It was the figure of an Indian crawling on his hands and knees towards the coach, scarcely forty yards away.  For the first time that afternoon Boyle’s calm good-humor was overswept by a blind and furious rage.  Yet even then he was sane enough to remember that a pistol shot would alarm the girl, and to keep that weapon as a last resource.  For an instant he crept forward as silently and stealthily as the savage, and then, with a sudden bound, leaped upon him, driving his head and shoulders down against the rocks before he could utter a cry, and sending the scalping knife he was carrying between his teeth flying with the shock from his battered jaw.  Boyle seized it—­his knee still in the man’s back—­but the prostrate body never moved beyond a slight contraction of the lower limbs.  The shock had broken the Indian’s neck.  He turned the inert man on his back—­the head hung loosely on the side.  But in that brief instant Boyle had recognized the “friendly” Indian of the station to whom he had given the card.

He rose dizzily to his feet.  The whole action had passed in a few seconds of time, and had not even been noticed by the sole occupant of the coach.  He mechanically cocked his revolver, but the man beneath him never moved again.  Neither was there any sign of flight or reinforcement from the thicket around him.  Again the whole truth flashed upon him.  This spy and traitor had been left behind by the marauders to return to the station and avert suspicion; he had been lurking around, but being without firearms, had not dared to attack the pair together.

It was a moment or two before Boyle regained his usual elastic good-humor.  Then he coolly returned to the spring, “washed himself of the Indian,” as he grimly expressed it to himself, brushed his clothes, picked up the shawl and flask, and returned to the coach.  It was getting dark now, but the glow of the western sky shone unimpeded through the windows, and the silence gave him a great fear.  He was relieved, however, on opening the door, to find Miss Cantire sitting stiffly in a corner.  “I am sorry I was so long,” he said, apologetically to her attitude, “but”—­

“I suppose you took your own time,” she interrupted in a voice of injured tolerance.  “I don’t blame you; anything’s better than being cooped up in this tiresome stage for goodness knows how long!”

“I was hunting for water,” he said humbly, “and have brought you some.”  He handed her the flask.

“And I see you have had a wash,” she said a little enviously.  “How spick and span you look!  But what’s the matter with your necktie?”

He put his hand to his neck hurriedly.  His necktie was loose, and had twisted to one side in the struggle.  He colored quite as much from the sensitiveness of a studiously neat man as from the fear of discovery.  “And what’s that?” she added, pointing to the shawl.

“One of my samples that I suppose was turned out of the coach and forgotten in the transfer,” he said glibly.  “I thought it might keep you warm.”