which are the real backbone of the band and make their effect by a
massing of voices in each part, having the place of honor and greatest
advantage. Of course it is understood that I am speaking of a concert
orchestra. In the case of theatrical or operatic bands the arrangement
of the forces is dependent largely upon the exigencies of space.

[Sidenote: _Solo instruments._]

Outside the strings the instruments are treated by composers as solo
instruments, a single flute, oboe, clarinet, or other wind instrument
sometimes doing the same work in the development of the composition as
the entire body of first violins. As a rule, the wood-winds are used
in pairs, the purpose of this being either to fill the harmony when
what I may call the principal thought of the composition is consigned
to a particular choir, or to strengthen a voice by permitting two
instruments to play in unison.

[Sidenote: _Groupings for harmony effects._]

[Sidenote: _Wagner's instrumental characterization._]

[Sidenote: _An instrumental language._]

Each choir, except the percussion instruments, is capable of playing
in full harmony; and this effect is frequently used by composers. In
"Lohengrin," which for that reason affords to the amateur an admirable
opportunity for orchestral study, Wagner resorts to this device in
some instances for the sake of dramatic characterization. _Elsa_, a
dreamy, melancholy maiden, crushed under the weight of wrongful
accusation, and sustained only by the vision of a seraphic champion