The last outdoor concert this season by the National Symphony Orchestra last night on the West Lawn of the U.S. Capitol ostensibly celebrated the bicentennial of the signing of the Treaty of Paris.

The performance itself, however, was one of many happenings distinguishing this event, which drew an estimated 60,000 revelers--many of whom sipped alcoholic libations, trying to stay reasonably cool and comfortable.

Conductor Hugh Wolff's program was divided between works by American and British composers. The first half, "given over to the Yanks"--as narrator Henry Tenenbaum of WRC-TV remarked--was distinguished by two firsts: The premiere of Washington composer Stephen Burton's "Fanfare for Peace" and pianist Alison Deane's debut with the NSO.

Tenenbaum opened the concert by asking the carpet of humanity before him to observe a moment of silence in tribute to the late senator Henry Jackson and the victims of the Korean jumbo jet reportedly shot down by the Soviets. "The Star-Spangled Banner" rarely ever sounded so poignant, set off by the brightly gleaming Capitol, and American flags flying half-mast against the night sky.

Burton's "Fanfare for Peace" was distinguished by its anthem-like quality and the puzzling, extensive use of minor chords. The short piece was graciously interpreted by Wolff, to the delight of the composer, who hugged the conductor during enthusiastic applause.

Leonard Bernstein's "Divertimento"--which is seemingly borrowed from his "Overture to Candide"--and the real crowd-pleaser, Gershwin's "Rhapsody in Blue," closed the first half. Pianist Deane--and Wolff--unfortunately missed Gershwin's many nuances of color and tempo; it was very ordinary, if satisfying. Deane has a fluid, buoyant touch, highly stylized, which complemented Wolff's idiosyncratic interpretation.

The first half opened on a theme of peace, and the second opened with "Mars"--the god of war--from Holst's "The Planets." Wolff drew a muscular, impressive, no-holds-barred performance of this ethereal music. The second, "British" half concluded with Britten's "The Young Person's Guide to the Orchestra."