Three characteristics may be said to distinguish the Symphonic Poem, which in the view of the extremists who follow the lead of Liszt is the logical outcome of the symphony and the only expression of its æsthetic principles consonant with modern thought and feeling. First, it is programmatic—that is, it is based upon a poetical idea, a sequence of incidents, or of soul-states, to which a clew is given either by the title or a motto; second, it is compacted in form to a single movement, though as a rule the changing phases delineated in the separate movements of the symphony are also to be found in the divisions of the work marked by changes in tempo, key, and character; third, the work generally has a principal subject of such plasticity that the composer can body forth a varied content by presenting it in a number of transformations.
Liszt's first pianoforte concerto.
The last two characteristics Liszt has carried over into his pianoforte concerto in E-flat. This has four distinct movements (viz.: I. Allegro maestoso; II. Quasi adagio; III. Allegretto vivace, scherzando; IV. Allegro marziale animato), but they are fused into a continuous whole, throughout which the principal thought of the work, the stupendously energetic phrase which the orchestra proclaims at the outset, is presented in various forms to make it express a great variety of moods and yet give unity to the concerto. "Thus, by means of this metamorphosis," says Mr. Edward Dannreuther, "the poetic unity of the whole musical tissue is made apparent, spite of very great diversity of details; and Coleridge's attempt at a definition of poetic unity—unity in multiety—is carried out to the letter."
Other cyclical forms.
Pianoforte and orchestra.
It will readily be understood that the other cyclical compositions which I have associated with a classic concert, that is, compositions belonging to the category of chamber music (see [Chapter III.]), and concertos for solo instruments with orchestral accompaniment, while conforming to the scheme which I have outlined, all have individual characteristics conditioned on the expressive capacity of the apparatus. The modern pianoforte is capable of asserting itself against a full orchestra, and concertos have been written for it in which it is treated as an orchestral integer rather than a solo instrument. In the older conception, the orchestra, though it frequently assumed the privilege of introducing the subject-matter, played a subordinate part to the solo instrument in its development. In violin as well as pianoforte concertos special opportunity is given to the player to exploit his skill and display the solo instrument free from structural restrictions in the cadenza introduced shortly before the close of the first, last, or both movements.
Cadenzas.
Improvisations by the player.
M. Ysaye's opinion of Cadenzas.
Cadenzas are a relic of a time when the art of improvisation was more generally practised than it is now, and when performers were conceded to have rights beyond the printed page. Solely for their display, it became customary for composers to indicate by a hold