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“Below the Thunders of the Upper Deep”
Movement 2 of Britten’s “Nocturne” for tenor and chamber orchestra
The bassoon—its low, murky depths combined with its generally sickly timbre, agility and thin, bloodless top—is perfectly cast for the role of the legendary deep-sea monster in Tennyson’s famous poem “The Kraken.” It immediately sets down a three-measure ground that will continue unchanged for most of this movement. This ground is completely diatonic, firmly establishing the key of B flat minor. (Ex. 7)
Just as the chromatics and clusters of the first movement were Britten’s way of telling us that things seemed unreal and unnatural, the clean triadic outlining of the ground and voice in this movement indicates to us that this imaginary underwater scene seems very real to our protagonist. The few angular intervals and the occasionally raised 3rds, 4ths, and 7ths in the voice instead contribute a salty flavor that adds to the maritime setting. After a short “B section” in the dominant (with the ground still remaining in the tonic!), the piece undergoes a dramatic dominant-to-tonic transition and recapitulates, proceeding just as the beginning of the movement until the “latter fire [that] heat[s] the deep” is mentioned. At that point, the ground instead dramatically begins to ascend in pitch and the Kraken “In roaring[...]rise[s] and on the surface die[s]” as the bassoon likewise surfaces to a sickly high A and expires.
This kind of concrete-representative text setting in the accompaniment is very reminiscent of Schubert. Just as the master of the liederkreis set the babbling of a brook, the creaking of a weathervane and the clip-clopping of a horse in his piano accompaniments, in this work Britten uses the obligato instruments to represent the subjects of the text, musically describing them as the voice tells the story. In many ways, Britten’s treatment of his librettos shows a poetic understanding uncommon to many composers. Porter rhapsodizes:
The whole corpus of Britten’s work is informed by a deeply poetical feeling[; ...] what poets have prefigured in words, he has reworked in music. This recognition of the fact that even a superb piece of poetry leaves something more to be said is what makes many of his settings as masterful.[...]The one great predecessor whose creative personality springs equally from an instinctively poetical nature is Schubert.[...H]e too can carry his most heartfelt works beyond words only into chamber music[....]For both Schubert and Britten the world in which music grows is a poetical place—ie., it is human, speculative, dramatic, aphoristic and spontaneous. From the world of philosophy springs the opposite achievement of the symphonic.
Move on to Part 4: Movement 3, “Encintured with a Twine of Leaves.”
 Peter Porter, “Composer and Poet,” Britten Companion, 272.