Out of unbeautiful noise sprang beautiful music. Men discovered that through the voice they could make not only expressive noises, but also pleasant tones; they found, perhaps by accident, that they could do much the same thing with reeds and strings; they observed that when they beat their drums at regular intervals to mark the motion of the dance, they not only danced together more easily, but also experienced joy in the very sounds they made; or that when they threshed the corn with rhythmic strokes or rowed a boat in rhythmic unison, their task was lightened and their wearied attention distracted to the pleasure of their noise. Hence at their dances of love or war or religion, they sang instead of shouted; and their instruments of irregular and expressive noise became instruments of rhythmical and melodious tones. Eventually, having experienced the pleasure there is in tones and rhythmical sounds, they made them for their own sake, apart from any connection with tribal festivals, and the free art of music was born. And yet, as we shall see, the significance of music depends largely upon the fact that tones are akin to noises; music could not take such a hold of the emotions of men did they not overhear in the tones the meaningful and poignant noises of voice and nature; to understand music, we must think of it against its background of expressive noise. In music we still seem to hear a voice that breaks the silence and speaks, the thunder that terrifies. The material of music consists of tones, the conscious counterparts of periodic, longitudinal vibrations of the air. Tones differ among themselves in many attributes, of which the following are of chief importance for music: pitch, determined by rate of vibration, through which tones differ as higher and lower; color, determined by the complexity of the vibration wave, the presence of overtones of different pitch along with the fundamental tone in the total sound; intensity, dependent upon the amplitude of the vibration, through which tones of the same pitch differ as soft or loud; and finally, quality, that specific character of a tone, by reason of which middle C, for example, is more like the C of the octave below or above than like its nearer neighbors, B or D, whence the series of tones, although in pitch linear and one-dimensional, is in quality periodic, returning again and again upon itself, as we go up or down the scale. [Footnote: "See Geza Revesz: _Tonpsychologie_."]