An Army Corps on the March Walt Whitman

With its cloud of skirmishers in advance,
With now the sound of a single shot snapping like a whip, and now an
        irregular volley,
The swarming ranks press on and on, the dense brigades press on,
Glittering dimly, toiling under the sun—the dust-cover'd men,
In columns rise and fall to the undulations of the ground,
With artillery interspers'd—the wheels rumble, the horses sweat,
As the army corps advances.