Once more the figure crossed the line of the scout’s vision. Texas Jack lay, scarcely moving in the grass, and with fingers on wrist counted his pulse while the Indian was in sight. In this way he learned something of the time it took for the sentinel to pace from end to end of his beat. He lay for some time and timed him back and forth to make sure that there was some regularity in the redskin’s actions. Then, at the right moment--as the sentinel passed out of view in one direction, Texas Jack darted forward like a serpent through the tall weeds. Although he ran on his feet and touched but one hand now and then to help retain his balance, the scout’s body could never have been seen above the waving tops of the grass and weeds. For several rods he ran in this way and then dropped down again, panting, hugging the earth, flattening his body upon it, and waiting with every nerve on the qui vive to discover if his actions had been noted. And well he knew that, if the sentinel had seen him, no shout--no sound--would be raised. The red would sneak up behind him, and his first audible sound would be the cry of triumph when the scalping-knife was plunged into the scout’s back! Jack twisted his neck to see back over his shoulder. After a moment the Indian sentinel appeared again. He walked upright. Jack could see his nodding topknot of feathers, and that he carried a gun of some kind. He passed on without even glancing in the scout’s direction. “Thanks be for that!” thought the scout. “Now, what’s ahead?” That the Sioux had but one ring of sentinels around the fort he knew was not the fact. There were two lines at least--possibly three. He raised his head like a turtle stretching from its shell and tried to pierce the gloom of the valley. And then it was that he suddenly beheld a tall figure standing motionless not far ahead of him and almost in his path. It was a chief of some importance from his war-bonnet, and he had perhaps been going the rounds of his sentinels. Now he stood motionless, his back to the scout, looking toward the fort, one elbow leaning upon a broken stub of a tree, the other hand holding his rifle, hanging idly by his side. The chief was evidently in a reverie--or was he listening? Had he heard the scout’s breathing--or some other sound that warned him of the white man’s presence? The question seared Texas Jack’s brain. It startled him to action. This was no moment for taking chances. He rose up like a shadow, and, with great, catlike strides, stole upon the statuelike Indian. It went against the grain for the scout to strike even a redskin from behind. Man to man and face to face in a fair struggle would have pleased Texas Jack better. But the entire success of his attempt to reach the fort depended upon the action of the next few seconds.