The entire multiformity of music at the beginning of the eighteenth century is expressed in the clavier-works of Bach. As yet the sonata-form with its two themes, and its “free” section in the middle of the movement, has not become the consecrated scheme;[81] and all the forces which had gradually worked towards this form exert themselves unfettered, in order to make themselves effective now in this, now in that combination of movements and parts of movements. “Thematic” is not neglected. To a series of suite-movements similar commencing motives are given, and the motives of earlier parts are taken up in the later. But this tendency to unity does not act as a restraint upon form, and does not reduce everything to one stiff mould. There is a fugue with a prelude, by Bach, that in E flat major (Wohltemp. Kl. i.), which offers perhaps the most delicate example of this unrestrained unity of motive. The Prelude, which is much longer than the fugue, begins with semiquaver figures, whose characteristic is melodious sustained passages advancing by sixths and sevenths; after this introduction, begins in toccata-fashion a kind of slow fugue, which unfolds the just heard motive in a terser form; and finally, in a third part, mingles itself with the former semiquaver figure. The fourth part is so to speak moulded in the fugue form, which in its “subject” makes use of the characteristic leap of a seventh, found in the Prelude, as a main feature, and brings the play to a conclusion in a busy and lively manner. The relations of motive are only to be _felt_, not seen; but they are _there_, and give to the formal freedom of this piece a vigour of its own. Thus, in many of Bach’s pieces, apart from the direct thematic motives, we shall find this indirect assonance, which, springing from a general feeling of unity, is, in fact, a more dainty framework for the piece than any unity that could be impressed on it from outside.