A few chords, however, lead Don Giovanni's questions at once back to the dominant of the principal key, and the forcible "Si" of the Commendatore answers with the tonic, the clear calm of which is destroyed at once by Leporello's C: the real conclusion is only arrived at circuitously. Very different in effect on both occasions is the occurrence of the same C in the bass. The first time, when C major follows decidedly on B major, it makes a fresh, elevating impression; the second time, when C follows the sustained E as the third below, and forms the basis for the chord of the third, fourth and sixth, it gives a shock to the ear. The vivid reality with which the two contrasting individualities are made to express themselves in so unusual a situation has necessitated the free form of the duet. Detached musical phrases, complete in themselves, follow the play of the emotions without the elaboration or repetition of any of the subjects; only Leporello's cry of terror recurs several times, and serves to a certain extent as a connecting link. Mozart has judiciously refrained from bringing the horror of a spectral apparition objectively before his hearers. Their imagination has been sufficiently worked upon by the {DON GIOVANNI.} (176) awful and imposing words of the Commendatore,[154] and their attention ought not to be diverted from Don Giovanni and Leporello. The freedom which permits of a playful treatment of Leporello's double fear and of Don Giovanni's consternation reposes mainly on the half-light in which the ghostly element is viewed. The spectator is impelled to accept the mixture of the horrible as a flavouring to the humorous; he is not in the least absorbed by horror. As soon as the ghost appears bodily, he comes to the foreground and gives tone and colour to all the rest; it is of advantage to the effect that none of the resources of musical delineation are employed to heighten this point. The true economy of an artist not only concentrates his resources on one point, but finds its truest expression in his appearing to disdain their use at another. The main point here was the audible voice of the statue, and Mozart gave it no support but the vibration of the horn note; this necessitated the greatest simplicity in the whole musical rendering of the situation.