Great music went non-stop for eight hours yesterday in Washington as the Chevy Chase Presbyterian Church presented a Bach Marathon from 12:30 to 8:30. Sixteen top area organists played half-hour stints during which almost every aspect of Bach's genius on the organ was vividly exploited. The church even went so far as to offer "Bach's lunches" for those who wanted to spend all eight hours there. Over a hundred fans were present at the beginning.

By 2:30 the church was filled. Many of the listeners had brought their own scores and were following each player with the music.

Mid-afternoon at Masur Auditorium at the National Institutes of Health, the Amadeus Quartet, which has no superior in the classic repertoire, was joined by violist Raphael Hillyer in the supernal beauties of Mozart's string quintets.

Only rarely is the G Minor Quintet played with the radiant sound and exquisite style heard yesterday.

To top off the day, Richard Bales and the National Gallery Orchestra opened the 35th American Music Festival at the Gallery with two symphonies: one by George Bristow, a New York City violinist and composer who was a member of the New York Philharmonic in 1842, the year of that orchestra's birth. The other was the first performance of the Ninth Symphony of Spencer Huffman, a work written especially for the occasion.