On the eve of the signing of the Preliminary Treaty of Paris 200 years ago today, and within reach of the very desk used in 1783 for the signing of the Real Treaty, a group of history buffs and diplomats prepared for next September's bicentennial celebration of the Treaty of Paris.

"Benjamin West invited the participants of the provisional treaty to his studio. So here we have John Jay, John Adams, Benjamin Franklin . . . and he reserved two spaces. But for real or diplomatic illness, the French and the British didn't come," said Clement E. Conger, the White House curator, explaining the unfinished painting above a fireplace in the State Department's Diplomatic Rooms. Nearby, British Ambassador to the U.S. Sir Oliver Wright was at a loss for a better explanation of the British absence. "I don't know," he added jokingly, "but America has done well since the Treaty of Paris."

The treaty, signed on Sept. 3, 1783, was the first signed by the United States and legally sealed the independence announced in 1776. This celebration was the brainchild of Joan Challinor, a professorial lecturer at American University. "I had worked with the Smithsonian on 1776, then the centennial of the end of Reconstruction. When I went to see who was organizing the bicentennial of the Treaty of Paris, I asked around and found no one was," explained Challinor.

The bicentennial committee includes a gaggle of former ambassadors, from W. Averell Harriman to Elliot Richardson as well as historians and clerics. Nothing in particular is expected from the committee, said Kingman Brewster, former envoy to Great Britain and former president of Yale. "But we should scratch our heads to come up with names of foundations and people who can help," he said.

Conger twice saluted the private sector for following President Reagan's appeal for subsidies of arts projects, using the State Department's Americana collection and the Treaty Bicentennial committee as examples. So far, Challinor said, $40,000 had been raised from the private sector, "and lots of in-kind support."

Swapping historical stories were Richardson, who once did the voice of John Adams in a Declaration of Independence bicentennial commemoration along with the Prince of Wales, who did George III; Secretary of the Army John O. Marsh Jr., former Iowa congressman Fred Schwengel, and support groups such as the Daughters of the American Revolution and the Sons of the American Revolution.