Such _rubato_ dancing raises that art itself to a poetic height; but it is perhaps vain to hope for it outside of a Viennese dance hall. As the younger Johann's waltzes ceased to be a mere accompaniment to dancing and assumed the function of interpreting the thoughts and feelings of lovers as they are whirled along, "imparadised in one another's arms," his harmonies became more and more piquant and novel, his instrumentation more tender, refined, dreamy and voluptuous. Berlioz, himself, in orchestrating Weber's superb "Invitation to the Dance," has not shown greater genius for instrumentation than Strauss the son has in his later waltzes. It might be said that whereas Haydn, Mozart, and Beethoven built up the symphony from dance forms, Strauss, conversely, applied the symphonic resources of the orchestra to his dance pieces. One can get no idea of their real charm at the piano; but Americans have been fortunate in having had in Mr. Theodore Thomas for many years such a sympathetic and animated interpreter, who knew how to give them the true Strauss swing. Not all of these waltzes are of equal value, and popularity is no test of merit. Thus, the "Blue Danube" Waltz, of which over a million copies have been sold, is really one of the poorest, just as Schubert's Serenade is far from being his best song and the Wedding March from being the gem of "Lohengrin." Their number is enormous--440 is the opus number of the "Gross-Wien" Walzer, the last one printed up to the end of 1891. When Strauss turned to composing operettas, there was great consternation, because it was feared that the Carnival in Vienna and elsewhere would have to dispense thereafter with its annual gifts from his pen. These fears were unfounded; his operettas were so full of waltz and polka buds and full-blown roses, that it was easy to pick them for a concert-hall and ball-room bouquet; so that some of his best recent dance pieces are taken from his operettas. Equally unfounded were the fears that after devoting more than a quarter of a century to the composition of dance music, Strauss would be unable to win distinction as a dramatic writer. In his first operettas, it is true, the libretto was little more than a peg to hang on waltzes, polkas and marches; but gradually he emancipated himself more and more from the simple saltatorial style, until, in "The Bat," the "Merry War" and subsequent works, he created a new type of operetta, with beautiful flowing, lyric melodies, and stirring dramatic ensembles. True, the "Waltz King" is never quite able to disguise his character, but in this very fact lie the originality and unique charm of the Strauss operetta. It is a new style of stage play--the Austrian operetta, a new "school" of comic opera; and in creating this, Strauss placed himself far above his father and his brothers. Millœcker would not have been possible but for Strauss, and Suppé did not write his best works till after Strauss had shown the way.