"I find my work relaxing... and socializing very strenuous," said national security adviser Zbigniew Brzezinski, who just moments before uttering those words had very gracefully danced across the floor of the Sheraton Park Ballroom and was now energetically downing salmon and grape leaf hord' oeuvres at the National Symphony Ball last night.

Nonetheless, there he was, looking as at ease in white tie and tails as the veterans of this ball, which has just a little to do with liking symphony music and everything to do with wanting to be part of one of Washington's grand social events.

"But it's important to show the administration's flag," Brzezinski continued, "to show we have savoir faire and that some day we will be ready to mix with the Georgetown social set."

Secretary of State Cyrus Vance was there, showing perhaps less savoir faire. Vance, whose wife is on the symphony board, did not wear tie and tails to this Washington party, which is one of the handful (if that many) in which such formal attire is requested. "I don't own any," he explained.

Although Brzezinski did say he was having a good time, he was game for explaining even further his agony in socializing. "Very strenuous," he repeated with a slightly furrowed brow when asked again, never pausing in his eating of the Jordanian delicacies. "Especially with beautiful women. You have to be extremely careful and very defensive."

The NSO ball, one of the oldest annual charity balls in Washington, is generally a whopping fund-raiser for the orchestra. This year at $125 a person, it is expected to raise $100,000. Few of the orchestra members, if any, actually go.

"I don't think they can afford it," said one woman who worked on the ball.

It is also a ball for which people come to see their friends and for which people come in from out of town to see people they know. And consequently everyone wants one of the tables that border the polished dance floor.

"I guess it's the old see-and-be seen," said ball reservations chairman Margaret Wimsatt with a wry smile as she gazed from the balcony, dotted with red poinsettia plants, at the dance floor glowing in soft yellow light.

Wimsatt has been reservations chairman of this ball for seven years. "I will not do seating," she said adamantly. "I don't want to have to leave town."

But she surmised that the people who do get the "ringside seats" are the ones "who've been good to the symphony, I suppose."

Despite the obvious purpose of raising money for the orchestra, few people were talking about it.

Though Austin Kiplinger, the new head of the symphony board, who took over just as the musicians went on strike, did say to this year's ball chairman, Juliet McLellan, that he had told his wife he might have to pull a few people aside by the arm and talk to them. But, he said his wife had insisted he not talk business.

Sheila Weidenfeld, former press secretary to Betty Ford and now the author of a new and very candid book about the Ford White House (she details much of the antics of the Ford children's dating and recreational habits), talked breathlessly with friends.

"The book doesn't come out for two months," she said, "I'm just getting the galley proofs. I don't know how other people are getting the galley proofs now." Newspapers around the country have seized on the more colorful things Weidenfeld has written about.The Fords, she said, unfortunately did not get their galley proofs. "That was part of the problem. It's really a very good book. It's very honest. It's been misunderstood. But it's a good book and it's important to me."

Meanwhile, the newly elected congressman from Maryland, Michael Barnes, was squirming just a bit in his formal attire. "I've never worn tails in my life," he said. Then he caught sight of Arthur Burns, former head of the Federal Reserve Board, looking like he was made for his tails. "Arthur Burns," Barnes said. "He looks like a man who should head the Federal Reserve." CAPTION: Picture, Emilie and Zbigniew Brzezinski at the National Symphony Ball last night, by Harry Naltchayan -- The Washington Post