176. A glee is a vocal composition in three or more parts, being usually more simple in style than the madrigal, and sometimes having more than one movement. The glee may be either gay or sad in mood, and seems to be a composition peculiar to the English people.
177. A part-song is a composition for two or more voices, (usually four) to be sung a capella. It is written in monophonic rather than in polyphonic style, thus differing from the madrigal and glee. Morley's "Now is the Month of Maying" is an example of the part-song, as is also Sullivan's "O Hush Thee, My Baby." The term part-song is often loosely applied to glees, madrigals, etc.
CHAPTER XVII
Rhythm, Melody, Harmony and Intervals
178. The four elements commonly attributed to music (in the order of their development) are: Rhythm, Melody, Harmony, and Timbre (or tone-color).
179. Rhythm is the regular recurrence of accent. In music it is more specifically the regular recurrence of groups of accented and non-accented beats (or pulses)—according to some specified measure-system. Since rhythm implies continuity, there must usually be at least two such measure groups in order to make musical rhythm possible. (See [p. 44], [Sec. 97].)
180. A melody is a succession of single tones of various pitches so arranged that the effect of the whole will be unified, coherent, and pleasing to the ear.
The soprano part of hymn-tunes and other simple harmonized compositions is often referred to as "the melody."