All sounds are the result of atmospheric vibrations affecting the ear. Musical sound, or tone, is produced by regular vibrations, and differs from mere noise whose vibrations are irregular and confused. The pitch of a musical tone rises in proportion with the rapidity of the vibrations that produce it. Tones may be perceived by the human ear ranging from about sixteen vibrations in a second to nearly forty thousand, more than eleven octaves. Only about seven octaves are used in music. The science of acoustics is full of interesting facts of this kind, and is of profound value to any one who would gain an insight into the structure of music. It is unfortunately much neglected.
The prime elements of music are Melody, Harmony and Rhythm. They are perhaps as little realized as its raw materials. Melody is a well ordered succession of musical sounds, heard one at a time, and selected from a defined, accepted series, not taken at random from a heterogeneous store. Harmony is a combination of well-ordered sounds heard simultaneously, and with suitable concord, or agreement. Rhythm is measured movement, or the periodical recurrence of accent; and signifies symmetry and proportion.
Melody, unexhausted and inexhaustible, is the initial force, or, as Dr. Marx has called it, the life-blood of music. Within itself it bears the germ of harmony and rhythm. A succession of tones without harmonious and rhythmic regulation would be felt to lack something. Melody has been designated the golden thread running through the maze of tone, by which the ear is guided and the heart reached. Helmholtz styled it the essential basis of music. In a special sense, it is artistically constructed song. The creation of an expressive melody is a sure mark of genius.
Harmony arranges musical sounds with reference to their union, and is regulated by artistic and æsthetic rules and requirements. It has endless modes of transforming, inverting and intensifying its materials, thus continually affording new means of development. All the intervals and chords used in music had to be discovered, one by one. It often took more than a century to bring into a general use a chord effect introduced by some adventuresome spirit. Our scale intervals are the slowly gained triumphs of the human mind. Modern music did not emerge from the darkness of the past until harmony, as we know it, came into active being.