There were some clavier sonatas written at that time too, which Nannerl was instructed to bring to Munich (December 21, 1774), the result being a commission from Baron Dürnitz for six sonatas (279-284 K.); they are often mentioned by Mozart on the Paris journey of 1777, and he played them frequently in Munich, Augsburg and Mannheim with great success. They consist, after the old fashion, of three movements; the fourth forms an exception to the general rule, containing a long adagio, two minuets (the second instead of a trio), and an allegro; the last is another exception, the first allegro being followed by a rondeau en polonaise--like the violin concerto (218 K.)--ending with variations. Mozart {INSTRUMENTAL MUSIC.} (324) spoke of sonatas as difficult which are now given as lessons to beginners (February 2, 1778). Nevertheless it is no small praise to him that, after the lapse of ninety years, the judicious treatment of the instrument, the healthy freshness and finished form of these compositions entitle them still to be considered as the best foundation for a musical education. Any one capable of appreciating a work of art will find all its essential conditions fulfilled in these simple sonatas. L. Mozart mentions in a letter (December 8, 1777) two four-hand sonatas, written by Wolfgang for himself and his sister. One may be the well-known B flat major sonata (358 K.) which Mozart wrote for from Vienna (June 27, 1781). The form is concise and little elaborated; the essential condition that each player shall contribute his independent share to the general effect is kept duly in view. A second sonata is not authenticated.[58] A trio for clavier, violin, and violoncello (254 K.), belongs to August, 1776, which, according to Mozart's Munich letters (October 6,1777), Nannerl played at Salzburg with Janitsch and Reicha. It displays, like all the compositions of this period, completeness and roundness of form with maturity and cleverness of conception, and surprises us by its animation and the tender beauty of many of its turns of expression. The clavier is the chief instrument, then the violin, more simply treated, but independent. The violoncello does not yet receive full justice; it is only used as a bass, often effectively, but never overstepping its narrow province. After the (violin?? DW) Concerto in D major (175 K.), composed in December, 1773, and played with applause at Mannheim (February 14, 1778), and, with a new finale, at Vienna (March 22, 1782), Mozart wrote no clavier music until January, 1776, when he composed a clavier Concerto in B flat major (238 K.), another in April in C major for the Countess Lützow (246 K.), and in January, 1777, one in E flat major for Madame Jenomy (271 K.). This industry {CLAVIER CONCERTO (271 K.)} (325)