Sir Lawrence Gowing, the distinguished English art historian who spent the 1986-87 academic year as the Samuel H. Kress Professor at the National Gallery of Art, will remain in the Washington museum world. On Sept. 8, Gowing, 69, assumes the chairmanship of the newly enlarged curatorial department at the Phillips Collection.

His appointment indicates the continuing strengthening of what was long an art world weakness here. Washington -- despite its many artists, its remarkable museums and exhibits, and its fine research facilities -- has never had a major university department of art history. Its world-class art historians have long been in short supply.

Gowing is not the only well-known scholar to move to Washington this fall. Charles S. Moffett, chief curator of the Fine Arts Museums of San Francisco, has been hired by the National Gallery as its new curator of 19th-century art. It was Moffett who organized "The New Painting: Impressionism 1874-1886," the superb reprise of the first impressionist exhibitions, which was shown here last year. Moffett conceived "Van Gogh in Arles," which was at the Metropolitan Museum of Art in 1984. He also was the coorganizer of the Manet retrospective shown in 1983 at the Louvre and the Met.

Moffett will replace Charles F. Stuckey, the curator responsible for the Berthe Morisot retrospective, which will open at the gallery on Sept. 6. Though Stuckey will continue working on the gallery's 1988 Gauguin retrospective, his loyalties have long been divided between 19th- and 20th-century art. Stuckey, who has written on Warhol and Man Ray, Duchamp and Scott Burton, is moving to the Midwest to become curator of 20th-century art at the Art Institute of Chicago.

Gowing, who was knighted in 1982, is a scholar of even wider range. His published monographs have dealt with artists as diverse as Vermeer and Ce'zanne, Constable and Matisse, Turner, Hogarth, Goya and the contemporary Lucian Freud. And he is not merely a writer. A former Slade Professor at University College, London, Gowing also has been principal of two well-known English art schools (the Chelsea School of Art in London and the King Edward VII School of Fine Art in Newcastle-upon-Tyne). He is a former deputy director of London's Tate Gallery. He also is well-known to British television audiences: Gowing has produced programs on Masaccio, Vermeer, Ce'zanne and other artists for the BBC.

And he's a painter, too. He has pictures in the Tate, the National Gallery of Canada and collections throughout England. Gowing, no doubt, was the first Kress Professor to use his National Gallery office as a studio. It is his credential as a painter that makes his appointment to the Phillips particularly appropriate.

That private art museum has always employed artists. The decision of one of them, Willem de Looper, 55, to spend more time on his painting was among the factors that led to Gowing's hiring. De Looper, who joined the Phillips as a guard in 1959 and who has served as the museum's curator since 1982, will have one-man shows this year in New York and Miami and, in October, at the Kornblatt Gallery on Seventh Street NW. Though relinquishing some of his curatorial duties, De Looper will remain on staff as a curatorial consultant with responsibilities for the museum's outdoor sculpture program and various contemporary shows.

It has been 56 years since the gallery's founder, the late Duncan Phillips, published his "The Artist Sees Differently."

"Sir Lawrence sees as a painter," says Director Laughlin Phillips. "That special artist's viewpoint is apparent in everything he's written. I think he and my father would have gotten along famously."

The Phillips is now involved in a $9.5 million program of refurbishment and expansion. When the project is completed in 1989, the Phillips will have available five high-ceilinged galleries for temporary shows.

In 1982, De Looper was the gallery's only full-time curator. In preparation for Gowing's arrival, the Phillips is promoting both Robert Cafritz and Eliza Rathbone from their positions as associate curators. Cafritz will become curator of 19th-century, Rathbone of 20th-century art. The Phillips has also hired a new administrator: She is Elizabeth Griffith, formerly administrator of the Thomas Jefferson home at Monticello.

Gowing is expected to have a major impact on the Phillips' publications. Laughlin Phillips says that Gowing (who will divide his time between his home in Sussex and a Washington apartment) will supervise the team now preparing a comprehensive catalogue of the Phillips' permanent collection, a project that is expected to be completed in 1990. "I hope he will also lecture frequently. He's told me he wants to select out artists from the collection -- say, Daumier -- and then publish monographs in connection with his shows. I expect him to greatly improve our publications. There is a special enthusiasm, a warmth, in everything he does."