They are the vanguard of the sun." "So they are.

And this is the vanguard of the Southern army!" He spoke the last words quickly and with excitement.
In front of them down the road they heard the crackle of a dozen rifle shots.

The Southern advance undoubtedly had come into contact with the Union sentinels and skirmishers.

After the first shots there was a moment's breathless silence, and then came a scattered and rapid fire, as if at least a hundred rifles were at work.
Dick's pulse began to beat hard, and he strained his eyes through the darkness, but he could not yet see the enemy.

He saw instead little jets of fire like red dots appearing on the horizon, and then the sound of the rifles came again.