Haydn and Mozart, who composed somewhat for the harpsichord (for until the closing years of the eighteenth century this instrument had not entirely yielded to the growing popularity of the piano-forte), distinguished themselves still more by their treatment of the latter instrument. They closely followed the maxims of Emanuel Bach. They aimed to please the public by sweet melody and agreeable harmony, by spontaneous elegance and cheerfulness, by suave and smooth simplicity. Their practice in writing for the orchestra and for voices modified their piano-forte style both as composers and players, but they never sacrificed that intelligible and simple charm which appeals to the universal heart to the taste for grand, complex, and eccentric effects, which has so dominated the efforts of their successors. Mozart's most distinguished contemporaries bear witness to his excellence as a player, and his great command over the piano-forte, and his own remarks on piano-playing are full of point and suggestion. He asserts "that the performer should possess a quiet and steady hand, with its natural lightness, smoothness, and gliding rapidity so well developed that the passages should flow like oil.... All notes, graces, accents, etc., should be brought out with fitting taste and expression.... In passages [technical figures], some notes may be left to their fate without notice, but is that right? Three things are necessary to a good performer"; and he pointed significantly to his head, his heart, and the tips of his fingers, as symbolical of understanding, sympathy, and technical skill. But it was fated that Clementi should be the Columbus in the domain of piano-forte playing and composition. He was the father of the school of modern piano technique, and by far surpassed all his contemporaries in the boldness, vigor, brilliancy, and variety of his execution, and he is entitled to be called first (in respect of date) of the great piano-forte virtuosos, Clementi wrote solely for this instrument (for his few orchestral works are now dead). The piano, as his sole medium of expression, became a vehicle of great eloquence and power, and his sonatas, as pure types of piano-forte compositions, are unsurpassed, even in this age of exuberant musical fertility. II.