And, speaking of Concertos, we must not forget the one for the violin, which surely ranks only after that by Beethoven, and is attempted by all the violinists. Its charm is never failing. The fine intensity of the impassioned Allegro has something feminine and far reaching in its quality, so that it was a rare pleasure to hear it interpreted by such an artist as Camilla Urso, with such true nervous grasp and accent. The middle movement seemed divine; and the finale, heralded by the brass _ff_, is so uncontainable and full of fire, so brilliant and impetuous, that it admits of being taken at the most rapid tempo. It is perhaps the most popular of all violin concertos. All the great masters have written string quartets. The Quartet for two violins, viola and 'cello, corresponding to the four essential parts in harmony, each maintaining its individuality, yet each essential to the whole, is the quintessence of musical expression. Any imperfection betrays itself inevitably; all is exposed; there is nothing hidden under an orchestral coloring or vague passages of mere effect. The four voices are four persons. Not to speak of Haydn, father and founder of the race, the greatest models are those of Mozart and Beethoven. Those of Beethoven often seem like foreshadowings in outline of later phases in his larger grand creations. Those of Mendelssohn are less purely quartet-like. They have more of a singing quality,--a melody with an accompaniment,--and seem to seek orchestral development. The early one in E flat is of highly impassioned character, and might be distinguished as the _Quartet Pathetique_. It has a pathetic introductory _Adagio_, followed by a passionate _Allegro_; then a _Canzonetta_, a quaint minor strain in the spirit of some sad old _Volkslied_ or Ballad; then an _Andante_ of profoundest melancholy; then a bold finale, in 12-8, running in very rapid triplets. The three Quartets of Op. 44 are in a riper style. But the first begins with a swift and fiery _Allegro_, of which the theme is strikingly symphonic, and which has been well said to be not quartet-writing at all, but a melody with a bass and a mere filling-in of middle parts; not a conversation between four distinct individualities. The Mendelssohnian ardor, depth of feeling, yearning aspiration, with all his grace, facility, and clearness, pervade these quartets; but more perfect as quartets are his part-songs for mixed and for male voices. His last quartet, in F minor, written just after the death of his beloved sister Fanny, so soon before his own, has spontaneous unity in all its movements. It is said to have been written in forty-eight hours, in one close closeting with grief.