love to the care of her friends and goes to denounce the libertine to the officers of the law. The last scene is reached. Don Giovanni, seated at his table, eats, drinks, indulges in badinage with his servant, and listens to the music of his private band. The musicians play melodies from popular operas of the period in which Mozart wrote--not Spanish melodies of the unfixed time in which the veritable Don Juan may have lived:-- [Musical excerpts--From Martin's "Una cosa rara." From "Fra i due litiganti" by Sarti. From "Nozze di Figaro."] Mozart feared anachronisms as little as Shakespeare. His Don Giovanni was contemporary with himself and familiar with the repertory of the Vienna Opera. The autograph discloses that the ingenious conceit was wholly Mozart's. It was he who wrote the words with which Leporello greets the melodies from "Una cosa rara," "I due Litiganti," and "Le Nozze di Figaro," and when Leporello hailed the tune "Non piu andrai" from the last opera with words "Questo poi la conosco pur troppo" ("This we know but too well"), he doubtless scored a point with his first audience in Prague which the German translator of the opera never dreamed of. Even the German critics of to-day seem dense in their unwillingness to credit Mozart with a purely amiable purpose in quoting the operas of his rivals, Martin and Sarti. The latter showed himself ungrateful for kindnesses received at Mozart's hands by publicly denouncing an harmonic progression in one of the famous six quartets dedicated to Haydn as a barbarism, but there was no ill-will in the use of the air from "I due Litiganti" as supper music for the delectation of the Don. Mozart liked the melody, and had written variations on it for the pianoforte.