The Mannheim experiences were not without result either in respect to the executive delivery of the orchestra. Mozart must have been particularly impressed with the effect of _crescendo_, for almost in every passage we meet with phrases built upon a long-drawn _crescendo_. The contrast between _piano_ and _forte_ is also made the most of. Regular alternations of long passages _forte_ and _piano_ were formerly the custom, but now we have a rapid succession of very varied shades, _fortissimo_ and _pianissimo_ being also brought into use. But all these are only the outward signs of a higher intellectual apprehension, for which it was necessary also to give credit to the performers; the composer, far from relying only on external effect, makes it the mere expression of the deeper meaning and intrinsic value of his compositions; it is from this point of view that the progress made by Mozart in the manipulation of his artistic materials acquires its true worth in the eyes of a musical critic. We may imagine that Mozart found it no easy task to substitute a completely new style of execution for the time-honoured customs of the Salzburg band. The energy with which he was able at a later date to inspire the Leipzig orchestra, wedded as it was to its own traditions, gives some indication of his way of proceeding as a young man at Salzburg. His cousin used to hold forth later on Mozart's eccentric behaviour when conducting, and we may imagine that she witnessed some of the extraordinary scenes she describes during her present visit to Salzburg. Mozart never appeared again as a violin-player, and we therefore find no compositions for the violin belonging to this period. After such an expression of opinion concerning the Salzburg public as that noted above, we cannot wonder that he was not over-anxious to appear before them as a clavier-player. We doubtless owe the Concerto for two claviers with orchestral accompaniment in E flat major (365 K., part 17) to his wish to play a duet with his sister.[5] {COURT SERVICE IN SALZBURG.} (92)