and ill, but he nodded silently, and Zagero said in a quiet voice: "Corazzini and myself too high up on the list of suspects, huh?"

"I wouldn't put either of you at the very foot," I said shortly. I waited till Mahler had climbed down then dropped the canvas and walked round to the driver's seat.

Theodore Mahler, strangely enough, proved only too anxious to talk – and keep on talking. It was so completely out of keeping with the idea I had formed of his character that I was more than surprised. Loneliness, perhaps, I thought, or trying to forget the situation, or trying to divert my thoughts and suspicions: how wrong I was on all three counts I wasn't to find out until later.

"Well, Mr Mahler, it looks as if the itinerary of your European trip is going to be upset a bit." I had almost to shout to make my words heard above the roar of the tractor.

"Not Europe, Dr Mason." I could hear the machine-gun-like chatter of his teeth. "Israel."

"You live there?"

"Never been there in my life.1 There was a pause, and when his voice came again it was all but drowned in the sound of the engine. I thought I caught the words 'My home'.

"You – you're going to start a new life there, Mr Mahler?"

Tm sixty-nine – tomorrow," he answered obliquely. "A new life? Let's say, rather, that I'm going to end an old one."

"And you're going to live there, make your home there – after sixty-nine years in another country?"

"Millions of us Jews have done just that, in the past ten years. Not that I've lived in America all my life. . . . "

And then he told me his story – a story of refugee oppression that I'd heard a hundred times, with a hundred variations. He was a Russian Jew, he said, one of the millions of the largest Jewry in the world that had been 'frozen' for over a century in the notorious Pale of Settlement, and in 1905 had been forced to flee with his father – leaving mother and two brothers behind – to escape the ruthless massacres carried out by the 'Black Hundreds' at the behest of the last of the Romanoff Tzars who was seeking scapegoats for his crushing defeat by the Japanese. His mother, he learned later, had just disappeared, while his two brothers had survived only to die in agony long years afterwards, one in the rising in the Bialystok ghetto, the other in the Treblinka gas chambers. He himself had found work in the clothing industry in New York, studied in night school, worked for an oil company, married and with the death of his wife that spring had set about fulfilling the agelong ambition of his race, the return to their holy land.

It was a touching story, pathetic and deeply moving, and I didn't believe a word of it.

Every twenty minutes I changed position with Jackstraw and so the long hours of the night dragged by as the cold deepened and the stars and the moon wheeled across the black vault of the sky. And then came moonset, the blackness of the arctic night rushed across the ice-cap, I slowed the Citroen gratefully to a stop and the silence, breathless and hushed and infinitely sweet, came flooding in to take the place of the nightlong clamour of the deafening roar of the big engine, the metallic clanking of the treads.