He was to let the rustlers pass him if they rode for the ford, and then help to cut off the retreat of any who escaped the sergeant, while if they found the ice too thin for loaded beasts or rode towards the bridge, a flash from his carbine would bring his comrades across in time to join the others who were watching that trail.

It had, as usual with Stimson's schemes, all been carefully thought out, and the plan was eminently workable, but unfortunately for the grizzled sergeant a better brain than his had foreseen the combination.
In the meanwhile the lad felt his limbs grow stiff and almost useless, and a lethargic numbness blunt the keenness of his faculties as the heat went out of him.

He had more than usual endurance, and utter cold, thirst, and the hunger that most ably helps the frost, are not infrequently the portion of the wardens of the prairie, but there is a limit to what man can bear, and the troopers who watched by the frozen river that night had almost reached it.

Shannon could not feel the stirrups with his feet.

One of his ears was tingling horribly as the blood that had almost left it resumed its efforts to penetrate the congealing flesh, while the mittened hands he beat upon his breast fell solidly on his wrappings without separate motion of the fingers.