Beginning with Beethoven, however, composers began to exhibit great freedom in the application of Sonata-Form. - Walter Raymond Spalding

A glance at the score shows how sadly the pedagogue might go astray in judgment of the work, without a hearing of it, and furthermore, the imagination of the hearer must be in sympathy with the imagination of the composer, if he would know full enjoyment: for this symphonic poem provokes swooning thoughts, such as come to the partakers of leaves and flowers of hemp; there are the stupefying perfumes of charred frankincense and grated sandal-root.

[T]he rhythm of music, akin to the human heart-beat and to the ceaseless change and motion, which is the basic fact in all life, apeals at once to our own physical vitality.

The sensational style of Prometheus is augmented by the use of a color machine which flashes upon a screen hues supposed to supplement the various moods of the music. How many of these experiments will be incorporated into the accepted idiom of music, time alone will tell; but they prove conclusively that modern music is thoroughly awake and is proving true to that spirit of freedom which is the breath of its being.