Haydn knew well what he owed to Philip Emanuel, and was as little chary to acknowledge it as Mozart. In actual essentials Haydn made no advance in clavier-music. The stream is perhaps a little clouded, and it is not till Mozart’s time that it again becomes clear. Haydn’s genius lay in composing for the orchestra, not for the piano. He has of course written clavier sonatas--they number thirty-five--and other pieces in which the clavier takes part; as numerous and light as the works of all these “galant” musicians. But his trios are to be preferred to the sonatas for piano only; there is more depth in them; and the ideas are lit up more brightly by the instrumental combination. Only in the sonatas after 1790, as in the first in E flat major (Br. and H.) does something more noteworthy emerge--but by that time Haydn had studied Mozart. Still further, in his pieces, Haydn is no great virtuoso. In his Trios he knows well how to make the most of the character of the clavier, by contrasting it with the strings, by means of arpeggios, all kinds of passages, full chords, and the beloved octave-melodies. But a more interesting virtuoso performance, such as that in the F minor variations, appears very rarely. The ornamental work is still extensive, but within limits; and much of it is written out in full, just as the cadenzas, which used to appear in small notes, are now preferably printed in the usual type. At the end of the century everything was taken away from the caprice of the player, except the great cadenzas at the conclusion of the concerto-movements. Philip Emanuel had taken a last important step, when, in his Sonata dedicated to the Prussian Princess Amalie, he wrote out exactly for the second time the ornamentations and alterations in the frequent repetitions of musical phrases of a few bars, instead of leaving them to the pleasure of the players. To judge by his preface, caprice in these matters must have flourished like a green bay-tree; and he takes great credit to himself for having been the first to offer accurately formulated “alternative _reprises_,” which run no risk of spoiling the whole aim and meaning of the piece. His point of view is interesting. It is, he says, not possible to avoid altering a musical phrase in repeating it. This conception is endorsed by all his contemporaries and successors in style, in their works: Haydn and Mozart cannot be conceived apart from this mannerism of altering a musical idea in repetition by slight turns and adornments. This method is the fixed law of movement of their musical ideas, and dictates their progress through long stretches in advance. Deep founded in the general delight in variation so characteristic of the time, it enables us to understand that great development which forms a whole branch of musical history--the development, namely, of improvised “manieren” into strict and firm melodies.