Lisle reflected rapidly as he followed up the crevasse, which showed no sign of narrowing. The snow was thick, the bitter wind increasing, and a plunge into icy water might prove disastrous. It was obvious that he must extricate his companion as soon as possible, but the means of accomplishing it was not clear. Crestwick was somewhere on the wrong side of the crack, which seemed to lead right across the stream toward the confusion of broken ridges and hummocks which, as Lisle remembered, fringed the opposite bank. He must endeavor to find the place where the lad had got across; but this was difficult, for fresh breaches and ridges drove him back from the edge. Presently the chasm ended in a wide opening filled with an inky flood, and Lisle, turning back a yard or two, braced himself and jumped.

He made out a shapeless white object ahead, and coming to another crack he scrambled to the top of an ice-block and leaped again. There was a sharp crackle when he came down, the piece he alighted on rocked, and Crestwick staggered.

“Look out!” he cried. “It’s tilting under!”

Lisle saw water lapping in upon the snow, but it flowed back, and the cake he had detached impinged upon the rest with a crash.

“Come on!” he shouted. “The stream will jamb it fast!”

They reached the larger mass and moved across it, but Lisle, clutching his companion’s arm, bewildered and almost blinded by the snow, doubted if he were retracing his steps. He did not remember some of the ridges and ragged blocks over which they stumbled, and the smaller rents seemed more numerous. It was evident that Crestwick was badly worn out and they must endeavor to reach the bank with as little delay as possible.

At last they came to the broad crevasse, farther up the stream, and Lisle turned to Crestwick.

“Better take off your skin-coat. You’ll have to jump.”

“I can’t,” said the other dejectedly. “It’s not nerve—the thing’s clean beyond me.”

His slack pose—for he was dimly visible amid the haze of driving snow—bore out his words. The long march he had made had brought him to the verge of exhaustion; his overtaxed muscles would respond to no further call on them. For a moment or two Lisle stood gazing at the dark water in the gap.