The Magic Flute chorus for several numbers (notably the finales of each act). Mozart also called for a "" (instrument of steel) to perform Papageno's magic bells; an instrument which has since been lost to history, though modern day scholars believe it to be a keyed glockenspiel, which is usually substituted with a celesta in modern-day performances. Charles Rosen has remarked on the character of Mozart's orchestration: "Die Zauberflöte" has the greatest variety of orchestral color that the eighteenth century was to know; the very lavishness, however, is paradoxically also an economy as each effect is a concentrated one, each one—Papageno's whistle, the
Libretto of The Magic Flute to draw a generalized observation from the proceedings on stage in order to promote virtue or condemn vice." Cairns attributes a taste for "didactic sentiment" specifically to the Viennese popular theater. Concerning "The Magic Flute" specifically, Rosen writes that it "develops ... a conception of music as a vehicle for simple moral truths." The opera's didacticism is concentrated in passages of poetry, set in the ensemble scenes, in which the characters cease to converse with each other and join in singing an edifying lesson to the audience. One example is found in the first act, just after Monostatos and his