=The Principles in Music=.—The leading principles in music are: Rhythm, Melody, Harmony, Color or Tone Quality, and in the execution of works of music, Dynamic Contrast, an essential factor in Expression. For ages after the birth of Music, Rhythm and Melody were the only real elements, Rhythm being first recognized. The potency of Rhythm, strong and irresistible in the early days of the race and with primitive man, is still acknowledged. Music that lacks a clearly-defined rhythm does not move the masses. Witness martial music, the dance airs and the “popular song.” All primitive languages were characterized by concise, figurative and picturesque qualities; they easily changed from the ordinary into the lofty and the impassioned. Intonation and changing inflection had much to do with meaning, as is the case with the Chinese language of today. Historians ascribe the origin of Melody to this principle of vocal expression. For years prior to the Christian Era, and long after, Rhythm and Melody were the only accepted elements of Music, and the art remained in a low grade of development. It was not until Harmony appeared, clear and unmistakable, that Music was able to claim a position equal to that accorded to the sister-arts, Poetry, Painting, Sculpture and Architecture. These principles, Rhythm, Melody and Harmony, became, when couched in the forms of expression adopted by the great masters, what we call Modern Music, and the story is one of a development from extreme simplicity to the complexity illustrated in modern orchestral scores. =Means of Expression=.—One more phase must be mentioned here, the means used to present to others the thoughts or feelings of the composer, that is, the human voice and its artistic use, instruments of various kinds, their primitive forms and gradual development, their use singly and in combination with other instruments. This phase is peculiarly associated with modern music; for it was not until the art had freed itself from the fetters imposed by vocal music, that absolute music, availing itself of perfected instruments, came into its own. From that time development was unprecedentedly rapid.