POWER DINING is nothing new in Washington. In the early 1800s, when the national capital still was a raw village, one of the best ways for a newcomer to get a foot in the door was to get his boots under a fashionable table.

Next to the president's, the top table in town was the one at Octagon House, winter home of Virginia tobacco baron John Tayloe III. A man made welcome at Tayloe's table was a made man.

Now everybody is welcome at the Octagon, which has recreated the sumptuous setting of a sit-down dinner in the formal dining room. Eat before you go, because about half the goodies on the table are real and replaced daily; the delicious aromas are almost more than a body can bear.

The magnificent display, for which the museum raided dozens of public and private collections, is the centerpiece of an exhibit that explores the table manners of all classes of our early residents, including the farmers and tradesmen who supplied truck for Tayloe's table and the servants and slaves who prepared and served it. Many of the exhibits are items unearthed by Alexandria's farsighted municipal archaeology department.

The exhibit's premise is that the way to a man's mind is through his stomach, and it works. We keep saying "man" here because early Washington really was a man's world: Wives seldom were invited to sit-down dinners, and when they were, they were expected to sit quietly and withdraw promptly after dessert.

"In company, the women do not cut much ice," a French visitor noted. "On returning from a party one will say of a woman who one wishes to praise, 'Madame behaved herself wonderfully: she didn't open her mouth.' " Ordinarily, the only woman present was the owner's wife, who, as another Frenchman observed, "punctiliously does the honors of her house, presides over her table without saying a word, and the rest of the time she is merely there, like a family portrait."

Meals were far less formal toward the other end of the social scale. Table knives, forks and even plates were seldom to be found in most Washington households, where a typical meal was a mess of meat, greens and whatever boiled together in a pot, which was set on the table for all to forage in, using shared wood or pewter spoons or, often, bare hands.

If invited to share a meal in the average household, you were expected to bring your own eating implements; if you produced a table fork, the others might ask what it was. Table knives had broad, rounded blades, the better to balance your peas on.

While in many cases this reflects widespread poverty -- 42 percent of the 1802 city budget went to poor relief -- it also could be a matter of preference. Many a prosperous person kept a spartan table because he thought that was the proper way to eat, and regarded investment in tableware as wasteful. Widespread use of coordinated crockery sets and individual place settings didn't come in until the Industrial Revolution made such goods plentiful and cheap.

It took a long, turbulent time for the world's first democracy to sort itself out. What we regard as good table manners sort of trickled down from the upper classes, although there also was a strong tide running the other way. Thomas Jefferson made no distinction of social rank at his White House table; he wrote out his own dinner invitations and seated his guests "pell-mell." A self-made backwoodsman might find himself at the president's right hand, while a baron of the diplomatic corps sat fuming below the salt.

Birth and breeding continued to count heavily in the upper social strata, but there was a conscious effort to give every man -- every free man, that is -- a fair shake. Financial or political success could gain social acceptance for just about anyone, so long as his appearance and manners didn't betray him. Books of etiquette were steady sellers, along with novels of manners such as "What Is Gentility?" by the keen-eyed and kind-hearted commentator Margaret Bayard Smith.

The gulf that newcomers had to find their way across can be gauged by Smith's experience with two brand-new United States senators from somewhere out West. Seeking social guidance, they called upon her one day and were captivated by the piano in her parlor; they not only had never seen a piano, they'd never heard of such an instrument.

The exhibit pays due attention to plain folks, including the basement kitchen where the slaves and servants labored, but the visitor will be drawn again to Tayloe's table and the splendid serving pieces, because we officially egalitarian Americans are aristocrats at heart. Imagine a meal where one course might include 30 different meats . . .

The exhibition is accompanied by Barbara G. Carson's fascinating catalogue, still in press but available next month at $16.95. Carson, curator Kym Rice and researcher Ellen Donald have created a sort of dinner theater, starring the people who set the style for the federal city.