I hurried across to where the tractor, sheeted in tarpaulin, lay close in to the high snow wall that had been cut down the middle of the drift. It took me a couple of minutes to clear away the accumulated snow at one end and wriggle in under the tarpaulin. There was no question of trying to lift it—its impregnated oils had frozen solid and it would have cracked and torn under any pressure.

The searchlight, fixed to a couple of bolts on the tractor bonnet, was held down by two quick-release butterfly nuts. In these latitudes, quick-release was a misnomer: the nuts invariably froze after even the briefest exposure. The accepted practice was to remove one's gloves and close mittened hands round the nuts until body heat warmed and expanded them enough to permit unscrewing. But there was no time for that tonight: I tapped the bolts with a spanner from the tool box and the steel pins, made brittle by the intense cold, sheared as if made from the cheapest cast iron.

I crawled out at the foot of the tarpaulin, searchlight clutched under one arm, and as soon as I straightened I heard it again—the roar of aero engines, closing rapidly. They sounded very near, very low, but I wasted no time trying to locate the plane. Head lowered against the wind and the needle-sharp lances of the flying ice, I felt rather than saw my way back to the cabin hatch and was brought up short by Jackstraw's steadying hand. He and Joss were busy loading equipment aboard the sledge and lashing it down, and as I stooped to help them something above my head fizzled and spluttered into a blinding white .re that threw everything into a harsh black and white relief of frozen snow and impenetrable shadow. Joss, remembering what I had completely forgotten—that dousing our cabin lights would have robbed the pilot of his beacon—had ignited a magnesium flare in the slats of the instrument shelter.