They looked his way several times, but the sergeant was so much in harmony with the color scheme of the earth on which he crept, that no blame lay upon them for not seeing him.
The sergeant was already hearing with his own ears.

He heard these pickets and others talking in low voices of the Northern army and of their own.

They knew that Buell's great force was approaching from different points and that a battle was expected on the morrow.

He knew this already, but he wanted to know how much of the Confederate army lay in Perryville, and he intended to see with his own eyes.
Having passed the first line of pickets the sergeant advanced more rapidly, although he still kept well under cover.

Advancing thus he reached the bed of the creek and hid himself against the bank, allowing his body to drop down in the water, in order that he might feel the glorious cool thrill again, and also that he might be hidden to the neck.