It was almost inevitable that in most concertos the genuinely musical element should be regarded as of less and less importance. The public expected, and indeed still expects, to hear or even to see a virtuoso display the uttermost limits of his skill in such pieces. The improvised cadenzas were in the hands of most players a nuisance which marred the work as a whole beyond repair. But the Mozart concertos, written as they were for occasions of his public appearance, have a true musical value. We know enough of his improvising to be sure that his cadenzas added and did not subtract from this. Their chief beauty is here, as in his other music, the melodious freshness of his themes, the delightful subtlety of his harmony. The constant stream of arabesque which the piano adds to this intrinsically beautiful foundation is in the main simple. It is surprising how little Mozart added to the virtuoso style of pianoforte literature, even how little he made use of what, through Clementi and Dussek, was already common property. There are practically no octave passages, and no passages in double notes. He uses only scales, arpeggios and trills. But his art of combining these with the orchestra has never been excelled. In this regard his concertos stand far above those of the virtuosi like Hummel, Dussek, and John Field. Their tone-color is not only that which the essentially colorless pianoforte can afford; it is a beautiful interweaving of many colors. His treatment of the orchestra is always distinguished, never haphazard or indifferent. Delicate as the coloring may be to ears now accustomed to heavier and more sensuous blendings, it is not watery and faded. It is still exquisitely clear and suggestive. As the first of composers to make such effective use of the cold yet brilliant tone of the pianoforte in combination with the various warmer tones of the orchestra, he may be said to have set a standard of excellence which subsequent concertos have oftener fallen short of than attained. Hundreds have been written. The fingers of one hand might perhaps count the number of those which as works of art are comparable to Mozart’s.