With what amounted to a 150 (plus or minus) string salute, conductor Yehudi Menuhin and the First American Violin Congress Orchestra concluded a unique five-day musical convocation Saturday night at the University of Maryland. This ad hoc orchestra, made up of amateur and professional musicians from throughout the United States and Canada, stood out for reasons beyond its visibly cramped quarters on the Tawes Theatre stage. Performances of Corelli's Concerto Grosso, Op. 6, No. 7, in D and Vivaldi's Concerto for Four Violins No. 7 in F were remarkably disciplined, powerful, but judiciously so. Credit the magic that is Menuhin and his amazing pool of violinists for pulling this off with only three rehearsals.

The evening was not entirely a spectacle of string strength. In fact, things began quietly with "Four Settings for Jay Pris Amors," renaissance music that involved four violinists. All other pieces before intermission were in the contemporary chamber vein and allowed violas, cellos and a string bass in on the activity. Two Pieces for String Octet, Op. 11, by Shostakovich got off to a wobbly start, but by piece two the players were of one mind, able to translate the score's nocturnal sounds into near-palpable images.

Menuhin presided over the 12 strings and harpsichord in Finnish composer Joonas Kokkonen's "Durch einen Spiegel" ("Through a Looking Glass"), the most impressive piece on the program. Stylistic elements from the last 200 years competed, even elbowed for space. Kokkonen's looking glass is more like a two-way mirror. The strings were devastatingly effective when massed in icy high-register textures.

Menuhin needed some help for his mammoth concerto presentations. The stage could never have held enough continuo players, so at his request for a "big Japanese organ," the mighty Yamaha Electone HX-1 filled in. Organist Hector Olivera discreetly provided harpsichord, cello and string bass timbres. Musician unions might grumble, but keys replaced strings quite well. As for Corelli and Vivaldi, there were no reported rumblings from the old country.