Between engagements in her busy musical career, Nokuthula Ngwenyama is studying non-Western religions at Harvard Divinity School--an appropriate avocation for one who plays the viola so divinely. Friday night at the Barns of Wolf Trap, she showed that her chosen instrument, the most neglected member of the bowed string family and the butt of innumerable jokes by musical insiders, is capable of matching the virtuoso tricks of the violin and producing a tone as creamy, as rich and almost as deep as the cello.

Those who go to a viola recital should expect to hear relatively unfamiliar music; the viola repertoire is abundant but it is not well known. Most good viola music is the work of viola players--in this concert, the viola was the primary instrument of composer Rebecca Clarke, whose Sonata for Viola and Piano combined brilliance with emotional appeal, and Paul Hindemith, whose fiendishly challenging Sonata for unaccompanied viola unveiled the depths of the instrument's soul.

It was a strong secondary instrument for violinist Henri Vieuxtemps, whose "Elegie" for Viola and Piano poured out serene melodies--elegantly phrased by Ngwenyama--and virtuoso fireworks that she made seem easy. And it was significant in the career of violin virtuoso Niccolo Paganini, whose "La Campanella" concluded the evening with music that was both familiar and technically dazzling. Viola recitals with no transcriptions seldom happen, and this was one of two transcriptions played by Ngwenyama, as if to show that her instrument can match the violin's pyrotechnics. A similar subtext may be suspected in her lyric performance of a Vivaldi sonata, originally written for cello, that opened the program. But the three works composed originally for viola were the heart of the evening and its most rewarding music.