Reprinted from yesterday's late editions.

It was Bach they were rehearsing in Harvard's Seaver Hall. A yound bass, an undergraduate, has just finished singing a short recitative with quiet and simple beauty, and the deceptively frail lady at the podium paused, motionless, for a long electric moment. No one in the chorus breathed. "You must make music your life," she siad to him. And then, intensely. "You must make music your life and study with me."

The bass was Thomas Beveridge and the conductor was the great teacher of musicians, Nadia Boulanger. She was pushing 75 at the time and I remember that she drove us through three hours of gureling rehearsal, rushed to a dinner where she gave a speech, and then topped off the evening by rehearsing the orchestra for three hours more.

Two weeks ago she celbrated her 90th birthday, and Thursday night the occasion was celebrated at the Library of Congress with the sort of concert she very well migh have put together herself Thomas Beveridge was again the bass soloist and there was music by Monteverdi, which she adored, by her beloved sister Lili Boulanger, who died much too young but left behind a large body of excellent and original music, by Elliott Carter and Aaron Copnad, her students, by Faure, her teacher, and by Stravinsky, her friend.

The participants were artists no-table not only for virutosity but also for their musicianship. Copland conducted his own Nonet for Stings. Beveridge and accompanist Martin Katz collaborated on the Faure "L' Horizon Chimerique."

Violinist Paul Zukofsky and painist Ursula Opeens teamed up on the Boulanger "Cortege" and "Norcturn" and the Carter Duo. And an marvelous quintet of soprano Linda Mabbs, mezzo Louise McClelland, tenors Douglas Robinson and Gene Tucker, and bass Thomas Beveridge, with Russell Woollen, another Boulanger pupil, conducting, gave a lustrous performance of five of Monteverdi's madrigals.