“Les Indes Galantes,” an heroic ballet, was the second work that Rameau gave to the Opéra. He was then fifty years of age. The public, who had become more accustomed to the musician’s peculiarly characteristic style, received this work in the most favorable manner. From that time forth, the master who had experienced such difficulty in obtaining access to the Opéra, was rewarded with one long series of triumphs. He reigned in the opinion of the musicians and the habitués of the Académie de Musique as an omnipotent sovereign of the art. “Les Fêtes d’Hébé,” “Dardanus,” “Zoroastre,” “Anacréon,” “Platée,” “Les Fêtes de Polymnie,” “Les Fêtes de l’Hymen et de l’Amour,” are works which bear the impress of Rameau’s genius. His talent appeared to the most advantage, however, in “Castor et Pollux,” his dramatic masterpiece, which indeed is a fine example of theatrical music. We mentioned above the theoretical works of Rameau, and now propose to make further reference to them. Rameau’s theory, which threw a flood of light upon what before his time was darkness and empiricism, is entirely based upon the eternal law governing the creation of chords by the resonances of the monochord. Rameau found in these resonances the _fundamental bass_ of the different chords composed of a succession of thirds. This discovery of the fundamental bass showed the true nature of the inversions of chords which before the theoretical exposition of the great Dijon master had been considered as so many peculiar kinds of chords. Rameau had discovered the natural formation of chords, a thing wonderful in itself and sufficient to make his name immortal; but in thus establishing the principles of harmony he had not established all its laws. He left to his didactic successors the work of laying down the important rules of the attraction of notes for the determination of chords, as also the rules governing their movement in modulation. It is thus that we find in Rameau’s work certain hazardous harmonies which are more due to the non-observance of these laws than offences against good taste or fancies of the composer’s imagination. We see, indeed, in the music of this artistic genius successions of fifths, faulty relation of notes, brusque modulations offensive to the ear, which are nothing more than faults in writing. Thus he who has been truly called the “Father of Harmony,” made mistakes in harmony which, even at the present day, in spite of the great liberty taken by composers of the advanced school with their successions of modified chords, still remain faults in musical grammar. Rameau wrote his last opera, “Les Paladins,” at the age of seventy-seven. In reading this score we find nothing to indicate any failing of the vigorous mind of this extraordinary musician, who, following Lully, was the pioneer in the great field of dramatic music that Gluck was destined to cover with incomparable power and genius. [Illustration: Fac-simile musical manuscript written by Rameau.