Sleep is so insidious in its approach that the sentry, as a usual thing, can only fight it off by incessant action. So long as he paces back and forth, his senses stay with him, but when he sits down a minute or so to rest, unconsciousness is sure to come. But Ogallah would not have assumed the easy position had he not felt sure of his self-control. It will be perceived that he had so placed himself that he had a perfect view of the camp, while he could see all that was possible of the surrounding gloom. If required, he could use the oak as a shield, and only a slight signal was needed on his part to rouse the sleeping warriors to instant wakefulness.