If, on the other hand, one of the regular cadences is omitted,—owing to the rapidity of the tempo, or a small denomination of measure,—the phrase will attain just double the ordinary length; that is, eight measures. An eight-measure phrase is called a Large phrase. For illustration:—
[Illustration: Example 38. Fragment of Beethoven.]
There is not the slightest evidence of repose or interruption in the fourth measure, nor of a new beginning in the fifth, wherefore the cadence is not expected until four more measures have passed by. The inferior points of repose in the upper parts, at the beginning of the 5th, 6th and 7th measures, serve only to establish melodic, or rather rhythmic, variety, and have no cadential force whatever. See Mendelssohn, Song No. 8; the first cadence appears to stand in the eighth measure; the tempo is rapid and the measures are small; it is obviously a large phrase. The phrase which follows is regular, however; there is a cadence in the twelfth measure, thus proving that Large phrases may appear in company with regular phrases, in the same composition. In other words, the omission of an expected cadence (or the insertion of an additional one) may be an occasional occurrence,—not necessarily constant. See, again, No. 22 of the Songs Without Words; the first and second phrases are small; the third phrase, however (reaching from measure 6 to 9 without cadential interruption), is of regular dimensions.
THE PRINCIPLE OF EXTENSION.—The other cause of modified phrase-dimension is one of extreme importance, as touching upon the most vital process in musical composition, namely, that of phrase-development.
Setting aside all critical discussion with reference to the question, "What is good music?" and simply accepting those types of classic composition universally acknowledged to be the best, as a defensible standard (to say the least), we find that such a page of music exhibits the pursuit of some leading thought (melodic motive or phrase), with precisely the same coherence and consistency, the same evidence of determined aim, as is displayed in the creation of a forcible essay, a masterly poem, an imposing architectural plan, or any other work of art that betrays intelligence and a definite, fixed, purpose. This is no more nor less than might be expected from the dominion of the law of Unity.
The equally inflexible demands of Variety are satisfied by presenting this self-same leading thought in ever new and changing aspects,—not by exchanging the thought itself for a new one at each successive angle. This latter faulty process would naturally lead to a conglomeration of impressions, baffling comprehension and jeopardizing real enjoyment.
In a classic page of music we perceive that each successive unit grows, more or less directly, out of those which go before; not so directly, or with such narrow insistence as to produce the impression of sameness and monotony, but with such consistency of design as to impart a unified physiognomy to the whole. Hence, it will often be found that every melodic figure, during a certain section (if not the whole) of a composition, may be traced to one or another of the figures which characterized the first phrase, or the first two or three phrases, of the piece. This was emphasized by our reference, near the end of the first chapter, to the 8th Song Without Words of Mendelssohn. If the student, in analyzing the melody of that composition, will endeavor to penetrate some of the clever disguises employed by the composer (for the sake of Variety), he will find the whole piece reducible to a very few melodic figures, announced at or near the beginning. See also No. 45 (C major), No. 36, No. 26. Also Schumann, op. 68, No. 7, No. 8, No. 18, No. 23. Also Beethoven, pianoforte sonata, op. 10, No. 2, last movement; op. 26, last movement.
In musical composition this process is known as thematic development, and it generally extends over the whole, or a greater part, of the piece.