"Behold, the sea itself, and on its limitless, heaving breast, the ships; see, where their white sails, bellying in the wind, speckle the green and blue."

THE WORDS are Walt Whitman's. What music can capture the picture they conjure up? Or that of the lines that soon follow: "Flaunt out, o sea, your separate flags of nations! Flaunt out visible as ever the various flags and ship-signals! But do you reserve especially for yourself and for the soul of man one flag above all the rest, a spiritual woven signal for all nations, emblem of man elate above death, token of all brave captains and of all intrepid sailors and mates, and all that went down doing their duty."

Well, there is music to catch Whitman's spirit, music that suggests the vast spaces of the ocean and the gallantry of those who, for centuries, sailed its depths. It is by Vaughan Williams, and it will be played and sung on Tuesday evening in the Kennedy Center by the Choral Arts Society, conducted by Norman Scribner, with soloists and orchestra.

Another English composer attracted to Whitman's "Sea Drift," was Frederick Delius who, in 1903, finished the cantata named for the poem. Delius wrote for orchestra, chorus, and baritone soloist. In 1903 Vaughan Williams, Delius' junior by 10 years, began work on what he eventually called "A Sea Symphony."

By 1910, a year after he had completed the Sea Symphony, the first of his nine works in the large form, Vaughan Williams was becoming widely known and admired among musicians. He conducted the world premiere of the new music at the Leeds Festival in October, 1910, when it shared the program with Sergei Rachmaninov's playing of his own second piano concerto. The next year, Vaughan Williams was conducting the world premiere of his Five Mystical Songs at the Worcester Festival. At one point he glanced at the last desk of violins. What he saw so astounded him he nearly dropped his baton. Sitting in that humble spot, playing away with the rest of the fiddles was Fritz Kreisler. He was warming up for the world premiere of the Elgar Concerto that was to come after intermission.

The Sea Symphony put Vaughan Williams on the map for a large public. Its orchestral resources are huge, supported by pipe organ, and dotted with handsome solos for soprano and baritone. Its four movements are those of the classic symphony: an opening allegro in sonato form is called "A Song for All Seas, All Ships." The ensuing slow movement is an exquisite nocturne whose text begins "On the beach at night, alone." The third movement is the scherzo, "The Waves."

For the finale, Williams write a large-scale movement not unlike certain Mahler finales being written around the same time. It is the only section of the symphony whose text does not come from "Sea Drift." Rather, it is taken from a Whitman poem called "The Explorers." Its opening lines, however, are as rapturous in feeling and as all-embracing in imagery as those that open the symphony. It begins, "O vast Rondure swimming in space, covered all over with visible power and beauty, alternate light and day and teeming spiritual darkness..." To the 38-year-old composer, it was precisely what was needed to end a work that today fully merits the label of "the first choral symphony."

Though there are voices, both singing and speaking, in several of his later symphonies, which were to occupy Vaughan Williams throughout the remaining half century of his life, he never returned to the same resplendent wealth of sounds of the Sea Symphony. Often, however, during those years, he turned again to Whitman's verse. And when, in the final year of his life, he was asked if his youthful enthusiasm for Whitman had continued, he answered, "I've never got over him, I'm glad to say."

On Tuesday evening, the Vaughan Williams symphony will be preceded by Benjamin Britten's "Nocturne," for tenor, strings and solo instruments. Here Britten turns again to themes that often appeared in some of his earlier writing: night and sleep. Touched upon in his first great triumph, the opera "Peter Grimes," in his "Winter Words," and to become a central element in his War Requiem, thoughts of sleep and night are found in much of Britten. His remarkable solo for guitar, written for Julian Bream, is called "Nocturnal."

The "Nocturne" to be heard Tuesday dates from 1958. Like so much of the greatest of Britten, it was written for his lifelong friend and colleague, Peter Pears. It includes lines from poets who were among Britten's favorites: Wordsworth, Shakespeare and Wilfrid Owen, whose World War I poetry gives the War Requiem much of its singular power.

With its accompaniment of strings and seven obbligato instruments, as well as its tenor 'solo, "Nocturne" should make a fine foil to the symphony's large resources. Gene Tucker will sing it, while soprano Phyllis Bryn-Julson and baritone William Parker will be the soloists in the symphony.

Norman Scribner had announced and begun preparing the War Requiem for Tuesday's program, with the same three soloists who are to be heard there. But in response to an urgent request from Mstislav Rostropovich, who has programmed the Requiem for the National Symphony next season, in which performance Scribner's chorus will sing, he switched to Vaughan Williams and other Britten music. The change thus allows Washingtonians to hear not only the Requiem, but the Nocturne and the Sea Symphony. All three have the mark of greatness.