CHAPTER IV.. Sound and Music.

SOUND AND MUSIC.

The difference between sounds and musical tones—The natural period of vibration of an elastic body—The effect of accumulated impulses—Free and forced vibrations—Breaking down a bridge with a pea-shooter—The vibration of a stretched string—Stationary waves—A string vibrating in segments—Acoustic resonance—Nodes and anti-nodes—The musical scale or gamut—Musical intervals—The natural gamuts and the scale of equal temperament—Concords and discords—Musical beats—Helmholtz’s theory of discords—Musical instruments—Pipes—Strings and plates—A pan-pipe—An organ-pipe—Open and closed organ-pipes—The distribution of air pressure and velocity in a sounding organ-pipe—Singing flames—Stringed instruments—The violin—The Stroh violin—The structure of the ear—The ear a wonderful air-wave detector and analyzer 147