The Period


The Period-form is obtained by the addition of a second

phrase to the first. It is therefore, in a sense, a double phrase;

that is, it consists of two connected phrases, covering eight ordinary

measures, or just double the number commonly assigned to the single

phrase.



Each one of these phrases must, of course, have its individual cadence,

or point of repose; the first--called the Antecedent phrase--has
ts

cadence in the fourth measure, and the second--called the Consequent

phrase--in the eighth measure. The effect of the Period-form is that

of a longer sentence interrupted exactly in the middle,--not unlike a

bridge of two spans, resting on a central pier. But, precisely as the

central pier is only an intermediate point of support, and not terra

firma, so the ending of the Antecedent phrase is never anything more

weighty than a semicadence, while the definite, conclusive, perfect

cadence appears at the end of the Consequent phrase,--or of the entire

period-form.



The reason for this distinction of cadence is obvious. A period is not

two separate phrases, but two related and coherent phrases which

mutually balance each other. The Consequent phrase is not merely an

addition to the first, but is its complement and fulfilment. The

two phrases represent the musical analogy of what, in rhetoric, would

be called thesis and antithesis, or, simply, question and answer. In a

well-constructed period the Antecedent phrase is, therefore, always

more or less interrogative, and the Consequent phrase responsive,

in character.



For illustration (Mendelssohn, No. 28):--





The co-operation, or interaction, of the principles of Unity and

Variety, is nowhere more strikingly shown than in the formulation of

the musical period. Either element has the right to predominate, to a

reasonable degree, though never to the exclusion or injury of the

other. In the above example, the principle of Unity predominates to a

somewhat unusual extent:--not only the figures (marked 1-2-3-4), and

the motives (a-b), are uniform, in the Antecedent phrase itself, but

the melody of the Consequent phrase corresponds very closely throughout

to that of the Antecedent, only excepting a trifling change in the

course (marked N. B.), and the last few tones, which are necessarily

so altered as to transform the semicadence into a perfect cadence. It

is this significant change, at the cadence, which prevents the second

phrase from being merely a repetition of the first one,--which makes

it a Consequent, a response to the one that precedes.



Further (Mendelssohn, No. 23):--



In this example also, the Consequent phrase is a complete affirmation

of its Antecedent, agreeing in its melodic form with the latter until

the cadence is nearly due, when an extra measure is inserted (as

extension), and the usual digression into the necessary perfect cadence

is made. The condition of Unity predominates, but a noticeable

infusion of Variety takes place.



Further (Mozart, pianoforte sonata):--





Here, again, the condition of Unity prevails, but with a still greater

infusion of Variety; the melody of the Consequent phrase resembles

that of the Antecedent in every detail; the rhythm is identical, and it

is evident that the second phrase is designed to balance the first,

figure for figure, the principal change being that some of the figures

are simply turned upside down (compare the places marked N. B.). The

semicadence rests upon a dominant chord (fifth-step) of D major; the

perfect cadence upon the same chord, it is true, but as tonic harmony

of A major, with keynote in the extreme parts. Being a keynote, though

not in the original key, it is valid as perfect cadence.



Further (Beethoven, pianoforte sonata, op. 13):--





In this example, the condition of Variety predominates decidedly. The

Consequent melody differs totally from the Antecedent, even in rhythm,

and the necessary portion of Unity is exhibited only in equality of

length, uniformity of accompaniment, and similarity of character

(tonality, and general harmonic and rhythmic effect). Observe the

diversity of melodic extent, in the two phrases, in consequence of the

preliminary tone borrowed from the semicadence for the Consequent

phrase. Greater variety than here will rarely be found between two

successive phrases that are intended to form the halves of one coherent

period.



For more minute technical details see the HOMOPHONIC FORMS, Chapter V.



More

;