FIGURE XVIII.
Here a broad and perfectly poised melody is evolved from two simple motifs by a deftly managed accretion. The effect reminds one of Beethoven; Haydn could scarcely have conceived it.
In harmony Mozart is more venturesome than his predecessor. His harmonic structure, while no less clear than Haydn’s, is less bald, less obvious. In the fifth of the quartets dedicated to Haydn, for example, in A-major, there is an early and pronounced modulation to C-major; after which the second theme comes in regularly in the dominant key. The effect of this insistence on a comparatively distant key is to blur slightly the contour of the form, and to prevent any possible sense of triteness. In the Finale of the third quartet, Mozart, after ending his first part strongly in C-major, jumps suddenly, quite without warning, to an emphatic chord of D-flat major,—a device by which we are irresistibly reminded of the complete shifts of tonality at the beginning of the coda of the first movement of the “Eroica” Symphony. Perhaps the most brilliant stroke of genius in harmonic conception that Mozart ever made, however, is the famous passage introducing the C-major Quartet. It runs as follows:
FIGURE XIX. INTRODUCTION TO MOZART’S C-MAJOR QUARTET.