The oxen in particular showed symptoms of weakness, and drew the wagon sluggishly; so that Swartboy's voice and long whip were kept in constant action.
But there were other reasons why they would have to halt when night came on.

The field-cornet was not so sure of the direction.

He would not be able to follow it by night, as there was not the semblance of a track to guide him.

Besides it would be dangerous to travel by night, for then the nocturnal robber of Africa--the fierce lion--is abroad.
They would be under the necessity, therefore, of halting for the night, water or no water.
It wanted yet half-an-hour of sundown when Von Bloom had arrived at this decision.

He only kept on a little farther in hopes of reaching a spot where there was grass.