Poe achieves variety in this rhythm by adding pauses, and he keeps the sound from becoming monotonous by making much use of consonance and assonance, or repetition of consonant and vowel sounds, respectively. In addition, Poe's use of a regular rhyme scheme in which every stanza uses words that rhyme with "more" to conclude the second, fourth, fifth and sixth lines creates a very strong unifying effect for the poem. In his "The Philosophy of Composition, "Poe states that he consciously chose the or sound because of its "sonorous" quality.