Departed music directors aren't always missed, but Ignat Solzhenitsyn's return to the Chamber Orchestra of Philadelphia was greeted with unusual dedication by the musicians, almost as if they were reclaiming an identity Monday at the Kimmel Center.
Solzhenitsyn's penchant for lesser-known works by major composers yielded a wonderful discovery in Schumann's Introduction and Allegro Appassionato (Op. 92; the conductor doubled as pianist), which tries to be urbane but has the composer's customary depths nonetheless. Every phrase had so much life that listeners had little room to stand back and ask how well the piece stands up to better-known Schumann.
Variations on a Theme of Frank Bridge (Op. 10), not as big a discovery but seldom heard, established Benjamin Britten as a major force in 1937. The theme is nothing very lyrical, but each variation creates a hugely different world, in both sound and substance. Whether eerie waltz, wordless opera scene, or mysterious exploration of the unknown, the variations felt so fully realized in this performance that, as in the Schumann, you never looked over your shoulder at what antecedents might have contributed to this confoundingly mature piece. Just when you knew where it was going, it went someplace better.