In publishing these six quartets together Mozart certainly did not intend them to be regarded in all their parts as one whole; his object was to bring to view the many-sidedness of expression and technical treatment of which this species of music was capable. The first quartet, in G major (387 K.), and the fourth, in E flat major (428 K.), have a certain relationship in their earnest and sustained tone; but how different is the expression of energetic decision in the first from that of contemplative reserve in the fourth; a difference most noticeable in the andantes of the two quartets. Again, in the third and fifth quartets, in B flat (458 K.) and A major (464 K.), the likeness in their general character is individualised by the difference in treatment throughout. The second quartet, in D minor (421 K.), and the sixth, in C major (465 K.), stand alone; the former by its affecting expression of melancholy, the latter by its revelation of that higher peace to which a noble mind attains through strife and suffering.
An equal wealth of characterisation and technical elaboration meets us in a comparison of the separate movements. The ground-plan of the first movement is the usual one, and the centre of gravity is always the working-out at the beginning of the second part, which is therefore distinguished by its length as a principal portion of the movement. The working-out of each quartet is peculiar to itself. In the two SIX QUARTETS, 1785. first the principal subject is made the groundwork, and combined with the subordinate subject closing the first part, but quite differently worked-out. In the G major quartet the first subject is spun out into a florid figure, which is turned hither and thither, broken off by the entry of the second subject, again resumed, only to be again broken off in order, by an easy play on the closing bar—