the flash of yellow flame that leaped from its summit, heard the sharp report of a gun, and saw Wasson crumble up, and go down, still clinging to his horse’s rein.  It came so suddenly, so unexpectedly, that the single living man left scarcely realized what had happened.  Yet dazed as he was, some swift impulse flung him, headlong, into the snow behind his pony, and even as he fell, his numbed fingers gripped for the revolver at his hip.  The hidden marksman shot twice, evidently discerning only dim outlines at which to aim; the red flame of discharge cut the gloom like a knife.  One ball hurtled past Hamlin’s head; the other found billet in Wade’s horse, and the stricken creature toppled over, bearing its dead burden with him.  The Sergeant ripped off his glove, found the trigger with his half-frozen fingers, and fired twice.  Then, with an oath, he leaped madly to his feet, and dashed straight at the silent hill.

CHAPTER XXVI

UNSEEN DANGER

Once he paused, blinded by the snow, flung up his arm, and fired, imagining he saw the dim shape of a man on the ridge summit.  There was no return shot, no visible movement.  Reckless, mad with rage, he sprang up the wind-swept side, and reached the crest.  It was deserted, except for tracks already nearly obliterated by the fierce wind.  Helpless, baffled, the Sergeant stared about him into the driving flakes, his ungloved, stiffening hand gripping the cold butt of his Colt, ready for any emergency.  Nothing but vacancy and silence encompassed him.  At his feet the snow was still trampled; he could see where the man had kneeled to fire; where he had run down the opposite side of the hill.  There had been only one—­a white man from the imprint—­and he had fled south, vanishing in the smother.

It required an effort for the Sergeant to recover, to realize his true position, and the meaning of this mysterious attack.  He was no longer numb with cold or staggering from weakness.  The excitement had sent the hot blood pulsing through his veins; had brought back to his heart the fighting instinct.  Every desire urged him forward, clamoring for revenge, but the aroused sense of a plainsman held him motionless, staring about, listening for any sound.  Behind him, down there in the hollow, were huddled the horses of his outfit, scarcely distinguishable from where he stood.  If he should venture farther off, he might never be able to find a way back again.  Even in the gray light of dawn he could see nothing distinctly a dozen yards distant.  And Wasson had the compass.  This was the thought which brought him tramping back through the drifts—­Wasson!  Wade was dead, Carroll little better, but the scout might have been only slightly wounded.  He waded through the snow to where the man lay, face downward, his hand still gripping the rein.  Before Hamlin turned him over, he saw the jagged wound and knew death