It was a lovely concert of Haydn, Mozart and Beethoven that the Smithson String Quartet played Tuesday night at the National Museum of American History -- when there was some light.

Promptly at 8 the musicians were ready to enter the museum's chamber music auditorium, the Hall of Instruments. Then it happened. The lights went out. Just in the auditorium. Nowhere else in the large and otherwise deserted building.

Engineers were called. Jim Weaver, the musuem's director of performances, announced in the dark that a timed switch of some sort had turned off the large central chandelier. The engineers got to work. At roughly 8:20 the lights flashed back on -- for about a second, and then went back out, never to come on again during the evening.

There were no candles. By about 8:35, cellist Kenneth Slowik had rigged up a dim floor lamp on stage. That got the concert started.

Haydn's pensive D Minor Quartet, Op. 9, No. 4, seemed especially well suited to the mellow, lightly inflected sound of the early instruments -- and the mellow light.

Mozart's glorious Clarinet Quintet, K. 581, went even better. The instruments' gut strings had a delicacy when blending with the rich colors of the clarinet (played by Lawrence McDonald) that can't quite be matched on bright modern instruments. The playing was full of interpretive felicities as well.

The Mozart was a hard act to follow, and the Beethoven Quartet, Op. 18, No. 4, is not one of that composer's many masterpieces. Still it moved along stylishly until near the end of the third movement. Fate intervened again. One of first violinist Jaap Schroeder's strings popped. Another delay. Gut strings don't wear as well as steel ones. Schroeder came back in about five minutes and they picked up where they had left off.

Bemoaned Weaver offstage: "I'm so embarrassed. I feel like a host who doesn't have any more food, or who has run out of gin."