SONATA FORMS, in music. The sonata forms (see SONATA above) cover the whole ground of instrumental music from C. P. E. Bach to the advent of Schumann's pianoforte lyrics and Liszt's symphonic poems, and are still living forms. Their rise made Gluck's reform of opera possible ; for they represent a general change in the language of music which made it a truly dramatic medium. They comprise the largest and most central problems of pure music ; and the outward forms must be studied in constant connection with instrumentation, harmony, melody, counterpoint and rhythm (qq.v.).
Elements of Form.—Two types of form are externally com mon to the true dramatic sonata style and the earlier melodic forms used in the suite (q.v.). The terms binary and ternary have been chosen for these ; and, as we shall see, badly chosen. A binary melody falls into two portions, of which the first ends away from tonic, and the second ends on the tonic. Barbara Allen, quoted in the article MELODY, is an exquisite example on the smallest pos sible scale. A ternary melody, such as The Bluebells of Scotland, has a complete first clause, a second clause not as complete, and a third clause consisting of the first over again; a form conven iently symbolized as ABA.
No view of music can be correct that neglects the fact that it moves in time ; though a composer may develop Mozart's capacity for seeing music spatially, i.e., like a picture, all at once. Now, when do we know that a melody is going to be "ternary"? Ob viously when its first clause has shown itself to be complete. If the sequel refuses to divide itself according to a "ternary" rule the ear is not going to reverse its judgments merely because we have chosen a bad term of classification. After the first clause, anything may happen. The rest of the tune may be no longer than the first clause. All that we can expect of it is that it will cover a wider ground than the first clause, even if in fewer notes or in less time. But this is not all. Every tune of several clauses lends itself to repeating its sections. Binary tunes repeat their two sections. Does a ternary tune repeat its three sections? Try the
experiment on the very typical ternary theme of the variations in Beethoven's Kreutzer sonata. Play the first clause with its repeat and try repeating the second clause before returning to the first. You will hardly have the patience to finish the experiment. It will at once reveal that under the test of repeats our "ternary" melody is not ABA but A, BA.
Thus while both these forms divide only into two repeatable portions the one named "binary" has an incomplete first part while the first part of the other is complete. Our pundits would make musical terminology less misleading if they would kindly find Greek or Latin names, not longer than the forms themselves, that should express "form-with-an-incomplete-first-part" on the one hand, and "form-with-a-complete-first-part" on the other. Clearly the distinction is that between higher organizations and lower, or sectional, forms. From the so-called binary form origi nates the sonata-form par excellence, that of the first movement of a sonata. From the so-called ternary form originate all those sectional forms of music that begin with a complete symmetrical melody, however many sections the form may eventually develop. Thus the "ternary" type underlies the rondo (q.v.).