Mention other clavier works by Bach. What improvements in technic did Bach introduce? LESSON XXIX. THE GERMAN SONATA COMPOSERS, TO HAYDN. =Formation of Harmonic Design=.—Side by side with the ultimate development of polyphonic music in its perfected instrumental form, the forms of the new harmonic style were being worked out, by long processes of development. Finally, just as the Fugue came to be adopted as the highest form of the old school, so the Sonata was chosen as the most dignified exponent of the new art. But, while the old school arrived at a high state of perfection at the hands of Handel and Bach, the necessity for inventing and experimenting with the possibilities of the new forms made the first attempts in this direction seem childish and crude beside Bach’s work; so that it was several generations after him before the harmonic style was brought to the stage at which it could be made to express ideas of equal magnitude, and do it successfully. =Development of the Sonata=.—The original plan associated with the Sonata was that of combining several movements in such a way as to appeal, in the completed product, to all kinds of _emotion_, _intellectual_, _spiritual_ and _physical_. In the hands of its founders, the Italian violinists, the exposition of this thought had been mainly contrapuntal. We have seen how Domenico Scarlatti arrived at a style in which a single part, supported by an accompaniment, was applied to the clavier, in a manner which brought out its striking characteristics; and we have now to trace the progress of this style in Germany, up to the point where the various contributions of different composers could be united into a systematic and fixed form, sufficient for the free expression of the highest musical inspiration, and adapted to all the varied demands of instrumental music. =Essential Elements of a Sonata=.—Certain points seem to have been generally agreed upon as necessary components of the Sonata. The first was its _union_ of _several movements_, from two up to five, or occasionally even more. The second was that the _first movement_ should display the most _ingenuity_ and _elaboration_. This movement thus came to receive the most attention, and showed a process of evolution from the simple dance form consisting of a modulation from a principal key to a contrasting key and back again, to a _highly organised_ and conventional _art-form_—a form, moreover, of such a capacity that it could be used as the mould for the principal movement of a wide range of compositions, from a short pianoforte sonata to a grand symphony.