In the first place as regards the themes themselves, Mozart’s are longer and more complex than Haydn’s. It is hard to imagine Haydn disposing his phrases with the ingenuity and mental grasp shown by the melody in Figure XV., written when Mozart was only six years old. The characteristic of this melody is that the phrases are not immediately repeated, thereby balancing in the most obvious way, but alternated with apparent whimsicality, which, however, eventually issues in order. This is even more conspicuously shown by the following theme from Mozart’s great G-minor Quintet: [Music: score] [Illustration: 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: [Music: score] [Illustration: FIGURE XIX. INTRODUCTION TO MOZART’S C-MAJOR QUARTET.] It was to passages of this kind (though even Mozart could not write many equalling it in supernal beauty and mystery of effect) that he owed his reputation for heterodoxy and radicalism among the pedants of the time. A musical connoisseur of Vienna is said to have torn up the instrumental parts of these quartets in his anger at finding that “the discords played by the musicians were really in the parts”; the parts were also returned from Italy as being “full of printer’s errors”; and even so good a musician as Fétis undertook to “correct” this very Introduction. Thus to scandalize the conservative is ever the effect of the daring, novel, and unprecedented conceptions of genius.