Of this nature is the Italian concerto in F major, which Bach composed for the piano alone. Eight concertos for clavier and orchestra (the latter consisting here, as was usual in that day, of string instruments and cembalo) are still extant. The one in D minor is considered the finest of all. Of still greater value are the concertos for two and three pianos, in which the form of the _concerto grosso_ is employed in a new manner. There even exists a concerto for four claviers and orchestra; this, however, is only an elaboration of a violin concerto by Vivaldi. It should be remarked in this connection that Bach regarded the organ as an instrument for church use exclusively and wrote no organ concertos, whereas Handel produced many works of that class. The clavier variations and suites composed by Bach are most characteristic and individual in style. We possess, to be sure, only two sets of variations by him, but the aria with thirty variations is a work which has marked out new paths for the variation form and exerted an influence extending through and beyond Beethoven to Schumann and Brahms. In the suite consisting of dance-forms, or the partita, the French had distinguished themselves as also the German clavier masters, Johann Jacob Froberger, Johann Krieger and Johann Kuhnau, from all of whom Bach made zealous attempts to learn. His three principal works of this sort are the so-styled French Suites, English Suites and the Partitas. Each collection contains six suites, but in Bach's lifetime only the Partitas were published in the engraved form. These compositions are pervaded by the wholesome freshness and cheerfulness characteristic of the German people, while they exhibit at the same time unusual firmness and delicacy of structure; Bach indeed imparted to the clavier suite the highest conceivable degree of finish. In the six violoncello suites without accompaniment, the form is presented to us in a different tone-material. This style of music was abandoned after the master's death and was succeeded by the clavier sonata, to which Bach had never paid any considerable attention. Another form in existence at this time was the orchestra suite, which differed from the clavier suite in respect to the arrangement of the dances and showed much greater freedom as to the choice and number of the same; it was often the case, moreover, that an overture served as introduction to the work. Bach left behind four such orchestral suites or partitas; he also employed the same form in three suites for violin without accompaniment, which were published in one volume, together with the three unaccompanied violin sonatas, in one of which occurs the famous D-minor violin chaconne. And, finally, this form was transferred by Bach to the clavier, as in the case of the B-minor partita, which he published in 1735 in second part of his clavier-Uebung.