The night before the first of a thousand objects ceased to be household furnishings and became museum pieces, Frances Lewis sat at her favorite desk for the last time.

"I'm going to leave the house, get out of town. I can't bear to watch the pieces go down the stairs," she said by phone Wednesday from the Richmond Fan-Light District house where she and her husband, Sydney, live.

As she spoke, she could stroke the sinous curves of the Hector Guimard desk, a spectacular achievement of the Art Nouveau period of exuberant craftsmanship and design. Among other treasures being packed up for the Virginia Museum of Art from the second-story study: the rest of the Guimard suite, an Emile Galle' chandelier with dandelion-ball lights, a Tiffany peony lamp with a turtle-back base and a Charles Voysey mantel clock.

But Lewis remembers most vividly buying the Guimard. "In just one weekend in Paris," she said, "we bought from two completely different sources the complete Guimard office -- the desk, three chairs, two vertical tambour filing cabinets -- and our bombastic Majorelle bedroom. We had to have them both . . .

"No, tears are not rolling down my face. As my husband put it, we'll have to get up in the morning and pat the pieces on their fannies and say goodbye."

Not long ago, Lewis sent invitations for lunch to her friends reading, "Last chance. The Virginia Museum says everything must go," said Fred Brandt, curator of the Lewis collection and now the museum's curator of 20th-century art.

Over the past two days most of the incredible personal collection was removed from the Lewis house. In addition to the 1,000-odd pieces of Art Nouveau and Art Deco furniture, silver, glass and other decorative objects, more than 80 pieces of sculpture (including the Cor Ten steel clothespin by Claes Oldenburg, which sits outside the house) and 1,100 paintings and drawings have been given to the museum. About one-third of the collection will be exhibited at the December opening of the new $22 million west wing.

"No other public exhibit of Art Nouveau and Art Deco will be comparable to ours for variety and scale," said Paul Perrot, director of the Virginia Museum.

"And no other owners I know of have lived with and used their art so intimately, as a part of their everyday life. No other collectors in the prime of life have divested themselves of their domestic possessions, starting out as fresh as newlyweds -- not because of death or divorce or bankruptcy, but solely for the pleasure of the public."

Frances Lewis explained, "Basically, we wanted everyone to enjoy the things. Mr. Lewis said he wasn't going to wait until he died and let the children have the fun of having the pieces installed. If you wait until after you're gone, you won't get to enjoy it.

"So we started to think about where it would go. We talked to lots of museums, and we decided that our state has been very supportive of arts. There aren't many state-supported museums. Virginia is the leader . . .

"Besides, we look forward to running down the road and seeing others enjoying our things. Of course, it will all look different. Everything here is chockablock. You know, when I looked at the mock-up of where things would go, I saw three pieces I'd forgotten we had."

Sydney and Frances Lewis and Paul and Rachael Mellon shared equally in a gift of $12 million to the new wing of the museum. The State of Virginia gave the rest. In addition to the Lewis collection, the wing will house 200 Impressionist and Post-Impressionist paintings from the Mellons.

Thursday morning, as Lewis put herself together for the day in her dressing room, she could choose, for the last time, to look into a great Art Nouveau dressing-table mirror by the American master Louis Tiffany or into a later, 1920s mirror by Emile-Jacques Ruhlmann, the Paris style-setter. She could turn on a Tiffany "Autumn Leaves" lamp or sit at a desk by R. Joubert and P. Petit that starred at the famous 1925 Paris Exposition Internationale des Arts De'coratifs et Industriels Modernes, from which the term "Art Deco" gets its name.

Down the hall was the Cocteau bedroom, made for the writer by Marcel Coard, a rather severe pine suite with a leather-padded headboard. An austere checkerboard-back chair by Scotsman Charles Mackintosh stood nearby. The room was softened by a screen of swans and embroidered nudes by Paul and Frances Ranson, ceramic boots by Marilyn Levine and other artwork by Morris Louis, Al Held, Sidney Goodman, Theodoros Stamos and Jim Nutt.

The Louis Majorelle bedroom suite -- a magnificent 1905 bed, armoire, four chairs and two night stands -- will go to the museum next week, along with living room furniture including a Mackintosh tea table and armchair and a black and white prototype of the famous Gerrit Rietveld chair.

The other guest bedroom gave up an incomparable 1930s Ruhlmann suite -- including a bed shaped like a sun disk, and a tall-case clock and table -- as well as a Tiffany fish shade on a mosaic lamp base and a Jean Puiforcat silver tea set atop a Eugene Printz and Jean Dunand bookcase. And gone from the wall is a 7-by-7-foot Philip Pearlstein painting of two female models reclining on a cast-iron bed.

The Lewises started collecting in 1963, when they began to spend less time with Best & Co., their very successful mail order firm.

"Mr. Lewis had to take things easier," said Frances Lewis. "We couldn't work as madly as we used to. So we went to Chicago and New York and walked around museums and art galleries. We had time then to look at the world around us and see this great art. Mr. Lewis has always been drawn to the superb. We bought a piece by a young Richmond woman, Helen Hattoff. And once you begin hunting, you have to go on.

"We had thought about 18th-century furniture for the house. We bought a wonderful dining room table -- which we're keeping, it won't go to the museum -- but we soon realized we wouldn't be able to get the best pieces. Mr. Lewis wants the greatest. An artist friend, Theodoros Stamos, was interested in Art Nouveau, and he introduced us to it. Once you're interested in 20th-century decorative objects, it's like a disease."

So after it's all gone, what will the Lewises sleep on, write on, love?

Frances Lewis is bringing a Majorelle desk home from her office. Her husband is keeping his Galle' table as a desk. A Ruhlmann sofa and chairs will remain in the living room. But the Lewises have already begun to refurnish their house with work by young American artists.

"We've commissioned a bed, very spectacular, by Dakota Jackson," Frances Lewis said. "We showed him the Majorelle suite and said we want something 1980s to replace it. We have a Michael Graves dressing table he made for the Memphis collection, and two chairs by Forrest Myers. We'll have lots of years of looking for things, coast to coast. We can participate in the energy of the times.

"You can't buy things because you think they are good," she added. "No one has infallible taste. But you should lay yourself open to art. The only mistake is to buy something you don't like. I think we have a grand opportunity to find some fabulous things -- whether they are comfortable to sit on or not."