Onomatopoeia

onomatopoeia: a figure of speech in which natural sounds are imitated in the sounds of words

"plumping volley"
            -The Red Badge of Courage
                     by Stephen Crane

Stephen Crane's The Red Badge of Courage is a war novel, which documents the experience of a youth, Henry Fleming, who comes to the realization of the mortality of the human, specifically of himself. Crane uses onomatopoeia to draw the reader's attention to this theme in the excerpt above. "Plumping" is how Crane describes the bullets, this gives the reader an auditory image of war and carnage. Bullets do not normally "plump," this is the sound they make when entering a body; Crane uses this to emphasize the carnage of war and the mortality of the body. Fleming is surrounded by bullets making this noise, which tells us, in effect, that he is surrounded by dead and dying men, a place in which the mortality of the body would be quite obvious.