Later composers began to use various characteristic instruments in their scores in order to obtain special effects of what is called instrumental color. Hector Berlioz (1803-1869) did very much to advance this line of development, and Richard Wagner (1813-1883) carried on the work. Not only are special instruments, such as the English horn (a wooden wind instrument with a pastoral tone, heard, for instance, as the shepherd's pipe in "Tannhäuser" and "Tristan and Isolde"), introduced, but the general mass of instruments is enlarged or diminished according to the composer's design. For instance, in the first scene of Act III., "Die Walküre," in which is the famous "Ride of the Valkyrs," Wagner uses two piccolos (small, high-pitched flutes, with a fife-like tone), two flutes, three oboes, one English horn, three clarinets, one bass clarinet, eight French horns, three bassoons, four trumpets, one bass trumpet, four trombones, one contrabass tuba (a very deep-toned brass instrument), four tympani, cymbals, snare-drums, two harps, and the usual body of strings. Wagner specifies thirty-two violins (sixteen first and sixteen second) as necessary to produce the proper balance of tone. Older composers were content to take their chances in such matters. In "Götterdämmerung" the funeral march is scored for three clarinets, one bass clarinet, four horns, three bassoons, two tenor tubas, two bass tubas, one contrabass tuba, one bass trumpet, four trombones, tympani, and strings. The absence of flutes, oboes and trumpets shows that Wagner was aiming at a gloomy color, to be obtained only by the omission of such instruments and the use of an increased number of those of low pitch. The orchestra of to-day consists of four groups of instruments, which can be enlarged or curtailed according to the design of the composer. These are, in the order in which they usually stand in the score, wind instruments of wood (the "wood wind"), wind instruments of brass (called simply "the brass"), instruments of percussion (drums, cymbals, etc.), and strings. The general plan of the orchestra, which has developed from the earliest attempts at instrumental contrast, contemplates such a distribution of instruments in each department as to make that department capable either of independent employment, or of combination with the whole or part of some other department, or of incorporation in the mass of tone produced by the whole orchestra. The wood wind, for example, consists of flutes and oboes, which are purely soprano instruments, clarinets, which extended from upper bass to moderately high soprano, English horn, which has a tenor range, bass clarinet, which runs from deep bass up into treble, and bassoons, which comprise bass, baritone, and tenor registers. That organization of instruments is capable of independent performance, possessing, as it does, all the components of full and extended harmony and a wide variety of color.