But he changed his plans for the night.

He had intended to keep only one man in ten on watch.

Instead, he kept half, and Sergeant Whitley, veteran of Indian wars, murmured words of approval under his breath.
Whitley and Pennington were in the early watch.

Dick and Warner were to come on later.

The colonel spoke as if he would keep watch all night.
All the horses were tethered carefully inside the ring of pickets.
"It doesn't need any mathematical calculation," said Warner, "to tell that the colonel expects trouble of some kind tonight.