“Don’t lose your grip, men! Better freeze to the walls than fall below there!” Captain Bartlot’s voice echoed through the great ice cave.

Dwarfed to mere fly-size by the immensity of vast ice columns and ice-frescoed sides of the cavern, Bartlot’s crew clung to the precarious ledges above the white-fanged wolf-pack that crouched waiting, waiting, below.

Sinister shapes, long-jawed, powerful, were those shaggy killers of the North. When they had burst, full cry, from the cave depths, a paralysis of fear had numbed the men’s brains for an instant. Another instant and they had gone leaping, scrambling, screaming up the ice wall,—with never a thought for food or weapons, never a thought for aught save putting space between them and those slavering, slashing jaws.

Endurance gains the wolf-pack its meat—relentless persistence in the chase and untiring watching and waiting for hunger, weakness and thirst to drop some beleaguered creature into their jaws.

Green eyes of hate glared up from the cave floor at the men trapped on the ice wall. Red tongues lolled hungrily over long jaws each time there was some faint movement of slipping or sliding, for it might presage a human losing grip and falling into the waiting death ring below.

One man did fall—Eric Borden, of the geological surveyors. The ice column against which his lank person was wedged broke and shot him, slipping and clawing, down the wall. The boom of the falling ice, Sanderson’s knife hurled below, the flash of the two shots left in Bartlot’s revolver—these created distraction enough to hurl back the wolves for a moment, while many hands reached down to rescue a comrade, to haul him back to the ledges.

Bartlot’s shots had killed a wolf. The knife had drawn blood on another. Snarling and howling, the pack leaped upon its own unfortunates, tore them asunder, devoured them.

The men on the ice above shivered and dug deeper into crack and crevice.

Wedged precariously between two crystal-white stalactites on the wall, Lee Renaud trusted to the pressure of knee and foot to hold him firm, and thus leave his hands free. In spite of weariness, in spite of nerve rack from the hundred-eyed monster that waited below, Lee forced his fur-clad fingers on with their tinkering at a tiny radio set he carried on his back, a finished, polished copy of his own crude portable outfit. Factory experts had carried out his ideas in a more compact, lighter arrangement than he had been able to achieve with the rough materials available in his backwoods laboratory. But whether this new arrangement would send the call for help as effectively as that old rattletrap had done during the Sargon flood—well, that was something to be proved.

Lee’s hands trembled as he pushed the wire framing of the folding aerial up and up over his head, while he crouched low to give room for it in the slanting niche in which his body was jammed.