Haydn improved not only in his method of developing the subjects of his movements, but in his knowledge of the kinds of themes best fitted for orchestral treatment, which are organically different from those suited to the piano. His experiments in instrumentation went far towards assisting composers to a true knowledge of the art of orchestration (writing for orchestra). He himself learned rapidly from the trials of his own combinations by the Esterhazy band. In his early days, for instance, he frequently wrote the same part for his first and second violins and the same part for his violas and basses, so that his strings were playing in only two real parts, and his harmony was very thin. His treatment of the wood wind was crude at first, but his experiments rapidly improved this, and by 1770 he had introduced the now familiar style of making the wind instruments intone long chords, while the strings played figured passages, or _vice versa_. The movements of all his symphonies are very short, and one who looks for great breadth or depth in them will be disappointed. They are bright and genial, except in their slow movements, which are generally tender without being pathetic. In the first movements the working out is usually short, and not at all involved, as if Haydn were timid about presenting too much for intellectual consideration at one time. The finale is generally in rondo form, so that there is only one real working out in the whole symphony. It must be borne in mind that the public taste of that time would hardly have been prepared for such advanced works as those of Beethoven, even if Haydn's technic of composition had been equal to the task of writing them. The composer was thoroughly in accord with the spirit of his time, and his influence in popularizing good music cannot be over-estimated. Haydn's later works show a marked advance over his earlier ones, which must be attributed to the influence of Mozart. The reader will remember that Mozart's life began after and ended before Haydn's. Mozart also had opportunities to learn something about the possibilities of orchestral music while he was at Mannheim in 1777. The band there was one of the finest in Europe at the time, and its excellent achievements in light and shade no doubt gave Mozart many valuable suggestions. Mozart wrote forty-nine symphonies, but only three of them are heard often to-day: that in E-flat major, op. 543, that in G minor, op. 550, and that in C major, op. 551, commonly called the "Jupiter" symphony. These were his last three symphonies, written in 1788, and it is notable that in none of the three is the full Beethoven orchestra employed. All three use only one flute. The E-flat symphony has clarinets, but no oboes. The other two have oboes, but no clarinets. The G minor has no drums nor trumpets, and none has trombones. Nevertheless, by the pure beauty of their melodic subjects, the clearness of their discussion, and their