=Beethoven= established the orchestra as “the composer’s instrument.” He added but little to the instruments used but he took the resources established by his predecessors and demonstrated what could be done with them. Every group of instruments was used with more detail and to produce characteristic effects both separately and in combination. In his first and second symphonies he uses the same orchestra: two flutes, two oboes, two clarinets, two bassoons, two horns, two trumpets, tympani and strings; in the “Eroica,” a third horn part is added; the fourth has the same orchestra as the first two, except that one flute is dropped; the fifth calls for piccolo, two flutes, two oboes, two clarinets, two bassoons, contra-bassoon, two horns, two trumpets, three trombones, tympani and strings; in the sixth he uses the same orchestra as in the fifth, except that he drops the contra-bassoon and one trombone; in the seventh and eighth the orchestra is the same as in his first and second symphonies. In the ninth (Choral Symphony) he calls for a larger orchestra: piccolo, two flutes, two oboes, two clarinets, two bassoons, contra-bassoon, four horns, two trumpets, three trombones, tympani, triangle, cymbals, bass drum and strings. It will be noted that Beethoven does _not use the harp_. It was not until 1820, seven years before Beethoven’s death, that Erard invented the double-action harp, an effective and a playable instrument. =Berlioz, Wagner and Richard Strauss=.—The composer who first made an exhaustive study of orchestral instruments, their distinctive qualities, separately and in combinations, was =Berlioz=, who gave to the world his knowledge in his “Treatise on Instrumentation,” published in 1844. Berlioz gave to every one of his works a more or less distinctive quality by varying the composition of his orchestra instead of using the conventional combinations. He made frequent use of the harp, bass clarinet, English horn, bass tuba, besides other less frequently used instruments. He very much enlarged the scope of orchestral music by the new effects he devised. =Richard Wagner=, in his great music dramas, makes use of many new means of dramatic musical effects, introducing new instruments, enlarging the various families, dividing the strings into eight parts, increasing the number of brass instruments, giving to his scores a richness of power and a sonorous quality unknown before his time. =Richard Strauss= is, today, the greatest master of the technic of orchestral writing. His tone-poems make greater demands on the resources of the instruments and contain effects beyond those of Wagner. [Illustration: HECTOR BERLIOZ.]