The wind was blowing _from the north_, and the swarm was directly _to the west_ of the kraal.

The cloud of locusts had approached from the north, as they almost invariably do in the southern parts of Africa.
"Yes," said Hendrik, who having been in their midst could tell what way they were drifting, "they came down upon us from a northerly direction.
When we headed our horses homewards, we soon galloped out from them, and they did not appear to fly after us; I am sure they were passing southwards." Von Bloom entertained hopes that as none appeared due north of the kraal, the swarm might pass on without extending to the borders of his farm.

He knew that they usually followed the direction of the wind.
Unless the wind changed they would not swerve from their course.
He continued to observe them anxiously.

He saw that the selvedge of the cloud came no nearer.

His hopes rose.