Mstislav Rostropovich and Pearl Bailey took over the west lawn of the U.S. Capitol on Saturday night to give a huge audience one of the great Fourth of July concerts in this city's history. Thier combined impact was far more than the simple coming together of two great performing artists.

Pearl Bailey stood there under the cloudless sky -- who would have believed at 4 in the afternoon that the concert could go on at all, so fierce had the rains been -- and talked about having been born only blocks away from the spot on which she was standing. At 7th and T, she said. And then she sang the national anthem as only she could sing it. It happened to be in the key of D flat for the first time in memory, but that was the right key for Bailey and that was all that mattered.

She came back later on to talk about Julia Ward Howe who wrote the words of "The Battle Hymn of the Republic." And, as Bailey said, Sulia Ward Howe, too, stood on that same spot and watched the Army of the Potomac and was inspired to write those words. Then, in some kind of mesmerizing process, Pearl Bailey sang two verses of the song. And no one would let her stop. She sang a verse again. And when the applause still refused to end, she said, "Well, I don't know what they are doing in the television studio. They are probably saying, 'What are we going to do?' But Maestro, would you play it again? And this time, you" -- turning to the thousands seated in front of her -- "you all sing, too."

And believe me, there were faces that looked Chinese and Puerto Rican and weatherbeaten-western, and young faces and old and everywhere you looked everyone was singing, "Glory, glory, hallelujah! His truth is marching on!" Slava, as Bailey called Rostropovich (She said, "He says I am Perla, and if I am good, he says I am Perlavich. I don't know what it means but it sounds great!"), led the music as if he, too, had been born at 7th and T. It was a moment, if only one of many, in a glorious evening.

The new partnership was back again when Bailey came out to sing and to lead the crowd in "God Bless America," and for a few minutes you could believe that those two could become the greatest evangelical team in history.

In its purely orchestral episodes, the concert included the Classical Symphony of Prokofiev, a rousing account of the "Jubilee" Overture by Chadwick, the Barber Adagio for Strings,

"The Incredible Flutist" by Walter Piston, "Fireworks" by Stravinsky and two Sousa marches, "Semper Fidelis" and "The Stars and Stripes Forever."

Just as the music was ending, bursts of rockets, glaring red and white and green and gold, could be seen from the grounds of the Washington Monument. It is hard to think of any other place you would want to be on the Fourth of July. But the National Symphoney will be back on the Capitol lawn again on Aug. 6, when Robert Shaw will conduct both chorus and orchestra. And on Labor Day Slava will return for the final Capitol concert of the year. Who wants to go away on Labor Day?