There remains little to be said of the æsthetic worth of his music. During the years of his most vigorous manhood he was almost invariably a virtuoso. Sheer delight in tonal effects rather than more sober need of self-expression stimulated him. The prevalence of trumpet figures such as those which constitute the opening phrases of the eleventh and fourteenth sonatas in the Breitkopf and Härtel edition already referred to, suggests that he took a good deal of material ready-made from the operas of the day. Burney says there are many passages in which he imitated the melody of tunes sung by carriers, muleteers, and common people. But what he added to these was his own. A number of pieces are conspicuous by especially free modulation and expansion of form; and in these, technical effects are not predominant, but rather a more serious interest in composition. It has therefore been suggested that these pieces are the work of later years.[15] Though it is said that while in Spain he grew too fat to cross his hands at the harpsichord as was his wont in his youth, this physical restriction is not alone responsible for the mellowness and warmth of such pieces as the so-called Pastoral in D minor, familiar to audiences in Tausig’s elaborated transcription. A great number of his pieces are rich in pure musical beauty; and the freshness which exhales from all true musical utterance is and probably always will be theirs. None of his contemporaries in Italy approached him in the peculiar skill which has made him conspicuous in the history of pianoforte music. Francesco Durante (1684-1755) and Nicolo Porpora (1686-1767), the great singing master, both wrote pieces for the harpsichord; the one, ‘sonatas’ in several movements, the other fugues; but their music lacks charm and can hardly be considered at all influential in the development of the art of writing for keyboard instruments. Domenico Alberti and P. D. Paradies will be considered in the following chapter. II The art of Couperin is flawless, the charm of his music not to be described. It has that quality of perfection with which Nature marks her smallest flowers. It is the miniature counterpart in music of a perfected system of living, of the court life of France under Louis XIV.