[Sidenote: _Repetition in poetry._]

The beginnings of poetic forms are also found in repetition; in
primitive poetry it is exemplified in the refrain or burden, in the
highly developed poetry of the Hebrews in parallelism. The Psalmist
wrote:

"O Lord, rebuke me not in thy wrath,
Neither chasten me in thy hot displeasure."

[Sidenote: _Key relationship._]

Here is a period of two members, the latter repeating the thought of
the former. A musical analyst might find in it an admirable analogue
for the first period of a simple melody. He would divide it into four
motives: "Rebuke me not | in thy wrath | neither chasten me | in thy
hot displeasure," and point out as intimate a relationship between
them as exists in the Creole tune. The bond of union between the
motives of the melody as well as that in the poetry illustrates a
principle of beauty which is the most important element in musical
design after repetition, which is its necessary vehicle. It is because
this principle guides the repetition of the tone-groups that together
they form a melody that is perfect, satisfying, and reposeful. It is
the principle of key-relationship, to discuss which fully would carry
me farther into musical science than I am permitted to go. Let this
suffice: A harmony is latent in each group, and the sequence of groups
is such a sequence as the experience of ages has demonstrated to be
most agreeable to the ear.

[Sidenote: _The rhythmical stamp._]