During Haydn’s comparative solitude at Eisenstadt, however, a wonderful youth had come into the European musical world, had absorbed with the facility of genius everything that musical science had to offer, had learned from Haydn what could be done with the symphony as he had learned from Gluck what could be done with opera, and had outshone and outdistanced every composer living at the time. What Haydn was able to give to Mozart was rendered back to him with abundant interest. Mozart made use of a richer and more flexible orchestration, achieved greater beauty and poignancy of expression; and Haydn, while retaining his individuality, still shows marked traces of this noble influence. The early works of Haydn were far in advance of his time, and were highly regarded; but they do not reveal the complete artist, and they have been almost entirely superseded in public favor by the London symphonies, composed after Mozart’s death. In these he reaches heights he had never before attained, not only in the high degree of technical skill, but in the flood of fresh and genial ideas, and in new, impressive harmonic progressions. The method of orchestration is much bolder and freer. The parts are rarely doubled, the bass and viola have their individual work, the parts for the wind instruments are better suited to their character, and greater attention is paid to musical nuances. In these last works Haydn arrived at that ‘spiritualization of music’ which makes the art a vehicle not only for intellectual ideas, but for deep and earnest emotion. Parallel with the growth of the symphonic form and its variety of treatment came also a real growth of the orchestra. The organization of 1750, consisting of four strings and four wind instruments, had become, in 1791, a group of thirty-five or forty pieces, consisting of, besides the strings, two flutes, two oboes, two bassoons, two horns, two trumpets and drums. To these were sometimes added clarinets, and occasionally special instruments, such as the triangle or cymbals. Thus, by the end of the century, the form of the symphony, according to modern understanding, was practically established, and the orchestra organized nearly according to its present state. Haydn represents the last stage of the preparatory period, and he was, in a very genuine and literal sense, the founder, and to some degree the creator, of the modern symphony.