Rates of exchange vary widely in these times of revolutionary upheavals. Who is rich and who is poor is not always easy to determine.

Currently, the National Gallery of Art owes the Olomouc Archbishopric Palace in Kromeriz, Czechoslovakia, a thank-you present, or rent -- whichever way you'd like to put it -- for the magnificent loan of the great Titian painting "The Flaying of Marsyas," as well as a fine Van Dyck, "Charles I and Queen Henrietta Marie." "Marsyas" is the climax of the "Titian, Prince of Painters" 500th-anniversary show, on exhibit through January in the West Building.

"With Titian's life's work -- the paintings in the other galleries -- it propels his art into the 20th century," said National Gallery Director J. Carter Brown of "Marsyas." "It's vital, crucial to the exhibit. The painting has had a wonderful reception. People are so moved by it, they don't want to leave its gallery. With the Beethoven quartet on the Acoustiguide, it's a total sensuous experience."

How the Titian, and the Van Dyck, got to the National Gallery from the far reaches of Czechoslovakia is an instructive peep into the black box whence the magician curators pull out the exhibits that so delight Washington.

"We wanted the Titian -- and the Van Dyck -- very much," said Brown. "But we had turn-downs from the people in Czechoslovakia. So we pleaded with Meda Mladek to go over on our behalf. We thought her loyalty to the National Gallery and to her native Czechoslovakia just might have an effect."

If anyone could talk the Czechs out of their paintings, it was Meda Mladek. During the Prague Spring of 1968, she organized a show of contemporary art from her homeland at the now-defunct Washington Gallery of Modern Art. In 1988 she was curator of the "Expressiv" exhibit of Central European art at the Hirshhorn Museum. Mladek, originally with her late husband, Jan, is a principal collector of 20th-century Czechoslovak art. Following the democratization of that country, Mladek lent much of her collection to the embassy here.

"The National Gallery had given up on the Titian," said Mladek, just back from one of her cultural shuttles. "One curator said to me: 'Forget the Titian. It's impossible. We'll never get it. Concentrate on the Van Dyck.' I thought to myself, if I get the Titian, the Van Dyck will come as well."

The Titian had been borrowed for a one-painting show here four years earlier. It had also been lent to the Venetian 500th-anniversary Titian show, the precursor of the National Gallery's.

"For Czechoslovakia, lending the Titian was as wrenching as for France to lend the 'Mona Lisa,' " said Mladek. "The biggest names in art wrote letters saying they were against it leaving the country.

"So I went everywhere. I spoke to the minister of culture; he said I must talk to the director of the {Czechoslovak} National Gallery. The director said I should speak to the cardinal, because the painting is in the Archbishopric Palace. The cardinal said it was for the archbishop to say. The archbishop said it was up to the museum director of the Statni Zamek, the palace in Kromeriz."

Kromeriz is not exactly in the suburbs of Prague. Brown remembers his earlier trip as taking him the better part of a day to get there. "The countryside is beautiful, wonderful churches, castles and mountains. But it is at a great distance."

"I had never been to Kromeriz," Mladek said. When she arrived, "the museum director was in Venice -- but not at the hotel telephone number his wife gave me. I thought, 'What can I do? He must be staying with a girlfriend. I'll never find him.' Then I found out, to save money he and two other men from the museum had taken a room together in a cheaper place. He said if I could get signatures of approval from all those -- I can't remember how many -- who had written letters against the loan, he would not oppose it.

"Always I am talking, talking, talking -- pointing out the United States saved us from Hitler, Americans are now giving us scholarships, et cetera, et cetera."

Mladek set out on her mission to get the art experts to approve the loans. In the end, she succeeded in signing up everybody she needed. The Titian and the Van Dyck were sent on to the National Gallery, to be feted with boar and even glazed rose hips (from events planner Genevera Higginson's own Massachusetts seaside garden) and Titian-age music supplied by Silvio Berlusconi Communications, which with Galileo Industrie Ottiche, also of Italy, was the sponsor of the exhibit and dinner.

Just as Mladek was leaving Kromeriz, the museum director hemmed and hawed a bit, trying to tell her what was in his heart. Finally, he confessed, "Doctor Brown has offered to lend us two chef-d'oeuvres, masterpieces, while ours are in the United States. You know, we have many, many masterpieces. However, our grounds man is too old to cut the grass by scythe any longer. And we have no way to copy our correspondence. It would cost Washington's gallery transportation and insurance to lend us paintings. Instead, could Doctor Brown please send us a grass-cutting machine and a Xerox?"

So now Carter Brown has a problem. "Our charter won't allow us to buy machines for them. We can arrange some technical assistance for their art, perhaps. We can only hope that somewhere someone in the private sector will donate a mower and a Xerox. If you know somebody, tell them to call me." The number is 202-842-6447.