=Sonata-Form as Fixed by Haydn=.—In these clavier sonatas, Haydn fixed the form which had been the subject of so many experiments, once and for all. The number of movements with him is almost invariably three, of which the first, at least, is in the sonata-form. This consists of a first section, the =Exposition=, in which the first subject, a distinct melody having the Teutonic individuality, is stated, defining the principal key; and a second subject, more lengthy and diverse in character, brings on a close in the contrasting key. In the second section, or =Development=, phrases or motives from the first section are cleverly intertwined in modulating keys, with running scales or arpeggios as connecting links. These, however, lead naturally into the first subject, in its original key, which opens the third section, or =Reprise=. This section is practically like the first, save that the second subject and the close are transferred into the principal key, in which the movement ends. =The Second Movement=.—The second, or slow movement, is cast sometimes in the same form, abbreviated, and sometimes in a simpler form. The lack of sustaining power in Haydn’s pianoforte, and his attempt to atone for this by trills and ornaments, make this less successful than the other movements; a result which is also caused by the fact that intensity and depth of emotion had not yet been developed in the harmonic school of music. In key, this movement was contrasted with the first, sometimes quite sharply, as in one of the sonatas in E-flat, in which the slow movement is in E major. =Third Movement=.—The lively third movement is frequently in the lighter form of the Rondo, or it may be a set of Variations, or a Minuet. This movement, though sprightly, is apt to be somewhat thin in its harmonies, and trivial in development. Nevertheless, these last two movements show an expansion of the forms of the older writers, and a definiteness of character which insured their future development. =Definiteness and Unity=.—This element of absolute definiteness is the most striking feature of Haydn’s work—definiteness none the less in the general form than in each individual component. Each part of each section ends with a cadence, giving it absolute finality, and making the whole a combination of small entities, which, though distinct, are yet relevant and nicely balanced.