One by one the musicians playing by candlelight Haydn's Farewell Symphony blew out their candles. Finally there were only two violins left playing. Then they stopped, and the conductor, Lazar Gosman, blew out his candle, too.

It was Leningrad, 1977. Gosman, leader of the Leningrad Chamber Orchestra, was to leave Russia the next day. Most of the audience knew. There were tears, and applause that wanted never to end.

Last night Gosman and his Soviet Emigre Orchestra reenacted the gesture at the diamond jubilee dinner of the American Jewish Committee at the Washington Hilton. Most of the 18 string players and five winds are Jewish or Russian or both.

"We did this every year in Russia," said Gosman, now associate concert-master of the St. Louis Symphony. "That last time the people were sad becaue they knew I was going but also because they knew so many musicians and dancers and poets were streaming out of Russia. And so many others wanted to leave."

Haydn wrote the symphony, No. 45, in 1772 as a gentle and witty way of telling his patron, Prince Esterhazy, that the musicians were tired of the summer palace and wanted to return to Vienna. It was written so that the players could leave the room one by one while the music carried on unhindered. The device is sure to charm audiences, however it is managed, by musicians simply laying down their instruments or actually leaving. Not the least of the charm is the way the music logically persists to its conclusion.

"It's really a symbol of the whole emigration process," Gosman said. "I brought my wife and son out, through official channels of course."

During World War II he was a student at the University of Moscow Conservatory. He has continued the tradition, serving now as professor of violin at the St. Louis Conservatory. He and American flutist David Barg founded the emigre orchestra in 1979.

The AJC is holding its 75th anniversary convention all this week.