In following Beethoven's symphonies from the First to the Ninth, we can see the modern orchestra developing under his hands from that handed over to him by Haydn and Mozart. In the First and Second Symphonies, Beethoven employs the usual strings, two flutes, two oboes, two clarinets, two bassoons, two horns, two trumpets and tympani. In the Third Symphony, the "Eroica," he adds a third horn part; in the Fifth a piccolo, trombones and contrabassoon. Although employed in the finale only, these instruments here make their first bow in the symphonic orchestra. In the Ninth Symphony Beethoven introduced two additional horns, the first use of four horns in a symphony. The scoring of these symphonies is given somewhat more in detail in the chapter "How the Orchestra Grew," in Mr. W. J. Henderson's "The Orchestra and Orchestral Music," a well conceived and logically developed book, in which the full story of the orchestra and its growth is clearly and interestingly told.
Beethoven not only understood to a greater degree than his predecessors the peculiar characteristics of orchestral instruments, he also compelled orchestral players to acquire a better technique by giving them more difficult music to execute. In point of greater difficulty in performance, a Beethoven symphony holds about the same relation to the symphonies of Mozart and Haydn as the Beethoven pianoforte sonatas do to the sonatas of those composers.
Just as Beethoven added only a few instruments to the orchestra of his predecessors, but showed greater skill in handling those instruments, so the modern musician--a Wagner or a Richard Strauss--achieves his striking instrumental effects by a still greater knowledge of instrumental resources. The Beethoven orchestra practically is the orchestra of to-day. Few, very few, instruments have been added. Modern composers steadily have asked for more and more instruments in each group; but that is quite a different thing from adding new instruments. They have required more instruments of the same kind, but have asked for very few instruments of new kinds. Let me illustrate this by two modern examples.
Firm, compact and eloquent as is Beethoven's orchestra in the Fifth Symphony, it cannot for a moment be compared in richness, sonority, tone color, searching power of expression and unflagging interest, with Wagner's orchestra in "Die Meistersinger." Yet Wagner has added only one trumpet, a harp and a tuba to the very orchestra which Beethoven employed when he scored for the Fifth Symphony; while for his "Symphonie Pathétique," one of the finest of modern orchestral works, Tschaikowsky adds only a bass tuba to the orchestra used by Beethoven. The simple fact is that modern composers have studied every possible phase of tone color and expression of which each instrument is capable. Furthermore, by skillfully dividing the orchestra into groups and using these groups like separate orchestras, yet uniting them into one great orchestra, they produce wonderfully rich contrapuntal effects, and thus make the modern orchestra sound, not seventy-five years, but five hundred years more advanced than that of Beethoven, however great we gladly acknowledge Beethoven to have been.