To find it would simplify matters, for the Indian had made them understand that the bluffs about the post lay nearly east of it.
Noon passed, and they still pressed forward without a halt, for there was little more than three hours' daylight left, and it was unthinkable that they should spend the night without food or shelter.

The horizon steadily narrowed as the snow thickened; there was a risk of their passing the guiding-marks, or even the factory.
It was nearly three o'clock when Harding stumbled and fell into the snow.

He found himself unable to get up until Benson helped him, and in his attempt to rise he further strained his weakened leg.

For a moment he leaned on his companion, his face contorted with pain.
"The fall seems to have hurt you," Benson said sympathetically.
"I'll have to go on," Harding gasped; and, setting his teeth, he strode forward; but he made only a few paces.

The pain was severe; his head reeled; his strength gave way and he sank down on his knees.
Benson and Blake stopped in consternation.
"If I've kept the right line, we can't be far from the factory," Blake said encouragingly.
"I'm played out," Harding declared.