ending the movement in a plunge that took up the slack and with a sudden jerk arrested his one hundred and fifty pounds. The load quivered, and from under the runners arose a crisp crackling.

“Haw!” Thornton commanded.

Buck duplicated the man�uvre, this time to the left. The crackling turned into a snapping, the sled pivoting and the runners slipping and grating several inches to the side. The sled was broken out. Men were holding their breaths, intensely unconscious of the fact.

“Now, MUSH!”

Thornton’s command cracked out like a pistol-shot. Buck threw himself forward, tightening the traces with a jarring lunge. His whole body was gathered compactly together in the tremendous effort, the