“Running the Batteries” gives an accurate account of the passage of gunboats and other Union ships past the Confederate batteries at Vicksburg. It is in the form of an on-the-spot narration by an observer at the Vicksburg anchorage. The New York Tribune account appears in the Rebellion Record, Volume VI, Doc. 546-548.
Melville’s use of the Tribune story can be more easily traced than can his use of any source so far discussed, partly because the poem abounds in verbal echoes. Apparently he merely ran his finger down the page, picking out key details and putting them in lines that rhymed. He makes one slight alteration from the account in the first two lines: “A moonless night—a friendly one; / A haze dimmed the shadowy shore.” One sentence from the Tribune provides the source for these opening lines, but Melville emphasizes inaccurately the darkness of the night: “The sunset was clear and beautiful, and the stars came out in full radiance. As the night deepened, a slight haze dimmed the bosom of the Mississippi, but the eye had no difficulty in making out the dark line of the opposite shore” (Doc. 547).
Melville’s two lines about the passage downriver of the first two boats, “The first boat melts; and a second keel / Is blent with the foliaged shade,” are a terse version of the Tribune account:

Sombre and silent it floated down, near the Louisiana shore; scarcely were its dark sides to be distinguished from the foliage lining the bank. Stealing slowly, it passed us, and at a point below took an oblique course, steering for the Mississippi side of the river; and in the gloom it was soon confounded with the dark shadow of the trees beyond.
Before this boat was lost sight of, another succeeded . . . (Doc. 547).

The Mississippi from Haines’s Bluff to below Grand Gulf, showing Gen. Grant’s and Admiral Farragut’s operations—Harper’s Weekly (May 23, 1863), p. 327.

Finally, as the Tribune tells it, all the boats disappeared, and the spectators stood on the decks of the anchored boats, holding their breath and speculating on the fate of the boats. “Suddenly a flame starts up! Another and another leaps into the darkness of the night. We can trace the course of our fleet by new flames that each moment startle the strained sight” (Doc. 547). The discovery by the rebels of the passing gunboats and their ensuing fire is rendered by Melville:

The remaining stanzas are composed from the same account, as the quickest comparison shows. For instance, the phrase “new flames that each moment startle the strained sight” (Doc. 547) is reflected in Melville’s “we strain our gaze.” The discovery by the onlookers of the searching Confederate beacon elicits the cry “‘Vicksburgh is on fire!’ . . . uttered in excited tones” (Doc. 547). Melville proclaims the same discovery in his line “‘The town is afire!’ crows Hugh.” The powerful Confederate beacon is described by the Tribune in these words: “So powerful was the light, that at the point where our fleet was moored, the shadow of a hand held a foot from the boat’s side was distinctly thrown upon it” (Doc. 548). Melville transforms this information into “So far and strong, that in phantom cheat/Lank on the deck our shadows lay.”
The lights, however, were as revealing to the Union marksmen as to the Confederates, a fact brought out by the Tribune in this passage:

The lights that showed the boats to the enemy revealed to our men the outlines of the batteries, and the roar which deafens the ear to every other sound is the peal of the heavy pieces on our gun-boats (Doc. 548).

Melville converts this passage to the following:

One final brief example will suffice in illustrating Melville’s use of the Tribune’s account. The Tribune describes the fire on board the transport in these words: “ . . . it wanted the mellow, vivid, space-piercing brilliancy of the beacon; above it rolled volumes of thick and curling smoke” of a “white color” (Doc. 548). Melville rephrases the imagery this way: “Not mellowly brilliant like the first,/But rolled in smoke, whose whitish volumes burst.”