Last night at the Library of Congress the Juilliard Quartet was in a rare introspective mood. Setting aside its often overly vigorous style, the ensemble reached deep to produce some playing of great inner beauty.

The evening's tone was set by the opening work, an incomplete Haydn quartet containing only two inner movements. Written in 1803, it was both his last quartet and his last composition. Though Haydn lived some six years longer, failing health kept him from further composing and he finally had the two movements published by themselves in 1806. Even apart from its special quality as Haydn's last recorded thoughts, the music is exceptionally moving, reflective in nature and structured in a free flow that calls to mind late Beethoven. The Julliard's subdued performance conveyed the quiet air of final summation that the two movements, which seem almost complete in their expressive depth, embody.

The ensemble followed up the Haydn with a strong performance of Bartok's first quartet, work that also possesses an intense inward quality.

The closing Beethoven Quartet, Op. 59, No. 1, had more of the Julliard's muscle, but after the intensity of the first two works a release into a more outward energy was almost inevitable.