In form the serenata resembles those written for the complete orchestra. It begins with a solemn Largo, which serves as introduction to a Molto allegro, worked out very like the first movement of a symphony. This is followed by a Minuet with two trios, than a broadly planned Adagio, and again a Minuet with three trios. To this is joined a Romanze (adagio), simple and lyrical, in two parts, interrupted by an Allegretto leading again to the Adagio, which is repeated and concluded by a coda. Then comes an Andante with six variations, and the finale, consisting of a cheerful Rondo. It is no easy task to write such a succession of pieces for wind instruments, for the tone-colouring, although striking and agreeable, must be moderately and carefully treated. People were certainly more accustomed to this kind of music at the time, but even at the present day the serenata does not produce a sense of fatigue. It has an interest as a proof of the minute study which Mozart bestowed on all instrumental forces, whereby he acquired that complete mastery of the orchestra which is displayed in "Idomeneo." But the work has a higher significance than that of a mere study of instrumentation, as is shown by the admiration it has excited in many places quite recently. The charm of the composition depends greatly upon the certainty with which the peculiar style of each instrument is made use of; but this forms only one side of the artistic construction of the idea, and the full force and beauty of the instrumental effects are only perceived when they are considered as a means of representing each part of the whole work in its due proportion. {IDOMENEO.} (168) Great delicacy and diversity are shown in the grouping and treatment of the different instruments. The first players naturally undertake the chief parts, the accompaniment falling to the secondary players, but the disposition of parts is so free and independent that the difference is not always apparent.[18] All the movements are well planned and constructed, rich in delicate and interesting touches of harmonic or thematic elaboration, and in general fresh and tuneful. The crown of them is the Adagio,[19] in which the musical expression of deep and earnest feeling rises to a purity and height which is impossible to the specified representations of certain frames of mind now in fashion. We here attain, by means of artistic catharsis, as Aristotle calls it (_purging, purifying_), to an absolute freedom and satisfaction, which it is granted to man to feel only in the perfect harmony and beauty of art. The means by which this highest of all effects is reached are so simple that a dissection of them would only be a confirmation of the old scripture that the letter killeth and the spirit giveth life.[20]