THE ORCHESTRAL FORMS
As already intimated, the symphony is an orchestral sonata, usually in four movements. Occasionally these movements are different from those of the sonata, and national dances may be used. Thus Tschaikovsky introduced the brilliant Russian Kamarinskaia, while Dvořák employed the melancholy Dumka and the wild Furiant. Berlioz and Tschaikovsky tried a waltz movement in a symphony; but the waltz is rather too informal for the best effects. Rubinstein "Ocean Symphony" contains seven movements.
The concerto is generally a three-movement orchestral sonata, with the scherzo omitted. Sometimes concerto movements merge into one another with no pause between them. This is true occasionally of the symphony also. Toward the close of the first movement in a concerto, and sometimes in the last movement, occurs what is known as a cadenza. This is an unaccompanied passage for the solo instrument. It is usually brilliant in character, giving the soloist a chance to display his technique. Sometimes the cadenza is written by the composer. More often, however, it is left to the performer. He may sometimes use a cadenza of his own, or one written by anybody, even when the composer has made his own cadenza. A number of cadenzas in great works have been published separately by famous performers. The place for the cadenza is indicated in the score by a hold on a dominant or 6/4 tonic chord. The performer ends the cadenza by a long-sustained trill, on a note that will allow the conductor to make the orchestra enter in proper harmony, -- usually the dominant degree.
Concertos may be written for more than one instrument of the same kind, or even for instruments of several kinds, with orchestra. The best concertos do not resemble instrumental solos with accompaniment, but are really orchestral works with one or more threads of solo music interwoven into their texture. Beethoven, who thought naturally for orchestra, wrote concertos that fulfilled