THE SUMMIT AT GENEVA : Nancy Reagan Takes Look at Her Borrowed Mansion

While her husband was fending off summit controversy, Nancy Reagan spent Sunday settling into the Reagans’ Geneva residence, the spectacular mansion loaned to them by the Aga Khan.

In her only public appearances Sunday, the First Lady took a brief stroll with the President through the garden of the 18th-Century mansion, the Maison de Saussure, and she helped her husband rehearse for the meetings with Soviet leader Mikhail S. Gorbachev.

While the President discusses nuclear disarmament and other issues, Mrs. Reagan has a heavy social schedule, beginning today with a tea with Ursula Furgler, the wife of Swiss President Kurt Furgler.

The event will be something of a warm-up for the teas that the First Lady will have Tuesday and Wednesday with Raisa Gorbachev, wife of the Soviet leader. Not since Jacqueline Kennedy had lunch with Nina Khrushchev in Vienna in 1961 have Soviet and American first ladies met.

No Agenda for Tea

No agenda of tea discussion topics has been set. But Elaine Crispen, Nancy Reagan’s press secretary, said she doubts that any controversial summit subjects will be brought up. “She’ll get into people, not policy,” Crispen said. “It’s a chance to get acquainted.”

During her stay, Mrs. Reagan will also visit La Picholette Farm drug rehabilitation program in Lausanne, take a boat ride on chilly (about 32 degrees) Lake Geneva, visit the picturesque town of St. Prex, participate (along with Mrs. Gorbachev) in a ground-breaking ceremony for a Red Cross museum and tour the College du Leman international school. The Soviets and Americans will also host small, informal dinners for one another on Tuesday and Wednesday evenings.

While the Gorbachevs will stay in the Soviet Mission, which looks much like an office building, the Reagans’ residence is a classically styled mansion in the countryside outside Geneva, facing the lake. It was designed by French architect Francois Blondel, who also designed some of the ancillary buildings of the Palace of Versailles, and was built in the early 1700s.

President Dwight D. Eisenhower stayed there in 1955 during a meeting of the leaders of the United States, the Soviet Union, Britain and France.

In the 18th Century the mansion served as a rendezvous point for Europe’s leading scientists and intellectuals. Named for Geneva scientist Horace Benedict de Saussure, the mansion is now owned by Daniel Pometta and is occupied by Prince Karim Aga Khan, Princess Salima Aga Khan and their three children.