Edgar Degas (1834-1917) loved the French ballet, its flimsy sets, its patrons, its gauzy gaslit colors. He loved its dancers, too, not only for their grace, but for their hard lives and hard labors and their unattended moments. He portrayed them all his life.

A long-awaited exhibition devoted to his dancers goes on public view today at the National Gallery of Art.

The ballet that we see portrayed here, that of the Paris Opera, is not the ballet we know now. It was a saucy institution, part men's club and part pick-up spot, a place where up-to-date gentlemen of leisure went to laugh with one another -- and with the lithe, available young things of the corps de ballet.

Those men in their black suits ogling the bare legs of the dancers -- Degas portrayed them often. "These gentlemen were all-powerful, and their will was final," observed one contemporary. "They had an exclusive, or almost exclusive, right of admission to the green room -- rigorously closed to the common crowd -- and there they were the masters of the situation." The men in the black suits attended dance rehearsals, strolled among the props and kissed the willing dancers behind the painted flats.

The dancers of the ballet then were not stars but starlets. Like chorus girls of latter days, they were frequently dismissed as sweet but rather dumb.

One feels no such disparagements in the paintings of Degas.

Degas is never vulgar. His is a gentlemanly genius. He frequented the race track, the brothels and the music halls. Yet nothing in his pictures approaches the salacious. A certain scrupulosity, a sense of perfect balance, an absolute correctness, is central to his art. -- --

Another sort of scruple or refusal of excess dims the show in the East Building.

Its title, "Degas: The Dancers," holds such promise that one expects the sort of Degas exhibition -- definitive, ambitious -- one sees once in a lifetime. But the Gallery's exhibit is something less than that. It is beautiful, of course. But not beautiful enough.

Its problem is its size. The exhibit is too small.

"At least one half of Degas' mature work was devoted to representations of dance subjects," writes George T.M. Shackelford, the young scholar who based the exhibition on the dissertation he submitted for his Yale doctorate. "There are approximately 1,500 paintings, pastels, prints, and drawings of dancers in Degas' oeuvre."

Of the 1,500 pictures of the dance that Degas left us, only 57, most of them on paper, are included in this show.

There are, no doubt, good reasons for the disappointing sparseness of Shackelford's exhibit. In this Degas year, the 150th anniversary of his birth, those who own his precious pictures are surely loath to lend. The National Gallery of Art has only so much clout, and cannot go all-out for every single loan show. And Shackelford, like many other curators, appears to be more interested in research and discovery than in "blockbuster" exhibits.

"I didn't want to mount a Degas retrospective," he says, "nor an exhibition of Degas' top hits."

But too many hits are missing here.

Many French Impressionists -- Renoir, for example -- were woefully uneven. For each "Luncheon of the Boating Party," for each masterpiece he painted, Renoir must have produced at least a dozen losers. A too-large and unedited exhibition of Renoir, of Pissarro or Utrillo, would produce a pounding headache. But like Ce'zanne or Matisse, Degas, that perfect master, almost always leaves the viewer hungering for more.

The Corcoran's "The Dancing School" (1873) is one of the finest, most complex of Degas' rehearsal pictures. It should be in this show. So should "The Rehearsal" from Glasgow, the Metropolitan's "Rehearsal Room" and a score of other pictures -- all of which are reproduced in Shackelford's fine catalogue. They are crucial to his argument -- and ought to be displayed.

Degas, when he paints the Ballet of the Opera, is pledging his allegiance to the modern, to the new. His dancers sweat and stretch and adjust their toe shoes. They are the working girls of Paris, not the nymphs and dryads of academic art.

The tiptoeing and toe-shoed art of the ballet is, of course, an art of artifice, but the beauty of these pictures is the beauty of the real, a beauty that in Degas' hands first accepts, and then surpasses, that of the ideal.

These are pictures that are poised between the art of the Old Masters and that of our own age.

Degas the traditionalist has a line as fluent and as accurate as that of Ingres (whom he met when he was young). And yet Degas the modernist is equally at peace with gestures that are wholly spontaneous and free. Look at the standing figure of Jules Perrot, the dance master, in the center of "The Dance Class," a masterpiece on loan from the Jeu de Paume in Paris. Perrot's hand is summarized, his fingers are a blur. Yet Degas lets us read every shining strand of Perrot's silver hair.

Degas somehow blended the cautious with the daring, the antique with the new. Many of his drawings here -- those highlighted with white, on sheets of gray or blue -- suggest the drawings of the Renaissance. Yet Degas' brightest colors -- that burst of orange cadmium light reflected on the floor of "The Rehearsal Room," the bright red of the sweater of the dancer seated, head in hand, on a double bass in "The Dance Lesson," or the chartreuse costumes in a superb late pastel here from 1898 -- are as wild and as lively as the colors of the Fauves.

The pictures here are carefully assembled from images the master has stockpiled and studied and patiently perfected. A dancer reaching back to scratch a shoulder blade might appear in a painting from 1874 -- or in a pastel from 30 years thereafter.

"It's all very well to copy what one sees," wrote Degas. "But it's much better to draw what one can only see in memory . . . There, your recollections and your fantasies are liberated from the tyranny which nature imposes."

Shackelford's demonstrations of the ways that Degas used his "repertoire of figures" is one of the major lessons of this show.

One of its most touching objects is a bronze of the "Little Fourteen-Year-Old Dancer" which the artist modeled in 1881. (Paul and Bunny Mellon own the wax original.) When she was first displayed, critics of the day, affronted by her naturalism, regarded her as bestial. Today we see her beauty. She is standing in the fourth position, her hands clasped behind her back. The poignance of her elbows is enough to break your heart.

Her name was Marie van Goethem. It is known she posed for painters, and that she hung out at a cafe' called The Dead Rat. "Her mother . . . but no, I don't want to talk about it," wrote one journalist who knew her. "I'd say things that would make you blush or cry."

Her statue is surrounded here by a suite of superb drawings which scholars long regarded as preliminary studies. Shackelford believes that Degas made these drawings, as he did the sculpture, as finished works of art in an effort to examine a single standing figure from multiple points of view.

Degas, it seems, learned something from the croppings of photography. He learned, too, from the Japanese, as one sees in the emptinesses of his many frieze-like paintings. But the genius of Degas was a genius of refinement. Most of all he learned from his own works of art.

Degas, as he aged, drifted toward abstraction. His outlining grew rougher, his colors became brighter, eventually he gave up oils for pastels. The painstaking precisionism of his early pictures is missing at the end. Degas was going blind.

Gradually he lost all but his peripheral vision. But still he kept on drawing the same young ballerinas he had portrayed all his life. During World War I, not long before he died, he wrote a letter to a friend: "I speak about the past because, excepting the heart, it seems to me that everything is getting older . . . And even the heart has something artifical about it. The dancers have sewn it up in a sack of pink satin, pink satin a little bit worn, like their dancing slippers."

"Degas: The Dancers" closes on March 10.