Legs. The gentlemen were discussing and comparing the legs. The line. The turn. The grain.

There was no question about it. The legs were admirable, if varied.

"Your chest looks great," said one lady to another. The other lady flushed with pleasure of the compliment.

And so ran the conversation at the National Gallery's East Building last evening as connoisseurs, collectors and curators gathered to evaluate what could easily be called an Anatomy of Americana. It wasn't, of course. The folks at the gallery decided to call it "In Praise of America," a show of masterworks of decorative arts that runs from Sunday through July 6.

"Decorative" was a debated term since the English call it "Applied" and the "Fine" folks sniff at it. Even the appreciators question what exactly the term means. "Let's just call it appendages of gracious living," said Graham Nood, director of the department of collections at Colonial Williamsburg.

Whatever you call it. It is American sort of. Actually the designs are European, mostly English, "but the Americans improved them, was the word heard over and over from Those Who Know (and Collect). But the good old capitalist American spirit surrounding these pieces and inflating their pieces is pure red, white and blue (or Chippendale, Sheraton and Empire).

"I love this stuff," said Clement Conger, curator for the State Department, "but I live with English. I can't afford American."

"Fifteen or 20 years ago, you could have picked up some of this for $150 to $250," said Edward Jones, lender to the exhibition who was introduced as the greatest authority on Early American furniture, chief architect in charge of the restoration of the White House and the eighth floor reception rooms of the State Department. "Now," said the architect who had come to classical furniture through his interest in classical architecture, "no one but a museum could touch it."

Warming to his subject, he gave a graphic example. "Fifteen years ago, someone in upstate New York paid $75 for a couch very much like the Empire piece in this show, and they cared so little about it that they never even picked it up. It is now worth hundreds of thousands of dollars, and is in a museum."

"You hear the wildest tales," said J. Howard Joynt, a Chippendale man who didn't have any truck with the Empire stuff. This was later, at an Early American dinner of barley soup, quail and ginger cake served on blue-and-white mattress-ticking-style tablecloths at tables with Early American weather-vane centerpieces.

Joynt is hardheaded about his collecting; even so, he evidences his true belief in the American (furniture) Success Story. Looking at the weather vanes scattered about the back room of the East Building with its throughly patriotic view of the Capitol dome, he murmured like a race-track tout with a hot tip, I'll tell you, 10, 15 years ago, nobody would have paid any attention to them. Now they're hot items. They used to be called "primitive art,' now they call it 'naive.'"

The word last night was: Hepplewhite is still a buy. Another was: Reproductions can never match originals because of the difference in the way mahogany is grown. Whole movements of populations, the stuff of which social history is made, can he measured in furniture design. "The whole thing [decorative arts] is taking off."

And the American tune was the score for the cashregister percussion of the evening as one State Department official noted, "Foreigners can't believe we had such a culture. They thought we were all out fighting Indians," referring to State's 18th-century collection on its eighth floor.

(Another hastened to point out that collection is now worth about $19 million.)

For some it was an evening of success and vindication. Said Carlisle Humelsine, NGA trustee and also a trustee of Colonial Williamsburg and the National Trust for Historic Preservation, voicing the thoughts of many who had waited for recognition of their favorite art form:

"I'm on the board here and I always come to all the openings. Great art. Sculpture. I come. Tonight I feel real comfortable here. Some of us feel this is more beautiful than painting.

"I have to be very careful about what I say; some of these pieces may come to us [at Williamsburg]," he said later to the crowd, which responded with an appreciative "o-h-h-h-h."

Now, that's American.