Will Crutchfield's long-running Bel Canto series at the Caramoor Festival, north of New York, had another happy outing last weekend with Guillaume Tell, Rossini's operatic valediction. (There is one more performance on Friday.) The cast wasn't flawless, but I'm not sure who'd be able to field a flawless cast in Tell these days. Michael Spyres certainly did not embarrass himself in the semi-impossible tenor role of Arnold, even if he struggled with the extreme upper register at times, and Daniel Mobbs supplied a steady center of gravity in the title role. The stars were the women: Julianna Di Giacomo, rich-voiced if a little uncontrolled as Mathilde; Talise Trevigne, glitteringly precise as Jemmy; and Vanessa Cariddi, displaying a smoky lower register in the mezzo role of Hedwige. Their Act IV trio was the vocal highlight of the night. Crutchfield conducted splendidly, generating palpable energy in the St. Luke's Orchestra. I also attended an afternoon seminar-concert with Crutchfield, the great Italian-opera scholar Philip Gossett (at the piano above), and young artists from the Caramoor program, in which we got to hear several numbers that Crutchfield elected to omit from the main presentation. (Charlotte Dobbs, whom I last heard singing The Book of the Hanging Gardens with Mitsuko Uchida at Marlboro, was especially fine in Jemmy's "Ah! que ton âme se rassure.") Gossett emphasized how the reputation of Tell was long distorted by its Italian-language version, which amounted to a political bowdlerization, with references to "liberty" and "tyrants" omitted. (When Muti conducted Tell in Italian at La Scala, Gossett insisted that he use an amended libretto. The Met, alas, ignores Gossett's work.) Gossett also spoke eloquently of the power of the ending — that slow finale that soars through a wide harmonic space, C major to A minor to F major to D minor to B-flat major to G minor to E-flat major, evoking the "horizon immense" of human possibility. That Rossini should have stopped composing opera after writing such a finale is shocking: it feels like the birth of a new world. These few minutes are in themselves worth the trip to Katonah.