What are the chances anyone with a "Duchess of" before her name will even set foot on a shuttle bus?

Not great, but if you're going to hold two simultaneous receptions for more than 1,000 people (including 150 members of the British nobility here for the National Gallery of Art's "Treasure Houses of Britain" exhibit) followed by dinners in 42 private homes, you try to think of everything. Transportation from a reception at the Folger Shakespeare Library to a reception at the National Gallery "for people who don't have cars with drivers," as one organizer of tonight's citywide party put it -- this kind of thing matters.

"I believe it was the invention of the devil," was how Folger Director of Development Michael Valentine described the planning for the array of parties in honor of the gallery's show and a related exhibit at the Folger. At least one behind-the-scenes participant let out a deep groan at the mere mention of the months of preparations, especially the process of parceling noblemen out to Washington hosts like so many prized party favors.

As several involved in choreographing the evening said, "We are dealing with 42 hostesses!" That, it would seem, says it all.

But not quite: The Hostesses are just the beginning. There are also more than 1,000 guests, including "Treasure Houses" corporate sponsors from Ford; members of the international council of New York's Museum of Modern Art, who just happen to be in town and have been included because Folger cochairwoman Ella Burling is involved with MOMA; the four chefs flown in from the Savoy hotels of London; and those British lenders. Not to mention the two cultural institutions themselves, both trying to massage the hearts and checkbooks of past, present and future supporters.

Call it Night of a Thousand Egos.

"Keeping 42 hostesses happy is the classical definition of a thankless job," said Valentine, who along with Pam Brown, wife of gallery Director J. Carter Brown, helped match up lenders and the Hostesses. "By and large, we provided the names for them," Valentine said. "There has been some negotiation on that. A couple of hostesses did not get a prime couple -- of course, I won't mention names."

Not that the 42 (which include several men, but are always "the Hostesses" to the people who know) are the types to complain in public. Writer Susan Mary Alsop; Sen. Jay Rockefeller (D-W.Va.); Washington Post Co. Chairman of the Board Katharine Graham; Evangeline Bruce, wife of the late U.S. Ambassador to Britain David Bruce; philanthropist Ethel Garrett and Washington doyenne Polly Fritchey -- there may not be titles before those names, but they are Washington's social nobility, the kind of people who don't pay a couple of pounds to visit the Treasure Houses; they stay there as guests. It will be old money, old power, old china and lots of familiar faces.

Like Prince Charles and Princess Diana, who will spend most of their upcoming visit hobnobbing with chairmen of the boards, movie stars and the kind of people who were jet-setters before there were jets, the lenders will hardly be out of their element.

"A great, great many of them are friends of mine," said Hostess Oatsie Charles. "And after all, Pam Brown asked one to do it, and of course one would do anything for her. She's a darling child."

Many of the lenders, in fact, are house guests of the Hostesses.

"We have a longtime friend, Lady Victoria Leatham from Burghley House. Lord and Lady Brocket, who gave some of their Chippendale. David Hicks, the decorator," said Maurice Tobin, former chairman of the National Theater. "They're all ensconced."

Joining Tobin's house guests for dinner tonight will be painter Jamie Wyeth, Nancy Reagan's chief of staff James Rosebush, Chief of Protocol Selwa Roosevelt and former White House deputy chief of staff Michael Deaver.

"It has nothing to do with the gallery," said Tobin. "These are all just personal friends."

This is a point of some importance to the Hostesses. They are welcoming very important visitors, not opening their houses to strangers.

"Mrs. Garrett, she's a very private person, and when she gives dinners, they're pretty much hand-picked," said Martha Rice, secretary to Ethel Garrett.

At least one Hostess, however, is new to the titled crowd.

"I asked a friend at the National Gallery to tell me a little bit about them, so I would not be absolutely cold," admitted Olivia Jones, a longtime supporter of the Folger and wife of Rep. James Jones (D-Okla.). In addition to requesting the briefing, Jones removed her silver from the safe outside her house where it usually resides.

Unlike many other Hostesses who accepted the "must-have" guests the museums provided and then invited other friends to round out dinner-table conversation, Jones stopped with the 22 guests on her assigned list.

"I didn't really know at the beginning it was an option," she said with a laugh. "I want to point that out so my wonderful friends won't be insulted I didn't ask them."

The whole dinner party thing started when the Folger decided its budget could pay for a nice exhibit, "The Compleat Gentleman: Books From English Country Houses," and a nice reception. But a nice dinner was too much. Calls went out to library supporters who might be interested in holding private dinners, but again and again the answer was, "I'm taken." The gallery had already started planning its round of parties.

So the bartering began, first for which institution got which Hostess.

"It was that kind of trade-off -- one very glittering hostess for another," said Valentine.

And then for which Hostess got which guest.

"They all have several lenders," said Pam Brown. "We could have sent just one lender, but sometimes it's nice to have a compatriot somewhere in the room. You could have 200 dinners and still leave people out. I'm afraid there are lots of people we all know who won't be able to come. We could have gone on until the cows came home, but we would have run out of lenders. If you can't send any lenders to a dinner, your point for having a dinner is no longer there."

The parties range in size from fewer than a dozen to more than 50, and guests include the likes of philanthropists Brooke Astor and David Lloyd Kreeger and French Ambassador Emmanuel de Margerie. Beyond that, details of the negotiations -- attended by Brown, Valentine and the chairwomen of the two receptions -- and the resulting guest lists are scarce. The Hostesses are not the sort to talk about anything as private as guest lists, menus or table settings.

This, their calm voices suggest, is nothing out of the ordinary.

Even the caterers are mum.

"Well, it's not secret," said Jeff Ellis, co-owner of Ridgewell's Caterers, as if the word was somehow indiscreet, but he would only say his company is providing the food for a variety of British-related events.

"I don't think I want to go advertising the names," said one of the Hostesses. "I don't think it would be very good taste. I don't think it would be proper."

"Proper," like "tiara" and "ma'am," is one of those words certain to be heard frequently as long as social Washington grapples with its current bout of Anglophilia. And with a night like tonight, the opportunities to commit an impropriety are legion. For example, many of the Hostesses were very upset, according to Valentine, because the guests lists were not completed until recently.

"All being very proper hostesses, they wanted to send invitations to all their guests written in their own hands," he said. But by the time it was clear who was coming to dinner, many of the lenders were already on their way. The last few days have been spent tracking them down here so that the handwritten invitations could be delivered.

As with the guest lists, even talking about tonight's food calls for diplomacy.

Savoy Hotel managing director Giles Shepard described the British smoked salmon Savoy flew in for the gallery reception as "the same salmon we have in some of the hotels," but in case anyone should think North American smoked salmon was being maligned, he quickly wrapped himself in a mantle of qualifications: "I think in some ways [it] can be some of the best in the world."

Even at the gallery reception, hosted by the National Trust of Britain and its American support group, the Royal Oak Foundation, and paid for by British Caledonian Airways and the Savoy Group (London's Savoy, Claridge's, Berkeley and Connaught hotels), guests may have trouble recognizing the influence of the four British chefs flown in for the event.

In the canape's, however, lies one distinction between American and British culture.

"They're rather smaller," said Shepard of the Savoyesque hors d'oeuvres. "It's generally what one does for a cocktail party, so you can pop the canape' in one's mouth -- you're not burdened with a plate and fork."

But aside from scaled-down canape's, serving traditional British food to the traditional British visitors would be about as gauche as you can get.

"Oh, no!" said Ethel Garrett's secretary, her voice curdling at the thought. "Mrs. Garrett doesn't do themes!"