William Merritt Chase is never anyone's favorite American painter, in the way that Winslow Homer or John Singer Sargent might be. But he's the kind of painter you'll go out of your way to look at. Generations of visitors to the Phillips Collection have made detours to see a Chase painting called "Hide and Seek," for instance -- a deliciously cool and genteel depiction of two little girls in frilly dresses playing in a darkened room where the light touches here and there on a big shiny floor.

Now there's a whole show of Chase in the East Building of the National Gallery -- 25 oils and large pastels done between 1891 and 1902 at Chase's summer home in Shinnecock, Long Island, out by the Hamptons. The show is a small gem, quietly esoteric and lovely. The subjects are the landscape outside his house, and his family inside it. He painted them while teaching outdoor painting -- he'd been hired to go out to Shinnecock as part of an effort to turn it into a resort for the gentry.

Like Sargent and 19th-century salon painters who were popular with the rich, Chase has long been the subject of bemused dismissals by the teachers of art history. Even in his heyday, when he maintained a huge and famous studio in Manhattan and played the role of the gentleman artist to the hilt, he aroused the suspicions of critics. In 1895, one called him "a technician of good taste, one with a feeling for the suave picturesqueness of some social life." Another said in 1889 that: "Whatever the bodily eye can see, Mr. Chase can paint, but with the eye of the imagination he does not see."

There are a number of reasons why we no longer feel this antagonism toward Chase. The 19th century and gentility are no longer the nightmare from which we're trying to awake. (It's the 20th century and modernism, now.) Also, in the midst of the great art boom in America, dealers, curators and scholars have been running short on grist for their mills -- they need more old painters to sell, hang and study. Finally, the sheer pleasure of looking at the work of Inness, Church, Bierstadt, Eakins or the American luminists has overcome doctrinaire reluctance to admire 19th-century American painters. (Whistler and Ryder got provisional memberships in the modernist club because of their strangeness, personal and esthetic -- unlike Chase and others, they possessed the paramount attribute of modernism, irony.)

In addition, the National Gallery is promoting Chase as an American impressionist.

J. Carter Brown, director of the National Gallery, said at a luncheon recently that the Chases demonstrate that "the good old U.S.A. is right in there in the sweepstakes."

This could be argued endlessly -- impressionism, after all, is a word that can describe artists as different as Manet and Pissarro. It denotes a list of artists and it draws crowds. It will mean even less if we call Chase an impressionist. There's none of the color theory, for one thing, and little of the startling immediacy of subject matter -- Chase's landscapes are tame ones, always a road or a child running through them. Chase told his pupils to avoid "recipes" of the impressionist sort, and one of his students recalled that he "held out to the end that no one saw bright color in shadows." Though here he's painting at the seashore, he hardly paints shadows at all. There's nothing shocking or even dramatic in these paintings, except for a frequent small flick of red in a hat or a bucket amid the browns and greens and yellows under the skies he seems to paint with particular affection.

In any case, these paintings are beautiful. (O dangerous word!) The clouds are timeless, the skies are transparent, you can almost hear the wind in the beach grass and the bushes. Chase paints so well. He acquired his bravura looseness in six years of study in Munich, where Hals and Vela'zquez were his heroes. He is wonderfully assured. There is none of the tension that marks, say, Homer's struggles to escape the gravity of illustration, no 20th-century edginess -- or turn-of-the-century muscularity, for that matter. They may never be quite so beautiful again. Like the National Gallery's show of American luminists, this show is greater than the sum of its parts.

For one thing, it surprises us by demonstrating that gentility and the bourgeois are not what Chase is all about. For another, the catalogue argues that these are the paintings of the greatest period of Chase's life, and that adds a valedictory poignance to them.

There's plenty here even for unreconstructed modernists, on second or third look: their unshadowed flatness and their asymmetrical composition -- as in "Swollen Stream at Shinnecock." They are largely free of anecdote, too, though a lovely exception is the National Gallery's own "A Friendly Call," which shows Chase's wife sitting on a couch and listening to a white-veiled guest. Did Chase mean to make us think his wife was being two-faced when he painted her reflection in the mirror? Is the guest -- so spectral she seems on the verge of vanishing -- someone Chase hoped would leave soon? Is this one painting where Chase was being ironic, especially in the title?

There are lots of mirrors and pictures within pictures in the Shinnecock interiors, and along with the subdued but playful nature of the landscapes, they point to a private Chase, one very different from the Chase who's been dismissed as a skilled society painter. The subject of these paintings is art as much as it is Shinnecock.

Finally, they evoke an ideal of summer that is more familiar to the 20th century than the 19th. Instead of showing parasols and horses at fashionable spas, it shows the empty fields of the kind of nature we prefer to contemplate from our decks, nowadays, tamed but not civilized. Chase focuses our gaze on distance, and gives us clouds and children that have a sovereign placidity.

This is not to make the argument that Chase is actually a modernist -- that would obscure the very different set of virtues at the heart of these paintings: the mastery, the taste, the almost somber fidelity to nature, the ease, the beauty.

The show was backed by a $125,000 grant from Bell Atlantic, and it continues through Nov. 29.