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 measurably upon the music, or the use to which the band
is to be put. Neither in instruments nor in numbers is there absolute
identity between a dramatic and a symphonic orchestra. The apparatus
of the former is generally much more varied and complex, because of
the vast development of variety in dramatic expression stimulated by
Wagner.