t
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
sent by Heaven to espouse her cause, is accompanied on her entrance
and sustained all through her scene of trial by the dulcet tones of
the wood-winds, the oboe most often carrying the melody. _Lohengrin's_
superterrestrial character as a Knight of the Holy Grail is prefigured
in the harmonies which seem to stream from the violins, and in the
prelude tell of the bringing of the sacred vessel of Christ's passion
to Monsalvat; but in his chivalric character he is greeted by the
militant trumpets in a strain of brilliant puissance and rhythmic
energy. Composers have studied the voices of the instruments so long
and well, and have noted the kind of melodies and harmonies in which
the voices are most effective, that they have formulated what might
almost be called an instrumental language. Though the effective
capacity of each instrument is restricted not only by its mechanics,
but also by the quality of its tones--a melody conceived for one
instrument sometimes becoming utterly inexpressive and unbeautiful by
transferrence to another--the range of effects is extended almost to
infinity by means of combination, or, as a painter might say, by
mixing the colors. The art of writing effectively for instruments in
combination is the art of instrumentation or orchestration, in which
Berlioz and Wagner were Past Grand Masters.

[Sidenote: _Number of instruments._]

The number of instruments of each kind in an orchestra may also be
said to depend m