The lights rise, the music swells, a froth of tulle and satin appears and another night of the social dance begins.

The stage last night was the National Gallery of Art, where, in front of the lithe figures of Edgar Degas' dancers, the social corps de ballet of art collectors and curators and museum directors glided gracefully through the galleries, stopping to join soloists Chief Justice Warren Burger and philanthropist Paul Mellon in a few brief steps, and then moving on.

Such a dance must include:

* A charming premise to provide plot, structure and a subject for good reviews.

Last night, it was the opening of "Degas: The Dancers," commemorating the 150th anniversary of the artist's birth.

"Isn't it exquisite?" asked New York art collector Margaret Horowitz, looking around at the exhibit, which will open to the public on Sunday. "This is just to die."

* A star who causes restrained, but definite, ripples of excitement as he moves across the stage.

Mellon is a quiet man. He is, nevertheless, a presence. But even a presence has worries. The subject of Mellon's concern last night was an exhibit of paintings by George Stubbs, soon to open at the Yale Center for British Art in New Haven. The museum, which he founded and funds, is now caught in the middle of a strike by clerical workers against the university.

"There hasn't been any trouble there," Mellon said, "no vandalism or anything, but the museum is only open limited hours. It's such a shame, because with a large exhibit like that, there are many people who would go, but with the strike they may stay away for a variety of reasons. They don't want to cross picket lines, they worry about some incident." Good sets.

"Ornamental kale," explained Pamela Brown, wife of National Gallery director J. Carter Brown, smiling at the frilly green and white plants gracing the dinner tables, after one of the 75 guests said they looked like some lovely kind of lettuce.

"The closest thing to a tutu," Brown said. Once she said it, you saw it.

"And Degas' colors, or as close as we could get," she added, fingering the pale blue overlays and the brown tablecloths below.

* A few graceful anecdotes to fill those quiet moments between acts.

"I saw all of these in Marseilles," said Burger, as he wandered through the exhibit before dinner. "I came into Marseilles about 20 years ago."

"More than that," his wife, Elvera Burger, said.

"I had been giving a series of lectures in The Hague," he said. "I had a cold, and stopped in Marseilles to recover from the cold. Walking outside, I found an exhibit which included, not all of these, but many of them. There were about 500 Degas."

* The tact and grace necessary for avoiding potentially unpleasant subjects.

"He had a reputation of being a difficult man," Francoise Cachin said of Degas. Cachin is a curator at the Muse'e d'Orsay in Paris, a lender for the exhibition. "He was bad-tempered. You don't feel that standing at the paintings. He is not at all cold-blooded."

* Something in French, for that touch of sophistication.

"Sometime soon the Gallery will have to start having surtitles like at the opera for their menus," said Corcoran director Michael Botwinick, studying the small card that told him he had just finished eating "Timbale Princesse d'Arcadie" and "Terrine de faisan Marie."

Whatever it was, it was delicious.