CLARA BARTON'S HOUSE The Clara Barton National Historic Site, at 5801 Oxford Road, Glen Echo, is open for tours four days a week: Thursday and Friday 10 to 5 (with reservations), Saturday 10 to 5 and Sunday 1 to 5. And interpretive programs, ranging from a genealogy lecture to a children's ice cream social, begin this Friday evening and continue through August 26. Programs run on alternate weeks - the Friday series, 7 to 8, features movies, slides and lectures on Barton and her times; Sunday presentations, 3 to 4, are oriented toward families with children. Free, no reservations required. Off-site programs are also available on request. Details: 492-6245.

"For a Victorian house, this place is pretty plain," Jeanne Sheeley is saying.

She's standing in a 66-foot-long, three-story-high entrance hall. A few wisps of daylight filter in through filmy lace curtains. It's raining, heightening the haunted-house effect. From the back doorway comes the glimmer of ruby windows.

Plain.

Well, maybe by Victorian standards. But in this corner-cutting age, when a prefab bay window is as close as most people get to character, the Clara Boston House is about as plain as a a rosebud in a field of dandelions.

It's a case of the exotic being right in your own back yard, if you know where to look. Drive out MacArthur Boulevard, turn left at the old Glen Echo amusement park and head toward the river, where the road narrows and the streets signs are written in flowing script. Everything here is on a small scale except the house, looming huge in the woods overlooking the C&O Canal.

The place was neglected for years. For a while it looked as if it would be torn down for a parking lot, until the Friends of Clara Barton came up with $50,000 to pay off the mortgage. They gave it to the Park Service in 1975. NPS restored it and recently opened it for tours.

Over the years, Barton's house went unnoticed, and she didn't fare much better. Somhow - while her peers, Susan B. Anthony, Frances Willard and other feminists - bask in the resurgence of interest in women's history, Barton has failed to capture the public attention. Is it because she's associated with the traditionally feminine occupation of nursing? It's a bum rap - she wasn't even a nurse.

What Barton did was lobby four presidents until she succeeded in founding the American Red Cross in 1882. The rambling, yellow-and-white frame house was Red Cross headquarters from 1897 to 1904, and Barton's home until her death in 1912.

Her contemporaries thought the house looked like a barn. It started out as a relief hotel, actually - one of four slapped together in Johnstown to house victims of the famous flood of 1889. In 1891, when Barton was ready to set up Red Cross headquaters near Washington, she had the hotel dismantled and brought to Glen Echo on the B&O Railroad.

Sheeley, the National Park Service tour guide, thinks it's plain because there are no ornate moldings, elaborate carvings or other Victorian excesses. To a gingerbread-starved child of today, though, there's much to drool over. The cavernous central hall, where Sheeley starts her tours, is bridged at the top by a third-floor bedroom balcony. Wood-paneled walls conceal huge closets. Lace curtains flutter throughout.

There are 38 rooms in all. Or 36. "I keep thinking someday I'll walk around and count," said Heather Hyuck, a Park Service historian who, along with two other researchers, lives in the house for security reasons.

Part of the house's eccentricity stems from its former multiple functions as private residence, business offices and warehouses. The 40 hidden closets, for example, were built wide and deep enough to store the wheel-chairs of the time, which didn't fold up.

The house isn't next to Glen Echo by accident. Barton was associated with the Chautauqua self-improvment-through-leisure movement going on at Glen Echo at the time. But when the amusement park was built in 1908 the roller coaster came out around the front of the house, running as close as eight feet in places. "Clara spent a lot of time in the back of the house," Sheeley said. "She was always afraid the train - she called it 'the train' - would crash into the front. She liked the park, but not the train . . . " Sheeley and the other members of the Park Service staff have been able to reconstruct Barton's Glen Echo days from her voluminous diaries.

In Barton's wondeful light-filled sitting room overlooking the C&O Canal, where she fled to escape the trains, the view hasn't changed a bit. The walls are insulated with layers of old canvas and newspapers and the ceilings are covered with a taut muslin canopy to keep out of the cold.

As the guides take you around, facts come tumbling out matter-of-factly, faster than you can absorb them. That's a nice drawing, somebody's says, pointing to one of the framed pictures that line the hallway. "Oh, yes, Clara was quite an artist." Also an author - wrote four books. She also founded the country's first free public school, in New Jersey. She was the first woman government office worker. In her spare time she was active in prison reform, temperance, abolition and the suffrage movement.

What kind of a background could have produced such a Renaissance woman? Barton was just one of the many "surplus" women whose old comfortable roles started to evaporate in the late 19th century, according to Huyck. Partly because of the Civil War, partly beacause the men were going West, the women couldn't find husbands. "You had the whole thing of the maiden aunt living with her brother or sister or parents. The polite thing, if you weren't the maiden aunt, was to be a governess - not a hot position, but at least it was genteel." The more adventurous became ministers, deaconesses, teachers, social workers. Religious orders got a big boost in the 19th century. Women's groups flourished.

The point is made that Barton is not to be pitied.

"We tend to look down on and feel sorry for these poor single women, but it was just very difficult for them to combine marriage with those kinds of careers. They had lots of friends. They had causes."

One thing becomes very clear from the picture being painted. Barton is a perfect candidate for Patron Saint of Mid-Life Crisis. Her greatest work was done after her 50s. She didn't move into this house until she was 75 and famous.

She was 83 and had been Red Cross president for 23 years when she was forced to retire. There was a Congressional investigation of her finances; she was very bitter. She was scrupulously honest, Huyuck says, but not oriented toward keeping the kind of records that were a CPA's dream.

She spent her last years gardening, lecturing and writing. She also founded the National Frist Aid Society. "She never quit," says Huyck.

Huyck hopes the days of "Clara Who?" are ending, as women's history defines itself and people realize the movement didn't begin and end with the suffragists. "You're goint to see much more interest in Barton," she says. "We're doing what we can do." CAPTION: Picture, THE HOUSE WITH "36 OR 38 ROOMS," 40 CLOSETS AND, FINALLY, NO TRAINS. By James M. Thresher.