If our own Smithsonian Institution has been called the attic of the nation (and it has), London's Victoria and Albert can claim to be the Noah's Ark of the world's decorative arts -- it preserves two of practically everything. For the past year and a half, a representative selection of these treasures has been traveling the U.S. Premiering in the fall of 1997 at the Baltimore Museum of Art, where it was organized, the show has traveled to Boston, Toronto, Houston and now to San Francisco, where it's on view at the California Palace of the Legion of Honor until May 9, 1999. After all that, the exhibition goes back across the Atlantic and will be seen (rather redundantly, one would have thought) at the V&A itself from Oct. 14 through the end of the year.

The exhibition is a jumble of 250 wildly assorted objects, but the variety is instructive of changing tastes, both in design and collecting. The V&A, originally called the Museum of Manufactures, was founded in 1852 following the Great Exhibition of the year before, housed temporarily in the Crystal Palace. Like the exhibition, the new museum considered its chief mission to be the display of the best in foreign design and the consequent raising of the British artistic standards and commercial competitiveness. Moving to the western edge of central London in 1957, the museum was renamed the South Kensington Museum; then in 1899 it was again renamed -- by Queen Victoria herself -- the Victoria and Albert. By then, a second focus had come to guide its collection policy: the preservation of national treasures.

With the whole world as its province, the V&A invented for itself a role unlike that of previous museums. Rather than being a princely repository of costly art and high-style for an audience of scholars and esthetes, the V&A would test the notion that the life of the average citizen could be improved through education. It was a radical notion then and one that still needs some defending today.

The V&A vision manifests itself in specific examples, of course, and many of those examples now on exhibition are glorious. Standouts include a Qing dynasty Imperial Throne in vermilion lacquer, a gilt armchair designed by Robert Adam and made by Thomas Chippendale, a wool and silk tapestry of Pomona designed by Sir Edward Burne-Jones and John Henry Dearle and made by Morris & Co. There is a vase of Gallé glass and a wealth of porcelain, a Nepalese Lotus Bearer and a Constable landscape, an Italian Renaissance pilaster capital and a 15th-century Flemish reliquary in the shape of a hand.

The parade of artistry, invention and craftsmanship is dazzling throughout until one reaches the final section of the show, devoted to work of the most recent decades. Here the quality suddenly plummets to the level of trivia and kitsch -- a telephone of pink transparent plastic, a photo of Twiggy on a bicycle, a pair of "mock-croc" platform shoes, a portable radio covered in leopard fur. "We are not amused, " Victoria would surely say.

We are left with two possible explanations, neither of them pleasant: Either the V&A curators and/or the show's organizers have applied different criteria to the postwar decades, or they have applied the same criteria and discovered our decorative arts in ruins. The latter explanation is easily dismissed, however. The inclusion of a single Eames chair would have been enough to puncture it.

Sponsors of the almost thoroughly splendid exhibition are Visa USA and Lockheed Martin, with support from the National Endowment for the Arts and other groups. The team of curators was led by Arnold L. Lehman and Brenda Richardson, and the curator for the San Francisco installation is Lee Hunt Miller.