By The thorny problem of the angry Quebecois separatists aside, nearly 1,000 Canadians gathered here on Sunday at the dramatic embassy on Pennsylvania Avenue for a Canada Day picnic complete with the traditional hot dogs and hamburgers. July 1 marks the 1867 British North American Act that formed Canada. The Sunday celebration was just for Canadians and, since the government doesn't pay for such an event, the food and Moosehead beer was donated; Ambassador Derek Burney and his wife, Joan, along with about 80 members of the embassy staff, cooked the food and served the drinks. There weren't the usual fireworks, but Sunday's fierce thunderstorm provided pyrotechnics around the Capitol dome for the picnickers who briefly took the party inside. Those who had done all the work were rewarded by being invited back to the ambassador's residence on Rock Creek Drive for a swim in the pool. The celebration at the embassy was initiated last year when the Burneys came to Washington replacing Ambassador Allan Gotlieb and his wife, Sondra.

And since the ambassador has such a spectacular view of the Capitol and the mall from the vast terrace off his office, he has invited a much smaller group of Washington's government and journalism community to celebrate the Fourth of July at a picnic there. Among some of the guests to view the fireworks and National Symphony concert are Agriculture Secretary Clayton Yeutter; Veterans Affairs Secretary Edward Derwinski; Health and Human Services Secretary Louis Sullivan; FBI Director William Sessions; Washington Capitals and Bullets owner Abe Pollin; former Democratic national chairman Robert Strauss; Republican National Committee Co-chairman Edward Rollins Jr.; and attorney Vernon Jordan Jr.

Out and About

This is not meant to be an all-Canada column, but some days it just happens that way. Rep. Pat Schroeder said she was sitting in her Alexandria home Sunday having a cup of coffee when she received a telephone call from Canadian Prime Minister Brian Mulroney. He had read a profile of the Colorado Democrat in the New York Times Sunday magazine and said enviously that with all his problems at home, he would virtually kill for such a positive article. Schroeder was moved by the gesture and said yesterday, "I can't even vote for him" ...

One of the performance artists whom the National Endowment for the Arts didn't reject has turned down the money in protest of the agency's veto of four grants last week. Rachel Rosenthal yesterday said she wouldn't accept the $11,250 grant approved by the arts agency. "I feel it's absolutely unconscionable that Chairman {John} Frohnmayer should have excluded these four people," Rosenthal told Knight-Ridder from Los Angeles. "These are four of the best performance artists we have, and I see absolutely no distinction between them and myself. Why should I be considered clean and they're considered dirty?" Rosenthal also refused to sign an agreement that she would not use the funds for "obscene" works ...

It has now appeared in the official real estate records: Patricia Kluge owns the Albemarle Farms 45-room mansion near Charlottesville, which had been reported to have been part of her divorce settlement from her husband, John Kluge. He is said to be the richest man in America, worth about $5.2 billion. The mansion goes along with the interest on $1 billion, an estimated $85 million annually for her to survive on. According to a memorandum filed in Albemarle County Circuit Court, Patricia Kluge, 41, has use of the estate's private Roman Catholic chapel and the family crypt. John Kluge, 76, appears to retain ownership of the estate's golf course, stables, tennis court, conservatory and greenhouse ...

More on the summer wedding circuit. If you are going to get married, Avignon, France, isn't a bad place to have the ceremony. Mark Johnson, who was Jim Wright's press secretary in the final days of his speakership, is marrying Channel 9 news producer Laura Sebree there Saturday ...