Haydn’s Op. 54 No. 2 contains a most extraordinaryslow movement inspired by melismatic, improvisedgypsy violin music. Webern’s extremely affectingshort pieces, meanwhile, compress the emotions ofa symphony into a few minutes, whereas Mozart’sK575 is hallmarked by its expansive melodiouswarmth and relaxation. Wistful, heartfelt beauty,perhaps inspired by Schubert, belongs to Brahms’sA minor String Quartet.