It is of more interest to note how a great master works within narrow limits, and with small means at his command, by a consideration of the six divertimenti for two oboes, two bassoons, and two horns (213, 240, 252, 253, 270, 289, K.), which were composed between 1775 and 1777. The destination of these trifling pieces, as table-music or such-like, allows neither greatness of conception nor any {THE QUARTET--JOS. HAYDN.} (309) expression of deep feeling; all must be pleasing, cheerful, and quickly over. But Mozart was not content with satisfying these conditions; his harmonie-musik is full of delicacy and grace, tender and pure in conception, and touched with the firm hand of a master. The details are carefully and neatly handled, without any exaggeration; little side touches are scattered freely about--here an imitation, there an original passage or turn in the middle parts, making the whole interesting and full of life; happy instrumental effects abound, and by varied combinations and changes of tone-colouring the outline of the symmetrical structure is thrown into clear relief, in spite of the limited means at command; just as a painter in monochrome shades his one colour with such skill as to give a plastic roundness to his forms.[44] This species of instrumental composition as it developed became limited, curiously enough, to stringed instruments, for the most part in quartets for two violins, tenor, and bass (replaced by the violoncello), more rarely in quintets, with either the tenor or the violoncello doubled, or in trios. They were still called divertimento or cassation, and did not originally differ from this class of composition, either in form or in liberty as to the number and arrangement of movements. The rule that the quartet (as the whole species came to be called) should consist, like the symphony and the sonata, of four fixed movements, was laid down by Joseph Haydn. It was his inexhaustibly fertile invention and his freedom in the treatment of form which nourished and developed the germ of this chamber-music, until it bore the most beautiful blossoms of German musical art. Mozart, destined later to surpass in this direction his freely acknowledged example, displays evident tokens of Haydn's influence even in his youth. On the whole, however, quartet music does not seem to have enjoyed much favour in Salzburg; Mozart's {INSTRUMENTAL MUSIC.} (310) not very numerous attempts fall in earlier years, and were not all written in Salzburg.