On stage, they're all brass and flash, these dancers in "Dancin'," brave smiles and cocked hips in tight-fitting costumes. Offstage, in the light of a bright summer's day, they sit in a careless coil of muscle and sinuous grace, every gesture an arpeggio of motion.

There are four of them sitting there, gypsies as they've come to be called, the kind of young dancers lionized a few years back in "A Chorus Line," living from show to show, mainlining romance, blinded by the footlights, full of the crazy courage that comes of youth, talent and agile bodies that can do anything they're told to do.

The kind of vagabond who can go on the road for years, taking Broadway shows to towns strung out like lanterns far from the Great White Way. Dancers like William H. Brown Jr., whose name sounds as if it belongs to some fast-talking attorney. "I wish I had an attorney's salary," he says. "And an attorney's job security." Brown does have the confidence, the quick way with words. He knows what Amarillo looks like from a Greyhound bus and looks like from a Greyhound bus and what it's like to spend three years on the road far from the comfort of friends and familiar routines.

"Dancin'" has been on the road for a year now, having opened its national tour in Milwaukee last summer. Now it's Washington for the next two weeks, and after that Boston, unless something happens that sends the whole company scurrying back to New York, lining up for the next audition, picking yp the unemployment checks. They like the show, like its nothing but high-voltage choreography that has them center stage most of the time. "A big juicy show," Brown calls it. "It's not like most shows where you're sitting in the dressing room smoking cigrettes most of the time with maybe 15 minutes on stage for the big number."

Brown is from St. Louis, a town, he says he was "bored with by the time I was 17. Community opera is all there was." By then he knew he wanted to be in the theater, knew it from the time he starred in a homegrown concoction called "Mulligan's Magic" at Beaumont High and all his friends were there shouting and clapping and hew was up ther on the stage getting drunk on the sound of applause.His mother had been a dancer before she had her six children; she thought it was great. His father's a cop. His borther's a cop. Two of his sisters are married to cops. How did they feel about his choice of a career? "They're proud of it now," he says.

It's an all right life on the road. They get used to it. "It's like Anne Bancroft says in 'The Turning Point,'" Brown explains. "Some cities are better than others. So are some nights.' Home is wherever you are."

The life they know about is a precarious one, sweet times and tough times and times when the only person looking you straight in the face and telling you you're going to make it is the one staring back from the mirror. Times when you're glad just to have the change to take the subway to dancing class instead of hiking those 20 blocks. Times when you can watch your fantasies ice over in the frost of a telephone that never rings. Times when you huddle with your friends for warmth. The best of times in their own odd way.

"We slept in sleeping bags in a studio apartment and ate tuna fish and yogurt and rice," Brown remembers. "We pretended like we were in 'West Side Story' -- we'd take the TV out on the fire escape and watch and talk. You realize how important your friends are to you. It was a wonderful time."

Then there are the times when they live on a succession of odd jobs, giving out pamphlets on street corners, working at Macy's, teaching for a time -- waiting for the next audition, trying to stay busy so there's no time to think about what kind of bad news is tapping at the window. "As long as I'm taking class and learning, it's all right," Brown says. "You figure you bring all the experiences in your life to your next job. That's why whenever I have a job I treat myself well. You enjoy it while it lasts."

It it lasts."

They often pride themselves on the way they can take it, on the toughness they maintain. Still there's a danger there. "I think it can make you cynical," says dancer Roumel Reaux. "You hope it doesn't overpower you. That it doesn't build up a callousness. You never know what's going to happen next."

At the audition, they could all tell Roumel Reaux was someone special. At least 300 dancers had answered the call at the King Studio; only 18 would be chosen, but they knew one of them would be Reaux. He is a slender man, his movements quick and catlike, his eyes intent and amused. Reaux also knew he would be chosen because he had to be: It was either that or a quick march into the world of 9-to-5. He had just come back to New York from Milwaukee, where he had choreographed a summer stock production of "The Wiz" when he heard that auditions for "Dancin'" he remembers saying at the time. "It's mine because I have to have it." There were three callbacks, and in the end, he was right; he got not only the job but a chance to dance a featured role.

Reaux is 26. Like the others, he doesn't know how long he'll be a gypsy. "Around 30, you start thinking about wanting to settle down eventually, about how long you're going to keep doing this. I think around that time you start moving on, you start taking your life seriously."

He and the others laugh tolerantly as they recall an 18-year-old kid who confided that he hoped he'd get the job "so I can see America." No, they say, they don't worry about the competition from the younger dancers. I'm glad I'm fabulous at 28," Brown says. "When you're 18, you know nothing about life."

"I was the kid who danced around the living room and the bedroom all the time," Jim Corti says with a wise smile. "My sister took tap and it was like the song in 'A Chorus Line,' I thought, 'I can do that.' When I was 9 years old I was like a whiz kid, I was really fast. But then I got into swimming and I thought tap was a little too frivolous."

In high school, he was in the drama club, but he was on the track team too and it wasn't until college at Loyola University that he began cutting all his other classes to take drama. He worked in California with the American Conservatory Theatre for a while before heading for New York and the familiar cycle of on and off-Broadway and in and out of the occasional odd job.

Corti is 31 now, a veteran. He likes the life. "You don't need a press agent to tell you how you're doing. The audience tells you that every night. That's what you live for," he says.

If you're looking for celebrity, you're looking in the wrong place, many of them say. "To be famous in this profession," says Reaux, "you have to defect from Russia."

"You don't go into this life to be famous," says Corti. "If you want to be famous, you can go to Hollywood and get a gimmick. It's a hard life, but you choose it and if you can't take it, then maybe you should be doing something else."