I brought it and when I returned Corazzini was sitting on the front of the tractor sled with a case before him. But it wasn't the leather-covered portable radio: it was Smallwood's robe case.

Corazzini snapped open the catches, pulled out Bible, robes and divinity hood, tossed them to one side then carefully brought out a metal box which looked exactly like a tape-recorder: indeed, when he shone his torch on it I could clearly see the word 'Grundig'. But it soon became apparent that it was like no tape-recorder that I had ever seen.

The twin spools he ripped off the top of the machine and sent spinning away into the darkness and the snow, the tape unwinding in a long convoluted streamer. By this time I would have taken long odds that anyone suspicious enough to investigate would have found that tape perfectly genuine: probably, I thought bitterly, Bach's organ music, in keeping with Smallwood's late ecclesiastical nature.

Still in silence, we watched Corazzini undo and fling away the false top of the recorder, but not before I had time to notice the padded spring clips on its underside—the perfect hiding place for a couple of automatics: revealed now were controls and calibrated dials that bore no resemblance to those of a tape-recorder. Corazzini straightened and erected a hinged telescopic aerial, clamped a set of headphones to his ears, made two switches and started to turn a dial, at the same time watching a green magic eye similar to those found in tape-recorders and many modern radios. Faintly, but unmistakably, I could hear a steady whine coming from the earphones, a whine which altered in pitch and intensity as Corazzini turned the dial. When it reached its maximum strength, he turned his attention to a built-in alcohol compass about three inches in diameter. A few moments later he doffed the earphones and turned round, apparently satisfied.

"Very strong, very clear," he announced to Small wood. "But there's too heavy a deviation factor from all the metal in the tractor and sledge. Back in two minutes. Your torch, Dr Mason."

He walked away for about fifty yards, taking the machine with him: it was with intense chagrin that I realised that it was perfectly in keeping with all that had gone before that Corazzini had probably forgotten more about navigation than I was ever likely to know. He returned soon, consulted a small chart—correcting for variation, no doubt—then grinned at Small wood.

"It's them, all right. Perfect signal. Bearing 268."

"Good." If Smallwood felt relieved or gratified at the news, no shadow of his feeling touched the thin immobile face. Their quiet certainty, their forethought, their foolproof organisation was dismaying, frightening. Now that I could see what manner of men they were it was unthinkable that they should have set themselves down in a vast featureless country such as this without some means of orientating themselves: what we had just seen in operation could only be a battery operated radio direction finder, and even to me, inexperienced though I was in such matters, it was obvious that Corazzini must have been taking a bearing on some continuous directional line-up signals transmitted by a vessel, or vessels, off-shore: trawlers, probably, or some other inconspicuous type of fishing vessel. ... I would have been less than human had I not wanted to shake this absolute confidence.

"You've miscalculated the hornet's nest you've stirred up. The Davis Strait, the coast of Greenland is alive with ships and planes. The scout planes of the carrier Triton will pick up every boat that's larger than a skiff. The trawlers will never get away with it: they won't get five miles."

"They don't have to." Implicit in Corazzini's words was confirmation of the accuracy of my guess about trawlers. "There are such things as submarines. In fact there is one, not far from here."

"You still won't—"

"Be quiet," Smallwood said coldly. He turned to Corazzini. "Two hundred and sixty-eight, eh—due west more or less. Distance?"

Corazzini shrugged, said nothing: Smallwood beckoned to me.

"We'll soon find it. That map, Dr Mason—indicate our position, accurately."

"You can go to hell," I said briefly.

"I expected nothing else. However, I'm not blind and your clumsy attempts at concealment have done little to hide the growing attachment between yourself and the young lady here." I glanced quickly at Margaret, saw the faint colour beginning to stain the pale cheek and looked as quickly away. "I am prepared to shoot Miss Ross."